From 8ab22804efefea9ecf3c68aa00f1fa69c70fcfad Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Tue, 12 May 2020 07:54:36 -0700 Subject: [PATCH] x86/fpu/xstate: Define new macros for supervisor and user xstates XCNTXT_MASK is 'all supported xfeatures' before introducing supervisor xstates. Rename it to XFEATURE_MASK_USER_SUPPORTED to make clear that these are user xstates. Replace XFEATURE_MASK_SUPERVISOR with the following: - XFEATURE_MASK_SUPERVISOR_SUPPORTED: Currently nothing. ENQCMD and Control-flow Enforcement Technology (CET) will be introduced in separate series. - XFEATURE_MASK_SUPERVISOR_UNSUPPORTED: Currently only Processor Trace. - XFEATURE_MASK_SUPERVISOR_ALL: the combination of above. Co-developed-by: Yu-cheng Yu Signed-off-by: Fenghua Yu Signed-off-by: Yu-cheng Yu Signed-off-by: Borislav Petkov Reviewed-by: Dave Hansen Reviewed-by: Tony Luck Link: https://lkml.kernel.org/r/20200512145444.15483-3-yu-cheng.yu@intel.com --- arch/x86/include/asm/fpu/xstate.h | 36 +++++++++++++++++++++++------------- arch/x86/kernel/fpu/init.c | 3 ++- arch/x86/kernel/fpu/xstate.c | 26 +++++++++++++------------- 3 files changed, 38 insertions(+), 27 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index fc4db51..b08fa82 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -21,19 +21,29 @@ #define XSAVE_YMM_SIZE 256 #define XSAVE_YMM_OFFSET (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET) -/* Supervisor features */ -#define XFEATURE_MASK_SUPERVISOR (XFEATURE_MASK_PT) - -/* All currently supported features */ -#define XCNTXT_MASK (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) +/* All currently supported user features */ +#define XFEATURE_MASK_USER_SUPPORTED (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) + +/* All currently supported supervisor features */ +#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (0) + +/* + * Unsupported supervisor features. When a supervisor feature in this mask is + * supported in the future, move it to the supported supervisor feature mask. + */ +#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT) + +/* All supervisor states including supported and unsupported states. */ +#define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \ + XFEATURE_MASK_SUPERVISOR_UNSUPPORTED) #ifdef CONFIG_X86_64 #define REX_PREFIX "0x48, " diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 6ce7e0a..61ddc3a 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -224,7 +224,8 @@ static void __init fpu__init_system_xstate_size_legacy(void) */ u64 __init fpu__get_supported_xfeatures_mask(void) { - return XCNTXT_MASK; + return XFEATURE_MASK_USER_SUPPORTED | + XFEATURE_MASK_SUPERVISOR_SUPPORTED; } /* Legacy code to initialize eager fpu mode. */ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 8ed6439..9997df7 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -208,14 +208,13 @@ void fpu__init_cpu_xstate(void) if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask) return; /* - * Make it clear that XSAVES supervisor states are not yet - * implemented should anyone expect it to work by changing - * bits in XFEATURE_MASK_* macros and XCR0. + * Unsupported supervisor xstates should not be found in + * the xfeatures mask. */ - WARN_ONCE((xfeatures_mask & XFEATURE_MASK_SUPERVISOR), - "x86/fpu: XSAVES supervisor states are not yet implemented.\n"); + WARN_ONCE((xfeatures_mask & XFEATURE_MASK_SUPERVISOR_UNSUPPORTED), + "x86/fpu: Found unsupported supervisor xstates.\n"); - xfeatures_mask &= ~XFEATURE_MASK_SUPERVISOR; + xfeatures_mask &= ~XFEATURE_MASK_SUPERVISOR_UNSUPPORTED; cr4_set_bits(X86_CR4_OSXSAVE); xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask); @@ -438,7 +437,7 @@ static int xfeature_uncompacted_offset(int xfeature_nr) * format. Checking a supervisor state's uncompacted offset is * an error. */ - if (XFEATURE_MASK_SUPERVISOR & BIT_ULL(xfeature_nr)) { + if (XFEATURE_MASK_SUPERVISOR_ALL & BIT_ULL(xfeature_nr)) { WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr); return -1; } @@ -475,7 +474,7 @@ int using_compacted_format(void) int validate_user_xstate_header(const struct xstate_header *hdr) { /* No unknown or supervisor features may be set */ - if (hdr->xfeatures & (~xfeatures_mask | XFEATURE_MASK_SUPERVISOR)) + if (hdr->xfeatures & ~(xfeatures_mask & XFEATURE_MASK_USER_SUPPORTED)) return -EINVAL; /* Userspace must use the uncompacted format */ @@ -768,7 +767,8 @@ void __init fpu__init_system_xstate(void) * Update info used for ptrace frames; use standard-format size and no * supervisor xstates: */ - update_regset_xstate_info(fpu_user_xstate_size, xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR); + update_regset_xstate_info(fpu_user_xstate_size, + xfeatures_mask & XFEATURE_MASK_USER_SUPPORTED); fpu__init_prepare_fx_sw_frame(); setup_init_fpu_buf(); @@ -996,7 +996,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of */ memset(&header, 0, sizeof(header)); header.xfeatures = xsave->header.xfeatures; - header.xfeatures &= ~XFEATURE_MASK_SUPERVISOR; + header.xfeatures &= XFEATURE_MASK_USER_SUPPORTED; /* * Copy xregs_state->header: @@ -1080,7 +1080,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i */ memset(&header, 0, sizeof(header)); header.xfeatures = xsave->header.xfeatures; - header.xfeatures &= ~XFEATURE_MASK_SUPERVISOR; + header.xfeatures &= XFEATURE_MASK_USER_SUPPORTED; /* * Copy xregs_state->header: @@ -1173,7 +1173,7 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) * The state that came in from userspace was user-state only. * Mask all the user states out of 'xfeatures': */ - xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR; + xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL; /* * Add back in the features that came in from userspace: @@ -1229,7 +1229,7 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) * The state that came in from userspace was user-state only. * Mask all the user states out of 'xfeatures': */ - xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR; + xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL; /* * Add back in the features that came in from userspace: -- 2.7.4