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x86/fpu: Factor out fpu/signal.c
fpu/xstate.c has a lot of generic FPU signal frame handling routines, move them into a separate file: fpu/signal.c. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar
parent
c681314421
commit
b992c660d3
@ -28,4 +28,6 @@ unsigned long
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fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
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unsigned long *buf_fx, unsigned long *size);
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extern void fpu__init_prepare_fx_sw_frame(void);
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#endif /* _ASM_X86_FPU_SIGNAL_H */
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@ -2,4 +2,4 @@
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# Build rules for the FPU support code:
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#
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obj-y += init.o bugs.o core.o xstate.o
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obj-y += init.o bugs.o core.o signal.o xstate.o
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404
arch/x86/kernel/fpu/signal.c
Normal file
404
arch/x86/kernel/fpu/signal.c
Normal file
@ -0,0 +1,404 @@
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/*
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* FPU signal frame handling routines.
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*/
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#include <linux/compat.h>
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#include <linux/cpu.h>
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#include <asm/fpu/internal.h>
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#include <asm/fpu/signal.h>
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#include <asm/fpu/regset.h>
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#include <asm/sigframe.h>
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static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
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/*
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* Check for the presence of extended state information in the
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* user fpstate pointer in the sigcontext.
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*/
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static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
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void __user *fpstate,
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struct _fpx_sw_bytes *fx_sw)
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{
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int min_xstate_size = sizeof(struct i387_fxsave_struct) +
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sizeof(struct xstate_header);
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unsigned int magic2;
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if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
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return -1;
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/* Check for the first magic field and other error scenarios. */
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if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
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fx_sw->xstate_size < min_xstate_size ||
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fx_sw->xstate_size > xstate_size ||
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fx_sw->xstate_size > fx_sw->extended_size)
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return -1;
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/*
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* Check for the presence of second magic word at the end of memory
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* layout. This detects the case where the user just copied the legacy
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* fpstate layout with out copying the extended state information
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* in the memory layout.
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*/
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if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
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|| magic2 != FP_XSTATE_MAGIC2)
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return -1;
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return 0;
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}
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/*
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* Signal frame handlers.
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*/
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static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
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{
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if (use_fxsr()) {
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struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
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struct user_i387_ia32_struct env;
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struct _fpstate_ia32 __user *fp = buf;
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convert_from_fxsr(&env, tsk);
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if (__copy_to_user(buf, &env, sizeof(env)) ||
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__put_user(xsave->i387.swd, &fp->status) ||
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__put_user(X86_FXSR_MAGIC, &fp->magic))
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return -1;
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} else {
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struct i387_fsave_struct __user *fp = buf;
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u32 swd;
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if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
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return -1;
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}
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return 0;
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}
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static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
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{
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struct xsave_struct __user *x = buf;
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struct _fpx_sw_bytes *sw_bytes;
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u32 xfeatures;
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int err;
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/* Setup the bytes not touched by the [f]xsave and reserved for SW. */
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sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
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err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
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if (!use_xsave())
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return err;
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err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
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/*
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* Read the xfeatures which we copied (directly from the cpu or
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* from the state in task struct) to the user buffers.
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*/
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err |= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
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/*
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* For legacy compatible, we always set FP/SSE bits in the bit
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* vector while saving the state to the user context. This will
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* enable us capturing any changes(during sigreturn) to
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* the FP/SSE bits by the legacy applications which don't touch
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* xfeatures in the xsave header.
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*
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* xsave aware apps can change the xfeatures in the xsave
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* header as well as change any contents in the memory layout.
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* xrestore as part of sigreturn will capture all the changes.
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*/
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xfeatures |= XSTATE_FPSSE;
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err |= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
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return err;
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}
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static inline int copy_fpregs_to_sigframe(struct xsave_struct __user *buf)
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{
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int err;
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if (use_xsave())
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err = copy_xregs_to_user(buf);
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else if (use_fxsr())
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err = copy_fxregs_to_user((struct i387_fxsave_struct __user *) buf);
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else
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err = copy_fregs_to_user((struct i387_fsave_struct __user *) buf);
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if (unlikely(err) && __clear_user(buf, xstate_size))
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err = -EFAULT;
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return err;
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}
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/*
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* Save the fpu, extended register state to the user signal frame.
