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-rw-r--r--arch/powerpc/Kconfig1
-rw-r--r--arch/powerpc/include/asm/ptrace.h17
2 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d5d5388973ac..6f105ee4f3cf 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -237,6 +237,7 @@ 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 9db8b16567e2..ea8f91fbc62f 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__