x86, xsave: dynamically allocate sigframes fpstate instead of static allocation

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / sigframe.h

diff --git a/arch/x86/kernel/sigframe.h b/arch/x86/kernel/sigframe.h
index 72bbb519d2dc1ed74e6f01d39842995871ed9e80..6dd7e2b70a4b8d8e0994760698025e384058c68e 100644 (file)
--- a/arch/x86/kernel/sigframe.h
+++ b/arch/x86/kernel/sigframe.h
@@ -3,9 +3,18 @@ struct sigframe {
        char __user *pretcode;
        int sig;
        struct sigcontext sc;
-       struct _fpstate fpstate;
+       /*
+        * fpstate is unused. fpstate is moved/allocated after
+        * retcode[] below. This movement allows to have the FP state and the
+        * future state extensions (xsave) stay together.
+        * And at the same time retaining the unused fpstate, prevents changing
+        * the offset of extramask[] in the sigframe and thus prevent any
+        * legacy application accessing/modifying it.
+        */
+       struct _fpstate fpstate_unused;
        unsigned long extramask[_NSIG_WORDS-1];
        char retcode[8];
+       /* fp state follows here */
 };
 
 struct rt_sigframe {
@@ -15,13 +24,14 @@ struct rt_sigframe {
        void __user *puc;
        struct siginfo info;
        struct ucontext uc;
-       struct _fpstate fpstate;
        char retcode[8];
+       /* fp state follows here */
 };
 #else
 struct rt_sigframe {
        char __user *pretcode;
        struct ucontext uc;
        struct siginfo info;
+       /* fp state follows here */
 };
 #endif