diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2022-01-25 15:55:24 +0100 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2022-02-09 09:13:59 +0100 |
| commit | 41918ec82eb6f80c8b401422f27ca76c85aa0cb7 (patch) | |
| tree | 1bd1010a1e6e5a52d3c4ed22d768f863ce10dc6a /arch/arm/kernel/entry-ftrace.S | |
| parent | 538b9265c063f081ca6b1228d242575a1db60711 (diff) | |
ARM: ftrace: enable the graph tracer with the EABI unwinder
Enable the function graph tracer in combination with the EABI unwinder,
so that Thumb2 builds or Clang ARM builds can make use of it.
This involves using the unwinder to locate the return address of an
instrumented function on the stack, so that it can be overridden and
made to refer to the ftrace handling routines that need to be called at
function return.
Given that for these builds, it is not guaranteed that the value of the
link register is stored on the stack, fall back to the stack slot that
will be used by the ftrace exit code to restore LR in the instrumented
function's execution context.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'arch/arm/kernel/entry-ftrace.S')
| -rw-r--r-- | arch/arm/kernel/entry-ftrace.S | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S index bbfa0954c385..3e7bcaca5e07 100644 --- a/arch/arm/kernel/entry-ftrace.S +++ b/arch/arm/kernel/entry-ftrace.S @@ -100,7 +100,8 @@ ftrace_regs_call: #ifdef CONFIG_FUNCTION_GRAPH_TRACER .globl ftrace_graph_regs_call ftrace_graph_regs_call: - mov r0, r0 +ARM( mov r0, r0 ) +THUMB( nop.w ) #endif @ pop saved regs @@ -112,13 +113,18 @@ ftrace_graph_regs_call: #ifdef CONFIG_FUNCTION_GRAPH_TRACER .macro __ftrace_graph_regs_caller - sub r0, fp, #4 @ lr of instrumented routine (parent) +#ifdef CONFIG_UNWINDER_FRAME_POINTER + sub r0, fp, #4 @ lr of instrumented routine (parent) +#else + add r0, sp, #S_LR +#endif @ called from __ftrace_regs_caller - ldr r1, [sp, #S_PC] @ instrumented routine (func) + ldr r1, [sp, #S_PC] @ instrumented routine (func) mcount_adjust_addr r1, r1 - mov r2, fp @ frame pointer + mov r2, fpreg @ frame pointer + add r3, sp, #PT_REGS_SIZE bl prepare_ftrace_return @ pop registers saved in ftrace_regs_caller @@ -149,14 +155,19 @@ ftrace_call\suffix: #ifdef CONFIG_FUNCTION_GRAPH_TRACER .globl ftrace_graph_call\suffix ftrace_graph_call\suffix: - mov r0, r0 +ARM( mov r0, r0 ) +THUMB( nop.w ) #endif mcount_exit .endm .macro __ftrace_graph_caller +#ifdef CONFIG_UNWINDER_FRAME_POINTER sub r0, fp, #4 @ &lr of instrumented routine (&parent) +#else + add r0, sp, #20 +#endif #ifdef CONFIG_DYNAMIC_FTRACE @ called from __ftrace_caller, saved in mcount_enter ldr r1, [sp, #16] @ instrumented routine (func) @@ -165,7 +176,8 @@ ftrace_graph_call\suffix: @ called from __mcount, untouched in lr mcount_adjust_addr r1, lr @ instrumented routine (func) #endif - mov r2, fp @ frame pointer + mov r2, fpreg @ frame pointer + add r3, sp, #24 bl prepare_ftrace_return mcount_exit .endm @@ -244,14 +256,14 @@ ENDPROC(ftrace_graph_regs_caller) .purgem mcount_exit #ifdef CONFIG_FUNCTION_GRAPH_TRACER - .globl return_to_handler -return_to_handler: +ENTRY(return_to_handler) stmdb sp!, {r0-r3} add r0, sp, #16 @ sp at exit of instrumented routine bl ftrace_return_to_handler mov lr, r0 @ r0 has real ret addr ldmia sp!, {r0-r3} ret lr +ENDPROC(return_to_handler) #endif ENTRY(ftrace_stub) |