From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C9F3C433E0 for ; Sat, 16 May 2020 15:10:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AE21206F4 for ; Sat, 16 May 2020 15:10:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727040AbgEPPKx (ORCPT ); Sat, 16 May 2020 11:10:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726936AbgEPPKa (ORCPT ); Sat, 16 May 2020 11:10:30 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1A3DC05BD0B; Sat, 16 May 2020 08:10:29 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jZySB-0000rf-BC; Sat, 16 May 2020 17:10:19 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id CB2B51C0440; Sat, 16 May 2020 17:10:18 +0200 (CEST) Date: Sat, 16 May 2020 15:10:18 -0000 From: "tip-bot2 for Yu-cheng Yu" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/fpu] x86/fpu/xstate: Separate user and supervisor xfeatures mask Cc: Fenghua Yu , "Yu-cheng Yu" , Borislav Petkov , Dave Hansen , Tony Luck , x86 , LKML In-Reply-To: <20200512145444.15483-4-yu-cheng.yu@intel.com> References: <20200512145444.15483-4-yu-cheng.yu@intel.com> MIME-Version: 1.0 Message-ID: <158964181873.17951.4665885919598599780.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/fpu branch of tip: Commit-ID: 524bb73bc15c56f5587e33c817e103a259b019d2 Gitweb: https://git.kernel.org/tip/524bb73bc15c56f5587e33c817e103a259b019d2 Author: Yu-cheng Yu AuthorDate: Tue, 12 May 2020 07:54:37 -07:00 Committer: Borislav Petkov CommitterDate: Wed, 13 May 2020 10:31:07 +02:00 x86/fpu/xstate: Separate user and supervisor xfeatures mask Before the introduction of XSAVES supervisor states, 'xfeatures_mask' is used at various places to determine XSAVE buffer components and XCR0 bits. It contains only user xstates. To support supervisor xstates, it is necessary to separate user and supervisor xstates: - First, change 'xfeatures_mask' to 'xfeatures_mask_all', which represents the full set of bits that should ever be set in a kernel XSAVE buffer. - Introduce xfeatures_mask_supervisor() and xfeatures_mask_user() to extract relevant xfeatures from xfeatures_mask_all. Co-developed-by: Fenghua 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/20200512145444.15483-4-yu-cheng.yu@intel.com --- arch/x86/include/asm/fpu/internal.h | 2 +- arch/x86/include/asm/fpu/xstate.h | 13 ++++- arch/x86/kernel/fpu/signal.c | 16 ++++-- arch/x86/kernel/fpu/xstate.c | 73 ++++++++++++++++------------ 4 files changed, 67 insertions(+), 37 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 44c48e3..ccb1bb3 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -92,7 +92,7 @@ static inline void fpstate_init_xstate(struct xregs_state *xsave) * XRSTORS requires these bits set in xcomp_bv, or it will * trigger #GP: */ - xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xfeatures_mask; + xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xfeatures_mask_all; } static inline void fpstate_init_fxstate(struct fxregs_state *fx) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index b08fa82..92104b2 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -51,7 +51,18 @@ #define REX_PREFIX #endif -extern u64 xfeatures_mask; +extern u64 xfeatures_mask_all; + +static inline u64 xfeatures_mask_supervisor(void) +{ + return xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_SUPPORTED; +} + +static inline u64 xfeatures_mask_user(void) +{ + return xfeatures_mask_all & XFEATURE_MASK_USER_SUPPORTED; +} + extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; extern void __init update_regset_xstate_info(unsigned int size, diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 585e365..3df0cfa 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -252,13 +252,17 @@ sanitize_restored_xstate(union fpregs_state *state, */ static int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only) { + u64 init_bv; + if (use_xsave()) { if (fx_only) { - u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE; + init_bv = xfeatures_mask_user() & ~XFEATURE_MASK_FPSSE; + copy_kernel_to_xregs(&init_fpstate.xsave, init_bv); return