1 files changed, 75 insertions, 71 deletions

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 831b25c5e705..51c4915a35f0 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -13,6 +13,7 @@
 #include <asm/fpu/xstate.h>
 
 #include <asm/sigframe.h>
+#include <asm/trapnr.h>
 #include <asm/trace/fpu.h>
 
 static struct _fpx_sw_bytes fx_sw_reserved __ro_after_init;
@@ -22,8 +23,8 @@ static struct _fpx_sw_bytes fx_sw_reserved_ia32 __ro_after_init;
  * Check for the presence of extended state information in the
  * user fpstate pointer in the sigcontext.
  */
-static inline int check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
-					   struct _fpx_sw_bytes *fx_sw)
+static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
+					    struct _fpx_sw_bytes *fx_sw)
 {
 	int min_xstate_size = sizeof(struct fxregs_state) +
 			      sizeof(struct xstate_header);
@@ -31,7 +32,7 @@ static inline int check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
 	unsigned int magic2;
 
 	if (__copy_from_user(fx_sw, &fxbuf->sw_reserved[0], sizeof(*fx_sw)))
-		return -EFAULT;
+		return false;
 
 	/* Check for the first magic field and other error scenarios. */
 	if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
@@ -47,10 +48,10 @@ static inline int check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
 	 * in the memory layout.
 	 */
 	if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size)))
-		return -EFAULT;
+		return false;
 
 	if (likely(magic2 == FP_XSTATE_MAGIC2))
-		return 0;
+		return true;
 setfx:
 	trace_x86_fpu_xstate_check_failed(&current->thread.fpu);
 
@@ -58,13 +59,13 @@ setfx:
 	fx_sw->magic1 = 0;
 	fx_sw->xstate_size = sizeof(struct fxregs_state);
 	fx_sw->xfeatures = XFEATURE_MASK_FPSSE;
-	return 0;
+	return true;
 }
 
 /*
  * Signal frame handlers.
  */
-static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
+static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
 {
 	if (use_fxsr()) {
 		struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
@@ -81,18 +82,19 @@ static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
 		if (__copy_to_user(buf, &env, sizeof(env)) ||
 		    __put_user(xsave->i387.swd, &fp->status) ||
 		    __put_user(X86_FXSR_MAGIC, &fp->magic))
-			return -1;
+			return false;
 	} else {
 		struct fregs_state __user *fp = buf;
 		u32 swd;
+
 		if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
-			return -1;
+			return false;
 	}
 
-	return 0;
+	return true;
 }
 
-static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
+static inline bool save_xstate_epilog(void __user *buf, int ia32_frame)
 {
 	struct xregs_state __user *x = buf;
 	struct _fpx_sw_bytes *sw_bytes;
@@ -104,7 +106,7 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
 	err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
 
 	if (!use_xsave())
-		return err;
+		return !err;
 
 	err |= __put_user(FP_XSTATE_MAGIC2,
 			  (__u32 __user *)(buf + fpu_user_xstate_size));
@@ -130,23 +132,17 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
 
 	err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
 
-	return err;
+	return !err;
 }
 
 static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
 {
-	int err;
-
 	if (use_xsave())
-		err = xsave_to_user_sigframe(buf);
-	else if (use_fxsr())
-		err = fxsave_to_user_sigframe((struct fxregs_state __user *) buf);
+		return xsave_to_user_sigframe(buf);
+	if (use_fxsr())
+		return fxsave_to_user_sigframe((struct fxregs_state __user *) buf);
 	else
-		err = fnsave_to_user_sigframe((struct fregs_state __user *) buf);
-
-	if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size))
-		err = -EFAULT;
-	return err;
+		return fnsave_to_user_sigframe((struct fregs_state __user *) buf);
 }
 
