Messages in this thread Patch in this message | | | Subject | Re: [PATCH v6 5/9] LoongArch/ftrace: Add DYNAMIC_FTRACE_WITH_REGS support | From | Qing Zhang <> | Date | Tue, 15 Nov 2022 18:44:50 +0800 |
| |
Hi, huacai On 2022/11/15 下午5:24, Huacai Chen wrote: > On Tue, Nov 15, 2022 at 5:22 PM Qing Zhang <zhangqing@loongson.cn> wrote: >> >> Hi, Huacai >> >> On 2022/11/15 下午4:41, Huacai Chen wrote: >>> Hi, Qing, >>> >>> Patch5 and Patch6 are small and related, maybe they can be combined >>> with a name "LoongArch/ftrace: Add DYNAMIC_FTRACE_WITH_{ARGS,REGS} >>> support" >> I think they should be independent due to different use scenarios. > From the commit message it seems DYNAMIC_FTRACE_WITH_ARGS depend on > DYNAMIC_FTRACE_WITH_REGS.
DYNAMIC_FTRACE_WITH_REGS : which allows trace function saved registers, It means that these registers can be modified, eg: Kprobe、Livepatch.
DYNAMIC_FTRACE_WITH_ARGS: uses pt_regs as a parameter for get sp, which means it can be used to access registers on the stack, and use graph_ops::func to install return_hooker to replace the special hook, eg: Livepatch.
From the following Kconfig, they are reasonable as separate patches. config LIVEPATCH bool "Kernel Live Patching" depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
Thanks - Qing > > Huacai >> >> Thanks, >> -Qing >>> >>> Huacai >>> >>> On Tue, Nov 15, 2022 at 10:55 AM Qing Zhang <zhangqing@loongson.cn> wrote: >>>> >>>> This patch implements DYNAMIC_FTRACE_WITH_REGS on LoongArch, which allows >>>> a traced function's arguments (and some other registers) to be captured >>>> into a struct pt_regs, allowing these to be inspected and modified. >>>> >>>> Co-developed-by: Jinyang He <hejinyang@loongson.cn> >>>> Signed-off-by: Jinyang He <hejinyang@loongson.cn> >>>> Signed-off-by: Qing Zhang <zhangqing@loongson.cn> >>>> --- >>>> arch/loongarch/Kconfig | 1 + >>>> arch/loongarch/include/asm/ftrace.h | 3 +++ >>>> arch/loongarch/kernel/ftrace_dyn.c | 17 ++++++++++++++ >>>> arch/loongarch/kernel/mcount-dyn.S | 36 +++++++++++++++++++++++++++-- >>>> 4 files changed, 55 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig >>>> index 615ce62422b8..12e3e91a68ae 100644 >>>> --- a/arch/loongarch/Kconfig >>>> +++ b/arch/loongarch/Kconfig >>>> @@ -90,6 +90,7 @@ config LOONGARCH >>>> select HAVE_DEBUG_STACKOVERFLOW >>>> select HAVE_DMA_CONTIGUOUS >>>> select HAVE_DYNAMIC_FTRACE >>>> + select HAVE_DYNAMIC_FTRACE_WITH_REGS >>>> select HAVE_EBPF_JIT >>>> select HAVE_EXIT_THREAD >>>> select HAVE_FAST_GUP >>>> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h >>>> index 76ca58767f4d..a3f974a7a5ce 100644 >>>> --- a/arch/loongarch/include/asm/ftrace.h >>>> +++ b/arch/loongarch/include/asm/ftrace.h >>>> @@ -28,6 +28,9 @@ struct dyn_ftrace; >>>> int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); >>>> #define ftrace_init_nop ftrace_init_nop >>>> >>>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS >>>> +#define ARCH_SUPPORTS_FTRACE_OPS 1 >>>> +#endif >>>> #endif /* CONFIG_DYNAMIC_FTRACE */ >>>> #endif /* __ASSEMBLY__ */ >>>> #endif /* CONFIG_FUNCTION_TRACER */ >>>> diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c >>>> index 3fe791b6783e..ec3d951be50c 100644 >>>> --- a/arch/loongarch/kernel/ftrace_dyn.c >>>> +++ b/arch/loongarch/kernel/ftrace_dyn.c >>>> @@ -99,6 +99,23 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, >>>> return ftrace_modify_code(pc, old, new, true); >>>> } >>>> >>>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS >>>> +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, >>>> + unsigned long addr) >>>> +{ >>>> + unsigned long pc; >>>> + long offset; >>>> + u32 old, new; >>>> + >>>> + pc = rec->ip + LOONGARCH_INSN_SIZE; >>>> + >>>> + old = larch_insn_gen_bl(pc, old_addr); >>>> + new = larch_insn_gen_bl(pc, addr); >>>> + >>>> + return ftrace_modify_code(pc, old, new, true); >>>> +} >>>> +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ >>>> + >>>> void arch_ftrace_update_code(int command) >>>> { >>>> command |= FTRACE_MAY_SLEEP; >>>> diff --git a/arch/loongarch/kernel/mcount-dyn.S b/arch/loongarch/kernel/mcount-dyn.S >>>> index 0c12cc108e6f..02835186b463 100644 >>>> --- a/arch/loongarch/kernel/mcount-dyn.S >>>> +++ b/arch/loongarch/kernel/mcount-dyn.S >>>> @@ -27,7 +27,7 @@ >>>> * follows the LoongArch psABI well. >>>> */ >>>> >>>> - .macro ftrace_regs_entry >>>> + .macro ftrace_regs_entry allregs=0 >>>> PTR_ADDI sp, sp, -PT_SIZE >>>> /* Save trace function ra at PT_ERA */ >>>> PTR_S ra, sp, PT_ERA >>>> @@ -43,16 +43,48 @@ >>>> PTR_S a7, sp, PT_R11 >>>> PTR_S fp, sp, PT_R22 >>>> >>>> + .if \allregs >>>> + 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 >>>> + PTR_S t5, sp, PT_R17 >>>> + PTR_S t6, sp, PT_R18 >>>> + PTR_S t7, sp, PT_R19 >>>> + PTR_S t8, sp, PT_R20 >>>> + PTR_S s0, sp, PT_R23 >>>> + PTR_S s1, sp, PT_R24 >>>> + PTR_S s2, sp, PT_R25 >>>> + PTR_S s3, sp, PT_R26 >>>> + PTR_S s4, sp, PT_R27 >>>> + PTR_S s5, sp, PT_R28 >>>> + PTR_S s6, sp, PT_R29 >>>> + PTR_S s7, sp, PT_R30 >>>> + PTR_S s8, sp, PT_R31 >>>> + PTR_S tp, sp, PT_R2 >>>> + /* Clear it for later use as a flag sometimes. */ >>>> + PTR_S zero, sp, PT_R0 >>>> + PTR_S $r21, sp, PT_R21 >>>> + .endif >>>> + >>>> PTR_ADDI t8, sp, PT_SIZE >>>> PTR_S t8, sp, PT_R3 >>>> >>>> .endm >>>> >>>> SYM_CODE_START(ftrace_caller) >>>> - ftrace_regs_entry >>>> + ftrace_regs_entry allregs=0 >>>> b ftrace_common >>>> SYM_CODE_END(ftrace_caller) >>>> >>>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS >>>> +SYM_CODE_START(ftrace_regs_caller) >>>> + ftrace_regs_entry allregs=1 >>>> + b ftrace_common >>>> +SYM_CODE_END(ftrace_regs_caller) >>>> +#endif >>>> + >>>> SYM_CODE_START(ftrace_common) >>>> PTR_ADDI a0, ra, -8 /* arg0: ip */ >>>> move a1, t0 /* arg1: parent_ip */ >>>> -- >>>> 2.36.0 >>>> >>>> >> >>
| |