[x32] PATCH: Remove ix86_promote_function_mode

[Richard Henderson]

On 06/20/2011 04:39 PM, H. Peter Anvin wrote:
> sys_foo:
> 	cmpl	$10, %edi
> 	jae	.L1
> 
> 	movq	foo_table(,%rdi,3), %rax
> 	retq
> .L1:
> 	movq	$-EINVAL, %rax
> 	retq
> 
> Enter this function with a non-normalized %rdi and you have a security
> hole even though the C is perfectly fine.

Yes, I get that.  Isn't it already the case that x86_64 defines the
upper half of 32-bit inputs as garbage?  Assuming you're never intending
to run an x32 kernel, but always an x32 environment within an x86_64
kernel, where does the talk of security holes wrt non-pointers come from?


r~