Merge branch 'tip/perf/core-4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core

12 files changed, 810 insertions, 383 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d14cc6b79ad..1324139612e1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -40,7 +40,6 @@ config X86
         select HAVE_FUNCTION_GRAPH_TRACER
         select HAVE_FUNCTION_GRAPH_FP_TEST
         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
-        select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
         select HAVE_SYSCALL_TRACEPOINTS
         select HAVE_KVM
         select HAVE_ARCH_KGDB
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 268c783ab1c0..18d9005d9e4f 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -34,6 +34,7 @@
 
 #ifndef __ASSEMBLY__
 extern void mcount(void);
+extern int modifying_ftrace_code;
 
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
@@ -50,6 +51,8 @@ struct dyn_arch_ftrace {
         /* No extra data needed for x86 */
 };
 
+int ftrace_int3_handler(struct pt_regs *regs);
+
 #endif /*  CONFIG_DYNAMIC_FTRACE */
 #endif /* __ASSEMBLY__ */
 #endif /* CONFIG_FUNCTION_TRACER */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index c9a281f272fd..4243e8bbdcb1 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -24,40 +24,21 @@
 #include <trace/syscall.h>
 
 #include <asm/cacheflush.h>
+#include <asm/kprobes.h>
 #include <asm/ftrace.h>
 #include <asm/nops.h>
-#include <asm/nmi.h>
-
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-/*
- * modifying_code is set to notify NMIs that they need to use
- * memory barriers when entering or exiting. But we don't want
- * to burden NMIs with unnecessary memory barriers when code
- * modification is not being done (which is most of the time).
- *
- * A mutex is already held when ftrace_arch_code_modify_prepare
- * and post_process are called. No locks need to be taken here.
- *
- * Stop machine will make sure currently running NMIs are done
- * and new NMIs will see the updated variable before we need
- * to worry about NMIs doing memory barriers.
- */
-static int modifying_code __read_mostly;
-static DEFINE_PER_CPU(int, save_modifying_code);
-
 int ftrace_arch_code_modify_prepare(void)
 {
         set_kernel_text_rw();
         set_all_modules_text_rw();
-        modifying_code = 1;
         return 0;
 }
 
 int ftrace_arch_code_modify_post_process(void)
 {
-        modifying_code = 0;
         set_all_modules_text_ro();
         set_kernel_text_ro();
         return 0;
@@ -90,134 +71,6 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
         return calc.code;
 }
 
-/*
- * Modifying code must take extra care. On an SMP machine, if
- * the code being modified is also being executed on another CPU
- * that CPU will have undefined results and possibly take a GPF.
- * We use kstop_machine to stop other CPUS from exectuing code.
- * But this does not stop NMIs from happening. We still need
- * to protect against that. We separate out the modification of
- * the code to take care of this.
- *
- * Two buffers are added: An IP buffer and a "code" buffer.
- *
- * 1) Put the instruction pointer into the IP buffer
- *    and the new code into the "code" buffer.
- * 2) Wait for any running NMIs to finish and set a flag that says
- *    we are modifying code, it is done in an atomic operation.
- * 3) Write the code
- * 4) clear the flag.
- * 5) Wait for any running NMIs to finish.
- *
- * If an NMI is executed, the first thing it does is to call
- * "ftrace_nmi_enter". This will check if the flag is set to write
- * and if it is, it will write what is in the IP and "code" buffers.
- *
- * The trick is, it does not matter if everyone is writing the same
- * content to the code location. Also, if a CPU is executing code
- * it is OK to write to that code location if the contents being written
- * are the same as what exists.
- */
-
-#define MOD_CODE_WRITE_FLAG (1 << 31)   /* set when NMI should do the write */
-static atomic_t nmi_running = ATOMIC_INIT(0);
-static int mod_code_status;             /* holds return value of text write */
-static void *mod_code_ip;               /* holds the IP to write to */
-static const void *mod_code_newcode;    /* holds the text to write to the IP */
-
-static unsigned nmi_wait_count;
-static atomic_t nmi_update_count = ATOMIC_INIT(0);
-
-int ftrace_arch_read_dyn_info(char *buf, int size)
-{
-        int r;
-
-        r = snprintf(buf, size, "%u %u",
-                     nmi_wait_count,
-                     atomic_read(&nmi_update_count));
-        return r;
-}
-
-static void clear_mod_flag(void)
-{
-        int old = atomic_read(&nmi_running);
-
-        for (;;) {
-                int new = old & ~MOD_CODE_WRITE_FLAG;
-
-                if (old == new)
-                        break;
-
-                old = atomic_cmpxchg(&nmi_running, old, new);
-        }
-}
-
-static void ftrace_mod_code(void)
-{
-        /*
-         * Yes, more than one CPU process can be writing to mod_code_status.
-         *    (and the code itself)
-         * But if one were to fail, then they all should, and if one were
-         * to succeed, then they all should.
-         */
-        mod_code_status = probe_kernel_write(mod_code_ip, mod_code_newcode,
-                                             MCOUNT_INSN_SIZE);
-
-        /* if we fail, then kill any new writers */
-        if (mod_code_status)
-                clear_mod_flag();
-}
-
-void ftrace_nmi_enter(void)
-{
-        __this_cpu_write(save_modifying_code, modifying_code);
-
-        if (!__this_cpu_read(save_modifying_code))
-                return;
-
-        if (atomic_inc_return(&nmi_running) & MOD_CODE_WRITE_FLAG) {
-                smp_rmb();
-                ftrace_mod_code();
-                atomic_inc(&nmi_update_count);
-        }
-        /* Must have previous changes seen before executions */
-        smp_mb();
-}
-
-void ftrace_nmi_exit(void)
-{
-        if (!__this_cpu_read(save_modifying_code))
-                return;
-
-        /* Finish all executions before clearing nmi_running */
-        smp_mb();
-        atomic_dec(&nmi_running);
-}
-
-static void wait_for_nmi_and_set_mod_flag(void)
-{
-        if (!atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG))
-                return;
-
-        do {
-                cpu_relax();
-        } while (atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG));
-
-        nmi_wait_count++;
-}
-
-static void wait_for_nmi(void)
-{
-        if (!atomic_read(&nmi_running))
-                return;
-
-        do {
-                cpu_relax();
-        } while (atomic_read(&nmi_running));
-
-        nmi_wait_count++;
-}
-
 static inline int
 within(unsigned long addr, unsigned long start, unsigned long end)
 {
@@ -238,26 +91,7 @@ do_ftrace_mod_code(unsigned long ip, const void *new_code)
         if (within(ip, (unsigned long)_text, (unsigned long)_etext))
                 ip = (unsigned long)__va(__pa(ip));
 
-        mod_code_ip = (void *)ip;
-        mod_code_newcode = new_code;
-
-        /* The buffers need to be visible before we let NMIs write them */
-        smp_mb();
-
-        wait_for_nmi_and_set_mod_flag();
-
-        /* Make sure all running NMIs have finished before we write the code */
-        smp_mb();
-
-        ftrace_mod_code();
-
-        /* Make sure the write happens before clearing the bit */
-        smp_mb();
-
-        clear_mod_flag();
-        wait_for_nmi();
-
-        return mod_code_status;
+        return probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE);
 }
 
 static const unsigned char *ftrace_nop_replace(void)
@@ -334,6 +168,347 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
         return ret;
 }
 
+int modifying_ftrace_code __read_mostly;
+
+/*
+ * A breakpoint was added to the code address we are about to
+ * modify, and this is the handle that will just skip over it.
+ * We are either changing a nop into a trace call, or a trace
+ * call to a nop. While the change is taking place, we treat
+ * it just like it was a nop.
+ */
+int ftrace_int3_handler(struct pt_regs *regs)
+{
+        if (WARN_ON_ONCE(!regs))
+                return 0;
+
+        if (!ftrace_location(regs->ip - 1))
+                return 0;
+
+        regs->ip += MCOUNT_INSN_SIZE - 1;
+
+        return 1;
+}
+
+static int ftrace_write(unsigned long ip, const char *val, int size)
+{
+        /*
+         * On x86_64, kernel text mappings are mapped read-only with
+         * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead
+         * of the kernel text mapping to modify the kernel text.
+         *
+         * For 32bit kernels, these mappings are same and we can use
+         * kernel identity mapping to modify code.
+         */
+        if (within(ip, (unsigned long)_text, (unsigned long)_etext))
+                ip = (unsigned long)__va(__pa(ip));
+
+        return probe_kernel_write((void *)ip, val, size);
+}
+
+static int add_break(unsigned long ip, const char *old)
+{
+        unsigned char replaced[MCOUNT_INSN_SIZE];
+        unsigned char brk = BREAKPOINT_INSTRUCTION;
+
+        if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+                return -EFAULT;
+
+        /* Make sure it is what we expect it to be */
+        if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
+                return -EINVAL;
+
+        if (ftrace_write(ip, &brk, 1))
+                return -EPERM;
+
+        return 0;
+}
+
+static int add_brk_on_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+        unsigned const char *old;
+        unsigned long ip = rec->ip;
+
+        old = ftrace_call_replace(ip, addr);
+
+        return add_break(rec->ip, old);
+}
+
+
+static int add_brk_on_nop(struct dyn_ftrace *rec)
+{
+        unsigned const char *old;
+
+        old = ftrace_nop_replace();
+
+        return add_break(rec->ip, old);
+}
+
+static int add_breakpoints(struct dyn_ftrace *rec, int enable)
+{
+        unsigned long ftrace_addr;
+        int ret;
+
+        ret = ftrace_test_record(rec, enable);
+
+        ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+        switch (ret) {
+        case FTRACE_UPDATE_IGNORE:
+                return 0;
+
+        case FTRACE_UPDATE_MAKE_CALL:
+                /* converting nop to call */
+                return add_brk_on_nop(rec);
+
+        case FTRACE_UPDATE_MAKE_NOP:
+                /* converting a call to a nop */
+                return add_brk_on_call(rec, ftrace_addr);
+        }
+        return 0;
+}
+
+/*
+ * On error, we need to remove breakpoints. This needs to
+ * be done caefully. If the address does not currently have a
+ * breakpoint, we know we are done. Otherwise, we look at the
+ * remaining 4 bytes of the instruction. If it matches a nop
+ * we replace the breakpoint with the nop. Otherwise we replace
+ * it with the call instruction.
+ */
+static int remove_breakpoint(struct dyn_ftrace *rec)
+{
+        unsigned char ins[MCOUNT_INSN_SIZE];
+        unsigned char brk = BREAKPOINT_INSTRUCTION;
+        const unsigned char *nop;
+        unsigned long ftrace_addr;
+        unsigned long ip = rec->ip;
+
+        /* If we fail the read, just give up */
+        if (probe_kernel_read(ins, (void *)ip, MCOUNT_INSN_SIZE))
+                return -EFAULT;
+
+        /* If this does not have a breakpoint, we are done */
+        if (ins[0] != brk)
+                return -1;
+
+        nop = ftrace_nop_replace();
+
+        /*
+         * If the last 4 bytes of the instruction do not match
+         * a nop, then we assume that this is a call to ftrace_addr.
+         */
+        if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0) {
+                /*
+                 * For extra paranoidism, we check if the breakpoint is on
+                 * a call that would actually jump to the ftrace_addr.
+                 * If not, don't touch the breakpoint, we make just create
+                 * a disaster.
+                 */
+                ftrace_addr = (unsigned long)FTRACE_ADDR;
+                nop = ftrace_call_replace(ip, ftrace_addr);
+
+                if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0)
+                        return -EINVAL;
+        }
+
+        return probe_kernel_write((void *)ip, &nop[0], 1);
+}
+
+static int add_update_code(unsigned long ip, unsigned const char *new)
+{
+        /* skip breakpoint */
+        ip++;
+        new++;
+        if (ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1))
+                return -EPERM;
+        return 0;
+}
+
+static int add_update_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+        unsigned long ip = rec->ip;
+        unsigned const char *new;
+
+        new = ftrace_call_replace(ip, addr);
+        return add_update_code(ip, new);
+}
+
+static int add_update_nop(struct dyn_ftrace *rec)
+{
+        unsigned long ip = rec->ip;
+        unsigned const char *new;
+
+        new = ftrace_nop_replace();
+        return add_update_code(ip, new);
+}
+
+static int add_update(struct dyn_ftrace *rec, int enable)
+{
+        unsigned long ftrace_addr;
+        int ret;
+
+        ret = ftrace_test_record(rec, enable);
+
+        ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+        switch (ret) {
+        case FTRACE_UPDATE_IGNORE:
+                return 0;
+
+        case FTRACE_UPDATE_MAKE_CALL:
+                /* converting nop to call */
+                return add_update_call(rec, ftrace_addr);
+
+        case FTRACE_UPDATE_MAKE_NOP:
+                /* converting a call to a nop */
+                return add_update_nop(rec);
+        }
+
+        return 0;
+}
+
+static int finish_update_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+        unsigned long ip = rec->ip;
+        unsigned const char *new;
+
+        new = ftrace_call_replace(ip, addr);
+
+        if (ftrace_write(ip, new, 1))
+                return -EPERM;
+
+        return 0;
+}
+
+static int finish_update_nop(struct dyn_ftrace *rec)
+{
+        unsigned long ip = rec->ip;
+        unsigned const char *new;
+
+        new = ftrace_nop_replace();
+
+        if (ftrace_write(ip, new, 1))
+                return -EPERM;
+        return 0;
+}
+
+static int finish_update(struct dyn_ftrace *rec, int enable)
+{
+        unsigned long ftrace_addr;
+        int ret;
+
+        ret = ftrace_update_record(rec, enable);
+
+        ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+        switch (ret) {
+        case FTRACE_UPDATE_IGNORE:
+                return 0;
+
+        case FTRACE_UPDATE_MAKE_CALL:
+                /* converting nop to call */
+                return finish_update_call(rec, ftrace_addr);
+
+        case FTRACE_UPDATE_MAKE_NOP:
+                /* converting a call to a nop */
+                return finish_update_nop(rec);
+        }
+
+        return 0;
+}
+
+static void do_sync_core(void *data)
+{
+        sync_core();
+}
+
+static void run_sync(void)
+{
+        int enable_irqs = irqs_disabled();
+
+        /* We may be called with interrupts disbled (on bootup). */
+        if (enable_irqs)
+                local_irq_enable();
+        on_each_cpu(do_sync_core, NULL, 1);
+        if (enable_irqs)
+                local_irq_disable();
+}
+
+static void ftrace_replace_code(int enable)
+{
+        struct ftrace_rec_iter *iter;
+        struct dyn_ftrace *rec;
+        const char *report = "adding breakpoints";
+        int count = 0;
+        int ret;
+
+        for_ftrace_rec_iter(iter) {
+                rec = ftrace_rec_iter_record(iter);
+
+                ret = add_breakpoints(rec, enable);
+                if (ret)
+                        goto remove_breakpoints;
+                count++;
+        }
+
+        run_sync();
+
+        report = "updating code";
+
+        for_ftrace_rec_iter(iter) {
+                rec = ftrace_rec_iter_record(iter);
+
+                ret = add_update(rec, enable);
+                if (ret)
+                        goto remove_breakpoints;
+        }
+
+        run_sync();
+
+        report = "removing breakpoints";
+
+        for_ftrace_rec_iter(iter) {
+                rec = ftrace_rec_iter_record(iter);
+
+                ret = finish_update(rec, enable);
+                if (ret)
+                        goto remove_breakpoints;
+        }
+
+        run_sync();
+
+        return;
+
+ remove_breakpoints:
+        ftrace_bug(ret, rec ? rec->ip : 0);
+        printk(KERN_WARNING "Failed on %s (%d):\n", report, count);
+        for_ftrace_rec_iter(iter) {
+                rec = ftrace_rec_iter_record(iter);
+                remove_breakpoint(rec);
+        }
+}
+
+void arch_ftrace_update_code(int command)
+{
+        modifying_ftrace_code++;
+
+        if (command & FTRACE_UPDATE_CALLS)
+                ftrace_replace_code(1);
+        else if (command & FTRACE_DISABLE_CALLS)
+                ftrace_replace_code(0);
+
+        if (command & FTRACE_UPDATE_TRACE_FUNC)
+                ftrace_update_ftrace_func(ftrace_trace_function);
+
+        if (command & FTRACE_START_FUNC_RET)
+                ftrace_enable_ftrace_graph_caller();
+        else if (command & FTRACE_STOP_FUNC_RET)
+                ftrace_disable_ftrace_graph_caller();
+
+        modifying_ftrace_code--;
+}
+
 int __init ftrace_dyn_arch_init(void *data)
 {
         /* The return code is retured via data */
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 47acaf319165..eb1539eac393 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -84,7 +84,7 @@ __setup("unknown_nmi_panic", setup_unknown_nmi_panic);
 
