On Sat, Apr 19, 2014 at 03:50:44PM -0700, tip-bot for Ricardo Neri wrote:
> Commit-ID: de05764e0b2a3d9559e099a2e134f8cef4500fdd
> Gitweb: http://git.kernel.org/tip/de05764e0b2a3d9559e099a2e134f8cef4500fdd
> Author: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
> AuthorDate: Thu, 27 Mar 2014 15:10:42 -0700
> Committer: Matt Fleming <matt.fleming@xxxxxxxxx>
> CommitDate: Thu, 17 Apr 2014 13:26:32 +0100
>
> x86/efi: Save and restore FPU context around efi_calls (x86_64)
>
> Do a complete FPU context save/restore around the EFI calls. This required
> as runtime EFI firmware may potentially use the FPU.
>
> This change covers only the x86_64 configuration.
>
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
> ---
> arch/x86/include/asm/efi.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index 19292e7..0b19187 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -1,6 +1,7 @@
> #ifndef _ASM_X86_EFI_H
> #define _ASM_X86_EFI_H
>
> +#include <asm/i387.h>
> /*
> * We map the EFI regions needed for runtime services non-contiguously,
> * with preserved alignment on virtual addresses starting from -4G down
> @@ -54,7 +55,9 @@ extern u64 asmlinkage efi_call(void *fp, ...);
> \
> efi_sync_low_kernel_mappings(); \
> preempt_disable(); \
> + __kernel_fpu_begin(); \
> __s = efi_call((void *)efi.systab->runtime->f, __VA_ARGS__); \
> + __kernel_fpu_end(); \
> preempt_enable(); \
I guess you can use the kernel_fpu_begin/end() variants here (i.e.,
without the "__") which disable and enable preemption and thus drop the
preempt_* calls:
efi_sync_low_kernel_mappings();
kernel_fpu_begin();
__s = efi_call((void *)efi.systab->runtime->f, __VA_ARGS__);
kernel_fpu_end();
__s;
I'm not sure about the
WARN_ON_ONCE(!irq_fpu_usable());
thing in kernel_fpu_begin() though, I guess it wouldn't hurt...
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
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