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Subject[PATCH 2/4] x86/fpu/xstate: Return NULL for disabled xstate component address
Date
From: Yu-cheng Yu <yu-cheng.yu@intel.com>

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 <yu-cheng.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
---
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];
}
/*
--
2.5.0
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