From 1f999ab5a1360afc388868cc0ef9afe8edeef3be Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Wed, 21 Jul 2010 19:03:57 +0200 Subject: x86, xsave: Disable xsave in i387 emulation mode xsave is broken for (!HAVE_HWFP). This is the case if config MATH_EMULATION is enabled, 'no387' kernel parameter is set and xsave exists. xsave will not work because x86/math-emu and xsave share the same memory. As this case can be treated as corner case we simply disable xsave then. Signed-off-by: Robert Richter LKML-Reference: <1279731838-1522-7-git-send-email-robert.richter@amd.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/i387.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86/kernel/i387.c') diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 1f11f5ce668..2605c50b11d 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -67,6 +67,12 @@ static void __cpuinit init_thread_xstate(void) */ if (!HAVE_HWFP) { + /* + * Disable xsave as we do not support it if i387 + * emulation is enabled. + */ + setup_clear_cpu_cap(X86_FEATURE_XSAVE); + setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); xstate_size = sizeof(struct i387_soft_struct); return; } -- cgit v1.2.3-70-g09d2 From 6ac8bac2684235f4caf22a410549c582aa7327d6 Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Fri, 3 Sep 2010 21:17:09 -0400 Subject: x86, fpu: Merge fpu_init() Make fpu_init() handle 32-bit setup. Signed-off-by: Brian Gerst Acked-by: Pekka Enberg Cc: Suresh Siddha LKML-Reference: <1283563039-3466-3-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/common.c | 7 ------- arch/x86/kernel/i387.c | 30 ++++++++++++++---------------- arch/x86/kernel/traps.c | 12 ------------ 3 files changed, 14 insertions(+), 35 deletions(-) (limited to 'arch/x86/kernel/i387.c') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 490dac63c2d..f9e23e8639e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1264,13 +1264,6 @@ void __cpuinit cpu_init(void) clear_all_debug_regs(); dbg_restore_debug_regs(); - /* - * Force FPU initialization: - */ - current_thread_info()->status = 0; - clear_used_math(); - mxcsr_feature_mask_init(); - fpu_init(); xsave_init(); } diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 2605c50b11d..82166519497 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -85,7 +85,6 @@ static void __cpuinit init_thread_xstate(void) #endif } -#ifdef CONFIG_X86_64 /* * Called at bootup to set up the initial FPU state that is later cloned * into all processes. @@ -93,12 +92,21 @@ static void __cpuinit init_thread_xstate(void) void __cpuinit fpu_init(void) { - unsigned long oldcr0 = read_cr0(); - - set_in_cr4(X86_CR4_OSFXSR); - set_in_cr4(X86_CR4_OSXMMEXCPT); + unsigned long cr0; + unsigned long cr4_mask = 0; - write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */ + if (cpu_has_fxsr) + cr4_mask |= X86_CR4_OSFXSR; + if (cpu_has_xmm) + cr4_mask |= X86_CR4_OSXMMEXCPT; + if (cr4_mask) + set_in_cr4(cr4_mask); + + cr0 = read_cr0(); + cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */ + if (!HAVE_HWFP) + cr0 |= X86_CR0_EM; + write_cr0(cr0); if (!smp_processor_id()) init_thread_xstate(); @@ -109,16 +117,6 @@ void __cpuinit fpu_init(void) clear_used_math(); } -#else /* CONFIG_X86_64 */ - -void __cpuinit fpu_init(void) -{ - if (!smp_processor_id()) - init_thread_xstate(); -} - -#endif /* CONFIG_X86_32 */ - void fpu_finit(struct fpu *fpu) { #ifdef CONFIG_X86_32 diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 60788dee0f8..d0029eb5858 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -881,18 +881,6 @@ void __init trap_init(void) #endif #ifdef CONFIG_X86_32 - if (cpu_has_fxsr) { - printk(KERN_INFO "Enabling fast FPU save and restore... "); - set_in_cr4(X86_CR4_OSFXSR); - printk("done.\n"); - } - if (cpu_has_xmm) { - printk(KERN_INFO - "Enabling unmasked SIMD FPU exception support... "); - set_in_cr4(X86_CR4_OSXMMEXCPT); - printk("done.\n"); - } - set_system_trap_gate(SYSCALL_VECTOR, &system_call); set_bit(SYSCALL_VECTOR, used_vectors); #endif -- cgit v1.2.3-70-g09d2 From 10c11f304986a1f84201c2261a428701f9d2dffc Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Fri, 3 Sep 2010 21:17:13 -0400 Subject: x86-64, fpu: Fix %cs value in convert_from_fxsr() While %ds still contains the userspace selector, %cs is KERNEL_CS at this point. Always get %cs from pt_regs even for the current task. Signed-off-by: Brian Gerst Acked-by: Pekka Enberg Cc: Suresh Siddha LKML-Reference: <1283563039-3466-7-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/i387.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) (limited to 'arch/x86/kernel/i387.c') diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 82166519497..f3775f5ef4a 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -389,19 +389,17 @@ convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) #ifdef CONFIG_X86_64 env->fip = fxsave->rip; env->foo = fxsave->rdp; + /* + * should be actually ds/cs at fpu exception time, but + * that information is not available in 64bit mode. + */ + env->fcs = task_pt_regs(tsk)->cs; if (tsk == current) { - /* - * should be actually ds/cs at fpu exception time, but - * that information is not available in 64bit mode. - */ - asm("mov %%ds, %[fos]" : [fos] "=r" (env->fos)); - asm("mov %%cs, %[fcs]" : [fcs] "=r" (env->fcs)); + savesegment(ds, env->fos); } else { - struct pt_regs *regs = task_pt_regs(tsk); - - env->fos = 0xffff0000 | tsk->thread.ds; - env->fcs = regs->cs; + env->fos = tsk->thread.ds; } + env->fos |= 0xffff0000; #else env->fip = fxsave->fip; env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16); -- cgit v1.2.3-70-g09d2 From 8eb91a577d7763d21628f6761045328784b1911c Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Fri, 3 Sep 2010 21:17:16 -0400 Subject: x86, fpu: Remove unnecessary ifdefs from i387 code. Remove ifdefs for code that the compiler can optimize away on 64-bit. Signed-off-by: Brian Gerst Acked-by: Pekka Enberg Cc: Suresh Siddha LKML-Reference: <1283563039-3466-10-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/i387.h | 12 ++++++------ arch/x86/kernel/i387.c | 4 ---- 2 files changed, 6 insertions(+), 10 deletions(-) (limited to 'arch/x86/kernel/i387.c') diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h index 768fcb25900..42b507e16d1 100644 --- a/arch/x86/include/asm/i387.h +++ b/arch/x86/include/asm/i387.h @@ -55,6 +55,12 @@ extern int save_i387_xstate_ia32(void __user *buf); extern int restore_i387_xstate_ia32(void __user *buf); #endif +#ifdef CONFIG_MATH_EMULATION +extern void finit_soft_fpu(struct i387_soft_struct *soft); +#else +static inline void finit_soft_fpu(struct i387_soft_struct *soft) {} +#endif + #define X87_FSW_ES (1 << 7) /* Exception Summary */ static __always_inline __pure bool use_xsaveopt(void) @@ -189,12 +195,6 @@ static inline void fpu_save_init(struct fpu *fpu) #else /* CONFIG_X86_32 */ -#ifdef CONFIG_MATH_EMULATION -extern void finit_soft_fpu(struct i387_soft_struct *soft); -#else -static inline void finit_soft_fpu(struct i387_soft_struct *soft) {} -#endif - /* perform fxrstor iff the processor has extended states, otherwise frstor */ static inline int fxrstor_checking(struct i387_fxsave_struct *fx) { diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index f3775f5ef4a..e795e360bd5 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -79,10 +79,8 @@ static void __cpuinit init_thread_xstate(void) if (cpu_has_fxsr) xstate_size = sizeof(struct i387_fxsave_struct); -#ifdef CONFIG_X86_32 else xstate_size = sizeof(struct i387_fsave_struct); -#endif } /* @@ -119,12 +117,10 @@ void __cpuinit fpu_init(void) void fpu_finit(struct fpu *fpu) { -#ifdef CONFIG_X86_32 if (!HAVE_HWFP) { finit_soft_fpu(&fpu->state->soft); return; } -#endif if (cpu_has_fxsr) { struct i387_fxsave_struct *fx = &fpu->state->fxsave; -- cgit v1.2.3-70-g09d2