When creating a kprobe on function entry through tracefs, enable arguments to be recorded to be specified using $argN syntax.
Signed-off-by: Naveen N Rao <nav...@kernel.org> --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/ptrace.h | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index bff5820b7cda14..bd76ae95146b42 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -233,6 +233,7 @@ config PPC select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_FAST_GUP select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_FUNCTION_DESCRIPTORS if PPC64_ELF_ABI_V1 select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index 0eb90a01334666..68ce2381b18ae1 100644 --- a/arch/powerpc/include/asm/ptrace.h +++ b/arch/powerpc/include/asm/ptrace.h @@ -397,6 +397,23 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, return 0; } +/** + * regs_get_kernel_argument() - get Nth function argument in kernel + * @regs: pt_regs of that context + * @n: function argument number (start from 0) + * + * We support up to 8 arguments and assume they are sent in through the GPRs. + * This will fail for fp/vector arguments, but those aren't usually found in + * kernel code. This is expected to be called from kprobes or ftrace with regs. + */ +static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, unsigned int n) +{ +#define NR_REG_ARGUMENTS 8 + if (n < NR_REG_ARGUMENTS) + return regs_get_register(regs, offsetof(struct pt_regs, gpr[3 + n])); + return 0; +} + #endif /* __ASSEMBLY__ */ #ifndef __powerpc64__ base-commit: bd517a8442b6c6646a136421cd4c1b95bf4ce32b -- 2.40.1