Messages in this thread | | | From | Song Shuai <> | Date | Mon, 28 Nov 2022 13:29:05 +0000 | Subject | Re: [PATCH 1/2] riscv/ftrace: add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support |
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Guo Ren <guoren@kernel.org> 于2022年11月28日周一 13:17写道: > > On Wed, Nov 23, 2022 at 10:20 PM Song Shuai <suagrfillet@gmail.com> wrote: > > > > This patch adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V. > > > > select the 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. > > > > To make the direct_caller and the other ftrace hooks (eg. function/fgraph > > tracer, k[ret]probes) co-exist, a temporary register is nominated to > > store the address of direct_caller in ftrace_regs_caller. After the > > setting of the address direct_caller by direct_ops->func and the > > RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to > > by the `jr` inst. > > > > Signed-off-by: Song Shuai <suagrfillet@gmail.com> > > --- > > arch/riscv/Kconfig | 1 + > > arch/riscv/include/asm/ftrace.h | 6 ++++++ > > arch/riscv/kernel/mcount-dyn.S | 4 ++++ > > 3 files changed, 11 insertions(+) > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index 39ec8d628cf6..d083ec08d0b6 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -278,6 +278,7 @@ config ARCH_RV64I > > select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 > > select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8) > > select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE > > + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS > > select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL > > select HAVE_FUNCTION_GRAPH_TRACER > > select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION > > diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h > > index 01bebb28eabe..be4d57566139 100644 > > --- a/arch/riscv/include/asm/ftrace.h > > +++ b/arch/riscv/include/asm/ftrace.h > > @@ -114,6 +114,12 @@ struct ftrace_regs; > > void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > > struct ftrace_ops *op, struct ftrace_regs *fregs); > > #define ftrace_graph_func ftrace_graph_func > > + > > +static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr) > > +{ > > + regs->t1 = addr; > > +} > > + > > #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > > > #endif /* __ASSEMBLY__ */ > > diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S > > index 466c6ef217b1..b89c85a58569 100644 > > --- a/arch/riscv/kernel/mcount-dyn.S > > +++ b/arch/riscv/kernel/mcount-dyn.S > > @@ -233,6 +233,7 @@ ENDPROC(ftrace_caller) > > #else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > ENTRY(ftrace_regs_caller) > > SAVE_ABI_REGS 1 > > + REG_S x0, PT_T1(sp) > ENTRY(ftrace_regs_caller) > + move t1, zero > SAVE_ABI_REGS 1 > PREPARE_ARGS > > Shall we use a move here, instead? That seems ok to me. Just move it. > > > PREPARE_ARGS > > > > ftrace_regs_call: > > @@ -241,7 +242,10 @@ ftrace_regs_call: > > > > > > RESTORE_ABI_REGS 1 > > + bnez t1,.Ldirect > > jr t0 > > +.Ldirect: > > + jr t1 > > ENDPROC(ftrace_regs_caller) > > > > ENTRY(ftrace_caller) > > -- > > 2.20.1 > > > > > -- > Best Regards > Guo Ren
-- Thanks, Song
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