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*
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* 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
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* state is copied.
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* 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
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*
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* buf == buf_fx for 64-bit frames and 32-bit fsave frame.
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* buf != buf_fx for 32-bit frames with fxstate.
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*
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* If the fpu, extended register state is live, save the state directly
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* to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
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* copy the thread's fpu state to the user frame starting at 'buf_fx'.
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*
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* If this is a 32-bit frame with fxstate, put a fsave header before
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* the aligned state at 'buf_fx'.
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*
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* For [f]xsave state, update the SW reserved fields in the [f]xsave frame
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* indicating the absence/presence of the extended state to the user.
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*/
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int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
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{
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struct xsave_struct *xsave = ¤t->thread.fpu.state.xsave;
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struct task_struct *tsk = current;
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int ia32_fxstate = (buf != buf_fx);
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ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
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config_enabled(CONFIG_IA32_EMULATION));
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if (!access_ok(VERIFY_WRITE, buf, size))
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return -EACCES;
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if (!static_cpu_has(X86_FEATURE_FPU))
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return fpregs_soft_get(current, NULL, 0,
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sizeof(struct user_i387_ia32_struct), NULL,
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(struct _fpstate_ia32 __user *) buf) ? -1 : 1;
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if (fpregs_active()) {
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/* Save the live register state to the user directly. */
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if (copy_fpregs_to_sigframe(buf_fx))
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return -1;
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/* Update the thread's fxstate to save the fsave header. */
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if (ia32_fxstate)
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copy_fxregs_to_kernel(&tsk->thread.fpu);
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} else {
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fpstate_sanitize_xstate(&tsk->thread.fpu);
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if (__copy_to_user(buf_fx, xsave, xstate_size))
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return -1;
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}
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/* Save the fsave header for the 32-bit frames. */
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if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
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return -1;
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if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
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return -1;
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return 0;
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}
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static inline void
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sanitize_restored_xstate(struct task_struct *tsk,
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struct user_i387_ia32_struct *ia32_env,
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u64 xfeatures, int fx_only)
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{
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struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
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struct xstate_header *header = &xsave->header;
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if (use_xsave()) {
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/* These bits must be zero. */
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memset(header->reserved, 0, 48);
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/*
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* Init the state that is not present in the memory
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* layout and not enabled by the OS.
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*/
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if (fx_only)
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header->xfeatures = XSTATE_FPSSE;
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else
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header->xfeatures &= (xfeatures_mask & xfeatures);
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}
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if (use_fxsr()) {
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/*
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* mscsr reserved bits must be masked to zero for security
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* reasons.
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*/
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xsave->i387.mxcsr &= mxcsr_feature_mask;
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convert_to_fxsr(tsk, ia32_env);
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}
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}
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/*
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* Restore the extended state if present. Otherwise, restore the FP/SSE state.
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*/
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static inline int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only)
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{
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if (use_xsave()) {
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if ((unsigned long)buf % 64 || fx_only) {
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u64 init_bv = xfeatures_mask & ~XSTATE_FPSSE;
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copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
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return copy_user_to_fxregs(buf);
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} else {
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u64 init_bv = xfeatures_mask & ~xbv;
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if (unlikely(init_bv))
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copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
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return copy_user_to_xregs(buf, xbv);
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}
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} else if (use_fxsr()) {
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return copy_user_to_fxregs(buf);
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} else
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return copy_user_to_fregs(buf);
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}
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static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
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{
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int ia32_fxstate = (buf != buf_fx);
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struct task_struct *tsk = current;
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struct fpu *fpu = &tsk->thread.fpu;
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int state_size = xstate_size;
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u64 xfeatures = 0;
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int fx_only = 0;
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ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
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config_enabled(CONFIG_IA32_EMULATION));
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if (!buf) {
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fpu__clear(fpu);
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return 0;
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}
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if (!access_ok(VERIFY_READ, buf, size))
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return -EACCES;
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fpu__activate_curr(fpu);
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if (!static_cpu_has(X86_FEATURE_FPU))
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return fpregs_soft_set(current, NULL,
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0, sizeof(struct user_i387_ia32_struct),
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NULL, buf) != 0;
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if (use_xsave()) {
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struct _fpx_sw_bytes fx_sw_user;
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if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
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/*
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* Couldn't find the extended state information in the
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* memory layout. Restore just the FP/SSE and init all
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* the other extended state.
