diff options
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 98 |
1 files changed, 38 insertions, 60 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index a85c64000218..1cadb2faf740 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -441,12 +441,35 @@ static void __init print_xstate_offset_size(void) } /* + * All supported features have either init state all zeros or are + * handled in setup_init_fpu() individually. This is an explicit + * feature list and does not use XFEATURE_MASK*SUPPORTED to catch + * newly added supported features at build time and make people + * actually look at the init state for the new feature. + */ +#define XFEATURES_INIT_FPSTATE_HANDLED \ + (XFEATURE_MASK_FP | \ + XFEATURE_MASK_SSE | \ + XFEATURE_MASK_YMM | \ + XFEATURE_MASK_OPMASK | \ + XFEATURE_MASK_ZMM_Hi256 | \ + XFEATURE_MASK_Hi16_ZMM | \ + XFEATURE_MASK_PKRU | \ + XFEATURE_MASK_BNDREGS | \ + XFEATURE_MASK_BNDCSR | \ + XFEATURE_MASK_PASID) + +/* * setup the xstate image representing the init state */ static void __init setup_init_fpu_buf(void) { static int on_boot_cpu __initdata = 1; + BUILD_BUG_ON((XFEATURE_MASK_USER_SUPPORTED | + XFEATURE_MASK_SUPERVISOR_SUPPORTED) != + XFEATURES_INIT_FPSTATE_HANDLED); + WARN_ON_FPU(!on_boot_cpu); on_boot_cpu = 0; @@ -466,10 +489,22 @@ static void __init setup_init_fpu_buf(void) copy_kernel_to_xregs_booting(&init_fpstate.xsave); /* - * Dump the init state again. This is to identify the init state - * of any feature which is not represented by all zero's. + * All components are now in init state. Read the state back so + * that init_fpstate contains all non-zero init state. This only + * works with XSAVE, but not with XSAVEOPT and XSAVES because + * those use the init optimization which skips writing data for + * components in init state. + * + * XSAVE could be used, but that would require to reshuffle the + * data when XSAVES is available because XSAVES uses xstate + * compaction. But doing so is a pointless exercise because most + * components have an all zeros init state except for the legacy + * ones (FP and SSE). Those can be saved with FXSAVE into the + * legacy area. Adding new features requires to ensure that init + * state is all zeroes or if not to add the necessary handling + * here. */ - copy_xregs_to_kernel_booting(&init_fpstate.xsave); + fxsave(&init_fpstate.fxsave); } static int xfeature_uncompacted_offset(int xfeature_nr) @@ -1402,60 +1437,3 @@ int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns, return 0; } #endif /* CONFIG_PROC_PID_ARCH_STATUS */ - -#ifdef CONFIG_IOMMU_SUPPORT -void update_pasid(void) -{ - u64 pasid_state; - u32 pasid; - - if (!cpu_feature_enabled(X86_FEATURE_ENQCMD)) - return; - - if (!current->mm) - return; - - pasid = READ_ONCE(current->mm->pasid); - /* Set the valid bit in the PASID MSR/state only for valid pasid. */ - pasid_state = pasid == PASID_DISABLED ? - pasid : pasid | MSR_IA32_PASID_VALID; - - /* - * No need to hold fregs_lock() since the task's fpstate won't - * be changed by others (e.g. ptrace) while the task is being - * switched to or is in IPI. - */ - if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { - /* The MSR is active and can be directly updated. */ - wrmsrl(MSR_IA32_PASID, pasid_state); - } else { - struct fpu *fpu = ¤t->thread.fpu; - struct ia32_pasid_state *ppasid_state; - struct xregs_state *xsave; - - /* - * The CPU's xstate registers are not currently active. Just - * update the PASID state in the memory buffer here. The - * PASID MSR will be loaded when returning to user mode. - */ - xsave = &fpu->state.xsave; - xsave->header.xfeatures |= XFEATURE_MASK_PASID; - ppasid_state = get_xsave_addr(xsave, XFEATURE_PASID); - /* - * Since XFEATURE_MASK_PASID is set in xfeatures, ppasid_state - * won't be NULL and no need to check its value. - * - * Only update the task's PASID state when it's different - * from the mm's pasid. - */ - if (ppasid_state->pasid != pasid_state) { - /* - * Invalid fpregs so that state restoring will pick up - * the PASID state. - */ - __fpu_invalidate_fpregs_state(fpu); - ppasid_state->pasid = pasid_state; - } - } -} -#endif /* CONFIG_IOMMU_SUPPORT */ |