Commit 8ab22804 authored by Fenghua Yu's avatar Fenghua Yu Committed by Borislav Petkov
Browse files

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: default avatarYu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarYu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200512145444.15483-3-yu-cheng.yu@intel.com
parent 5274e6c1

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

+23 −13
Original line number Diff line number Diff line
@@ -21,11 +21,8 @@ 
#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 | \

/* All currently supported user features */

#define XFEATURE_MASK_USER_SUPPORTED (XFEATURE_MASK_FP | \

				      XFEATURE_MASK_SSE | \

				      XFEATURE_MASK_YMM | \

				      XFEATURE_MASK_OPMASK | \
@@ -35,6 +32,19 @@ 
				      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, "

#else

arch/x86/kernel/fpu/init.c

+2 −1
Original line number Diff line number Diff line
@@ -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. */

arch/x86/kernel/fpu/xstate.c

+13 −13
Original line number Diff line number Diff line
@@ -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:

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