1 files changed, 336 insertions, 181 deletions

diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 3d3e20709119..ada87a329edc 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -10,9 +10,7 @@
 #include <linux/compat.h>
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
-#ifdef CONFIG_IA32_EMULATION
-#include <asm/sigcontext32.h>
-#endif
+#include <asm/sigframe.h>
 #include <asm/xcr.h>
 
 /*
@@ -23,13 +21,9 @@ u64 pcntxt_mask;
 /*
  * Represents init state for the supported extended state.
  */
-static struct xsave_struct *init_xstate_buf;
-
-struct _fpx_sw_bytes fx_sw_reserved;
-#ifdef CONFIG_IA32_EMULATION
-struct _fpx_sw_bytes fx_sw_reserved_ia32;
-#endif
+struct xsave_struct *init_xstate_buf;
 
+static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
 static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
 
 /*
@@ -44,9 +38,9 @@ static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
  */
 void __sanitize_i387_state(struct task_struct *tsk)
 {
-        u64 xstate_bv;
-        int feature_bit = 0x2;
         struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
+        int feature_bit = 0x2;
+        u64 xstate_bv;
 
         if (!fx)
                 return;
@@ -104,213 +98,326 @@ void __sanitize_i387_state(struct task_struct *tsk)
  * Check for the presence of extended state information in the
  * user fpstate pointer in the sigcontext.
  */
-int check_for_xstate(struct i387_fxsave_struct __user *buf,
-                     void __user *fpstate,
-                     struct _fpx_sw_bytes *fx_sw_user)
+static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
+                                   void __user *fpstate,
+                                   struct _fpx_sw_bytes *fx_sw)
 {
         int min_xstate_size = sizeof(struct i387_fxsave_struct) +
                               sizeof(struct xsave_hdr_struct);
         unsigned int magic2;
-        int err;
 
-        err = __copy_from_user(fx_sw_user, &buf->sw_reserved[0],
-                               sizeof(struct _fpx_sw_bytes));
-        if (err)
-                return -EFAULT;
+        if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
+                return -1;
 
-        /*
-         * First Magic check failed.
-         */
-        if (fx_sw_user->magic1 != FP_XSTATE_MAGIC1)
-                return -EINVAL;
+        /* 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 error scenarios.
-         */
-        if (fx_sw_user->xstate_size < min_xstate_size ||
-            fx_sw_user->xstate_size > xstate_size ||
-            fx_sw_user->xstate_size > fx_sw_user->extended_size)
-                return -EINVAL;
-
-        err = __get_user(magic2, (__u32 *) (((void *)fpstate) +
-                                            fx_sw_user->extended_size -
-                                            FP_XSTATE_MAGIC2_SIZE));
-        if (err)
-                return err;
-        /*
          * 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 (magic2 != FP_XSTATE_MAGIC2)
-                return -EFAULT;
+        if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
+            || magic2 != FP_XSTATE_MAGIC2)
+                return -1;
 
         return 0;
 }
 
-#ifdef CONFIG_X86_64
 /*
  * Signal frame handlers.
  */
-
-int save_i387_xstate(void __user *buf)
+static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
 {
-        struct task_struct *tsk = current;
-        int err = 0;
-
-        if (!access_ok(VERIFY_WRITE, buf, sig_xstate_size))
-                return -EACCES;
+        if (use_fxsr()) {
+                struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+                struct user_i387_ia32_struct env;
+                struct _fpstate_ia32 __user *fp = buf;
 
-        BUG_ON(sig_xstate_size < xstate_size);
+                convert_from_fxsr(&env, tsk);
 
-        if ((unsigned long)buf % 64)
-                pr_err("%s: bad fpstate %p\n", __func__, buf);
-
-        if (!used_math())
-                return 0;
-
-        if (user_has_fpu()) {
-                if (use_xsave())
-                        err = xsave_user(buf);
-                else
-                        err = fxsave_user(buf);
-
-                if (err)
-                        return err;
-                user_fpu_end();
+                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 {
-                sanitize_i387_state(tsk);
-                if (__copy_to_user(buf, &tsk->thread.fpu.state->fxsave,
-                                   xstate_size))
+                struct i387_fsave_struct __user *fp = buf;
+                u32 swd;
+                if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
                         return -1;
         }
 
-        clear_used_math(); /* trigger finit */
+        return 0;
+}
 
-        if (use_xsave()) {
-                struct _fpstate __user *fx = buf;
-                struct _xstate __user *x = buf;
-                u64 xstate_bv;
+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 xstate_bv;
+        int err;
 
-                err = __copy_to_user(&fx->sw_reserved, &fx_sw_reserved,
-                                     sizeof(struct _fpx_sw_bytes));
+        /* 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));
 
-                err |= __put_user(FP_XSTATE_MAGIC2,
-                                  (__u32 __user *) (buf + sig_xstate_size
-                                                    - FP_XSTATE_MAGIC2_SIZE));
+        if (!use_xsave())
+                return err;
 
-                /*
-                 * Read the xstate_bv which we copied (directly from the cpu or
-                 * from the state in task struct) to the user buffers and
-                 * set the FP/SSE bits.
-                 */
-                err |= __get_user(xstate_bv, &x->xstate_hdr.xstate_bv);
+        err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
 
-                /*
-                 * 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
-                 * xstate_bv in the xsave header.
-                 *
-                 * xsave aware apps can change the xstate_bv in the xsave
-                 * header as well as change any contents in the memory layout.
-                 * xrestore as part of sigreturn will capture all the changes.
-                 */
-                xstate_bv |= XSTATE_FPSSE;
+        /*
+         * Read the xstate_bv which we copied (directly from the cpu or
+         * from the state in task struct) to the user buffers.
+         */
+        err |= __get_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
 
-                err |= __put_user(xstate_bv, &x->xstate_hdr.xstate_bv);
+        /*
+         * 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
+         * xstate_bv in the xsave header.
+         *
+         * xsave aware apps can change the xstate_bv in the xsave
+         * header as well as change any contents in the memory layout.
+         * xrestore as part of sigreturn will capture all the changes.
+         */
+        xstate_bv |= XSTATE_FPSSE;
 
-                if (err)
-                        return err;
-        }
+        err |= __put_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
 
-        return 1;
+        return err;
+}
+
+static inline int save_user_xstate(struct xsave_struct __user *buf)
+{
+        int err;
+
+        if (use_xsave())
+                err = xsave_user(buf);
+        else if (use_fxsr())
+                err = fxsave_user((struct i387_fxsave_struct __user *) buf);
+        else
+                err = fsave_user((struct i387_fsave_struct __user *) buf);
+
+        if (unlikely(err) && __clear_user(buf, xstate_size))
+                err = -EFAULT;
+        return err;
 }
 
 /*
- * Restore the extended state if present. Otherwise, restore the FP/SSE
- * state.
+ * 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.
  */
-static int restore_user_xstate(void __user *buf)
+int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
 {
-        struct _fpx_sw_bytes fx_sw_user;
-        u64 mask;
-        int err;
+        struct xsave_struct *xsave = &current->thread.fpu.state->xsave;
+        struct task_struct *tsk = current;
+        int ia32_fxstate = (buf != buf_fx);
 
-        if (((unsigned long)buf % 64) ||
-             check_for_xstate(buf, buf, &fx_sw_user))
-                goto fx_only;
+        ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+                         config_enabled(CONFIG_IA32_EMULATION));
 
-        mask = fx_sw_user.xstate_bv;
+        if (!access_ok(VERIFY_WRITE, buf, size))
+                return -EACCES;
 
-        /*
-         * restore the state passed by the user.
-         */
-        err = xrestore_user(buf, mask);
-        if (err)
-                return err;
+        if (!HAVE_HWFP)
+                return fpregs_soft_get(current, NULL, 0,
+                        sizeof(struct user_i387_ia32_struct), NULL,
+                        (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
 
-        /*
-         * init the state skipped by the user.
-         */
-        mask = pcntxt_mask & ~mask;
-        if (unlikely(mask))
-                xrstor_state(init_xstate_buf, mask);
+        if (user_has_fpu()) {
+                /* Save the live register state to the user directly. */
+                if (save_user_xstate(buf_fx))
+                        return -1;
+                /* Update the thread's fxstate to save the fsave header. */
+                if (ia32_fxstate)
+                        fpu_fxsave(&tsk->thread.fpu);
+        } else {
+                sanitize_i387_state(tsk);
+                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;
+
+        drop_init_fpu(tsk);     /* trigger finit */
 
         return 0;
+}
 
-fx_only:
-        /*
-         * couldn't find the extended state information in the
-         * memory layout. Restore just the FP/SSE and init all
-         * the other extended state.
-         */
-        xrstor_state(init_xstate_buf, pcntxt_mask & ~XSTATE_FPSSE);
-        return fxrstor_checking((__force struct i387_fxsave_struct *)buf);
+static inline void
+sanitize_restored_xstate(struct task_struct *tsk,
+                         struct user_i387_ia32_struct *ia32_env,
+                         u64 xstate_bv, int fx_only)
+{
+        struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+        struct xsave_hdr_struct *xsave_hdr = &xsave->xsave_hdr;
+
+        if (use_xsave()) {
+                /* These bits must be zero. */
+                xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
+
+                /*
+                 * Init the state that is not present in the memory
+                 * layout and not enabled by the OS.
+                 */
+                if (fx_only)
+                        xsave_hdr->xstate_bv = XSTATE_FPSSE;
+                else
+                        xsave_hdr->xstate_bv &= (pcntxt_mask & xstate_bv);
+        }
+
+        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);
+        }
 }
 
 /*
- * This restores directly out of user space. Exceptions are handled.
+ * Restore the extended state if present. Otherwise, restore the FP/SSE state.
  */
-int restore_i387_xstate(void __user *buf)
+static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
 {
+        if (use_xsave()) {
+                if ((unsigned long)buf % 64 || fx_only) {
+                        u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
+                        xrstor_state(init_xstate_buf, init_bv);
+                        return fxrstor_user(buf);
+                } else {
+                        u64 init_bv = pcntxt_mask & ~xbv;
+                        if (unlikely(init_bv))
+                                xrstor_state(init_xstate_buf, init_bv);
+                        return xrestore_user(buf, xbv);
+                }
+        } else if (use_fxsr()) {
+                return fxrstor_user(buf);
+        } else
+                return frstor_user(buf);
+}
+
+int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
+{
+        int ia32_fxstate = (buf != buf_fx);
         struct task_struct *tsk = current;
-        int err = 0;
+        int state_size = xstate_size;
+        u64 xstate_bv = 0;
+        int fx_only = 0;
+
+        ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+                         config_enabled(CONFIG_IA32_EMULATION));
 
         if (!buf) {
-                if (used_math())
-                        goto clear;
+                drop_init_fpu(tsk);
                 return 0;
-        } else
-                if (!access_ok(VERIFY_READ, buf, sig_xstate_size))
-                        return -EACCES;
+        }
 
-        if (!used_math()) {
-                err = init_fpu(tsk);
-                if (err)
-                        return err;
+        if (!access_ok(VERIFY_READ, buf, size))
+                return -EACCES;
+
+        if (!used_math() && init_fpu(tsk))
+                return -1;
+
+        if (!HAVE_HWFP) {
+                return fpregs_soft_set(current, NULL,
+                                       0, sizeof(struct user_i387_ia32_struct),
+                                       NULL, buf) != 0;
         }
 
-        user_fpu_begin();
-        if (use_xsave())
-                err = restore_user_xstate(buf);
-        else
-                err = fxrstor_checking((__force struct i387_fxsave_struct *)
-                                       buf);
-        if (unlikely(err)) {
+        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;
+                        xstate_bv = fx_sw_user.xstate_bv;
+                }
+        }
+
+        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 xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+                struct user_i387_ia32_struct env;
+                int err = 0;
+
+                /*
+                 * Drop the current fpu which clears used_math(). 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
+                 * set_used_math() is again set.
+                 */
+                drop_fpu(tsk);
+
+                if (__copy_from_user(xsave, buf_fx, state_size) ||
+                    __copy_from_user(&env, buf, sizeof(env))) {
+                        err = -1;
+                } else {
+                        sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
+                        set_used_math();
+                }
+
+                if (use_eager_fpu())
+                        math_state_restore();
+
+                return err;
+        } else {
                 /*
-                 * Encountered an error while doing the restore from the
-                 * user buffer, clear the fpu state.
+                 * For 64-bit frames and 32-bit fsave frames, restore the user
+                 * state to the registers directly (with exceptions handled).
                  */
-clear:
-                clear_fpu(tsk);
-                clear_used_math();
+                user_fpu_begin();
+                if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
+                        drop_init_fpu(tsk);
+                        return -1;
+                }
         }
-        return err;
+
+        return 0;
 }
-#endif
 
 /*
  * Prepare the SW reserved portion of the fxsave memory layout, indicating
@@ -321,31 +428,22 @@ clear:
  */
 static void prepare_fx_sw_frame(void)
 {
-        int size_extended = (xstate_size - sizeof(struct i387_fxsave_struct)) +
-                             FP_XSTATE_MAGIC2_SIZE;
+        int fsave_header_size = sizeof(struct i387_fsave_struct);
+        int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
 
-        sig_xstate_size = sizeof(struct _fpstate) + size_extended;
-
-#ifdef CONFIG_IA32_EMULATION
-        sig_xstate_ia32_size = sizeof(struct _fpstate_ia32) + size_extended;
-#endif
-
-        memset(&fx_sw_reserved, 0, sizeof(fx_sw_reserved));
+        if (config_enabled(CONFIG_X86_32))
+                size += fsave_header_size;
 
         fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
-        fx_sw_reserved.extended_size = sig_xstate_size;
+        fx_sw_reserved.extended_size = size;
         fx_sw_reserved.xstate_bv = pcntxt_mask;
         fx_sw_reserved.xstate_size = xstate_size;
-#ifdef CONFIG_IA32_EMULATION
-        memcpy(&fx_sw_reserved_ia32, &fx_sw_reserved,
-               sizeof(struct _fpx_sw_bytes));
-        fx_sw_reserved_ia32.extended_size = sig_xstate_ia32_size;
-#endif
-}
 
-#ifdef CONFIG_X86_64
-unsigned int sig_xstate_size = sizeof(struct _fpstate);
-#endif
+        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
@@ -384,19 +482,21 @@ static void __init setup_xstate_features(void)
 /*
  * setup the xstate image representing the init state
  */
-static void __init setup_xstate_init(void)
+static void __init setup_init_fpu_buf(void)
 {
-        setup_xstate_features();
-
         /*
          * Setup init_xstate_buf to represent the init state of
          * all the features managed by the xsave
          */
         init_xstate_buf = alloc_bootmem_align(xstate_size,
                                               __alignof__(struct xsave_struct));
-        init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
+        fx_finit(&init_xstate_buf->i387);
+
+        if (!cpu_has_xsave)
+                return;
+
+        setup_xstate_features();
 
-        clts();
         /*
          * Init all the features state with header_bv being 0x0
          */
@@ -406,9 +506,21 @@ static void __init setup_xstate_init(void)
          * of any feature which is not represented by all zero's.
          */
         xsave_state(init_xstate_buf, -1);
-        stts();
 }
 
+static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
+static int __init eager_fpu_setup(char *s)
+{
+        if (!strcmp(s, "on"))
+                eagerfpu = ENABLE;
+        else if (!strcmp(s, "off"))
+                eagerfpu = DISABLE;
+        else if (!strcmp(s, "auto"))
+                eagerfpu = AUTO;
+        return 1;
+}
+__setup("eagerfpu=", eager_fpu_setup);
+
 /*
  * Enable and initialize the xsave feature.
  */
@@ -445,8 +557,11 @@ static void __init xstate_enable_boot_cpu(void)
 
         update_regset_xstate_info(xstate_size, pcntxt_mask);
         prepare_fx_sw_frame();
+        setup_init_fpu_buf();
 
-        setup_xstate_init();
+        /* Auto enable eagerfpu for xsaveopt */
+        if (cpu_has_xsaveopt && eagerfpu != DISABLE)
+                eagerfpu = ENABLE;
 
         pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n",
                 pcntxt_mask, xstate_size);
@@ -471,3 +586,43 @@ void __cpuinit xsave_init(void)
         next_func = xstate_enable;
         this_func();
 }
+
+static inline void __init eager_fpu_init_bp(void)
+{
+        current->thread.fpu.state =
+            alloc_bootmem_align(xstate_size, __alignof__(struct xsave_struct));
+        if (!init_xstate_buf)
+                setup_init_fpu_buf();
+}
+
+void __cpuinit eager_fpu_init(void)
+{
+        static __refdata void (*boot_func)(void) = eager_fpu_init_bp;
+
+        clear_used_math();
+        current_thread_info()->status = 0;
+
+        if (eagerfpu == ENABLE)
+                setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
+
+        if (!cpu_has_eager_fpu) {
+                stts();
+                return;
+        }
+
+        if (boot_func) {
+                boot_func();
+                boot_func = NULL;
+        }
+
+        /*
+         * This is same as math_state_restore(). But use_xsave() is
+         * not yet patched to use math_state_restore().
+         */
+        init_fpu(current);
+        __thread_fpu_begin(current);
+        if (cpu_has_xsave)
+                xrstor_state(init_xstate_buf, -1);
+        else
+                fxrstor_checking(&init_xstate_buf->i387);
+}