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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-20 20:07:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-20 20:07:44 -0800 |
| commit | 8831d718aa5a9540aaeb527a582af5fc140aed6e (patch) | |
| tree | 0ad3bfa743e5201654da6dbb6f09d18c5a6797f5 /arch/x86/include/asm/fpu/api.h | |
| parent | d00c4ed02e90c1a4290acdd4f9bc4d056a573859 (diff) | |
| parent | 0a74d61c7d842b583f33f74d7a9e93201826f4c5 (diff) | |
| download | linux-8831d718aa5a9540aaeb527a582af5fc140aed6e.tar.gz linux-8831d718aa5a9540aaeb527a582af5fc140aed6e.tar.bz2 linux-8831d718aa5a9540aaeb527a582af5fc140aed6e.zip | |
Merge tag 'x86_fpu_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 FPU updates from Borislav Petkov:
"x86 fpu usage optimization and cleanups:
- make 64-bit kernel code which uses 387 insns request a x87 init
(FNINIT) explicitly when using the FPU
- misc cleanups"
* tag 'x86_fpu_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu/xstate: Use sizeof() instead of a constant
x86/fpu/64: Don't FNINIT in kernel_fpu_begin()
x86/fpu: Make the EFI FPU calling convention explicit
Diffstat (limited to 'arch/x86/include/asm/fpu/api.h')
| -rw-r--r-- | arch/x86/include/asm/fpu/api.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index 67a4f1cb2aac..ed33a14188f6 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -32,7 +32,19 @@ extern void fpregs_mark_activate(void); /* Code that is unaware of kernel_fpu_begin_mask() can use this */ static inline void kernel_fpu_begin(void) { +#ifdef CONFIG_X86_64 + /* + * Any 64-bit code that uses 387 instructions must explicitly request + * KFPU_387. + */ + kernel_fpu_begin_mask(KFPU_MXCSR); +#else + /* + * 32-bit kernel code may use 387 operations as well as SSE2, etc, + * as long as it checks that the CPU has the required capability. + */ kernel_fpu_begin_mask(KFPU_387 | KFPU_MXCSR); +#endif } /* |