Re: [PATCH v3 10/27] linux-user/i386: Implement setup_sigtramp

[Richard Henderson]

On 9/24/21 2:01 PM, Philippe Mathieu-Daudé wrote:
> > +static void install_sigtramp(void *tramp)
> > +{
> > +    /* This is popl %eax ; movl $syscall,%eax ; int $0x80 */
> > +    __put_user(0xb858, (uint16_t *)(tramp + 0));
> > +    __put_user(TARGET_NR_sigreturn, (int *)(tramp + 2));
>
> I know this is mostly code movement, but using uint32_t would
> make it easier to read.

I'll give you int32_t here, since the value is signed.

> > +    __put_user(TARGET_NR_rt_sigreturn, (int *)(tramp + 1));
>
> and uint32_t.

Likewise.

> > +    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
>
> Shouldn't this be 8 + 7?

Does it really matter if we write 15 or 16 bytes of this page?


r~