On Thu, Mar 19, 2020 at 1:54 PM Michal Suchanek <msucha...@suse.de> wrote:
>
> Merge the 32bit and 64bit version.
>
> Halve the check constants on 32bit.
>
> Use STACK_TOP since it is defined.
>
> Passing is_64 is now redundant since is_32bit_task() is used to
> determine which callchain variant should be used. Use STACK_TOP and
> is_32bit_task() directly.
>
> This removes a page from the valid 32bit area on 64bit:
> #define TASK_SIZE_USER32 (0x0000000100000000UL - (1 * PAGE_SIZE))
> #define STACK_TOP_USER32 TASK_SIZE_USER32
...
> +static inline int valid_user_sp(unsigned long sp)
> +{
> + bool is_64 = !is_32bit_task();
> +
> + if (!sp || (sp & (is_64 ? 7 : 3)) || sp > STACK_TOP - (is_64 ? 32 :
> 16))
> + return 0;
> + return 1;
> +}
Perhaps better to read
if (!sp)
return 0;
if (is_32bit_task()) {
if (sp & 0x03)
return 0;
if (sp > STACK_TOP - 16)
return 0;
} else {
...
}
return 1;
Other possibility:
unsigned long align = is_32bit_task() ? 3 : 7;
unsigned long top = STACK_TOP - (is_32bit_task() ? 16 : 32);
return !(!sp || (sp & align) || sp > top);
--
With Best Regards,
Andy Shevchenko
