Commit ffd3e504 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

x86/fpu/xstate: Provide and use for_each_xfeature() 



These loops evaluating xfeature bits are really hard to read. Create an
iterator and use for_each_set_bit_from() inside which already does the right
thing.

No functional changes.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011538.958107505@linutronix.de
parent 126fe040

arch/x86/kernel/fpu/xstate.c

+23 −33
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 *

 * Author: Suresh Siddha <suresh.b.siddha@intel.com>

 */

#include <linux/bitops.h>

#include <linux/compat.h>

#include <linux/cpu.h>

#include <linux/mman.h>
@@ -20,6 +21,10 @@ 


#include "xstate.h"



#define for_each_extended_xfeature(bit, mask)				\

	(bit) = FIRST_EXTENDED_XFEATURE;				\

	for_each_set_bit_from(bit, (unsigned long *)&(mask), 8 * sizeof(mask))



/*

 * Although we spell it out in here, the Processor Trace

 * xfeature is completely unused.  We use other mechanisms
@@ -184,10 +189,7 @@ static void __init setup_xstate_features(void) 
	xstate_sizes[XFEATURE_SSE]	= sizeof_field(struct fxregs_state,

						       xmm_space);



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

		if (!xfeature_enabled(i))

			continue;



	for_each_extended_xfeature(i, xfeatures_mask_all) {

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



		xstate_sizes[i] = eax;
@@ -291,20 +293,15 @@ static void __init setup_xstate_comp_offsets(void) 
	xstate_comp_offsets[XFEATURE_SSE] = offsetof(struct fxregs_state,

						     xmm_space);



	if (!boot_cpu_has(X86_FEATURE_XSAVES)) {

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

			if (xfeature_enabled(i))

	if (!cpu_feature_enabled(X86_FEATURE_XSAVES)) {

		for_each_extended_xfeature(i, xfeatures_mask_all)

			xstate_comp_offsets[i] = xstate_offsets[i];

		}

		return;

	}



	next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE;



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

		if (!xfeature_enabled(i))

			continue;



	for_each_extended_xfeature(i, xfeatures_mask_all) {

		if (xfeature_is_aligned(i))

			next_offset = ALIGN(next_offset, 64);
@@ -328,8 +325,8 @@ static void __init setup_supervisor_only_offsets(void) 


	next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE;



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

		if (!xfeature_enabled(i) || !xfeature_is_supervisor(i))

	for_each_extended_xfeature(i, xfeatures_mask_all) {

		if (!xfeature_is_supervisor(i))

			continue;



		if (xfeature_is_aligned(i))
@@ -347,9 +344,7 @@ static void __init print_xstate_offset_size(void) 
{

	int i;



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

		if (!xfeature_enabled(i))

			continue;

	for_each_extended_xfeature(i, xfeatures_mask_all) {

		pr_info("x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n",

			 i, xstate_comp_offsets[i], i, xstate_sizes[i]);

	}
@@ -554,10 +549,7 @@ static void do_extra_xstate_size_checks(void) 
	int paranoid_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;

	int i;



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

		if (!xfeature_enabled(i))

			continue;



	for_each_extended_xfeature(i, xfeatures_mask_all) {

		check_xstate_against_struct(i);

		/*

		 * Supervisor state components can be managed only by
@@ -586,7 +578,6 @@ static void do_extra_xstate_size_checks(void) 
	XSTATE_WARN_ON(paranoid_xstate_size != fpu_kernel_xstate_size);

}





/*

 * Get total size of enabled xstates in XCR0 | IA32_XSS.

 *
@@ -969,6 +960,7 @@ void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, 
	struct xregs_state *xinit = &init_fpstate.xsave;

	struct xstate_header header;

	unsigned int zerofrom;

	u64 mask;

	int i;



	memset(&header, 0, sizeof(header));
@@ -1022,17 +1014,15 @@ void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, 


	zerofrom = offsetof(struct xregs_state, extended_state_area);



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

	/*

		 * The ptrace buffer is in non-compacted XSAVE format.

		 * In non-compacted format disabled features still occupy

		 * state space, but there is no state to copy from in the

		 * compacted init_fpstate. The gap tracking will zero this

		 * later.

	 * The ptrace buffer is in non-compacted XSAVE format.  In

	 * non-compacted format disabled features still occupy state space,

	 * but there is no state to copy from in the compacted

	 * init_fpstate. The gap tracking will zero these states.

	 */

		if (!(xfeatures_mask_uabi() & BIT_ULL(i)))

			continue;

	mask = xfeatures_mask_uabi();



	for_each_extended_xfeature(i, mask) {

		/*

		 * If there was a feature or alignment gap, zero the space

		 * in the destination buffer.