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powerpc/trace: Add support for HAVE_FUNCTION_ARG_ACCESS_API

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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 <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230614085926.2176641-1-naveen@kernel.org
This commit is contained in:
Naveen N Rao 2023-06-14 14:29:26 +05:30 committed by Michael Ellerman
parent d42f55e8ae
commit f01b0edd56
2 changed files with 18 additions and 0 deletions
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1
arch/powerpc/Kconfig
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@ -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

17
arch/powerpc/include/asm/ptrace.h
View File

@ -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__