 #define nmi_to_desc(type) (&nmi_desc[type])
 
-static int notrace __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b)
+static int __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b)
 {
         struct nmi_desc *desc = nmi_to_desc(type);
         struct nmiaction *a;
@@ -209,7 +209,7 @@ void unregister_nmi_handler(unsigned int type, const char *name)
 
 EXPORT_SYMBOL_GPL(unregister_nmi_handler);
 
-static notrace __kprobes void
+static __kprobes void
 pci_serr_error(unsigned char reason, struct pt_regs *regs)
 {
         pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n",
@@ -236,7 +236,7 @@ pci_serr_error(unsigned char reason, struct pt_regs *regs)
         outb(reason, NMI_REASON_PORT);
 }
 
-static notrace __kprobes void
+static __kprobes void
 io_check_error(unsigned char reason, struct pt_regs *regs)
 {
         unsigned long i;
@@ -263,7 +263,7 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
         outb(reason, NMI_REASON_PORT);
 }
 
-static notrace __kprobes void
+static __kprobes void
 unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
 {
         int handled;
@@ -305,7 +305,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
 static DEFINE_PER_CPU(bool, swallow_nmi);
 static DEFINE_PER_CPU(unsigned long, last_nmi_rip);
 
-static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
+static __kprobes void default_do_nmi(struct pt_regs *regs)
 {
         unsigned char reason = 0;
         int handled;
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ff9281f16029..92d5756d85fc 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -50,6 +50,7 @@
 #include <asm/processor.h>
 #include <asm/debugreg.h>
 #include <linux/atomic.h>
+#include <asm/ftrace.h>
 #include <asm/traps.h>
 #include <asm/desc.h>
 #include <asm/i387.h>
@@ -303,8 +304,13 @@ gp_in_kernel:
 }
 
 /* May run on IST stack. */
-dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
+dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
 {
+#ifdef CONFIG_DYNAMIC_FTRACE
+        /* ftrace must be first, everything else may cause a recursive crash */
+        if (unlikely(modifying_ftrace_code) && ftrace_int3_handler(regs))
+                return;
+#endif
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
         if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
                                 SIGTRAP) == NOTIFY_STOP)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 72a6cabb4d5b..0b5590330bca 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -286,6 +286,12 @@ struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 
+#define for_ftrace_rec_iter(iter)               \
+        for (iter = ftrace_rec_iter_start();    \
+             iter;                              \
+             iter = ftrace_rec_iter_next(iter))
+
+
 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
 void ftrace_run_stop_machine(int command);
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 645231c373c8..c0d34420a913 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -480,15 +480,16 @@ do {									\
 
 #define trace_printk(fmt, args...)                                      \
 do {                                                                    \
+        static const char *trace_printk_fmt                             \
+                __attribute__((section("__trace_printk_fmt"))) =        \
+                __builtin_constant_p(fmt) ? fmt : NULL;                 \
+                                                                        \
         __trace_printk_check_format(fmt, ##args);                       \
-        if (__builtin_constant_p(fmt)) {                                \
-                static const char *trace_printk_fmt                     \
-                  __attribute__((section("__trace_printk_fmt"))) =      \
-                        __builtin_constant_p(fmt) ? fmt : NULL;         \
                                                                         \
+        if (__builtin_constant_p(fmt))                                  \
                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
-        } else                                                          \
-                __trace_printk(_THIS_IP_, fmt, ##args);         \
+        else                                                            \
+                __trace_printk(_THIS_IP_, fmt, ##args);                 \
 } while (0)
 
 extern __printf(2, 3)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 7be2e88f23fd..6c8835f74f79 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -96,9 +96,11 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k
         __ring_buffer_alloc((size), (flags), &__key);   \
 })
 
+#define RING_BUFFER_ALL_CPUS -1
+
 void ring_buffer_free(struct ring_buffer *buffer);
 
-int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
+int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu);
 
 void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
 
@@ -129,7 +131,7 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
 
-unsigned long ring_buffer_size(struct ring_buffer *buffer);
+unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu);
 
 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
 void ring_buffer_reset(struct ring_buffer *buffer);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index cf8d11e91efd..2d5eb3320827 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -449,6 +449,7 @@ struct ring_buffer_per_cpu {
         raw_spinlock_t                  reader_lock;    /* serialize readers */
         arch_spinlock_t                 lock;
         struct lock_class_key           lock_key;
+        unsigned int                    nr_pages;
         struct list_head                *pages;
         struct buffer_page              *head_page;     /* read from head */
         struct buffer_page              *tail_page;     /* write to tail */
@@ -466,10 +467,12 @@ struct ring_buffer_per_cpu {
         unsigned long                   read_bytes;
         u64                             write_stamp;
         u64                             read_stamp;
+        /* ring buffer pages to update, > 0 to add, < 0 to remove */
+        int                             nr_pages_to_update;
+        struct list_head                new_pages; /* new pages to add */
 };
 
 struct ring_buffer {
-        unsigned                        pages;
         unsigned                        flags;
         int                             cpus;
         atomic_t                        record_disabled;
@@ -963,14 +966,10 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
         return 0;
 }
 