 /*
@@ -170,7 +166,7 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
  * 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)
+bool copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 {
 	struct task_struct *tsk = current;
 	int ia32_fxstate = (buf != buf_fx);
@@ -181,13 +177,25 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 
 	if (!static_cpu_has(X86_FEATURE_FPU)) {
 		struct user_i387_ia32_struct fp;
+
 		fpregs_soft_get(current, NULL, (struct membuf){.p = &fp,
 						.left = sizeof(fp)});
-		return copy_to_user(buf, &fp, sizeof(fp)) ? -EFAULT : 0;
+		return !copy_to_user(buf, &fp, sizeof(fp));
 	}
 
 	if (!access_ok(buf, size))
-		return -EACCES;
+		return false;
+
+	if (use_xsave()) {
+		struct xregs_state __user *xbuf = buf_fx;
+
+		/*
+		 * Clear the xsave header first, so that reserved fields are
+		 * initialized to zero.
+		 */
+		if (__clear_user(&xbuf->header, sizeof(xbuf->header)))
+			return false;
+	}
 retry:
 	/*
 	 * Load the FPU registers if they are not valid for the current task.
@@ -205,19 +213,19 @@ retry:
 	fpregs_unlock();
 
 	if (ret) {
-		if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size))
+		if (!__clear_user(buf_fx, fpu_user_xstate_size))
 			goto retry;
-		return -EFAULT;
+		return false;
 	}
 
 	/* Save the fsave header for the 32-bit frames. */
-	if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
-		return -1;
+	if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
+		return false;
 
-	if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
-		return -1;
+	if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate))
+		return false;
 
-	return 0;
+	return true;
 }
 
 static int __restore_fpregs_from_user(void __user *buf, u64 xrestore,
@@ -246,8 +254,8 @@ static int __restore_fpregs_from_user(void __user *buf, u64 xrestore,
  * Attempt to restore the FPU registers directly from user memory.
  * Pagefaults are handled and any errors returned are fatal.
  */
-static int restore_fpregs_from_user(void __user *buf, u64 xrestore,
-				    bool fx_only, unsigned int size)
+static bool restore_fpregs_from_user(void __user *buf, u64 xrestore,
+				     bool fx_only, unsigned int size)
 {
 	struct fpu *fpu = &current->thread.fpu;
 	int ret;
@@ -275,13 +283,12 @@ retry:
 		fpregs_unlock();
 
 		/* Try to handle #PF, but anything else is fatal. */
-		if (ret != -EFAULT)
-			return -EINVAL;
+		if (ret != X86_TRAP_PF)
+			return false;
 
-		ret = fault_in_pages_readable(buf, size);
-		if (!ret)
+		if (!fault_in_pages_readable(buf, size))
 			goto retry;
-		return ret;
+		return false;
 	}
 
 	/*
@@ -298,11 +305,11 @@ retry:
 
 	fpregs_mark_activate();
 	fpregs_unlock();
-	return 0;
+	return true;
 }
 
-static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,
-			     bool ia32_fxstate)
+static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
+			      bool ia32_fxstate)
 {
 	int state_size = fpu_kernel_xstate_size;
 	struct task_struct *tsk = current;
@@ -310,14 +317,14 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,
 	struct user_i387_ia32_struct env;
 	u64 user_xfeatures = 0;
 	bool fx_only = false;
-	int ret;
+	bool success;
+
 
 	if (use_xsave()) {
 		struct _fpx_sw_bytes fx_sw_user;
 
-		ret = check_xstate_in_sigframe(buf_fx, &fx_sw_user);
-		if (unlikely(ret))
-			return ret;
+		if (!check_xstate_in_sigframe(buf_fx, &fx_sw_user))
+			return false;
 
 		fx_only = !fx_sw_user.magic1;
 		state_size = fx_sw_user.xstate_size;
@@ -342,9 +349,8 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,
 	 * to be ignored for histerical raisins. The legacy state is folded
 	 * in once the larger state has been copied.
 	 */
-	ret = __copy_from_user(&env, buf, sizeof(env));
-	if (ret)
-		return ret;
+	if (__copy_from_user(&env, buf, sizeof(env)))
+		return false;
 
