1 files changed, 160 insertions, 58 deletions

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 60c60ccf5e3c..70e2a736be1f 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -5,6 +5,9 @@
  *
  * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
  *
+ * Added function graph tracer code, taken from x86 that was written
+ * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
+ *
  */
 
 #include <linux/spinlock.h>
@@ -20,14 +23,6 @@
 #include <asm/code-patching.h>
 #include <asm/ftrace.h>
 
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(fmt , ...)       do { } while (0)
-#endif
-
-static unsigned int ftrace_nop = PPC_NOP_INSTR;
-
 #ifdef CONFIG_PPC32
 # define GET_ADDR(addr) addr
 #else
@@ -35,37 +30,23 @@ static unsigned int ftrace_nop = PPC_NOP_INSTR;
 # define GET_ADDR(addr) (*(unsigned long *)addr)
 #endif
 
-
-static unsigned int ftrace_calc_offset(long ip, long addr)
+#ifdef CONFIG_DYNAMIC_FTRACE
+static unsigned int ftrace_nop_replace(void)
 {
-        return (int)(addr - ip);
+        return PPC_INST_NOP;
 }
 
-static unsigned char *ftrace_nop_replace(void)
+static unsigned int
+ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
 {
-        return (char *)&ftrace_nop;
-}
-
-static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
-{
-        static unsigned int op;
+        unsigned int op;
 
-        /*
-         * It would be nice to just use create_function_call, but that will
-         * update the code itself. Here we need to just return the
-         * instruction that is going to be modified, without modifying the
-         * code.
-         */
         addr = GET_ADDR(addr);
 
-        /* Set to "bl addr" */
-        op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc);
+        /* if (link) set op to 'bl' else 'b' */
+        op = create_branch((unsigned int *)ip, addr, link ? 1 : 0);
 
-        /*
-         * No locking needed, this must be called via kstop_machine
-         * which in essence is like running on a uniprocessor machine.
-         */
-        return (unsigned char *)&op;
+        return op;
 }
 
 #ifdef CONFIG_PPC64
@@ -77,10 +58,9 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
 #endif
 
 static int
-ftrace_modify_code(unsigned long ip, unsigned char *old_code,
-                   unsigned char *new_code)
+ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
 {
-        unsigned char replaced[MCOUNT_INSN_SIZE];
+        unsigned int replaced;
 
         /*
          * Note: Due to modules and __init, code can
@@ -93,15 +73,15 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
          */
 
         /* read the text we want to modify */
-        if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+        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_code, MCOUNT_INSN_SIZE) != 0)
+        if (replaced != old)
                 return -EINVAL;
 
         /* replace the text with the new text */
-        if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
+        if (probe_kernel_write((void *)ip, &new, MCOUNT_INSN_SIZE))
                 return -EPERM;
 
         flush_icache_range(ip, ip + 8);
@@ -119,6 +99,8 @@ static int test_24bit_addr(unsigned long ip, unsigned long addr)
         return create_branch((unsigned int *)ip, addr, 0);
 }
 
+#ifdef CONFIG_MODULES
+
 static int is_bl_op(unsigned int op)
 {
         return (op & 0xfc000003) == 0x48000001;
@@ -175,7 +157,7 @@ __ftrace_make_nop(struct module *mod,
          * 0xe8, 0x4c, 0x00, 0x28,    ld      r2,40(r12)
          */
 
-        DEBUGP("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
+        pr_debug("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
 
         /* Find where the trampoline jumps to */
         if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
@@ -183,7 +165,7 @@ __ftrace_make_nop(struct module *mod,
                 return -EFAULT;
         }
 
-        DEBUGP(" %08x %08x", jmp[0], jmp[1]);
+        pr_debug(" %08x %08x", jmp[0], jmp[1]);
 
         /* verify that this is what we expect it to be */
         if (((jmp[0] & 0xffff0000) != 0x3d820000) ||
@@ -199,18 +181,18 @@ __ftrace_make_nop(struct module *mod,
         offset = ((unsigned)((unsigned short)jmp[0]) << 16) +
                 (int)((short)jmp[1]);
 
-        DEBUGP(" %x ", offset);
+        pr_debug(" %x ", offset);
 
         /* get the address this jumps too */
         tramp = mod->arch.toc + offset + 32;
-        DEBUGP("toc: %lx", tramp);
+        pr_debug("toc: %lx", tramp);
 
         if (probe_kernel_read(jmp, (void *)tramp, 8)) {
                 printk(KERN_ERR "Failed to read %lx\n", tramp);
                 return -EFAULT;
         }
 