-static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
-                             unsigned nr_pages)
+static int __rb_allocate_pages(int nr_pages, struct list_head *pages, int cpu)
 {
+        int i;
         struct buffer_page *bpage, *tmp;
-        LIST_HEAD(pages);
-        unsigned i;
-
-        WARN_ON(!nr_pages);
 
         for (i = 0; i < nr_pages; i++) {
                 struct page *page;
@@ -981,15 +980,13 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
                  */
                 bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
                                     GFP_KERNEL | __GFP_NORETRY,
-                                    cpu_to_node(cpu_buffer->cpu));
+                                    cpu_to_node(cpu));
                 if (!bpage)
                         goto free_pages;
 
-                rb_check_bpage(cpu_buffer, bpage);
+                list_add(&bpage->list, pages);
 
-                list_add(&bpage->list, &pages);
-
-                page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu),
+                page = alloc_pages_node(cpu_to_node(cpu),
                                         GFP_KERNEL | __GFP_NORETRY, 0);
                 if (!page)
                         goto free_pages;
@@ -997,6 +994,27 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
                 rb_init_page(bpage->page);
         }
 
+        return 0;
+
+free_pages:
+        list_for_each_entry_safe(bpage, tmp, pages, list) {
+                list_del_init(&bpage->list);
+                free_buffer_page(bpage);
+        }
+
+        return -ENOMEM;
+}
+
+static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
+                             unsigned nr_pages)
+{
+        LIST_HEAD(pages);
+
+        WARN_ON(!nr_pages);
+
+        if (__rb_allocate_pages(nr_pages, &pages, cpu_buffer->cpu))
+                return -ENOMEM;
+
         /*
          * The ring buffer page list is a circular list that does not
          * start and end with a list head. All page list items point to
@@ -1005,20 +1023,15 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
         cpu_buffer->pages = pages.next;
         list_del(&pages);
 
+        cpu_buffer->nr_pages = nr_pages;
+
         rb_check_pages(cpu_buffer);
 
         return 0;
-
- free_pages:
-        list_for_each_entry_safe(bpage, tmp, &pages, list) {
-                list_del_init(&bpage->list);
-                free_buffer_page(bpage);
-        }
-        return -ENOMEM;
 }
 
 static struct ring_buffer_per_cpu *
-rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
+rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
         struct buffer_page *bpage;
@@ -1052,7 +1065,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
 
         INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
 
-        ret = rb_allocate_pages(cpu_buffer, buffer->pages);
+        ret = rb_allocate_pages(cpu_buffer, nr_pages);
         if (ret < 0)
                 goto fail_free_reader;
 
@@ -1113,7 +1126,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 {
         struct ring_buffer *buffer;
         int bsize;
-        int cpu;
+        int cpu, nr_pages;
 
         /* keep it in its own cache line */
         buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
@@ -1124,14 +1137,14 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
         if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
                 goto fail_free_buffer;
 
-        buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+        nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
         buffer->flags = flags;
         buffer->clock = trace_clock_local;
         buffer->reader_lock_key = key;
 
         /* need at least two pages */
-        if (buffer->pages < 2)
-                buffer->pages = 2;
+        if (nr_pages < 2)
+                nr_pages = 2;
 
         /*
          * In case of non-hotplug cpu, if the ring-buffer is allocated
@@ -1154,7 +1167,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 
         for_each_buffer_cpu(buffer, cpu) {
                 buffer->buffers[cpu] =
-                        rb_allocate_cpu_buffer(buffer, cpu);
+                        rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
                 if (!buffer->buffers[cpu])
                         goto fail_free_buffers;
         }
@@ -1276,6 +1289,18 @@ out:
         raw_spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
+static void update_pages_handler(struct ring_buffer_per_cpu *cpu_buffer)
+{
+        if (cpu_buffer->nr_pages_to_update > 0)
+                rb_insert_pages(cpu_buffer, &cpu_buffer->new_pages,
+                                cpu_buffer->nr_pages_to_update);
+        else
+                rb_remove_pages(cpu_buffer, -cpu_buffer->nr_pages_to_update);
+        cpu_buffer->nr_pages += cpu_buffer->nr_pages_to_update;
+        /* reset this value */
+        cpu_buffer->nr_pages_to_update = 0;
+}
+
 /**
  * ring_buffer_resize - resize the ring buffer
  * @buffer: the buffer to resize.
@@ -1285,14 +1310,12 @@ out:
  *
  * Returns -1 on failure.
  */
-int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
+int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
+                        int cpu_id)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
-        unsigned nr_pages, rm_pages, new_pages;
-        struct buffer_page *bpage, *tmp;
-        unsigned long buffer_size;
-        LIST_HEAD(pages);
-        int i, cpu;
+        unsigned nr_pages;
+        int cpu;
 
         /*
          * Always succeed at resizing a non-existent buffer:
@@ -1302,15 +1325,11 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
 
         size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
         size *= BUF_PAGE_SIZE;
-        buffer_size = buffer->pages * BUF_PAGE_SIZE;
 
         /* we need a minimum of two pages */
         if (size < BUF_PAGE_SIZE * 2)
                 size = BUF_PAGE_SIZE * 2;
 
-        if (size == buffer_size)
-                return size;
-
         atomic_inc(&buffer->record_disabled);
 
         /* Make sure all writers are done with this buffer. */
@@ -1321,68 +1340,56 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
 
         nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
 
-        if (size < buffer_size) {
-
-                /* easy case, just free pages */
-                if (RB_WARN_ON(buffer, nr_pages >= buffer->pages))
-                        goto out_fail;
-
-                rm_pages = buffer->pages - nr_pages;
-
+        if (cpu_id == RING_BUFFER_ALL_CPUS) {
+                /* calculate the pages to update */
                 for_each_buffer_cpu(buffer, cpu) {
                         cpu_buffer = buffer->buffers[cpu];
-                        rb_remove_pages(cpu_buffer, rm_pages);
-                }
-                goto out;
-        }
 
-        /*
-         * This is a bit more difficult. We only want to add pages
-         * when we can allocate enough for all CPUs. We do this
-         * by allocating all the pages and storing them on a local
-         * link list. If we succeed in our allocation, then we
-         * add these pages to the cpu_buffers. Otherwise we just free
-         * them all and return -ENOMEM;
-         */
-        if (RB_WARN_ON(buffer, nr_pages <= buffer->pages))
-                goto out_fail;
+                        cpu_buffer->nr_pages_to_update = nr_pages -
+                                                        cpu_buffer->nr_pages;
 
-        new_pages = nr_pages - buffer->pages;
+                        /*
+                         * nothing more to do for removing pages or no update
+                         */
+                        if (cpu_buffer->nr_pages_to_update <= 0)
+                                continue;
 
-        for_each_buffer_cpu(buffer, cpu) {
-                for (i = 0; i < new_pages; i++) {
-                        struct page *page;
                         /*
-                         * __GFP_NORETRY flag makes sure that the allocation
-                         * fails gracefully without invoking oom-killer and
-                         * the system is not destabilized.
+                         * to add pages, make sure all new pages can be
+                         * allocated without receiving ENOMEM
                          */
-                        bpage = kzalloc_node(ALIGN(sizeof(*bpage),
-                                                  cache_line_size()),
-                                            GFP_KERNEL | __GFP_NORETRY,
-                                            cpu_to_node(cpu));
-                        if (!bpage)
-                                goto free_pages;
-                        list_add(&bpage->list, &pages);
-                        page = alloc_pages_node(cpu_to_node(cpu),
-                                                GFP_KERNEL | __GFP_NORETRY, 0);
-                        if (!page)
-                                goto free_pages;
-                        bpage->page = page_address(page);
-                        rb_init_page(bpage->page);
+                        INIT_LIST_HEAD(&cpu_buffer->new_pages);
+                        if (__rb_allocate_pages(cpu_buffer->nr_pages_to_update,
+                                                &cpu_buffer->new_pages, cpu))
+                                /* not enough memory for new pages */
+                                goto no_mem;
                 }
-        }
 
