mxcsr_feature_mask_init() depends on TS being cleared, as it executes
an FXSAVE instruction.
After later changes we will move the TS setup into fpu__init_cpu(),
which will interact with this - so clear the TS flag explicitly.
Reviewed-by: Borislav Petkov <b...@alien8.de>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/kernel/fpu/init.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 2752b4bae854..567e7e6cdc6b 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -214,6 +214,13 @@ void fpu__init_system(void)
fpu__init_cpu();
/*
+ * But don't leave CR0::TS set yet, as some of the FPU setup methods
depend
+ * on being able to execute FPU instructions that will fault on a set
TS,
+ * such as the FXSAVE in mxcsr_feature_mask_init().
+ */
+ clts();
+
+ /*
* Set up the legacy init FPU context. (xstate init might overwrite this
* with a more modern format, if the CPU supports it.)
*/
--
2.1.0
--
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