Unverified Commit 70eee556 authored by Jeff Xie's avatar Jeff Xie Committed by Palmer Dabbelt
Browse files

riscv: ptrace: add argn syntax 



This enables ftrace kprobe events to access kernel function
arguments via $argN syntax.

Signed-off-by: default avatarJeff Xie <huan.xie@suse.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent 9eb4fcff

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ config RISCV 
	select HAVE_PERF_REGS

	select HAVE_PERF_USER_STACK_DUMP

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_FUNCTION_ARG_ACCESS_API

	select HAVE_STACKPROTECTOR

	select HAVE_SYSCALL_TRACEPOINTS

	select IRQ_DOMAIN

arch/riscv/include/asm/ptrace.h

+31 −0
Original line number Diff line number Diff line
@@ -141,6 +141,37 @@ static inline unsigned long regs_get_register(struct pt_regs *regs, 


	return *(unsigned long *)((unsigned long)regs + offset);

}



/**

 * regs_get_kernel_argument() - get Nth function argument in kernel

 * @regs:       pt_regs of that context

 * @n:          function argument number (start from 0)

 *

 * regs_get_argument() returns @n th argument of the function call.

 *

 * Note you can get the parameter correctly if the function has no

 * more than eight arguments.

 */

static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,

						unsigned int n)

{

	static const int nr_reg_arguments = 8;

	static const unsigned int argument_offs[] = {

		offsetof(struct pt_regs, a0),

		offsetof(struct pt_regs, a1),

		offsetof(struct pt_regs, a2),

		offsetof(struct pt_regs, a3),

		offsetof(struct pt_regs, a4),

		offsetof(struct pt_regs, a5),

		offsetof(struct pt_regs, a6),

		offsetof(struct pt_regs, a7),

	};



	if (n < nr_reg_arguments)

		return regs_get_register(regs, argument_offs[n]);

	return 0;

}



#endif /* __ASSEMBLY__ */



#endif /* _ASM_RISCV_PTRACE_H */