-        for_each_buffer_cpu(buffer, cpu) {
-                cpu_buffer = buffer->buffers[cpu];
-                rb_insert_pages(cpu_buffer, &pages, new_pages);
-        }
+                /* wait for all the updates to complete */
+                for_each_buffer_cpu(buffer, cpu) {
+                        cpu_buffer = buffer->buffers[cpu];
+                        if (cpu_buffer->nr_pages_to_update) {
+                                update_pages_handler(cpu_buffer);
+                        }
+                }
+        } else {
+                cpu_buffer = buffer->buffers[cpu_id];
+                if (nr_pages == cpu_buffer->nr_pages)
+                        goto out;
 
-        if (RB_WARN_ON(buffer, !list_empty(&pages)))
-                goto out_fail;
+                cpu_buffer->nr_pages_to_update = nr_pages -
+                                                cpu_buffer->nr_pages;
+
+                INIT_LIST_HEAD(&cpu_buffer->new_pages);
+                if (cpu_buffer->nr_pages_to_update > 0 &&
+                        __rb_allocate_pages(cpu_buffer->nr_pages_to_update,
+                                                &cpu_buffer->new_pages, cpu_id))
+                        goto no_mem;
+
+                update_pages_handler(cpu_buffer);
+        }
 
  out:
-        buffer->pages = nr_pages;
         put_online_cpus();
         mutex_unlock(&buffer->mutex);
 
@@ -1390,25 +1397,24 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
 
         return size;
 
- free_pages:
-        list_for_each_entry_safe(bpage, tmp, &pages, list) {
-                list_del_init(&bpage->list);
-                free_buffer_page(bpage);
+ no_mem:
+        for_each_buffer_cpu(buffer, cpu) {
+                struct buffer_page *bpage, *tmp;
+                cpu_buffer = buffer->buffers[cpu];
+                /* reset this number regardless */
+                cpu_buffer->nr_pages_to_update = 0;
+                if (list_empty(&cpu_buffer->new_pages))
+                        continue;
+                list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages,
+                                        list) {
+                        list_del_init(&bpage->list);
+                        free_buffer_page(bpage);
+                }
         }
         put_online_cpus();
         mutex_unlock(&buffer->mutex);
         atomic_dec(&buffer->record_disabled);
         return -ENOMEM;
-
-        /*
-         * Something went totally wrong, and we are too paranoid
-         * to even clean up the mess.
-         */
- out_fail:
-        put_online_cpus();
-        mutex_unlock(&buffer->mutex);
-        atomic_dec(&buffer->record_disabled);
-        return -1;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_resize);
 
@@ -1510,7 +1516,7 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
          * assign the commit to the tail.
          */
  again:
-        max_count = cpu_buffer->buffer->pages * 100;
+        max_count = cpu_buffer->nr_pages * 100;
 
         while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
                 if (RB_WARN_ON(cpu_buffer, !(--max_count)))
@@ -3588,9 +3594,18 @@ EXPORT_SYMBOL_GPL(ring_buffer_read);
  * ring_buffer_size - return the size of the ring buffer (in bytes)
  * @buffer: The ring buffer.
  */
-unsigned long ring_buffer_size(struct ring_buffer *buffer)
+unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu)
 {
-        return BUF_PAGE_SIZE * buffer->pages;
+        /*
+         * Earlier, this method returned
+         *      BUF_PAGE_SIZE * buffer->nr_pages
+         * Since the nr_pages field is now removed, we have converted this to
+         * return the per cpu buffer value.
+         */
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
+                return 0;
+
+        return BUF_PAGE_SIZE * buffer->buffers[cpu]->nr_pages;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_size);
 
@@ -3765,8 +3780,11 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
             !cpumask_test_cpu(cpu, buffer_b->cpumask))
                 goto out;
 
+        cpu_buffer_a = buffer_a->buffers[cpu];
+        cpu_buffer_b = buffer_b->buffers[cpu];
+
         /* At least make sure the two buffers are somewhat the same */
-        if (buffer_a->pages != buffer_b->pages)
+        if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
                 goto out;
 
         ret = -EAGAIN;
@@ -3780,9 +3798,6 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
         if (atomic_read(&buffer_b->record_disabled))
                 goto out;
 
-        cpu_buffer_a = buffer_a->buffers[cpu];
-        cpu_buffer_b = buffer_b->buffers[cpu];
-
         if (atomic_read(&cpu_buffer_a->record_disabled))
                 goto out;
 
@@ -4071,6 +4086,8 @@ static int rb_cpu_notify(struct notifier_block *self,
         struct ring_buffer *buffer =
                 container_of(self, struct ring_buffer, cpu_notify);
         long cpu = (long)hcpu;
+        int cpu_i, nr_pages_same;
+        unsigned int nr_pages;
 
         switch (action) {
         case CPU_UP_PREPARE:
@@ -4078,8 +4095,23 @@ static int rb_cpu_notify(struct notifier_block *self,
                 if (cpumask_test_cpu(cpu, buffer->cpumask))
                         return NOTIFY_OK;
 
+                nr_pages = 0;
+                nr_pages_same = 1;
+                /* check if all cpu sizes are same */
+                for_each_buffer_cpu(buffer, cpu_i) {
+                        /* fill in the size from first enabled cpu */
+                        if (nr_pages == 0)
+                                nr_pages = buffer->buffers[cpu_i]->nr_pages;
+                        if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
+                                nr_pages_same = 0;
+                                break;
+                        }
+                }
+                /* allocate minimum pages, user can later expand it */
+                if (!nr_pages_same)
+                        nr_pages = 2;
                 buffer->buffers[cpu] =
-                        rb_allocate_cpu_buffer(buffer, cpu);
+                        rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
                 if (!buffer->buffers[cpu]) {
                         WARN(1, "failed to allocate ring buffer on CPU %ld\n",
                              cpu);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ed7b5d1e12f4..f11a285ee5bb 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -629,7 +629,6 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 {
         int len;
-        void *ret;
 
         if (s->len <= s->readpos)
                 return -EBUSY;
@@ -637,9 +636,7 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
         len = s->len - s->readpos;
         if (cnt > len)
                 cnt = len;
-        ret = memcpy(buf, s->buffer + s->readpos, cnt);
-        if (!ret)
-                return -EFAULT;
+        memcpy(buf, s->buffer + s->readpos, cnt);
 
         s->readpos += cnt;
         return cnt;
@@ -841,7 +838,8 @@ __acquires(kernel_lock)
 
                 /* If we expanded the buffers, make sure the max is expanded too */
                 if (ring_buffer_expanded && type->use_max_tr)
-                        ring_buffer_resize(max_tr.buffer, trace_buf_size);
+                        ring_buffer_resize(max_tr.buffer, trace_buf_size,
+                                                RING_BUFFER_ALL_CPUS);
 
                 /* the test is responsible for initializing and enabling */
                 pr_info("Testing tracer %s: ", type->name);
@@ -857,7 +855,8 @@ __acquires(kernel_lock)
 
