On Fri, Aug 28, 2020 at 05:02:46PM +0530, Vamshi K Sthambamkadi wrote:
> On i386, the order of parameters passed on regs is eax,edx,and ecx
> (as per regparm(3) calling conventions).
>
> Change the mapping in regs_get_kernel_argument(), so that arg1=ax
> arg2=dx, and arg3=cx.
>
> Running the selftests testcase kprobes_args_use.tc shows the result
> as passed.
>
Fixes: 3c88ee194c28 ("x86: ptrace: Add function argument access API")
> Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamk...@gmail.com>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
> ---
> arch/x86/include/asm/ptrace.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
> index 40aa69d..d8324a2 100644
> --- a/arch/x86/include/asm/ptrace.h
> +++ b/arch/x86/include/asm/ptrace.h
> @@ -327,8 +327,8 @@ static inline unsigned long
> regs_get_kernel_argument(struct pt_regs *regs,
> static const unsigned int argument_offs[] = {
> #ifdef __i386__
> offsetof(struct pt_regs, ax),
> - offsetof(struct pt_regs, cx),
> offsetof(struct pt_regs, dx),
> + offsetof(struct pt_regs, cx),
> #define NR_REG_ARGUMENTS 3
> #else
> offsetof(struct pt_regs, di),
> --
> 2.7.4
>
