[hurd, commited] hurd: Do not restore xstate when it is not initialized

[Samuel Thibault]

If the process has never used fp before getting a signal, xstate is set
(and thus the x87 state is not initialized) but xstate->initialized is still
0, and we should not restore anything.
---
 sysdeps/mach/hurd/i386/sigreturn.c   | 37 +++++++++++++++-------------
 sysdeps/mach/hurd/x86_64/sigreturn.c | 37 +++++++++++++++-------------
 2 files changed, 40 insertions(+), 34 deletions(-)

diff --git a/sysdeps/mach/hurd/i386/sigreturn.c 
b/sysdeps/mach/hurd/i386/sigreturn.c
index 37fa984070..dc57d6122c 100644
--- a/sysdeps/mach/hurd/i386/sigreturn.c
+++ b/sysdeps/mach/hurd/i386/sigreturn.c
@@ -126,24 +126,27 @@ __sigreturn (struct sigcontext *scp)
     ss->sigaltstack.ss_flags &= ~SS_ONSTACK;
 
 #ifdef i386_XFLOAT_STATE
-  if ((scp->xstate) && (scp->xstate->initialized))
+  if (scp->xstate)
     {
-      unsigned eax, ebx, ecx, edx;
-      __cpuid_count(0xd, 0, eax, ebx, ecx, edx);
-      switch (scp->xstate->fp_save_kind)
-        {
-        case 0: // FNSAVE
-          asm volatile("frstor %0" : : "m" (scp->xstate->hw_state));
-          break;
-        case 1: // FXSAVE
-          asm volatile("fxrstor %0" : : "m" (scp->xstate->hw_state),    \
-                       "a" (eax), "d" (edx));
-          break;
-        default: // XSAVE, XSAVEOPT, XSAVEC, XSAVES
-          asm volatile("xrstor %0" : : "m" (scp->xstate->hw_state),     \
-                       "a" (eax), "d" (edx));
-          break;
-        }
+      if (scp->xstate->initialized)
+       {
+         unsigned eax, ebx, ecx, edx;
+         __cpuid_count(0xd, 0, eax, ebx, ecx, edx);
+         switch (scp->xstate->fp_save_kind)
+           {
+           case 0: // FNSAVE
+             asm volatile("frstor %0" : : "m" (scp->xstate->hw_state));
+             break;
+           case 1: // FXSAVE
+             asm volatile("fxrstor %0" : : "m" (scp->xstate->hw_state),    \
+                          "a" (eax), "d" (edx));
+             break;
+           default: // XSAVE, XSAVEOPT, XSAVEC, XSAVES
+             asm volatile("xrstor %0" : : "m" (scp->xstate->hw_state),     \
+                          "a" (eax), "d" (edx));
+             break;
+           }
+       }
     }
   else
 #endif
diff --git a/sysdeps/mach/hurd/x86_64/sigreturn.c 
b/sysdeps/mach/hurd/x86_64/sigreturn.c
index dff8e76dc8..773c00f86d 100644
--- a/sysdeps/mach/hurd/x86_64/sigreturn.c
+++ b/sysdeps/mach/hurd/x86_64/sigreturn.c
@@ -119,24 +119,27 @@ __sigreturn (struct sigcontext *scp)
     ss->sigaltstack.ss_flags &= ~SS_ONSTACK;
 
 #ifdef i386_XFLOAT_STATE
-  if ((scp->xstate) && (scp->xstate->initialized))
+  if (scp->xstate)
     {
-      unsigned eax, ebx, ecx, edx;
-      __cpuid_count(0xd, 0, eax, ebx, ecx, edx);
-      switch (scp->xstate->fp_save_kind)
-        {
-        case 0: // FNSAVE
-          asm volatile("frstor %0" : : "m" (scp->xstate->hw_state));
-          break;
-        case 1: // FXSAVE
-          asm volatile("fxrstor %0" : : "m" (scp->xstate->hw_state),    \
-                       "a" (eax), "d" (edx));
-          break;
-        default: // XSAVE, XSAVEOPT, XSAVEC, XSAVES
-          asm volatile("xrstor %0" : : "m" (scp->xstate->hw_state),     \
-                       "a" (eax), "d" (edx));
-          break;
-        }
+      if (scp->xstate->initialized)
+       {
+         unsigned eax, ebx, ecx, edx;
+         __cpuid_count(0xd, 0, eax, ebx, ecx, edx);
+         switch (scp->xstate->fp_save_kind)
+           {
+           case 0: // FNSAVE
+             asm volatile("frstor %0" : : "m" (scp->xstate->hw_state));
+             break;
+           case 1: // FXSAVE
+             asm volatile("fxrstor %0" : : "m" (scp->xstate->hw_state),    \
+                          "a" (eax), "d" (edx));
+             break;
+           default: // XSAVE, XSAVEOPT, XSAVEC, XSAVES
+             asm volatile("xrstor %0" : : "m" (scp->xstate->hw_state),     \
+                          "a" (eax), "d" (edx));
+             break;
+           }
+       }
     }
   else
 #endif
-- 
2.47.2