From e8a496ac8cd00cabbdaa373db4818a9ad19a1c5a Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Fri, 23 May 2008 16:26:37 -0700 Subject: [PATCH] x86: fix broken math-emu with lazy allocation of fpu area Fix the math emulation that got broken with the recent lazy allocation of FPU area. init_fpu() need to be added for the math-emulation path aswell for the FPU area allocation. math emulation enabled kernel booted fine with this, in the presence of "no387 nofxsr" boot param. Signed-off-by: Suresh Siddha Cc: hpa@zytor.com Cc: mingo@elte.hu Signed-off-by: Thomas Gleixner --- arch/x86/kernel/i387.c | 44 +++++++++++++++++++++++------------ arch/x86/math-emu/fpu_entry.c | 13 +++++++---- include/asm-x86/i387.h | 2 ++ 3 files changed, 39 insertions(+), 20 deletions(-) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index e03cc952f23..eb9ddd8efb8 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -56,6 +56,11 @@ void __cpuinit mxcsr_feature_mask_init(void) void __init init_thread_xstate(void) { + if (!HAVE_HWFP) { + xstate_size = sizeof(struct i387_soft_struct); + return; + } + if (cpu_has_fxsr) xstate_size = sizeof(struct i387_fxsave_struct); #ifdef CONFIG_X86_32 @@ -94,7 +99,7 @@ void __cpuinit fpu_init(void) int init_fpu(struct task_struct *tsk) { if (tsk_used_math(tsk)) { - if (tsk == current) + if (HAVE_HWFP && tsk == current) unlazy_fpu(tsk); return 0; } @@ -109,6 +114,15 @@ int init_fpu(struct task_struct *tsk) return -ENOMEM; } +#ifdef CONFIG_X86_32 + if (!HAVE_HWFP) { + memset(tsk->thread.xstate, 0, xstate_size); + finit(); + set_stopped_child_used_math(tsk); + return 0; + } +#endif + if (cpu_has_fxsr) { struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave; @@ -330,13 +344,13 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, struct user_i387_ia32_struct env; int ret; - if (!HAVE_HWFP) - return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf); - ret = init_fpu(target); if (ret) return ret; + if (!HAVE_HWFP) + return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf); + if (!cpu_has_fxsr) { return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &target->thread.xstate->fsave, 0, @@ -360,15 +374,15 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, struct user_i387_ia32_struct env; int ret; - if (!HAVE_HWFP) - return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf); - ret = init_fpu(target); if (ret) return ret; set_stopped_child_used_math(target); + if (!HAVE_HWFP) + return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf); + if (!cpu_has_fxsr) { return user_regset_copyin(&pos, &count, &kbuf, &ubuf, &target->thread.xstate->fsave, 0, -1); @@ -474,18 +488,18 @@ static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf) int restore_i387_ia32(struct _fpstate_ia32 __user *buf) { int err; + struct task_struct *tsk = current; - if (HAVE_HWFP) { - struct task_struct *tsk = current; - + if (HAVE_HWFP) clear_fpu(tsk); - if (!used_math()) { - err = init_fpu(tsk); - if (err) - return err; - } + if (!used_math()) { + err = init_fpu(tsk); + if (err) + return err; + } + if (HAVE_HWFP) { if (cpu_has_fxsr) err = restore_i387_fxsave(buf); else diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index 6e38d877ea7..c7b06feb139 100644 --- a/arch/x86/math-emu/fpu_entry.c +++ b/arch/x86/math-emu/fpu_entry.c @@ -30,6 +30,7 @@ #include #include #include +#include #include "fpu_system.h" #include "fpu_emu.h" @@ -146,6 +147,13 @@ asmlinkage void math_emulate(long arg) unsigned long code_limit = 0; /* Initialized to stop compiler warnings */ struct desc_struct code_descriptor; + if (!used_math()) { + if (init_fpu(current)) { + do_group_exit(SIGKILL); + return; + } + } + #ifdef RE_ENTRANT_CHECKING if (emulating) { printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n"); @@ -153,11 +161,6 @@ asmlinkage void math_emulate(long arg) RE_ENTRANT_CHECK_ON; #endif /* RE_ENTRANT_CHECKING */ - if (!used_math()) { - finit(); - set_used_math(); - } - SETUP_DATA_AREA(arg); FPU_ORIG_EIP = FPU_EIP; diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h index 6b722d31593..37672f79dcc 100644 --- a/include/asm-x86/i387.h +++ b/include/asm-x86/i387.h @@ -193,6 +193,8 @@ static inline int restore_i387(struct _fpstate __user *buf) #else /* CONFIG_X86_32 */ +extern void finit(void); + static inline void tolerant_fwait(void) { asm volatile("fnclex ; fwait"); -- 2.41.1