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*/
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state_size = sizeof(struct i387_fxsave_struct);
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fx_only = 1;
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} else {
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state_size = fx_sw_user.xstate_size;
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xfeatures = fx_sw_user.xfeatures;
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}
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}
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if (ia32_fxstate) {
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/*
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* For 32-bit frames with fxstate, copy the user state to the
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* thread's fpu state, reconstruct fxstate from the fsave
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* header. Sanitize the copied state etc.
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*/
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struct fpu *fpu = &tsk->thread.fpu;
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struct user_i387_ia32_struct env;
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int err = 0;
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/*
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* Drop the current fpu which clears fpu->fpstate_active. This ensures
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* that any context-switch during the copy of the new state,
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* avoids the intermediate state from getting restored/saved.
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* Thus avoiding the new restored state from getting corrupted.
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* We will be ready to restore/save the state only after
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* fpu->fpstate_active is again set.
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*/
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fpu__drop(fpu);
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if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
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__copy_from_user(&env, buf, sizeof(env))) {
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fpstate_init(&fpu->state);
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err = -1;
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} else {
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sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
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}
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fpu->fpstate_active = 1;
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if (use_eager_fpu()) {
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preempt_disable();
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fpu__restore();
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preempt_enable();
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}
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return err;
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} else {
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/*
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* For 64-bit frames and 32-bit fsave frames, restore the user
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* state to the registers directly (with exceptions handled).
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*/
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user_fpu_begin();
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if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
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fpu__clear(fpu);
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return -1;
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}
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}
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return 0;
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}
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static inline int xstate_sigframe_size(void)
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{
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return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
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}
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/*
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* Restore FPU state from a sigframe:
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*/
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int fpu__restore_sig(void __user *buf, int ia32_frame)
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{
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void __user *buf_fx = buf;
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int size = xstate_sigframe_size();
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if (ia32_frame && use_fxsr()) {
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buf_fx = buf + sizeof(struct i387_fsave_struct);
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size += sizeof(struct i387_fsave_struct);
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}
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return __fpu__restore_sig(buf, buf_fx, size);
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}
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unsigned long
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fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
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unsigned long *buf_fx, unsigned long *size)
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{
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unsigned long frame_size = xstate_sigframe_size();
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*buf_fx = sp = round_down(sp - frame_size, 64);
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if (ia32_frame && use_fxsr()) {
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frame_size += sizeof(struct i387_fsave_struct);
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sp -= sizeof(struct i387_fsave_struct);
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}
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*size = frame_size;
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return sp;
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}
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/*
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* Prepare the SW reserved portion of the fxsave memory layout, indicating
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* the presence of the extended state information in the memory layout
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* pointed by the fpstate pointer in the sigcontext.
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* This will be saved when ever the FP and extended state context is
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* saved on the user stack during the signal handler delivery to the user.
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*/
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void fpu__init_prepare_fx_sw_frame(void)
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{
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int fsave_header_size = sizeof(struct i387_fsave_struct);
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int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
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if (config_enabled(CONFIG_X86_32))
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size += fsave_header_size;
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fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
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fx_sw_reserved.extended_size = size;
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fx_sw_reserved.xfeatures = xfeatures_mask;
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fx_sw_reserved.xstate_size = xstate_size;
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if (config_enabled(CONFIG_IA32_EMULATION)) {
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fx_sw_reserved_ia32 = fx_sw_reserved;
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fx_sw_reserved_ia32.extended_size += fsave_header_size;
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}
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}
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@ -10,7 +10,7 @@
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#include <asm/fpu/internal.h>
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#include <asm/fpu/signal.h>
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#include <asm/fpu/regset.h>
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#include <asm/sigframe.h>
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#include <asm/tlbflush.h>
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static const char *xfeature_names[] =
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@ -31,7 +31,6 @@ static const char *xfeature_names[] =
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*/
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u64 xfeatures_mask __read_mostly;
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static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
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static unsigned int xstate_offsets[XFEATURES_NR_MAX], xstate_sizes[XFEATURES_NR_MAX];
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static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
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@ -154,395 +153,6 @@ void fpstate_sanitize_xstate(struct fpu *fpu)
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}
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}
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/*
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* Check for the presence of extended state information in the
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* user fpstate pointer in the sigcontext.
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*/
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static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
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void __user *fpstate,
|
||||
struct _fpx_sw_bytes *fx_sw)
|
||||
{
|
||||
int min_xstate_size = sizeof(struct i387_fxsave_struct) +
|
||||
sizeof(struct xstate_header);
|
||||
unsigned int magic2;
|
||||
|
||||
if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
|
||||
return -1;
|
||||
|
||||
/* Check for the first magic field and other error scenarios. */
|
||||
if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
|
||||
fx_sw->xstate_size < min_xstate_size ||
|
||||
fx_sw->xstate_size > xstate_size ||
|
||||
fx_sw->xstate_size > fx_sw->extended_size)
|
||||
return -1;
|
||||
|
||||
/*
|
||||
* Check for the presence of second magic word at the end of memory
|
||||
* layout. This detects the case where the user just copied the legacy
|
||||
* fpstate layout with out copying the extended state information
|
||||
* in the memory layout.
|
||||
*/
|
||||
if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
|
||||
|| magic2 != FP_XSTATE_MAGIC2)
|
||||
return -1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Signal frame handlers.
|
||||
*/
|
||||
static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
|
||||
{
|
||||
if (use_fxsr()) {
|
||||
struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
|
||||
struct user_i387_ia32_struct env;
|
||||
struct _fpstate_ia32 __user *fp = buf;
|
||||
|
||||
convert_from_fxsr(&env, tsk);
|
||||
|
||||
if (__copy_to_user(buf, &env, sizeof(env)) ||
|
||||
__put_user(xsave->i387.swd, &fp->status) ||
|
||||
__put_user(X86_FXSR_MAGIC, &fp->magic))
|
||||
return -1;
|
||||
} else {
|
||||
struct i387_fsave_struct __user *fp = buf;
|
||||
u32 swd;
|
||||
if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
|
||||
return -1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
|
||||
{
|
||||
struct xsave_struct __user *x = buf;
|
||||
struct _fpx_sw_bytes *sw_bytes;
|
||||
u32 xfeatures;
|
||||
int err;
|
||||
|
||||
/* Setup the bytes not touched by the [f]xsave and reserved for SW. */
|
||||
sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
|
||||
err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
|
||||
|
||||
if (!use_xsave())
|
||||
return err;
|
||||
|
||||
err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
|
||||
|
||||
/*
|
||||
* Read the xfeatures which we copied (directly from the cpu or
|
||||
* from the state in task struct) to the user buffers.
|
||||
*/
|
||||
err |= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
|
||||
|
||||
/*
|
||||
* For legacy compatible, we always set FP/SSE bits in the bit
|
||||
* vector while saving the state to the user context. This will
|
||||
* enable us capturing any changes(during sigreturn) to
|
||||
* the FP/SSE bits by the legacy applications which don't touch
|
||||
* xfeatures in the xsave header.