                 /* Shrink the max buffer again */
                 if (ring_buffer_expanded && type->use_max_tr)
-                        ring_buffer_resize(max_tr.buffer, 1);
+                        ring_buffer_resize(max_tr.buffer, 1,
+                                                RING_BUFFER_ALL_CPUS);
 
                 printk(KERN_CONT "PASSED\n");
         }
@@ -1498,25 +1497,119 @@ static void __trace_userstack(struct trace_array *tr, unsigned long flags)
 
 #endif /* CONFIG_STACKTRACE */
 
+/* created for use with alloc_percpu */
+struct trace_buffer_struct {
+        char buffer[TRACE_BUF_SIZE];
+};
+
+static struct trace_buffer_struct *trace_percpu_buffer;
+static struct trace_buffer_struct *trace_percpu_sirq_buffer;
+static struct trace_buffer_struct *trace_percpu_irq_buffer;
+static struct trace_buffer_struct *trace_percpu_nmi_buffer;
+
+/*
+ * The buffer used is dependent on the context. There is a per cpu
+ * buffer for normal context, softirq contex, hard irq context and
+ * for NMI context. Thise allows for lockless recording.
+ *
+ * Note, if the buffers failed to be allocated, then this returns NULL
+ */
+static char *get_trace_buf(void)
+{
+        struct trace_buffer_struct *percpu_buffer;
+        struct trace_buffer_struct *buffer;
+
+        /*
+         * If we have allocated per cpu buffers, then we do not
+         * need to do any locking.
+         */
+        if (in_nmi())
+                percpu_buffer = trace_percpu_nmi_buffer;
+        else if (in_irq())
+                percpu_buffer = trace_percpu_irq_buffer;
+        else if (in_softirq())
+                percpu_buffer = trace_percpu_sirq_buffer;
+        else
+                percpu_buffer = trace_percpu_buffer;
+
+        if (!percpu_buffer)
+                return NULL;
+
+        buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
+
+        return buffer->buffer;
+}
+
+static int alloc_percpu_trace_buffer(void)
+{
+        struct trace_buffer_struct *buffers;
+        struct trace_buffer_struct *sirq_buffers;
+        struct trace_buffer_struct *irq_buffers;
+        struct trace_buffer_struct *nmi_buffers;
+
+        buffers = alloc_percpu(struct trace_buffer_struct);
+        if (!buffers)
+                goto err_warn;
+
+        sirq_buffers = alloc_percpu(struct trace_buffer_struct);
+        if (!sirq_buffers)
+                goto err_sirq;
+
+        irq_buffers = alloc_percpu(struct trace_buffer_struct);
+        if (!irq_buffers)
+                goto err_irq;
+
+        nmi_buffers = alloc_percpu(struct trace_buffer_struct);
+        if (!nmi_buffers)
+                goto err_nmi;
+
+        trace_percpu_buffer = buffers;
+        trace_percpu_sirq_buffer = sirq_buffers;
+        trace_percpu_irq_buffer = irq_buffers;
+        trace_percpu_nmi_buffer = nmi_buffers;
+
+        return 0;
+
+ err_nmi:
+        free_percpu(irq_buffers);
+ err_irq:
+        free_percpu(sirq_buffers);
+ err_sirq:
+        free_percpu(buffers);
+ err_warn:
+        WARN(1, "Could not allocate percpu trace_printk buffer");
+        return -ENOMEM;
+}
+
+void trace_printk_init_buffers(void)
+{
+        static int buffers_allocated;
+
+        if (buffers_allocated)
+                return;
+
+        if (alloc_percpu_trace_buffer())
+                return;
+
+        pr_info("ftrace: Allocated trace_printk buffers\n");
+
+        buffers_allocated = 1;
+}
+
 /**
  * trace_vbprintk - write binary msg to tracing buffer
  *
  */
 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 {
-        static arch_spinlock_t trace_buf_lock =
-                (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
-        static u32 trace_buf[TRACE_BUF_SIZE];
-
         struct ftrace_event_call *call = &event_bprint;
         struct ring_buffer_event *event;
         struct ring_buffer *buffer;
         struct trace_array *tr = &global_trace;
-        struct trace_array_cpu *data;
         struct bprint_entry *entry;
         unsigned long flags;
-        int disable;
-        int cpu, len = 0, size, pc;
+        char *tbuffer;
+        int len = 0, size, pc;
 
         if (unlikely(tracing_selftest_running || tracing_disabled))
                 return 0;
@@ -1526,43 +1619,36 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 
         pc = preempt_count();
         preempt_disable_notrace();
-        cpu = raw_smp_processor_id();
-        data = tr->data[cpu];
 
-        disable = atomic_inc_return(&data->disabled);
-        if (unlikely(disable != 1))
+        tbuffer = get_trace_buf();
+        if (!tbuffer) {
+                len = 0;
                 goto out;
+        }
 
-        /* Lockdep uses trace_printk for lock tracing */
-        local_irq_save(flags);
-        arch_spin_lock(&trace_buf_lock);
-        len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+        len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
 
-        if (len > TRACE_BUF_SIZE || len < 0)
-                goto out_unlock;
+        if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
+                goto out;
 
+        local_save_flags(flags);
         size = sizeof(*entry) + sizeof(u32) * len;
         buffer = tr->buffer;
         event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
                                           flags, pc);
         if (!event)
-                goto out_unlock;
+                goto out;
         entry = ring_buffer_event_data(event);
         entry->ip                       = ip;
         entry->fmt                      = fmt;
 
-        memcpy(entry->buf, trace_buf, sizeof(u32) * len);
+        memcpy(entry->buf, tbuffer, sizeof(u32) * len);
         if (!filter_check_discard(call, entry, buffer, event)) {
                 ring_buffer_unlock_commit(buffer, event);
                 ftrace_trace_stack(buffer, flags, 6, pc);
         }
 
-out_unlock:
-        arch_spin_unlock(&trace_buf_lock);
-        local_irq_restore(flags);
-
 out:
-        atomic_dec_return(&data->disabled);
         preempt_enable_notrace();
         unpause_graph_tracing();
 
@@ -1588,58 +1674,53 @@ int trace_array_printk(struct trace_array *tr,
 int trace_array_vprintk(struct trace_array *tr,
                         unsigned long ip, const char *fmt, va_list args)
 {
-        static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
-        static char trace_buf[TRACE_BUF_SIZE];
-
         struct ftrace_event_call *call = &event_print;
         struct ring_buffer_event *event;
         struct ring_buffer *buffer;
-        struct trace_array_cpu *data;
-        int cpu, len = 0, size, pc;
+        int len = 0, size, pc;
         struct print_entry *entry;
-        unsigned long irq_flags;
-        int disable;
+        unsigned long flags;
+        char *tbuffer;
 
         if (tracing_disabled || tracing_selftest_running)
                 return 0;
 
+        /* Don't pollute graph traces with trace_vprintk internals */
+        pause_graph_tracing();
+
         pc = preempt_count();
         preempt_disable_notrace();
-        cpu = raw_smp_processor_id();
-        data = tr->data[cpu];
 
-        disable = atomic_inc_return(&data->disabled);
-        if (unlikely(disable != 1))
+
+        tbuffer = get_trace_buf();
+        if (!tbuffer) {
+                len = 0;
                 goto out;
+        }
 
-        pause_graph_tracing();
-        raw_local_irq_save(irq_flags);
-        arch_spin_lock(&trace_buf_lock);
-        len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+        len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
+        if (len > TRACE_BUF_SIZE)
+                goto out;
 
