Commit f01b0edd authored by Naveen N Rao's avatar Naveen N Rao Committed by Michael Ellerman
Browse files

powerpc/trace: Add support for HAVE_FUNCTION_ARG_ACCESS_API 



When creating a kprobe on function entry through tracefs, enable
arguments to be recorded to be specified using $argN syntax.

Signed-off-by: default avatarNaveen N Rao <naveen@kernel.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230614085926.2176641-1-naveen@kernel.org
parent d42f55e8

arch/powerpc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/include/asm/ptrace.h

+17 −0
Original line number Diff line number Diff line
@@ -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__