|
||||
*
|
||||
* xsave aware apps can change the xfeatures in the xsave
|
||||
* header as well as change any contents in the memory layout.
|
||||
* xrestore as part of sigreturn will capture all the changes.
|
||||
*/
|
||||
xfeatures |= XSTATE_FPSSE;
|
||||
|
||||
err |= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
static inline int copy_fpregs_to_sigframe(struct xsave_struct __user *buf)
|
||||
{
|
||||
int err;
|
||||
|
||||
if (use_xsave())
|
||||
err = copy_xregs_to_user(buf);
|
||||
else if (use_fxsr())
|
||||
err = copy_fxregs_to_user((struct i387_fxsave_struct __user *) buf);
|
||||
else
|
||||
err = copy_fregs_to_user((struct i387_fsave_struct __user *) buf);
|
||||
|
||||
if (unlikely(err) && __clear_user(buf, xstate_size))
|
||||
err = -EFAULT;
|
||||
return err;
|
||||
}
|
||||
|
||||
/*
|
||||
* Save the fpu, extended register state to the user signal frame.
|
||||
*
|
||||
* 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
|
||||
* state is copied.
|
||||
* 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
|
||||
*
|
||||
* buf == buf_fx for 64-bit frames and 32-bit fsave frame.
|
||||
* buf != buf_fx for 32-bit frames with fxstate.
|
||||
*
|
||||
* If the fpu, extended register state is live, save the state directly
|
||||
* to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
|
||||
* copy the thread's fpu state to the user frame starting at 'buf_fx'.
|
||||
*
|
||||
* If this is a 32-bit frame with fxstate, put a fsave header before
|
||||
* the aligned state at 'buf_fx'.
|
||||
*
|
||||
* For [f]xsave state, update the SW reserved fields in the [f]xsave frame
|
||||
* indicating the absence/presence of the extended state to the user.
|
||||
*/
|
||||
int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
|
||||
{
|
||||
struct xsave_struct *xsave = ¤t->thread.fpu.state.xsave;
|
||||
struct task_struct *tsk = current;
|
||||
int ia32_fxstate = (buf != buf_fx);
|
||||
|
||||
ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
|
||||
config_enabled(CONFIG_IA32_EMULATION));
|
||||
|
||||
if (!access_ok(VERIFY_WRITE, buf, size))
|
||||
return -EACCES;
|
||||
|
||||
if (!static_cpu_has(X86_FEATURE_FPU))
|
||||
return fpregs_soft_get(current, NULL, 0,
|
||||
sizeof(struct user_i387_ia32_struct), NULL,
|
||||
(struct _fpstate_ia32 __user *) buf) ? -1 : 1;
|
||||
|
||||
if (fpregs_active()) {
|
||||
/* Save the live register state to the user directly. */
|
||||
if (copy_fpregs_to_sigframe(buf_fx))
|
||||
return -1;
|
||||
/* Update the thread's fxstate to save the fsave header. */
|
||||
if (ia32_fxstate)
|
||||
copy_fxregs_to_kernel(&tsk->thread.fpu);
|
||||
} else {
|
||||
fpstate_sanitize_xstate(&tsk->thread.fpu);
|
||||
if (__copy_to_user(buf_fx, xsave, xstate_size))
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* Save the fsave header for the 32-bit frames. */
|
||||
if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
|
||||
return -1;
|
||||
|
||||
if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
|
||||
return -1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline void
|
||||
sanitize_restored_xstate(struct task_struct *tsk,
|
||||
struct user_i387_ia32_struct *ia32_env,
|
||||
u64 xfeatures, int fx_only)
|
||||
{
|
||||
struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
|
||||
struct xstate_header *header = &xsave->header;
|
||||
|
||||
if (use_xsave()) {
|
||||
/* These bits must be zero. */
|
||||
memset(header->reserved, 0, 48);
|
||||
|
||||
/*
|
||||
* Init the state that is not present in the memory
|
||||
* layout and not enabled by the OS.
|
||||
*/
|
||||
if (fx_only)
|
||||
header->xfeatures = XSTATE_FPSSE;
|
||||
else
|
||||
header->xfeatures &= (xfeatures_mask & xfeatures);
|
||||
}
|
||||
|
||||
if (use_fxsr()) {
|
||||
/*
|
||||
* mscsr reserved bits must be masked to zero for security
|
||||
* reasons.
|
||||
*/
|
||||
xsave->i387.mxcsr &= mxcsr_feature_mask;
|
||||
|
||||
convert_to_fxsr(tsk, ia32_env);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Restore the extended state if present. Otherwise, restore the FP/SSE state.
|
||||
*/
|
||||
static inline int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only)
|
||||
{
|
||||
if (use_xsave()) {
|
||||
if ((unsigned long)buf % 64 || fx_only) {
|
||||
u64 init_bv = xfeatures_mask & ~XSTATE_FPSSE;
|
||||
copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
|
||||
return copy_user_to_fxregs(buf);
|
||||
} else {
|
||||
u64 init_bv = xfeatures_mask & ~xbv;
|
||||
if (unlikely(init_bv))
|
||||
copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
|
||||
return copy_user_to_xregs(buf, xbv);
|
||||
}
|
||||
} else if (use_fxsr()) {
|
||||
return copy_user_to_fxregs(buf);
|
||||
} else
|
||||
return copy_user_to_fregs(buf);
|
||||
}
|
||||
|
||||
static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
|
||||
{
|
||||
int ia32_fxstate = (buf != buf_fx);
|
||||
struct task_struct *tsk = current;
|
||||
struct fpu *fpu = &tsk->thread.fpu;
|
||||
int state_size = xstate_size;
|
||||
u64 xfeatures = 0;
|
||||
int fx_only = 0;
|
||||
|
||||
ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
|
||||
config_enabled(CONFIG_IA32_EMULATION));
|
||||
|
||||
if (!buf) {
|
||||
fpu__clear(fpu);
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (!access_ok(VERIFY_READ, buf, size))
|
||||
return -EACCES;
|
||||
|
||||
fpu__activate_curr(fpu);
|
||||
|
||||
if (!static_cpu_has(X86_FEATURE_FPU))
|
||||
return fpregs_soft_set(current, NULL,
|
||||
0, sizeof(struct user_i387_ia32_struct),
|
||||
NULL, buf) != 0;
|
||||
|
||||
if (use_xsave()) {
|
||||
struct _fpx_sw_bytes fx_sw_user;
|
||||
if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
|
||||
/*
|
||||
* Couldn't find the extended state information in the
|
||||
* memory layout. Restore just the FP/SSE and init all
|
||||
* the other extended state.
|
||||
*/
|
||||
state_size = sizeof(struct i387_fxsave_struct);
|
||||
fx_only = 1;
|
||||
} else {
|
||||
state_size = fx_sw_user.xstate_size;
|
||||
xfeatures = fx_sw_user.xfeatures;
|
||||
}
|
||||
}
|
||||
|
||||
if (ia32_fxstate) {
|
||||
/*
|
||||
* For 32-bit frames with fxstate, copy the user state to the
|
||||
* thread's fpu state, reconstruct fxstate from the fsave
|
||||
* header. Sanitize the copied state etc.
|
||||
*/
|
||||
struct fpu *fpu = &tsk->thread.fpu;
|
||||
struct user_i387_ia32_struct env;
|
||||
int err = 0;
|
||||
|
||||
/*
|
||||
* Drop the current fpu which clears fpu->fpstate_active. This ensures
|
||||
* that any context-switch during the copy of the new state,
|
||||
* avoids the intermediate state from getting restored/saved.
|
||||
* Thus avoiding the new restored state from getting corrupted.
|
||||
* We will be ready to restore/save the state only after
|
||||
* fpu->fpstate_active is again set.
|
||||
*/
|
||||
fpu__drop(fpu);
|
||||
|
||||
if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
|
||||
__copy_from_user(&env, buf, sizeof(env))) {
|
||||
fpstate_init(&fpu->state);
|
||||
err = -1;
|
||||
} else {
|
||||
sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
|
||||
}
|
||||
|
||||
fpu->fpstate_active = 1;
|
||||
if (use_eager_fpu()) {
|
||||
preempt_disable();
|
||||
fpu__restore();
|
||||
preempt_enable();
|
||||
}
|
||||
|
||||
return err;
|
||||
} else {
|
||||
/*
|
||||
* For 64-bit frames and 32-bit fsave frames, restore the user
|
||||
* state to the registers directly (with exceptions handled).
|
||||
*/
|
||||
user_fpu_begin();
|
||||
if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
|
||||
fpu__clear(fpu);
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline int xstate_sigframe_size(void)
|
||||
{
|
||||
return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
|
||||
}
|
||||
|
||||
/*
|
||||
* Restore FPU state from a sigframe:
|
||||
*/
|
||||
int fpu__restore_sig(void __user *buf, int ia32_frame)
|
||||
{
|
||||
void __user *buf_fx = buf;
|
||||
int size = xstate_sigframe_size();
|
||||
|
||||
if (ia32_frame && use_fxsr()) {
|
||||
buf_fx = buf + sizeof(struct i387_fsave_struct);
|
||||
size += sizeof(struct i387_fsave_struct);
|
||||
}
|
||||
|
||||
return __fpu__restore_sig(buf, buf_fx, size);
|
||||
}
|
||||
|
||||
unsigned long
|
||||
fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
|
||||
unsigned long *buf_fx, unsigned long *size)
|
||||
{
|
||||
unsigned long frame_size = xstate_sigframe_size();
|
||||
|
||||
*buf_fx = sp = round_down(sp - frame_size, 64);
|
||||
if (ia32_frame && use_fxsr()) {
|
||||
frame_size += sizeof(struct i387_fsave_struct);
|
||||
sp -= sizeof(struct i387_fsave_struct);
|
||||
}
|
||||
|
||||
*size = frame_size;
|
||||
|
||||
return sp;
|
||||
}
|
||||
/*
|
||||
* Prepare the SW reserved portion of the fxsave memory layout, indicating
|
||||
* the presence of the extended state information in the memory layout
|
||||
* pointed by the fpstate pointer in the sigcontext.
|
||||
* This will be saved when ever the FP and extended state context is
|
||||
* saved on the user stack during the signal handler delivery to the user.
|
||||
*/
|
||||
static void prepare_fx_sw_frame(void)
|
||||
{
|
||||
int fsave_header_size = sizeof(struct i387_fsave_struct);
|
||||
int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
|
||||
|
||||
if (config_enabled(CONFIG_X86_32))
|
||||
size += fsave_header_size;
|
||||
|
||||
fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
|
||||
fx_sw_reserved.extended_size = size;
|
||||
fx_sw_reserved.xfeatures = xfeatures_mask;
|
||||
fx_sw_reserved.xstate_size = xstate_size;
|
||||
|
||||
if (config_enabled(CONFIG_IA32_EMULATION)) {
|
||||
fx_sw_reserved_ia32 = fx_sw_reserved;
|
||||
fx_sw_reserved_ia32.extended_size += fsave_header_size;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Enable the extended processor state save/restore feature.
|
||||
* Called once per CPU onlining.
|
||||
@ -741,7 +351,7 @@ void fpu__init_system_xstate(void)
|
||||
init_xstate_size();
|
||||
|
||||
update_regset_xstate_info(xstate_size, xfeatures_mask);
|
||||
prepare_fx_sw_frame();
|
||||
fpu__init_prepare_fx_sw_frame();
|
||||
setup_init_fpu_buf();
|
||||
|
||||
pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is 0x%x bytes, using '%s' format.\n",
|
||||
|
||||
Loading…
Reference in New Issue
Block a user