-        DEBUGP(" %08x %08x\n", jmp[0], jmp[1]);
+        pr_debug(" %08x %08x\n", jmp[0], jmp[1]);
 
         ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
 
@@ -287,7 +269,7 @@ __ftrace_make_nop(struct module *mod,
          *  0x4e, 0x80, 0x04, 0x20  bctr
          */
 
-        DEBUGP("ip:%lx jumps to %lx", ip, tramp);
+        pr_debug("ip:%lx jumps to %lx", ip, tramp);
 
         /* Find where the trampoline jumps to */
         if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
@@ -295,7 +277,7 @@ __ftrace_make_nop(struct module *mod,
                 return -EFAULT;
         }
 
-        DEBUGP(" %08x %08x ", jmp[0], jmp[1]);
+        pr_debug(" %08x %08x ", jmp[0], jmp[1]);
 
         /* verify that this is what we expect it to be */
         if (((jmp[0] & 0xffff0000) != 0x3d600000) ||
@@ -311,7 +293,7 @@ __ftrace_make_nop(struct module *mod,
         if (tramp & 0x8000)
                 tramp -= 0x10000;
 
-        DEBUGP(" %x ", tramp);
+        pr_debug(" %lx ", tramp);
 
         if (tramp != addr) {
                 printk(KERN_ERR
@@ -320,7 +302,7 @@ __ftrace_make_nop(struct module *mod,
                 return -EINVAL;
         }
 
-        op = PPC_NOP_INSTR;
+        op = PPC_INST_NOP;
 
         if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
                 return -EPERM;
@@ -330,12 +312,13 @@ __ftrace_make_nop(struct module *mod,
         return 0;
 }
 #endif /* PPC64 */
+#endif /* CONFIG_MODULES */
 
 int ftrace_make_nop(struct module *mod,
                     struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char *old, *new;
         unsigned long ip = rec->ip;
+        unsigned int old, new;
 
         /*
          * If the calling address is more that 24 bits away,
@@ -344,11 +327,12 @@ int ftrace_make_nop(struct module *mod,
          */
         if (test_24bit_addr(ip, addr)) {
                 /* within range */
-                old = ftrace_call_replace(ip, addr);
+                old = ftrace_call_replace(ip, addr, 1);
                 new = ftrace_nop_replace();
                 return ftrace_modify_code(ip, old, new);
         }
 
+#ifdef CONFIG_MODULES
         /*
          * Out of range jumps are called from modules.
          * We should either already have a pointer to the module
@@ -373,9 +357,13 @@ int ftrace_make_nop(struct module *mod,
                 mod = rec->arch.mod;
 
         return __ftrace_make_nop(mod, rec, addr);
-
+#else
+        /* We should not get here without modules */
+        return -EINVAL;
+#endif /* CONFIG_MODULES */
 }
 
+#ifdef CONFIG_MODULES
 #ifdef CONFIG_PPC64
 static int
 __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -392,7 +380,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
          *  b +8; ld r2,40(r1)
          */
         if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) &&
-            ((op[0] != PPC_NOP_INSTR) || (op[1] != PPC_NOP_INSTR))) {
+            ((op[0] != PPC_INST_NOP) || (op[1] != PPC_INST_NOP))) {
                 printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]);
                 return -EINVAL;
         }
@@ -414,7 +402,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
         /* ld r2,40(r1) */
         op[1] = 0xe8410028;
 
-        DEBUGP("write to %lx\n", rec->ip);
+        pr_debug("write to %lx\n", rec->ip);
 
         if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
                 return -EPERM;
@@ -435,7 +423,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
                 return -EFAULT;
 
         /* It should be pointing to a nop */
-        if (op != PPC_NOP_INSTR) {
+        if (op != PPC_INST_NOP) {
                 printk(KERN_ERR "Expected NOP but have %x\n", op);
                 return -EINVAL;
         }
@@ -454,7 +442,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
                 return -EINVAL;
         }
 
-        DEBUGP("write to %lx\n", rec->ip);
+        pr_debug("write to %lx\n", rec->ip);
 
         if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
                 return -EPERM;
@@ -464,11 +452,12 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
         return 0;
 }
 #endif /* CONFIG_PPC64 */
+#endif /* CONFIG_MODULES */
 
