x86/fpu/xstate: Separate user and supervisor xfeatures mask (524bb73b) · Commits · 戴 / test

arch/x86/include/asm/fpu/internal.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -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)

arch/x86/include/asm/fpu/xstate.h

+12 −1

Original line number	Diff line number	Diff line
		@@ -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,

arch/x86/kernel/fpu/signal.c

+11 −5

Original line number	Diff line number	Diff line
		@@ -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) \|\|

arch/x86/kernel/fpu/xstate.c

+43 −30

Original line number	Diff line number	Diff line
		@@ -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:

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