[patch V2 17/52] x86/fpu: Remove fpstate_sanitize_xstate()

Thomas Gleixner
2021-06-14T16:38:42Z

No more users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: New patch
---
arch/x86/include/asm/fpu/internal.h | 2
arch/x86/kernel/fpu/xstate.c | 79 ------------------------------------
2 files changed, 81 deletions(-)

--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -87,8 +87,6 @@ extern void fpstate_init_soft(struct swr
static inline void fpstate_init_soft(struct swregs_state *soft) {}
#endif

-extern void fpstate_sanitize_xstate(struct fpu *fpu);
-
#define user_insn(insn, output, input...) \
({ \
int err; \
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -129,85 +129,6 @@ static bool xfeature_is_supervisor(int x
}

/*
- * When executing XSAVEOPT (or other optimized XSAVE instructions), if
- * a processor implementation detects that an FPU state component is still
- * (or is again) in its initialized state, it may clear the corresponding
- * bit in the header.xfeatures field, and can skip the writeout of registers
- * to the corresponding memory layout.
- *
- * This means that when the bit is zero, the state component might still contain
- * some previous - non-initialized register state.
- *
- * Before writing xstate information to user-space we sanitize those components,
- * to always ensure that the memory layout of a feature will be in the init state
- * if the corresponding header bit is zero. This is to ensure that user-space doesn't
- * see some stale state in the memory layout during signal handling, debugging etc.
- */
-void fpstate_sanitize_xstate(struct fpu *fpu)
-{
- struct fxregs_state *fx = &fpu->state.fxsave;
- int feature_bit;
- u64 xfeatures;
-
- if (!use_xsaveopt())
- return;
-
- xfeatures = fpu->state.xsave.header.xfeatures;
-
- /*
- * 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_all) == xfeatures_mask_all)
- return;
-
- /*
- * FP is in init state
- */
- if (!(xfeatures & XFEATURE_MASK_FP)) {
- fx->cwd = 0x37f;
- fx->swd = 0;
- fx->twd = 0;
- fx->fop = 0;
- fx->rip = 0;
- fx->rdp = 0;
- memset(fx->st_space, 0, sizeof(fx->st_space));
- }
-
- /*
- * SSE is in init state
- */
- if (!(xfeatures & XFEATURE_MASK_SSE))
- memset(fx->xmm_space, 0, sizeof(fx->xmm_space));
-
- /*
- * First two features are FPU and SSE, which above we handled
- * in a special way already:
- */
- feature_bit = 0x2;
- xfeatures = (xfeatures_mask_user() & ~xfeatures) >> 2;
-
- /*
- * Update all the remaining memory layouts according to their
- * standard xstate layout, if their header bit is in the init
- * state:
- */
- while (xfeatures) {
- if (xfeatures & 0x1) {
- int offset = xstate_comp_offsets[feature_bit];
- int size = xstate_sizes[feature_bit];
-
- memcpy((void *)fx + offset,
- (void *)&init_fpstate.xsave + offset,
- size);
- }
-
- xfeatures >>= 1;
- feature_bit++;
- }
-}
-
-/*
* Enable the extended processor state save/restore feature.
* Called once per CPU onlining.
*/