diff options
Diffstat (limited to 'arch/x86/include/asm/pkru.h')
| -rw-r--r-- | arch/x86/include/asm/pkru.h | 17 |
1 files changed, 4 insertions, 13 deletions
diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h index 7e4550911c51..ccc539faa5bb 100644 --- a/arch/x86/include/asm/pkru.h +++ b/arch/x86/include/asm/pkru.h @@ -41,23 +41,14 @@ static inline u32 read_pkru(void) static inline void write_pkru(u32 pkru) { - struct pkru_state *pk; - if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) return; - - pk = get_xsave_addr(¤t->thread.fpu.state.xsave, XFEATURE_PKRU); - /* - * The PKRU value in xstate needs to be in sync with the value that is - * written to the CPU. The FPU restore on return to userland would - * otherwise load the previous value again. + * WRPKRU is relatively expensive compared to RDPKRU. + * Avoid WRPKRU when it would not change the value. */ - fpregs_lock(); - if (pk) - pk->pkru = pkru; - __write_pkru(pkru); - fpregs_unlock(); + if (pkru != rdpkru()) + wrpkru(pkru); } static inline void pkru_write_default(void) |