On Fri, 7 Mar 2008, Roland McGrath wrote:
quoted text
> 
> This makes 64-bit ptrace calls setting the 64-bit orig_ax field
> for a 32-bit task sign-extend the low 32 bits up to 64.  This
> matches what a 64-bit debugger expects when tracing a 32-bit task.

Hmm. Why make this conditional on CONFIG_IA32_EMULATION and TIF_IA32?

That field is never really 64-bit anyway. The only allowable values are
 - system call number (== small positive value)
 - a small negative number for traps

So I'd suggest just making it entirely unconditionally just do

	case offsetof(struct user_regs_struct, orig_ax):
		value = (long) (s32) value;
		break;

and be done with it. Why have arbitrarily different code on x86 and x86-64 
when there is no real reason for it?

		Linus
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