+        local_save_flags(flags);
         size = sizeof(*entry) + len + 1;
         buffer = tr->buffer;
         event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
-                                          irq_flags, pc);
+                                          flags, pc);
         if (!event)
-                goto out_unlock;
+                goto out;
         entry = ring_buffer_event_data(event);
         entry->ip = ip;
 
-        memcpy(&entry->buf, trace_buf, len);
+        memcpy(&entry->buf, tbuffer, len);
         entry->buf[len] = '\0';
         if (!filter_check_discard(call, entry, buffer, event)) {
                 ring_buffer_unlock_commit(buffer, event);
-                ftrace_trace_stack(buffer, irq_flags, 6, pc);
+                ftrace_trace_stack(buffer, flags, 6, pc);
         }
-
- out_unlock:
-        arch_spin_unlock(&trace_buf_lock);
-        raw_local_irq_restore(irq_flags);
-        unpause_graph_tracing();
  out:
-        atomic_dec_return(&data->disabled);
         preempt_enable_notrace();
+        unpause_graph_tracing();
 
         return len;
 }
@@ -2974,7 +3055,14 @@ int tracer_init(struct tracer *t, struct trace_array *tr)
         return t->init(tr);
 }
 
-static int __tracing_resize_ring_buffer(unsigned long size)
+static void set_buffer_entries(struct trace_array *tr, unsigned long val)
+{
+        int cpu;
+        for_each_tracing_cpu(cpu)
+                tr->data[cpu]->entries = val;
+}
+
+static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
 {
         int ret;
 
@@ -2985,19 +3073,32 @@ static int __tracing_resize_ring_buffer(unsigned long size)
          */
         ring_buffer_expanded = 1;
 
-        ret = ring_buffer_resize(global_trace.buffer, size);
+        ret = ring_buffer_resize(global_trace.buffer, size, cpu);
         if (ret < 0)
                 return ret;
 
         if (!current_trace->use_max_tr)
                 goto out;
 
-        ret = ring_buffer_resize(max_tr.buffer, size);
+        ret = ring_buffer_resize(max_tr.buffer, size, cpu);
         if (ret < 0) {
-                int r;
+                int r = 0;
+
+                if (cpu == RING_BUFFER_ALL_CPUS) {
+                        int i;
+                        for_each_tracing_cpu(i) {
+                                r = ring_buffer_resize(global_trace.buffer,
+                                                global_trace.data[i]->entries,
+                                                i);
+                                if (r < 0)
+                                        break;
+                        }
+                } else {
+                        r = ring_buffer_resize(global_trace.buffer,
+                                                global_trace.data[cpu]->entries,
+                                                cpu);
+                }
 
-                r = ring_buffer_resize(global_trace.buffer,
-                                       global_trace.entries);
                 if (r < 0) {
                         /*
                          * AARGH! We are left with different
@@ -3019,14 +3120,21 @@ static int __tracing_resize_ring_buffer(unsigned long size)
                 return ret;
         }
 
-        max_tr.entries = size;
+        if (cpu == RING_BUFFER_ALL_CPUS)
+                set_buffer_entries(&max_tr, size);
+        else
+                max_tr.data[cpu]->entries = size;
+
  out:
-        global_trace.entries = size;
+        if (cpu == RING_BUFFER_ALL_CPUS)
+                set_buffer_entries(&global_trace, size);
+        else
+                global_trace.data[cpu]->entries = size;
 
         return ret;
 }
 
-static ssize_t tracing_resize_ring_buffer(unsigned long size)
+static ssize_t tracing_resize_ring_buffer(unsigned long size, int cpu_id)
 {
         int cpu, ret = size;
 
@@ -3042,12 +3150,19 @@ static ssize_t tracing_resize_ring_buffer(unsigned long size)
                         atomic_inc(&max_tr.data[cpu]->disabled);
         }
 
-        if (size != global_trace.entries)
-                ret = __tracing_resize_ring_buffer(size);
+        if (cpu_id != RING_BUFFER_ALL_CPUS) {
+                /* make sure, this cpu is enabled in the mask */
+                if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+        }
 
+        ret = __tracing_resize_ring_buffer(size, cpu_id);
         if (ret < 0)
                 ret = -ENOMEM;
 
+out:
         for_each_tracing_cpu(cpu) {
                 if (global_trace.data[cpu])
                         atomic_dec(&global_trace.data[cpu]->disabled);
@@ -3078,7 +3193,8 @@ int tracing_update_buffers(void)
 
         mutex_lock(&trace_types_lock);
         if (!ring_buffer_expanded)
-                ret = __tracing_resize_ring_buffer(trace_buf_size);
+                ret = __tracing_resize_ring_buffer(trace_buf_size,
+                                                RING_BUFFER_ALL_CPUS);
         mutex_unlock(&trace_types_lock);
 
         return ret;
@@ -3102,7 +3218,8 @@ static int tracing_set_tracer(const char *buf)
         mutex_lock(&trace_types_lock);
 
         if (!ring_buffer_expanded) {
-                ret = __tracing_resize_ring_buffer(trace_buf_size);
+                ret = __tracing_resize_ring_buffer(trace_buf_size,
+                                                RING_BUFFER_ALL_CPUS);
                 if (ret < 0)
                         goto out;
                 ret = 0;
@@ -3128,8 +3245,8 @@ static int tracing_set_tracer(const char *buf)
                  * The max_tr ring buffer has some state (e.g. ring->clock) and
                  * we want preserve it.
                  */
-                ring_buffer_resize(max_tr.buffer, 1);
-                max_tr.entries = 1;
+                ring_buffer_resize(max_tr.buffer, 1, RING_BUFFER_ALL_CPUS);
+                set_buffer_entries(&max_tr, 1);
         }
         destroy_trace_option_files(topts);
 
@@ -3137,10 +3254,17 @@ static int tracing_set_tracer(const char *buf)
 
         topts = create_trace_option_files(current_trace);
         if (current_trace->use_max_tr) {
-                ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
-                if (ret < 0)
-                        goto out;
-                max_tr.entries = global_trace.entries;
+                int cpu;
+                /* we need to make per cpu buffer sizes equivalent */
+                for_each_tracing_cpu(cpu) {
+                        ret = ring_buffer_resize(max_tr.buffer,
+                                                global_trace.data[cpu]->entries,
+                                                cpu);
+                        if (ret < 0)
+                                goto out;
+                        max_tr.data[cpu]->entries =
+                                        global_trace.data[cpu]->entries;
+                }
         }
 
         if (t->init) {
@@ -3642,30 +3766,82 @@ out_err:
         goto out;
 }
 
+struct ftrace_entries_info {
+        struct trace_array      *tr;
+        int                     cpu;
+};
+
+static int tracing_entries_open(struct inode *inode, struct file *filp)
+{
+        struct ftrace_entries_info *info;
+
+        if (tracing_disabled)
+                return -ENODEV;
+
+        info = kzalloc(sizeof(*info), GFP_KERNEL);
+        if (!info)
+                return -ENOMEM;
+
+        info->tr = &global_trace;
+        info->cpu = (unsigned long)inode->i_private;
+
+        filp->private_data = info;
+
+        return 0;
+}
+
 static ssize_t
 tracing_entries_read(struct file *filp, char __user *ubuf,
                      size_t cnt, loff_t *ppos)
 {
-        struct trace_array *tr = filp->private_data;
-        char buf[96];
-        int r;
+        struct ftrace_entries_info *info = filp->private_data;
+        struct trace_array *tr = info->tr;
+        char buf[64];
+        int r = 0;
+        ssize_t ret;
 