 	/*
 	 * By setting TIF_NEED_FPU_LOAD it is ensured that our xstate is
@@ -371,18 +377,17 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,
 	fpregs_unlock();
 
 	if (use_xsave() && !fx_only) {
-		ret = copy_sigframe_from_user_to_xstate(&fpu->state.xsave, buf_fx);
-		if (ret)
-			return ret;
+		if (copy_sigframe_from_user_to_xstate(&fpu->state.xsave, buf_fx))
+			return false;
 	} else {
 		if (__copy_from_user(&fpu->state.fxsave, buf_fx,
 				     sizeof(fpu->state.fxsave)))
-			return -EFAULT;
+			return false;
 
 		if (IS_ENABLED(CONFIG_X86_64)) {
 			/* Reject invalid MXCSR values. */
 			if (fpu->state.fxsave.mxcsr & ~mxcsr_feature_mask)
-				return -EINVAL;
+				return false;
 		} else {
 			/* Mask invalid bits out for historical reasons (broken hardware). */
 			fpu->state.fxsave.mxcsr &= mxcsr_feature_mask;
@@ -410,17 +415,18 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,
 		u64 mask = user_xfeatures | xfeatures_mask_supervisor();
 
 		fpu->state.xsave.header.xfeatures &= mask;
-		ret = os_xrstor_safe(&fpu->state.xsave, xfeatures_mask_all);
+		success = !os_xrstor_safe(&fpu->state.xsave, xfeatures_mask_all);
 	} else {
-		ret = fxrstor_safe(&fpu->state.fxsave);
+		success = !fxrstor_safe(&fpu->state.fxsave);
 	}
 
-	if (likely(!ret))
+	if (likely(success))
 		fpregs_mark_activate();
 
 	fpregs_unlock();
-	return ret;
+	return success;
 }
+
 static inline int xstate_sigframe_size(void)
 {
 	return use_xsave() ? fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE :
@@ -430,17 +436,17 @@ static inline int xstate_sigframe_size(void)
 /*
  * Restore FPU state from a sigframe:
  */
-int fpu__restore_sig(void __user *buf, int ia32_frame)
+bool fpu__restore_sig(void __user *buf, int ia32_frame)
 {
 	unsigned int size = xstate_sigframe_size();
 	struct fpu *fpu = &current->thread.fpu;
 	void __user *buf_fx = buf;
 	bool ia32_fxstate = false;
-	int ret;
+	bool success = false;
 
 	if (unlikely(!buf)) {
 		fpu__clear_user_states(fpu);
-		return 0;
+		return true;
 	}
 
 	ia32_frame &= (IS_ENABLED(CONFIG_X86_32) ||
@@ -456,23 +462,21 @@ int fpu__restore_sig(void __user *buf, int ia32_frame)
 		ia32_fxstate = true;
 	}
 
-	if (!access_ok(buf, size)) {
-		ret = -EACCES;
+	if (!access_ok(buf, size))
 		goto out;
-	}
 
 	if (!IS_ENABLED(CONFIG_X86_64) && !cpu_feature_enabled(X86_FEATURE_FPU)) {
-		ret = fpregs_soft_set(current, NULL, 0,
-				      sizeof(struct user_i387_ia32_struct),
-				      NULL, buf);
+		success = !fpregs_soft_set(current, NULL, 0,
+					   sizeof(struct user_i387_ia32_struct),
+					   NULL, buf);
 	} else {
-		ret = __fpu_restore_sig(buf, buf_fx, ia32_fxstate);
+		success = __fpu_restore_sig(buf, buf_fx, ia32_fxstate);
 	}
 
 out:
-	if (unlikely(ret))
+	if (unlikely(!success))
 		fpu__clear_user_states(fpu);
-	return ret;
+	return success;
 }
 
 unsigned long