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| author | Youling Tang <tangyouling@loongson.cn> | 2023-05-01 12:19:53 +0300 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2023-05-01 12:19:53 +0300 |
| commit | 9cdc3b6a299c6314485bcfb695546c11d35dac4c (patch) | |
| tree | 2ede544fd74e92ec4668bf5cdfd17c2f0cad9c60 /arch/loongarch/kernel/mcount_dyn.S | |
| parent | 24d4f52791dae16e478741cc397ba660a95b9d02 (diff) | |
| download | linux-9cdc3b6a299c6314485bcfb695546c11d35dac4c.tar.xz | |
LoongArch: ftrace: Add direct call support
Select the HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide the
register_ftrace_direct[_multi] interfaces allowing users to register
the customed trampoline (direct_caller) as the mcount for one or more
target functions. And modify_ftrace_direct[_multi] are also provided
for modifying direct_caller.
There are a few cases to distinguish:
- If a direct call ops is the only one tracing a function AND the direct
called trampoline is within the reach of a 'bl' instruction
-> the ftrace patchsite jumps to the trampoline
- Else
-> the ftrace patchsite jumps to the ftrace_regs_caller trampoline points
to ftrace_list_ops so it iterates over all registered ftrace ops,
including the direct call ops and calls its call_direct_funcs handler
which stores the direct called trampoline's address in the ftrace_regs
and the ftrace_regs_caller trampoline will return to that address
instead of returning to the traced function
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/kernel/mcount_dyn.S')
| -rw-r--r-- | arch/loongarch/kernel/mcount_dyn.S | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S index bbabf06244c2..c7d961fc72c2 100644 --- a/arch/loongarch/kernel/mcount_dyn.S +++ b/arch/loongarch/kernel/mcount_dyn.S @@ -42,7 +42,6 @@ .if \allregs PTR_S tp, sp, PT_R2 PTR_S t0, sp, PT_R12 - PTR_S t1, sp, PT_R13 PTR_S t2, sp, PT_R14 PTR_S t3, sp, PT_R15 PTR_S t4, sp, PT_R16 @@ -64,6 +63,8 @@ PTR_S zero, sp, PT_R0 .endif PTR_S ra, sp, PT_ERA /* Save trace function ra at PT_ERA */ + move t1, zero + PTR_S t1, sp, PT_R13 PTR_ADDI t8, sp, PT_SIZE PTR_S t8, sp, PT_R3 .endm @@ -104,8 +105,12 @@ ftrace_common_return: PTR_L a7, sp, PT_R11 PTR_L fp, sp, PT_R22 PTR_L t0, sp, PT_ERA + PTR_L t1, sp, PT_R13 PTR_ADDI sp, sp, PT_SIZE + bnez t1, .Ldirect jr t0 +.Ldirect: + jr t1 SYM_CODE_END(ftrace_common) SYM_CODE_START(ftrace_caller) @@ -147,3 +152,9 @@ SYM_CODE_START(return_to_handler) jr ra SYM_CODE_END(return_to_handler) #endif + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +SYM_CODE_START(ftrace_stub_direct_tramp) + jr t0 +SYM_CODE_END(ftrace_stub_direct_tramp) +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ |