From afac9e894364418731d1d7e66c1118b31fd130e8 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 23 Jun 2021 14:01:45 +0200 Subject: [PATCH] x86/fpu: Remove fpstate_sanitize_xstate() No more users. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210623121453.124819167@linutronix.de --- arch/x86/include/asm/fpu/internal.h | 2 - arch/x86/kernel/fpu/xstate.c | 79 ------------------------------------- 2 files changed, 81 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 9ed9846..0148791 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -86,8 +86,6 @@ extern void fpstate_init_soft(struct swregs_state *soft); 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; \ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 8d023a2..e17fde9 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -129,85 +129,6 @@ static bool xfeature_is_supervisor(int xfeature_nr) } /* - * 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. */ -- 2.7.4