[PATCH] x86: Properly match CPU feature [BZ #27222]

[H.J. Lu]

On Thu, Jan 21, 2021 at 11:47 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> /proc/cpuinfo has
>
> flags           : fpu vme de pse ... ssse3 ...
>
> SSE3 in /proc/cpuinfo is displaced as "pni".  Search "pni" instead of
> "sse3" for SSE3.  After finding a match for a string, verify the previous
> character is space and the next character is space or null byte to avoid
> matching "XXXYYYXXX" with "YYY".
> ---
>  sysdeps/x86/tst-cpu-features-cpuinfo.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/sysdeps/x86/tst-cpu-features-cpuinfo.c b/sysdeps/x86/tst-cpu-features-cpuinfo.c
> index 771771c959..9308349869 100644
> --- a/sysdeps/x86/tst-cpu-features-cpuinfo.c
> +++ b/sysdeps/x86/tst-cpu-features-cpuinfo.c
> @@ -64,7 +64,12 @@ check_proc (const char *proc_name, int flag, int usable, const char *name)
>        return 0;
>      }
>    printf ("  %s: %d\n", name, flag);
> -  if (strstr (cpu_flags, proc_name) != NULL)
> +  char *str = strstr (cpu_flags, proc_name);
> +  size_t len = strlen (proc_name);
> +  /* Don't match "ssse3" with "sse3".  */
> +  if (str != NULL
> +      && str[-1] == ' '
> +      && (str[len] == ' ' || str[len] == '\0'))
>      found = 1;
>    printf ("  cpuinfo (%s): %d\n", proc_name, found);
>
> @@ -206,7 +211,7 @@ do_test (int argc, char **argv)
>    fails += CHECK_PROC (ssbd, SSBD);
>    fails += CHECK_PROC (sse, SSE);
>    fails += CHECK_PROC (sse2, SSE2);
> -  fails += CHECK_PROC (sse3, SSE3);
> +  fails += CHECK_PROC (pni, SSE3);
>    fails += CHECK_PROC (sse4_1, SSE4_1);
>    fails += CHECK_PROC (sse4_2, SSE4_2);
>    fails += CHECK_PROC (sse4a, SSE4A);
> --
> 2.29.2
>

I am checking it in.

-- 
H.J.