copy_user_to_fxregs(buf); } else { - u64 init_bv = xfeatures_mask & ~xbv; + init_bv = xfeatures_mask_user() & ~xbv; + if (unlikely(init_bv)) copy_kernel_to_xregs(&init_fpstate.xsave, init_bv); return copy_user_to_xregs(buf, xbv); @@ -358,7 +362,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) if (use_xsave() && !fx_only) { - u64 init_bv = xfeatures_mask & ~xfeatures; + u64 init_bv = xfeatures_mask_user() & ~xfeatures; if (using_compacted_format()) { ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx); @@ -389,7 +393,9 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) fpregs_lock(); if (use_xsave()) { - u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE; + u64 init_bv; + + init_bv = xfeatures_mask_user() & ~XFEATURE_MASK_FPSSE; copy_kernel_to_xregs(&init_fpstate.xsave, init_bv); } @@ -465,7 +471,7 @@ void fpu__init_prepare_fx_sw_frame(void) fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1; fx_sw_reserved.extended_size = size; - fx_sw_reserved.xfeatures = xfeatures_mask; + fx_sw_reserved.xfeatures = xfeatures_mask_user(); fx_sw_reserved.xstate_size = fpu_user_xstate_size; if (IS_ENABLED(CONFIG_IA32_EMULATION) || diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 9997df7..fa71af6 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -54,9 +54,10 @@ static short xsave_cpuid_features[] __initdata = { }; /* - * Mask of xstate features supported by the CPU and the kernel: + * This represents the full set of bits that should ever be set in a kernel + * XSAVE buffer, both supervisor and user xstates. */ -u64 xfeatures_mask __read_mostly; +u64 xfeatures_mask_all __read_mostly; static unsigned int xstate_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; static unsigned int xstate_sizes[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; @@ -76,7 +77,7 @@ unsigned int fpu_user_xstate_size; */ int cpu_has_xfeatures(u64 xfeatures_needed, const char **feature_name) { - u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask; + u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask_all; if (unlikely(feature_name)) { long xfeature_idx, max_idx; @@ -150,7 +151,7 @@ void fpstate_sanitize_xstate(struct fpu *fpu) * None of the feature bits are in init state. So nothing else * to do for us, as the memory layout is up to date. */ - if ((xfeatures & xfeatures_mask) == xfeatures_mask) + if ((xfeatures & xfeatures_mask_all) == xfeatures_mask_all) return; /* @@ -177,7 +178,7 @@ void fpstate_sanitize_xstate(struct fpu *fpu) * in a special way already: */ feature_bit = 0x2; - xfeatures = (xfeatures_mask & ~xfeatures) >> 2; + xfeatures = (xfeatures_mask_user() & ~xfeatures) >> 2; /* * Update all the remaining memory layouts according to their @@ -205,19 +206,28 @@ void fpstate_sanitize_xstate(struct fpu *fpu) */ void fpu__init_cpu_xstate(void) { - if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask) + u64 unsup_bits; + + if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask_all) return; /* * Unsupported supervisor xstates should not be found in * the xfeatures mask. */ - WARN_ONCE((xfeatures_mask & XFEATURE_MASK_SUPERVISOR_UNSUPPORTED), - "x86/fpu: Found unsupported supervisor xstates.\n"); + unsup_bits = xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_UNSUPPORTED; + WARN_ONCE(unsup_bits, "x86/fpu: Found unsupported supervisor xstates: 0x%llx\n", + unsup_bits); - xfeatures_mask &= ~XFEATURE_MASK_SUPERVISOR_UNSUPPORTED; + xfeatures_mask_all &= ~XFEATURE_MASK_SUPERVISOR_UNSUPPORTED; cr4_set_bits(X86_CR4_OSXSAVE); - xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask); + + /* + * XCR_XFEATURE_ENABLED_MASK (aka. XCR0) sets user features + * managed by XSAVE{C, OPT, S} and XRSTOR{S}. Only XSAVE user + * states can be set here. + */ + xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user()); } /* @@ -225,9 +235,9 @@ void fpu__init_cpu_xstate(void) * functions here: one for user xstates and the other for * system xstates. For now, they are the same. */ -static int xfeature_enabled(enum xfeature xfeature) +static bool xfeature_enabled(enum xfeature xfeature) { - return !!