diff options
Diffstat (limited to 'arch/arm/kernel/entry-common.S')
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 235 |
1 files changed, 0 insertions, 235 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 6bb09d4abdea..f8ccc21fa032 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -109,241 +109,6 @@ ENDPROC(ret_from_fork) #undef CALL #define CALL(x) .long x -#ifdef CONFIG_FUNCTION_TRACER -/* - * When compiling with -pg, gcc inserts a call to the mcount routine at the - * 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: - * - * push {lr} - * bl __gnu_mcount_nc - * - * With these compilers, frame pointers are not necessary. - * - * mcount can be thought of as a function called in the middle of a subroutine - * call. As such, it needs to be transparent for both the caller and the - * callee: the original lr needs to be restored when leaving mcount, and no - * registers should be clobbered. (In the __gnu_mcount_nc implementation, we - * 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 -#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 -.endm - -.macro __mcount suffix - mcount_enter - ldr r0, =ftrace_trace_function - ldr r2, [r0] - adr r0, .Lftrace_stub - cmp r0, r2 - bne 1f - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - ldr r1, =ftrace_graph_return - ldr r2, [r1] - cmp r0, r2 - bne ftrace_graph_caller\suffix - - ldr r1, =ftrace_graph_entry - ldr r2, [r1] - ldr r0, =ftrace_graph_entry_stub - cmp r0, r2 - bne ftrace_graph_caller\suffix -#endif - - mcount_exit - -1: mcount_get_lr r1 @ lr of instrumented func - mcount_adjust_addr r0, lr @ instrumented function - adr lr, BSYM(2f) - mov pc, r2 -2: mcount_exit -.endm - -.macro __ftrace_caller suffix - mcount_enter - - mcount_get_lr r1 @ lr of instrumented func - mcount_adjust_addr r0, lr @ instrumented function - - .globl ftrace_call\suffix -ftrace_call\suffix: - bl ftrace_stub - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - .globl ftrace_graph_call\suffix -ftrace_graph_call\suffix: - mov r0, r0 -#endif - - mcount_exit -.endm - -.macro __ftrace_graph_caller - sub r0, fp, #4 @ &lr of instrumented routine (&parent) -#ifdef CONFIG_DYNAMIC_FTRACE - @ called from __ftrace_caller, saved in mcount_enter - ldr r1, [sp, #16] @ instrumented routine (func) - mcount_adjust_addr r1, r1 -#else - @ called from __mcount, untouched in lr - mcount_adjust_addr r1, lr @ instrumented routine (func) -#endif - mov r2, fp @ frame pointer - bl prepare_ftrace_return - 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 - */ - -.macro mcount_enter -/* - * This pad compensates for the push {lr} at the call site. Note that we are - * unable to unwind through a function which does not otherwise save its lr. - */ - UNWIND(.pad #4) - stmdb sp!, {r0-r3, lr} - UNWIND(.save {r0-r3, lr}) -.endm - -.macro mcount_get_lr reg - ldr \reg, [sp, #20] -.endm - -.macro mcount_exit - ldmia sp!, {r0-r3, ip, lr} - ret ip -.endm - -ENTRY(__gnu_mcount_nc) -UNWIND(.fnstart) -#ifdef CONFIG_DYNAMIC_FTRACE - mov ip, lr - ldmia sp!, {lr} - ret ip -#else - __mcount -#endif -UNWIND(.fnend) -ENDPROC(__gnu_mcount_nc) - -#ifdef CONFIG_DYNAMIC_FTRACE -ENTRY(ftrace_caller) -UNWIND(.fnstart) - __ftrace_caller -UNWIND(.fnend) -ENDPROC(ftrace_caller) -#endif - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller) -UNWIND(.fnstart) - __ftrace_graph_caller -UNWIND(.fnend) -ENDPROC(ftrace_graph_caller) -#endif - -.purgem mcount_enter -.purgem mcount_get_lr -.purgem mcount_exit - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - .globl return_to_handler -return_to_handler: - stmdb sp!, {r0-r3} - mov r0, fp @ frame pointer - bl ftrace_return_to_handler - mov lr, r0 @ r0 has real ret addr - ldmia sp!, {r0-r3} - ret lr -#endif - -ENTRY(ftrace_stub) -.Lftrace_stub: - ret lr -ENDPROC(ftrace_stub) - -#endif /* CONFIG_FUNCTION_TRACER */ - /*============================================================================= * SWI handler *----------------------------------------------------------------------------- |