         mutex_lock(&trace_types_lock);
-        if (!ring_buffer_expanded)
-                r = sprintf(buf, "%lu (expanded: %lu)\n",
-                            tr->entries >> 10,
-                            trace_buf_size >> 10);
-        else
-                r = sprintf(buf, "%lu\n", tr->entries >> 10);
+
+        if (info->cpu == RING_BUFFER_ALL_CPUS) {
+                int cpu, buf_size_same;
+                unsigned long size;
+
+                size = 0;
+                buf_size_same = 1;
+                /* check if all cpu sizes are same */
+                for_each_tracing_cpu(cpu) {
+                        /* fill in the size from first enabled cpu */
+                        if (size == 0)
+                                size = tr->data[cpu]->entries;
+                        if (size != tr->data[cpu]->entries) {
+                                buf_size_same = 0;
+                                break;
+                        }
+                }
+
+                if (buf_size_same) {
+                        if (!ring_buffer_expanded)
+                                r = sprintf(buf, "%lu (expanded: %lu)\n",
+                                            size >> 10,
+                                            trace_buf_size >> 10);
+                        else
+                                r = sprintf(buf, "%lu\n", size >> 10);
+                } else
+                        r = sprintf(buf, "X\n");
+        } else
+                r = sprintf(buf, "%lu\n", tr->data[info->cpu]->entries >> 10);
+
         mutex_unlock(&trace_types_lock);
 
-        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+        ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+        return ret;
 }
 
 static ssize_t
 tracing_entries_write(struct file *filp, const char __user *ubuf,
                       size_t cnt, loff_t *ppos)
 {
+        struct ftrace_entries_info *info = filp->private_data;
         unsigned long val;
         int ret;
 
@@ -3680,7 +3856,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
         /* value is in KB */
         val <<= 10;
 
-        ret = tracing_resize_ring_buffer(val);
+        ret = tracing_resize_ring_buffer(val, info->cpu);
         if (ret < 0)
                 return ret;
 
@@ -3689,6 +3865,16 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
         return cnt;
 }
 
+static int
+tracing_entries_release(struct inode *inode, struct file *filp)
+{
+        struct ftrace_entries_info *info = filp->private_data;
+
+        kfree(info);
+
+        return 0;
+}
+
 static ssize_t
 tracing_total_entries_read(struct file *filp, char __user *ubuf,
                                 size_t cnt, loff_t *ppos)
@@ -3700,7 +3886,7 @@ tracing_total_entries_read(struct file *filp, char __user *ubuf,
 
         mutex_lock(&trace_types_lock);
         for_each_tracing_cpu(cpu) {
-                size += tr->entries >> 10;
+                size += tr->data[cpu]->entries >> 10;
                 if (!ring_buffer_expanded)
                         expanded_size += trace_buf_size >> 10;
         }
@@ -3734,7 +3920,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp)
         if (trace_flags & TRACE_ITER_STOP_ON_FREE)
                 tracing_off();
         /* resize the ring buffer to 0 */
-        tracing_resize_ring_buffer(0);
+        tracing_resize_ring_buffer(0, RING_BUFFER_ALL_CPUS);
 
         return 0;
 }
@@ -3933,9 +4119,10 @@ static const struct file_operations tracing_pipe_fops = {
 };
 
 static const struct file_operations tracing_entries_fops = {
-        .open           = tracing_open_generic,
+        .open           = tracing_entries_open,
         .read           = tracing_entries_read,
         .write          = tracing_entries_write,
+        .release        = tracing_entries_release,
         .llseek         = generic_file_llseek,
 };
 
@@ -4387,6 +4574,9 @@ static void tracing_init_debugfs_percpu(long cpu)
 
         trace_create_file("stats", 0444, d_cpu,
                         (void *) cpu, &tracing_stats_fops);
+
+        trace_create_file("buffer_size_kb", 0444, d_cpu,
+                        (void *) cpu, &tracing_entries_fops);
 }
 
 #ifdef CONFIG_FTRACE_SELFTEST
@@ -4716,7 +4906,7 @@ static __init int tracer_init_debugfs(void)
                         (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
 
         trace_create_file("buffer_size_kb", 0644, d_tracer,
-                        &global_trace, &tracing_entries_fops);
+                        (void *) RING_BUFFER_ALL_CPUS, &tracing_entries_fops);
 
         trace_create_file("buffer_total_size_kb", 0444, d_tracer,
                         &global_trace, &tracing_total_entries_fops);
@@ -4955,6 +5145,10 @@ __init static int tracer_alloc_buffers(void)
         if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
                 goto out_free_buffer_mask;
 
+        /* Only allocate trace_printk buffers if a trace_printk exists */
+        if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
+                trace_printk_init_buffers();
+
         /* To save memory, keep the ring buffer size to its minimum */
         if (ring_buffer_expanded)
                 ring_buf_size = trace_buf_size;
@@ -4973,7 +5167,6 @@ __init static int tracer_alloc_buffers(void)
                 WARN_ON(1);
                 goto out_free_cpumask;
         }
-        global_trace.entries = ring_buffer_size(global_trace.buffer);
         if (global_trace.buffer_disabled)
                 tracing_off();
 
@@ -4986,7 +5179,6 @@ __init static int tracer_alloc_buffers(void)
                 ring_buffer_free(global_trace.buffer);
                 goto out_free_cpumask;
         }
-        max_tr.entries = 1;
 #endif
 
         /* Allocate the first page for all buffers */
@@ -4995,6 +5187,11 @@ __init static int tracer_alloc_buffers(void)
                 max_tr.data[i] = &per_cpu(max_tr_data, i);
         }
 
+        set_buffer_entries(&global_trace, ring_buf_size);
+#ifdef CONFIG_TRACER_MAX_TRACE
+        set_buffer_entries(&max_tr, 1);
+#endif
+
         trace_init_cmdlines();
 
         register_tracer(&nop_trace);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 95059f091a24..1c8b7c6f7b3b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -131,6 +131,7 @@ struct trace_array_cpu {
         atomic_t                disabled;
         void                    *buffer_page;   /* ring buffer spare */
 
+        unsigned long           entries;
         unsigned long           saved_latency;
         unsigned long           critical_start;
         unsigned long           critical_end;
@@ -152,7 +153,6 @@ struct trace_array_cpu {
  */
 struct trace_array {
         struct ring_buffer      *buffer;
-        unsigned long           entries;
         int                     cpu;
         int                     buffer_disabled;
         cycle_t                 time_start;
@@ -826,6 +826,8 @@ extern struct list_head ftrace_events;
 extern const char *__start___trace_bprintk_fmt[];
 extern const char *__stop___trace_bprintk_fmt[];
 
+void trace_printk_init_buffers(void);
+
 #undef FTRACE_ENTRY
 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter)     \
         extern struct ftrace_event_call                                 \
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 6fd4ffd042f9..a9077c1b4ad3 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -51,6 +51,10 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
         const char **iter;
         char *fmt;
 
+        /* allocate the trace_printk per cpu buffers */
+        if (start != end)
+                trace_printk_init_buffers();
+
         mutex_lock(&btrace_mutex);
         for (iter = start; iter < end; iter++) {
                 struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);