(xfeatures_mask & (1UL << xfeature)); + return xfeatures_mask_all & BIT_ULL(xfeature); } /* @@ -414,7 +424,7 @@ static void __init setup_init_fpu_buf(void) if (boot_cpu_has(X86_FEATURE_XSAVES)) init_fpstate.xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | - xfeatures_mask; + xfeatures_mask_all; /* * Init all the features state with header.xfeatures being 0x0 @@ -474,7 +484,7 @@ 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_USER_SUPPORTED)) + if (hdr->xfeatures & ~xfeatures_mask_user()) return -EINVAL; /* Userspace must use the uncompacted format */ @@ -609,7 +619,7 @@ static void do_extra_xstate_size_checks(void) /* - * Get total size of enabled xstates in XCR0/xfeatures_mask. + * Get total size of enabled xstates in XCR0 | IA32_XSS. * * Note the SDM's wording here. "sub-function 0" only enumerates * the size of the *user* states. If we use it to size a buffer @@ -699,7 +709,7 @@ static int __init init_xstate_size(void) */ static void fpu__init_disable_system_xstate(void) { - xfeatures_mask = 0; + xfeatures_mask_all = 0; cr4_clear_bits(X86_CR4_OSXSAVE); setup_clear_cpu_cap(X86_FEATURE_XSAVE); } @@ -734,16 +744,21 @@ void __init fpu__init_system_xstate(void) return; } + /* + * Find user xstates supported by the processor. + */ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); - xfeatures_mask = eax + ((u64)edx << 32); + xfeatures_mask_all = eax + ((u64)edx << 32); - if ((xfeatures_mask & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { + /* Place supervisor features in xfeatures_mask_all here */ + if ((xfeatures_mask_user() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { /* * This indicates that something really unexpected happened * with the enumeration. Disable XSAVE and try to continue * booting without it. This is too early to BUG(). */ - pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask); + pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", + xfeatures_mask_all); goto out_disable; } @@ -752,10 +767,10 @@ void __init fpu__init_system_xstate(void) */ for (i = 0; i < ARRAY_SIZE(xsave_cpuid_features); i++) { if (!boot_cpu_has(xsave_cpuid_features[i])) - xfeatures_mask &= ~BIT(i); + xfeatures_mask_all &= ~BIT_ULL(i); } - xfeatures_mask &= fpu__get_supported_xfeatures_mask(); + xfeatures_mask_all &= fpu__get_supported_xfeatures_mask(); /* Enable xstate instructions to be able to continue with initialization: */ fpu__init_cpu_xstate(); @@ -767,8 +782,7 @@ 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_USER_SUPPORTED); + update_regset_xstate_info(fpu_user_xstate_size, xfeatures_mask_user()); fpu__init_prepare_fx_sw_frame(); setup_init_fpu_buf(); @@ -776,7 +790,7 @@ void __init fpu__init_system_xstate(void) print_xstate_offset_size(); pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n", - xfeatures_mask, + xfeatures_mask_all, fpu_kernel_xstate_size, boot_cpu_has(X86_FEATURE_XSAVES) ? "compacted" : "standard"); return; @@ -795,7 +809,7 @@ void fpu__resume_cpu(void) * Restore XCR0 on xsave capable CPUs: */ if (boot_cpu_has(X86_FEATURE_XSAVE)) - xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask); + xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user()); } /* @@ -840,10 +854,9 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr) /* * We should not ever be requesting features that we - * have not enabled. Remember that xfeatures_mask is - * what we write to the XCR0 register. + * have not enabled. */ - WARN_ONCE(!(xfeatures_mask & BIT_ULL(xfeature_nr)), + WARN_ONCE(!(xfeatures_mask_all & BIT_ULL(xfeature_nr)), "get of unsupported state"); /* * This assumes the last 'xsave*' instruction to @@ -996,7 +1009,7 @@ 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_USER_SUPPORTED; + header.xfeatures &= xfeatures_mask_user(); /* * Copy xregs_state->header: @@ -1080,7 +1093,7 @@ 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_USER_SUPPORTED; + header.xfeatures &= xfeatures_mask_user(); /* * Copy xregs_state->header: