1 files changed, 22 insertions, 79 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index cd37469b54ee..c9a281f272fd 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -19,6 +19,7 @@
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/list.h>
+#include <linux/module.h>
 
 #include <trace/syscall.h>
 
@@ -49,6 +50,7 @@ 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;
 }
@@ -56,6 +58,7 @@ int ftrace_arch_code_modify_prepare(void)
 int ftrace_arch_code_modify_post_process(void)
 {
         modifying_code = 0;
+        set_all_modules_text_ro();
         set_kernel_text_ro();
         return 0;
 }
@@ -120,7 +123,7 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
 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 void *mod_code_newcode;          /* holds the text to write to the IP */
+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);
@@ -167,9 +170,9 @@ static void ftrace_mod_code(void)
 
 void ftrace_nmi_enter(void)
 {
-        __get_cpu_var(save_modifying_code) = modifying_code;
+        __this_cpu_write(save_modifying_code, modifying_code);
 
-        if (!__get_cpu_var(save_modifying_code))
+        if (!__this_cpu_read(save_modifying_code))
                 return;
 
         if (atomic_inc_return(&nmi_running) & MOD_CODE_WRITE_FLAG) {
@@ -183,7 +186,7 @@ void ftrace_nmi_enter(void)
 
 void ftrace_nmi_exit(void)
 {
-        if (!__get_cpu_var(save_modifying_code))
+        if (!__this_cpu_read(save_modifying_code))
                 return;
 
         /* Finish all executions before clearing nmi_running */
@@ -222,7 +225,7 @@ within(unsigned long addr, unsigned long start, unsigned long end)
 }
 
 static int
-do_ftrace_mod_code(unsigned long ip, void *new_code)
+do_ftrace_mod_code(unsigned long ip, const void *new_code)
 {
         /*
          * On x86_64, kernel text mappings are mapped read-only with
@@ -257,19 +260,14 @@ do_ftrace_mod_code(unsigned long ip, void *new_code)
         return mod_code_status;
 }
 
-
-
-
-static unsigned char ftrace_nop[MCOUNT_INSN_SIZE];
-
-static unsigned char *ftrace_nop_replace(void)
+static const unsigned char *ftrace_nop_replace(void)
 {
-        return ftrace_nop;
+        return ideal_nops[NOP_ATOMIC5];
 }
 
 static int
-ftrace_modify_code(unsigned long ip, unsigned char *old_code,
-                   unsigned char *new_code)
+ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
+                   unsigned const char *new_code)
 {
         unsigned char replaced[MCOUNT_INSN_SIZE];
 
@@ -303,7 +301,7 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 int ftrace_make_nop(struct module *mod,
                     struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char *new, *old;
+        unsigned const char *new, *old;
         unsigned long ip = rec->ip;
 
         old = ftrace_call_replace(ip, addr);
@@ -314,7 +312,7 @@ int ftrace_make_nop(struct module *mod,
 
 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char *new, *old;
+        unsigned const char *new, *old;
         unsigned long ip = rec->ip;
 
         old = ftrace_nop_replace();
@@ -338,62 +336,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 
 int __init ftrace_dyn_arch_init(void *data)
 {
-        extern const unsigned char ftrace_test_p6nop[];
-        extern const unsigned char ftrace_test_nop5[];
-        extern const unsigned char ftrace_test_jmp[];
-        int faulted = 0;
-
-        /*
-         * There is no good nop for all x86 archs.
-         * We will default to using the P6_NOP5, but first we
-         * will test to make sure that the nop will actually
-         * work on this CPU. If it faults, we will then
-         * go to a lesser efficient 5 byte nop. If that fails
-         * we then just use a jmp as our nop. This isn't the most
-         * efficient nop, but we can not use a multi part nop
-         * since we would then risk being preempted in the middle
-         * of that nop, and if we enabled tracing then, it might
-         * cause a system crash.
-         *
-         * TODO: check the cpuid to determine the best nop.
-         */
-        asm volatile (
-                "ftrace_test_jmp:"
-                "jmp ftrace_test_p6nop\n"
-                "nop\n"
-                "nop\n"
-                "nop\n"  /* 2 byte jmp + 3 bytes */
-                "ftrace_test_p6nop:"
-                P6_NOP5
-                "jmp 1f\n"
-                "ftrace_test_nop5:"
-                ".byte 0x66,0x66,0x66,0x66,0x90\n"
-                "1:"
-                ".section .fixup, \"ax\"\n"
-                "2:     movl $1, %0\n"
-                "       jmp ftrace_test_nop5\n"
-                "3:     movl $2, %0\n"
-                "       jmp 1b\n"
-                ".previous\n"
-                _ASM_EXTABLE(ftrace_test_p6nop, 2b)
-                _ASM_EXTABLE(ftrace_test_nop5, 3b)
-                : "=r"(faulted) : "0" (faulted));
-
-        switch (faulted) {
-        case 0:
-                pr_info("converting mcount calls to 0f 1f 44 00 00\n");
-                memcpy(ftrace_nop, ftrace_test_p6nop, MCOUNT_INSN_SIZE);
-                break;
-        case 1:
-                pr_info("converting mcount calls to 66 66 66 66 90\n");
-                memcpy(ftrace_nop, ftrace_test_nop5, MCOUNT_INSN_SIZE);
-                break;
-        case 2:
-                pr_info("converting mcount calls to jmp . + 5\n");
-                memcpy(ftrace_nop, ftrace_test_jmp, MCOUNT_INSN_SIZE);
-                break;
-        }
-
         /* The return code is retured via data */
         *(unsigned long *)data = 0;
 
@@ -495,18 +437,19 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
                 return;
         }
 
-        if (ftrace_push_return_trace(old, self_addr, &trace.depth,
-                    frame_pointer) == -EBUSY) {
-                *parent = old;
-                return;
-        }
-
         trace.func = self_addr;
+        trace.depth = current->curr_ret_stack + 1;
 
         /* Only trace if the calling function expects to */
         if (!ftrace_graph_entry(&trace)) {
-                current->curr_ret_stack--;
                 *parent = old;
+                return;
+        }
+
+        if (ftrace_push_return_trace(old, self_addr, &trace.depth,
+                    frame_pointer) == -EBUSY) {
+                *parent = old;
+                return;
         }
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */