Mailing List Archive

* src/hwf-x86.c (FORCE_FUNC_FRAME_POINTER): Remove.
(CFI_ADJUST_CFA_OFFSET, CFI_PUSH4, CFI_POP4): New.
(is_cpuid_available): Use CFI statements instead of frame-pointer
attribute.
--

With newer GCC, "no-omit-frame-pointer" attribute no longer
enforces frame pointer usage in function.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
---
src/hwf-x86.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/hwf-x86.c b/src/hwf-x86.c
index c6f493eb..5240a460 100644
--- a/src/hwf-x86.c
+++ b/src/hwf-x86.c
@@ -39,14 +39,17 @@
#if defined (__i386__) && SIZEOF_UNSIGNED_LONG == 4 && defined (__GNUC__)
# define HAS_X86_CPUID 1

-#if _GCRY_GCC_VERSION >= 40700 /* 4.7 */
-# define FORCE_FUNC_FRAME_POINTER \
- __attribute__ ((optimize("no-omit-frame-pointer")))
+#ifdef HAVE_GCC_ASM_CFI_DIRECTIVES
+# define CFI_ADJUST_CFA_OFFSET(off) ".cfi_adjust_cfa_offset " #off "\n\t"
+# define CFI_PUSH4 CFI_ADJUST_CFA_OFFSET(4)
+# define CFI_POP4 CFI_ADJUST_CFA_OFFSET(-4)
#else
-# define FORCE_FUNC_FRAME_POINTER
+# define CFI_ADJUST_CFA_OFFSET(off)
+# define CFI_PUSH4
+# define CFI_POP4
#endif

-static FORCE_FUNC_FRAME_POINTER int
+static int
is_cpuid_available(void)
{
int has_cpuid = 0;
@@ -55,15 +58,23 @@ is_cpuid_available(void)
vs 32 bit pushf/popf). */
asm volatile
("pushf\n\t" /* Copy flags to EAX. */
+ CFI_PUSH4
"popl %%eax\n\t"
+ CFI_POP4
"movl %%eax, %%ecx\n\t" /* Save flags into ECX. */
"xorl $0x200000, %%eax\n\t" /* Toggle ID bit and copy it to the flags. */
"pushl %%eax\n\t"
+ CFI_PUSH4
"popf\n\t"
+ CFI_POP4
"pushf\n\t" /* Copy changed flags again to EAX. */
+ CFI_PUSH4
"popl %%eax\n\t"
+ CFI_POP4
"pushl %%ecx\n\t" /* Restore flags from ECX. */
+ CFI_PUSH4
"popf\n\t"
+ CFI_POP4
"xorl %%eax, %%ecx\n\t" /* Compare flags against saved flags. */
"jz .Lno_cpuid%=\n\t" /* Toggling did not work, thus no CPUID. */
"movl $1, %0\n" /* Worked. true -> HAS_CPUID. */
--
2.39.2


_______________________________________________
Gcrypt-devel mailing list
Gcrypt-devel@gnupg.org
https://lists.gnupg.org/mailman/listinfo/gcrypt-devel