diff options
| -rw-r--r-- | arch/x86/events/intel/lbr.c | 6 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/xstate.h | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 98 |
3 files changed, 54 insertions, 55 deletions
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 2fa2df3d4e9b..f338645071c8 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -491,7 +491,7 @@ static void intel_pmu_arch_lbr_xrstors(void *ctx) { struct x86_perf_task_context_arch_lbr_xsave *task_ctx = ctx; - copy_kernel_to_independent_supervisor(&task_ctx->xsave, XFEATURE_MASK_LBR); + xrstors(&task_ctx->xsave, XFEATURE_MASK_LBR); } static __always_inline bool lbr_is_reset_in_cstate(void *ctx) @@ -576,7 +576,7 @@ static void intel_pmu_arch_lbr_xsaves(void *ctx) { struct x86_perf_task_context_arch_lbr_xsave *task_ctx = ctx; - copy_independent_supervisor_to_kernel(&task_ctx->xsave, XFEATURE_MASK_LBR); + xsaves(&task_ctx->xsave, XFEATURE_MASK_LBR); } static void __intel_pmu_lbr_save(void *ctx) @@ -992,7 +992,7 @@ static void intel_pmu_arch_lbr_read_xsave(struct cpu_hw_events *cpuc) intel_pmu_store_lbr(cpuc, NULL); return; } - copy_independent_supervisor_to_kernel(&xsave->xsave, XFEATURE_MASK_LBR); + xsaves(&xsave->xsave, XFEATURE_MASK_LBR); intel_pmu_store_lbr(cpuc, xsave->lbr.entries); } diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index a55bd5cabb59..7de2384628e2 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -104,8 +104,9 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); int xfeature_size(int xfeature_nr); int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf); int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf); -void copy_independent_supervisor_to_kernel(struct xregs_state *xstate, u64 mask); -void copy_kernel_to_independent_supervisor(struct xregs_state *xstate, u64 mask); + +void xsaves(struct xregs_state *xsave, u64 mask); +void xrstors(struct xregs_state *xsave, u64 mask); enum xstate_copy_mode { XSTATE_COPY_FP, diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 27246a83ecb9..735d44c3efb6 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1162,76 +1162,74 @@ int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, return copy_uabi_to_xstate(xsave, NULL, ubuf); } +static bool validate_xsaves_xrstors(u64 mask) +{ + u64 xchk; + + if (WARN_ON_FPU(!cpu_feature_enabled(X86_FEATURE_XSAVES))) + return false; + /* + * Validate that this is either a task->fpstate related component + * subset or an independent one. + */ + if (mask & xfeatures_mask_independent()) + xchk = ~xfeatures_mask_independent(); + else + xchk = ~xfeatures_mask_all; + + if (WARN_ON_ONCE(!mask || mask & xchk)) + return false; + + return true; +} + /** - * copy_independent_supervisor_to_kernel() - Save independent supervisor states to - * an xsave area - * @xstate: A pointer to an xsave area - * @mask: Represent the independent supervisor features saved into the xsave area + * xsaves - Save selected components to a kernel xstate buffer + * @xstate: Pointer to the buffer + * @mask: Feature mask to select the components to save * - * Only the independent supervisor states sets in the mask are saved into the xsave - * area (See the comment in XFEATURE_MASK_INDEPENDENT for the details of independent - * supervisor feature). Besides the independent supervisor states, the legacy - * region and XSAVE header are also saved into the xsave area. The supervisor - * features in the XFEATURE_MASK_SUPERVISOR_SUPPORTED and - * XFEATURE_MASK_SUPERVISOR_UNSUPPORTED are not saved. + * The @xstate buffer must be 64 byte aligned and correctly initialized as + * XSAVES does not write the full xstate header. Before first use the + * buffer should be zeroed otherwise a consecutive XRSTORS from that buffer + * can #GP. * - * The xsave area must be 64-bytes aligned. + * The feature mask must either be a subset of the independent features or + * a subset of the task->fpstate related features. */ -void copy_independent_supervisor_to_kernel(struct xregs_state *xstate, u64 mask) +void xsaves(struct xregs_state *xstate, u64 mask) { - u64 independent_mask = xfeatures_mask_independent() & mask; - u32 lmask, hmask; int err; - if (WARN_ON_FPU(!boot_cpu_has(X86_FEATURE_XSAVES))) + if (!validate_xsaves_xrstors(mask)) return; - if (WARN_ON_FPU(!independent_mask)) - return; - - lmask = independent_mask; - hmask = independent_mask >> 32; - - XSTATE_OP(XSAVES, xstate, lmask, hmask, err); - - /* Should never fault when copying to a kernel buffer */ - WARN_ON_FPU(err); + XSTATE_OP(XSAVES, xstate, (u32)mask, (u32)(mask >> 32), err); + WARN_ON_ONCE(err); } /** - * copy_kernel_to_independent_supervisor() - Restore independent supervisor states from - * an xsave area - * @xstate: A pointer to an xsave area - * @mask: Represent the independent supervisor features restored from the xsave area + * xrstors - Restore selected components from a kernel xstate buffer + * @xstate: Pointer to the buffer + * @mask: Feature mask to select the components to restore + * + * The @xstate buffer must be 64 byte aligned and correctly initialized + * otherwise XRSTORS from that buffer can #GP. * - * Only the independent supervisor states sets in the mask are restored from the - * xsave area (See the comment in XFEATURE_MASK_INDEPENDENT for the details of - * independent supervisor feature). Besides the independent supervisor states, the - * legacy region and XSAVE header are also restored from the xsave area. The - * supervisor features in the XFEATURE_MASK_SUPERVISOR_SUPPORTED and - * XFEATURE_MASK_SUPERVISOR_UNSUPPORTED are not restored. + * Proper usage is to restore the state which was saved with + * xsaves() into @xstate. * - * The xsave area must be 64-bytes aligned. + * The feature mask must either be a subset of the independent features or + * a subset of the task->fpstate related features. */ -void copy_kernel_to_independent_supervisor(struct xregs_state *xstate, u64 mask) +void xrstors(struct xregs_state *xstate, u64 mask) { - u64 independent_mask = xfeatures_mask_independent() & mask; - u32 lmask, hmask; int err; - if (WARN_ON_FPU(!boot_cpu_has(X86_FEATURE_XSAVES))) + if (!validate_xsaves_xrstors(mask)) return; - if (WARN_ON_FPU(!independent_mask)) - return; - - lmask = independent_mask; - hmask = independent_mask >> 32; - - XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); - - /* Should never fault when copying from a kernel buffer */ - WARN_ON_FPU(err); + XSTATE_OP(XRSTORS, xstate, (u32)mask, (u32)(mask >> 32), err); + WARN_ON_ONCE(err); } #ifdef CONFIG_PROC_PID_ARCH_STATUS |