Messages in this thread Patch in this message | | | From | Yu-cheng Yu <> | Subject | [PATCH 5/6] x86/fpu/xstate: Define new functions for clearing fpregs and xstates | Date | Wed, 25 Sep 2019 08:10:21 -0700 |
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From: Fenghua Yu <fenghua.yu@intel.com>
Currently, fpu__clear() clears all fpregs and xstates. Once XSAVES supervisor states are introduced, supervisor settings must remain active for signals; it is necessary to have separate functions:
- Create fpu__clear_user_states(): clear only user settings for signals; - Create fpu__clear_all(): clear both user and supervisor settings in flush_thread().
Also modify copy_init_fpstate_to_fpregs() to take a mask from above two functions.
Co-developed-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> --- arch/x86/include/asm/fpu/internal.h | 3 ++- arch/x86/kernel/fpu/core.c | 32 ++++++++++++++++++----------- arch/x86/kernel/fpu/signal.c | 4 ++-- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/signal.c | 2 +- 5 files changed, 26 insertions(+), 17 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index f56ad1248b5d..ec08351fd5b4 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -31,7 +31,8 @@ extern void fpu__save(struct fpu *fpu); extern int fpu__restore_sig(void __user *buf, int ia32_frame); extern void fpu__drop(struct fpu *fpu); extern int fpu__copy(struct task_struct *dst, struct task_struct *src); -extern void fpu__clear(struct fpu *fpu); +extern void fpu__clear_user_states(struct fpu *fpu); +extern void fpu__clear_all(struct fpu *fpu); extern int fpu__exception_code(struct fpu *fpu, int trap_nr); extern int dump_fpu(struct pt_regs *ptregs, struct user_i387_struct *fpstate); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 12c70840980e..2c946ba78b1d 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -294,12 +294,12 @@ void fpu__drop(struct fpu *fpu) * Clear FPU registers by setting them up from * the init fpstate: */ -static inline void copy_init_fpstate_to_fpregs(void) +static inline void copy_init_fpstate_to_fpregs(u64 features_mask) { fpregs_lock(); if (use_xsave()) - copy_kernel_to_xregs(&init_fpstate.xsave, -1); + copy_kernel_to_xregs(&init_fpstate.xsave, features_mask); else if (static_cpu_has(X86_FEATURE_FXSR)) copy_kernel_to_fxregs(&init_fpstate.fxsave); else @@ -312,24 +312,32 @@ static inline void copy_init_fpstate_to_fpregs(void) fpregs_unlock(); } +static void fpu__clear_states(struct fpu *fpu, u64 xfeatures_mask) +{ + WARN_ON_FPU(fpu != ¤t->thread.fpu); + + fpu__drop(fpu); + + /* Make sure fpstate is cleared and initialized. */ + fpu__initialize(fpu); + if (static_cpu_has(X86_FEATURE_FPU)) + copy_init_fpstate_to_fpregs(xfeatures_mask); +} + /* * Clear the FPU state back to init state. * * Called by sys_execve(), by the signal handler code and by various * error paths. */ -void fpu__clear(struct fpu *fpu) +void fpu__clear_user_states(struct fpu *fpu) { - WARN_ON_FPU(fpu != ¤t->thread.fpu); /* Almost certainly an anomaly */ - - fpu__drop(fpu); + fpu__clear_states(fpu, xfeatures_mask_user()); +} - /* - * Make sure fpstate is cleared and initialized. - */ - fpu__initialize(fpu); - if (static_cpu_has(X86_FEATURE_FPU)) - copy_init_fpstate_to_fpregs(); +void fpu__clear_all(struct fpu *fpu) +{ + fpu__clear_states(fpu, xfeatures_mask_all); } /* diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index c1f0688f35cf..25e7dddbc6fd 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -288,7 +288,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) IS_ENABLED(CONFIG_IA32_EMULATION)); if (!buf) { - fpu__clear(fpu); + fpu__clear_user_states(fpu); return 0; } @@ -412,7 +412,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) err_out: if (ret) - fpu__clear(fpu); + fpu__clear_user_states(fpu); return ret; } diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 75fea0d48c0e..d360bf4d696b 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -139,7 +139,7 @@ void flush_thread(void) flush_ptrace_hw_breakpoint(tsk); memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); - fpu__clear(&tsk->thread.fpu); + fpu__clear_all(&tsk->thread.fpu); } void disable_TSC(void) diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 8eb7193e158d..ce9421ec285f 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -763,7 +763,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) /* * Ensure the signal handler starts with the new fpu state. */ - fpu__clear(fpu); + fpu__clear_user_states(fpu); } signal_setup_done(failed, ksig, stepping); } -- 2.17.1
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