ARM: 6318/1: ftrace: fix and update dynamic ftrace

[pandora-kernel.git] / arch / arm / kernel / entry-common.S

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index f5e75de..e02790f 100644 (file)
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -127,6 +127,10 @@ ENDPROC(ret_from_fork)
  * clobber the ip register.  This is OK because the ARM calling convention
  * allows it to be clobbered in subroutines and doesn't use it to hold
  * parameters.)
+ *
+ * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
+ * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
+ * arch/arm/kernel/ftrace.c).
  */
 
 #ifndef CONFIG_OLD_MCOUNT
@@ -136,30 +140,45 @@ ENDPROC(ret_from_fork)
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-ENTRY(mcount)
+ENTRY(__gnu_mcount_nc)
+       mov     ip, lr
+       ldmia   sp!, {lr}
+       mov     pc, ip
+ENDPROC(__gnu_mcount_nc)
+
+ENTRY(ftrace_caller)
        stmdb   sp!, {r0-r3, lr}
        mov     r0, lr
        sub     r0, r0, #MCOUNT_INSN_SIZE
+       ldr     r1, [sp, #20]
 
-       .globl mcount_call
-mcount_call:
+       .global ftrace_call
+ftrace_call:
        bl      ftrace_stub
-       ldr     lr, [fp, #-4]                   @ restore lr
-       ldmia   sp!, {r0-r3, pc}
+       ldmia   sp!, {r0-r3, ip, lr}
+       mov     pc, ip
+ENDPROC(ftrace_caller)
+
+#ifdef CONFIG_OLD_MCOUNT
+ENTRY(mcount)
+       stmdb   sp!, {lr}
+       ldr     lr, [fp, #-4]
+       ldmia   sp!, {pc}
 ENDPROC(mcount)
 
-ENTRY(ftrace_caller)
+ENTRY(ftrace_caller_old)
        stmdb   sp!, {r0-r3, lr}
        ldr     r1, [fp, #-4]
        mov     r0, lr
        sub     r0, r0, #MCOUNT_INSN_SIZE
 
-       .globl ftrace_call
-ftrace_call:
+       .globl ftrace_call_old
+ftrace_call_old:
        bl      ftrace_stub
        ldr     lr, [fp, #-4]                   @ restore lr
        ldmia   sp!, {r0-r3, pc}
-ENDPROC(ftrace_caller)
+ENDPROC(ftrace_caller_old)
+#endif
 
 #else