diff options
Diffstat (limited to 'arch/arm/kernel/entry-ftrace.S')
-rw-r--r-- | arch/arm/kernel/entry-ftrace.S | 75 |
1 files changed, 4 insertions, 71 deletions
diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S index efcd9f25a14b..0be69e551a64 100644 --- a/arch/arm/kernel/entry-ftrace.S +++ b/arch/arm/kernel/entry-ftrace.S @@ -15,23 +15,8 @@ * start of every function. In mcount, apart from the function's address (in * lr), we need to get hold of the function's caller's address. * - * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this: - * - * bl mcount - * - * These versions have the limitation that in order for the mcount routine to - * be able to determine the function's caller's address, an APCS-style frame - * pointer (which is set up with something like the code below) is required. - * - * mov ip, sp - * push {fp, ip, lr, pc} - * sub fp, ip, #4 - * - * With EABI, these frame pointers are not available unless -mapcs-frame is - * specified, and if building as Thumb-2, not even then. - * - * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount, - * with call sites like: + * Newer GCCs (4.4+) solve this problem by using a version of mcount with call + * sites like: * * push {lr} * bl __gnu_mcount_nc @@ -46,17 +31,10 @@ * 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). + * When using dynamic ftrace, we patch out the mcount call by a "pop {lr}" + * instead of the __gnu_mcount_nc call (see arch/arm/kernel/ftrace.c). */ -#ifndef CONFIG_OLD_MCOUNT -#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)) -#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0. -#endif -#endif - .macro mcount_adjust_addr rd, rn bic \rd, \rn, #1 @ clear the Thumb bit if present sub \rd, \rd, #MCOUNT_INSN_SIZE @@ -209,51 +187,6 @@ ftrace_graph_call\suffix: mcount_exit .endm -#ifdef CONFIG_OLD_MCOUNT -/* - * mcount - */ - -.macro mcount_enter - stmdb sp!, {r0-r3, lr} -.endm - -.macro mcount_get_lr reg - ldr \reg, [fp, #-4] -.endm - -.macro mcount_exit - ldr lr, [fp, #-4] - ldmia sp!, {r0-r3, pc} -.endm - -ENTRY(mcount) -#ifdef CONFIG_DYNAMIC_FTRACE - stmdb sp!, {lr} - ldr lr, [fp, #-4] - ldmia sp!, {pc} -#else - __mcount _old -#endif -ENDPROC(mcount) - -#ifdef CONFIG_DYNAMIC_FTRACE -ENTRY(ftrace_caller_old) - __ftrace_caller _old -ENDPROC(ftrace_caller_old) -#endif - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller_old) - __ftrace_graph_caller -ENDPROC(ftrace_graph_caller_old) -#endif - -.purgem mcount_enter -.purgem mcount_get_lr -.purgem mcount_exit -#endif - /* * __gnu_mcount_nc */ |