Commit-ID:  5060b91513b866f774da15dfd82157864c4b1683
Gitweb:     http://git.kernel.org/tip/5060b91513b866f774da15dfd82157864c4b1683
Author:     Yu-cheng Yu <[email protected]>
AuthorDate: Mon, 11 Jul 2016 09:18:55 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Mon, 11 Jul 2016 16:44:00 +0200

x86/fpu/xstate: Return NULL for disabled xstate component address

It is an error to request a disabled XSAVE/XSAVES component address.
For that case, make __raw_xsave_addr() return a NULL and issue a
warning.

Signed-off-by: Yu-cheng Yu <[email protected]>
Signed-off-by: Fenghua Yu <[email protected]>
Reviewed-by: Dave Hansen <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi V Shankar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/kernel/fpu/xstate.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index f8d1aff..4fb8dd7 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -760,6 +760,11 @@ void *__raw_xsave_addr(struct xregs_state *xsave, int 
xstate_feature_mask)
 {
        int feature_nr = fls64(xstate_feature_mask) - 1;
 
+       if (!xfeature_enabled(feature_nr)) {
+               WARN_ON_FPU(1);
+               return NULL;
+       }
+
        return (void *)xsave + xstate_comp_offsets[feature_nr];
 }
 /*

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