 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char *old, *new;
         unsigned long ip = rec->ip;
+        unsigned int old, new;
 
         /*
          * If the calling address is more that 24 bits away,
@@ -478,10 +467,11 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
         if (test_24bit_addr(ip, addr)) {
                 /* within range */
                 old = ftrace_nop_replace();
-                new = ftrace_call_replace(ip, addr);
+                new = ftrace_call_replace(ip, addr, 1);
                 return ftrace_modify_code(ip, old, new);
         }
 
+#ifdef CONFIG_MODULES
         /*
          * Out of range jumps are called from modules.
          * Being that we are converting from nop, it had better
@@ -493,16 +483,20 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
         }
 
         return __ftrace_make_call(rec, addr);
+#else
+        /* We should not get here without modules */
+        return -EINVAL;
+#endif /* CONFIG_MODULES */
 }
 
 int ftrace_update_ftrace_func(ftrace_func_t func)
 {
         unsigned long ip = (unsigned long)(&ftrace_call);
-        unsigned char old[MCOUNT_INSN_SIZE], *new;
+        unsigned int old, new;
         int ret;
 
-        memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
-        new = ftrace_call_replace(ip, (unsigned long)func);
+        old = *(unsigned int *)&ftrace_call;
+        new = ftrace_call_replace(ip, (unsigned long)func, 1);
         ret = ftrace_modify_code(ip, old, new);
 
         return ret;
@@ -517,3 +511,111 @@ int __init ftrace_dyn_arch_init(void *data)
 
         return 0;
 }
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_graph_call(void);
+extern void ftrace_graph_stub(void);
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+        unsigned long ip = (unsigned long)(&ftrace_graph_call);
+        unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+        unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+        unsigned int old, new;
+
+        old = ftrace_call_replace(ip, stub, 0);
+        new = ftrace_call_replace(ip, addr, 0);
+
+        return ftrace_modify_code(ip, old, new);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+        unsigned long ip = (unsigned long)(&ftrace_graph_call);
+        unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+        unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+        unsigned int old, new;
+
+        old = ftrace_call_replace(ip, addr, 0);
+        new = ftrace_call_replace(ip, stub, 0);
+
+        return ftrace_modify_code(ip, old, new);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_PPC64
+extern void mod_return_to_handler(void);
+#endif
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+{
+        unsigned long old;
+        int faulted;
+        struct ftrace_graph_ent trace;
+        unsigned long return_hooker = (unsigned long)&return_to_handler;
+
+        if (unlikely(atomic_read(&current->tracing_graph_pause)))
+                return;
+
+#ifdef CONFIG_PPC64
+        /* non core kernel code needs to save and restore the TOC */
+        if (REGION_ID(self_addr) != KERNEL_REGION_ID)
+                return_hooker = (unsigned long)&mod_return_to_handler;
+#endif
+
+        return_hooker = GET_ADDR(return_hooker);
+
+        /*
+         * Protect against fault, even if it shouldn't
+         * happen. This tool is too much intrusive to
+         * ignore such a protection.
+         */
+        asm volatile(
+                "1: " PPC_LL "%[old], 0(%[parent])\n"
+                "2: " PPC_STL "%[return_hooker], 0(%[parent])\n"
+                "   li %[faulted], 0\n"
+                "3:\n"
+
+                ".section .fixup, \"ax\"\n"
+                "4: li %[faulted], 1\n"
+                "   b 3b\n"
+                ".previous\n"
+
+                ".section __ex_table,\"a\"\n"
+                        PPC_LONG_ALIGN "\n"
+                        PPC_LONG "1b,4b\n"
+                        PPC_LONG "2b,4b\n"
+                ".previous"
+
+                : [old] "=r" (old), [faulted] "=r" (faulted)
+                : [parent] "r" (parent), [return_hooker] "r" (return_hooker)
+                : "memory"
+        );
+
+        if (unlikely(faulted)) {
+                ftrace_graph_stop();
+                WARN_ON(1);
+                return;
+        }
+
+        if (ftrace_push_return_trace(old, self_addr, &trace.depth) == -EBUSY) {
+                *parent = old;
+                return;
+        }
+
+        trace.func = self_addr;
+
+        /* Only trace if the calling function expects to */
+        if (!ftrace_graph_entry(&trace)) {
+                current->curr_ret_stack--;
+                *parent = old;
+        }
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */