The following commit has been merged into the x86/fpu branch of tip: Commit-ID: ffd3e504c9e0de8b85755f3c7eabbbdd984cfeed Gitweb: https://git.kernel.org/tip/ffd3e504c9e0de8b85755f3c7eabbbdd984cfeed Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Fri, 15 Oct 2021 03:16:09 +02:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Wed, 20 Oct 2021 15:27:26 +02:00 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: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20211015011538.958107505@xxxxxxxxxxxxx --- arch/x86/kernel/fpu/xstate.c | 56 ++++++++++++++--------------------- 1 file changed, 23 insertions(+), 33 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 259951d..a2bdc0c 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -4,6 +4,7 @@ * * Author: Suresh Siddha <suresh.b.siddha@xxxxxxxxx> */ +#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)) - xstate_comp_offsets[i] = xstate_offsets[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. - */ - if (!(xfeatures_mask_uabi() & BIT_ULL(i))) - continue; + /* + * 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. + */ + 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.
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