Commit d0be2d53 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 fpu updates from Ingo Molnar:
 "Misc changes:

   - add a pkey sanity check

   - three commits to improve and future-proof xstate/xfeature handling
     some more"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pkeys: Add check for pkey "overflow"
  x86/fpu/xstate: Warn when checking alignment of disabled xfeatures
  x86/fpu/xstate: Fix XSAVES offsets in setup_xstate_comp()
  x86/fpu/xstate: Fix last_good_offset in setup_xstate_features()
parents fdf5563a 16171bff

arch/x86/include/asm/pkeys.h

+5 −0
Original line number Diff line number Diff line
@@ -4,6 +4,11 @@ 


#define ARCH_DEFAULT_PKEY	0



/*

 * If more than 16 keys are ever supported, a thorough audit

 * will be necessary to ensure that the types that store key

 * numbers and masks have sufficient capacity.

 */

#define arch_max_pkey() (boot_cpu_has(X86_FEATURE_OSPKE) ? 16 : 1)



extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,

arch/x86/kernel/fpu/xstate.c

+39 −36
Original line number Diff line number Diff line
@@ -120,11 +120,6 @@ static bool xfeature_is_supervisor(int xfeature_nr) 
	return ecx & 1;

}



static bool xfeature_is_user(int xfeature_nr)

{

	return !xfeature_is_supervisor(xfeature_nr);

}



/*

 * When executing XSAVEOPT (or other optimized XSAVE instructions), if

 * a processor implementation detects that an FPU state component is still
@@ -265,21 +260,25 @@ static void __init setup_xstate_features(void) 


		cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);



		xstate_sizes[i] = eax;



		/*

		 * If an xfeature is supervisor state, the offset

		 * in EBX is invalid. We leave it to -1.

		 * If an xfeature is supervisor state, the offset in EBX is

		 * invalid, leave it to -1.

		 */

		if (xfeature_is_user(i))

		if (xfeature_is_supervisor(i))

			continue;



		xstate_offsets[i] = ebx;



		xstate_sizes[i] = eax;

		/*

		 * In our xstate size checks, we assume that the

		 * highest-numbered xstate feature has the

		 * highest offset in the buffer.  Ensure it does.

		 * In our xstate size checks, we assume that the highest-numbered

		 * xstate feature has the highest offset in the buffer.  Ensure

		 * it does.

		 */

		WARN_ONCE(last_good_offset > xstate_offsets[i],

			  "x86/fpu: misordered xstate at %d\n", last_good_offset);



		last_good_offset = xstate_offsets[i];

	}

}
@@ -326,6 +325,13 @@ static int xfeature_is_aligned(int xfeature_nr) 
	u32 eax, ebx, ecx, edx;



	CHECK_XFEATURE(xfeature_nr);



	if (!xfeature_enabled(xfeature_nr)) {

		WARN_ONCE(1, "Checking alignment of disabled xfeature %d\n",

			  xfeature_nr);

		return 0;

	}



	cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);

	/*

	 * The value returned by ECX[1] indicates the alignment
@@ -338,11 +344,11 @@ static int xfeature_is_aligned(int xfeature_nr) 
/*

 * This function sets up offsets and sizes of all extended states in

 * xsave area. This supports both standard format and compacted format

 * of the xsave aread.

 * of the xsave area.

 */

static void __init setup_xstate_comp(void)

static void __init setup_xstate_comp_offsets(void)

{

	unsigned int xstate_comp_sizes[XFEATURE_MAX];

	unsigned int next_offset;

	int i;



	/*
@@ -356,31 +362,23 @@ static void __init setup_xstate_comp(void) 


	if (!boot_cpu_has(X86_FEATURE_XSAVES)) {

		for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {

			if (xfeature_enabled(i)) {

			if (xfeature_enabled(i))

				xstate_comp_offsets[i] = xstate_offsets[i];

				xstate_comp_sizes[i] = xstate_sizes[i];

			}

		}

		return;

	}



	xstate_comp_offsets[FIRST_EXTENDED_XFEATURE] =

		FXSAVE_SIZE + XSAVE_HDR_SIZE;

	next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE;



	for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {

		if (xfeature_enabled(i))

			xstate_comp_sizes[i] = xstate_sizes[i];

		else

			xstate_comp_sizes[i] = 0;



		if (i > FIRST_EXTENDED_XFEATURE) {

			xstate_comp_offsets[i] = xstate_comp_offsets[i-1]

					+ xstate_comp_sizes[i-1];

		if (!xfeature_enabled(i))

			continue;



		if (xfeature_is_aligned(i))

				xstate_comp_offsets[i] =

					ALIGN(xstate_comp_offsets[i], 64);

		}

			next_offset = ALIGN(next_offset, 64);



		xstate_comp_offsets[i] = next_offset;

		next_offset += xstate_sizes[i];

	}

}
@@ -774,7 +772,7 @@ void __init fpu__init_system_xstate(void) 


	fpu__init_prepare_fx_sw_frame();

	setup_init_fpu_buf();

	setup_xstate_comp();

	setup_xstate_comp_offsets();

	print_xstate_offset_size();



	pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
@@ -897,8 +895,6 @@ const void *get_xsave_field_ptr(int xfeature_nr) 


#ifdef CONFIG_ARCH_HAS_PKEYS



#define NR_VALID_PKRU_BITS (CONFIG_NR_PROTECTION_KEYS * 2)

#define PKRU_VALID_MASK (NR_VALID_PKRU_BITS - 1)

/*

 * This will go out and modify PKRU register to set the access

 * rights for @pkey to @init_val.
@@ -917,6 +913,13 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, 
	if (!boot_cpu_has(X86_FEATURE_OSPKE))

		return -EINVAL;



	/*

	 * This code should only be called with valid 'pkey'

	 * values originating from in-kernel users.  Complain

	 * if a bad value is observed.

	 */

	WARN_ON_ONCE(pkey >= arch_max_pkey());



	/* Set the bits we need in PKRU:  */

	if (init_val & PKEY_DISABLE_ACCESS)

		new_pkru_bits |= PKRU_AD_BIT;

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