Messages in this thread Patch in this message | | | From | Song Shuai <> | Subject | [PATCH 1/2] riscv/ftrace: add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support | Date | Wed, 23 Nov 2022 22:20:24 +0800 |
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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) 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
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