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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, "Andy Lutomirski" <luto@kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	kvm@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>,
	"Rik van Riel" <riel@surriel.com>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: [PATCH 28/29] x86/fpu: Merge the two code paths in __fpu__restore_sig()
Date: Wed, 28 Nov 2018 23:20:34 +0100	[thread overview]
Message-ID: <20181128222035.2996-29-bigeasy@linutronix.de> (raw)
In-Reply-To: <20181128222035.2996-1-bigeasy@linutronix.de>

The ia32_fxstate case (32bit with fxsr) and the other (64bit, 32bit
without fxsr) restore both from kernel memory and sanitize the content.
The !ia32_fxstate version restores missing xstates from "init state"
while the ia32_fxstate doesn't and skips it.

Merge the two code paths and keep the !ia32_fxstate version. Copy only
the user_i387_ia32_struct data structure in the ia32_fxstate.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/x86/kernel/fpu/signal.c | 162 ++++++++++++++---------------------
 1 file changed, 65 insertions(+), 97 deletions(-)

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 339a8c113517e..fb16d0da71bca 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -228,6 +228,11 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 	struct task_struct *tsk = current;
 	struct fpu *fpu = &tsk->thread.fpu;
 	int state_size = fpu_kernel_xstate_size;
+	union fpregs_state *state;
+	void *tmp;
+	struct user_i387_ia32_struct env;
+	struct user_i387_ia32_struct *envp = NULL;
+	int ret = 0;
 	u64 xfeatures = 0;
 	int fx_only = 0;
 
@@ -264,106 +269,69 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 		}
 	}
 
+	tmp = kzalloc(sizeof(*state) + fpu_kernel_xstate_size + 64, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+	state = PTR_ALIGN(tmp, 64);
+
+	if ((unsigned long)buf_fx % 64)
+		fx_only = 1;
+
+	/*
+	 * For 32-bit frames with fxstate, copy the fxstate so it can be
+	 * reconstructed later.
+	 */
 	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. Validate and sanitize the copied state.
-		 */
-		union fpregs_state *state;
-		void *tmp;
-		struct user_i387_ia32_struct env;
-		int err = 0;
-
-		tmp = kzalloc(sizeof(*state) + fpu_kernel_xstate_size + 64, GFP_KERNEL);
-		if (!tmp)
-			return -ENOMEM;
-		state = PTR_ALIGN(tmp, 64);
-
-		if (using_compacted_format()) {
-			err = copy_user_to_xstate(&state->xsave, buf_fx);
-		} else {
-			err = __copy_from_user(&state->xsave, buf_fx, state_size);
-
-			if (!err && state_size > offsetof(struct xregs_state, header))
-				err = validate_xstate_header(&state->xsave.header);
-		}
-
-		if (err || __copy_from_user(&env, buf, sizeof(env))) {
-			err = -1;
-		} else {
-			sanitize_restored_xstate(state, &env,
-						 xfeatures, fx_only);
-			copy_kernel_to_fpregs(state);
-		}
-
-		kfree(tmp);
-		return err;
-	} else {
-		union fpregs_state *state;
-		void *tmp;
-		int ret;
-
-		tmp = kzalloc(sizeof(*state) + fpu_kernel_xstate_size + 64, GFP_KERNEL);
-		if (!tmp)
-			return -ENOMEM;
-		state = PTR_ALIGN(tmp, 64);
-
-		/*
-		 * For 64-bit frames and 32-bit fsave frames, restore the user
-		 * state to the registers directly (with exceptions handled).
-		 */
-		if ((unsigned long)buf_fx % 64)
-			fx_only = 1;
-
-		if (use_xsave() && !fx_only) {
-			u64 init_bv = xfeatures_mask & ~xfeatures;
-
-			if (using_compacted_format()) {
-				ret = copy_user_to_xstate(&state->xsave, buf_fx);
-			} else {
-				ret = __copy_from_user(&state->xsave, buf_fx, state_size);
-
-				if (!ret && state_size > offsetof(struct xregs_state, header))
-					ret = validate_xstate_header(&state->xsave.header);
-			}
-			if (ret)
-				goto err_out;
-			sanitize_restored_xstate(state, NULL, xfeatures,
-						 fx_only);
-
-			if (unlikely(init_bv))
-				copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
-			ret = copy_users_to_xregs(&state->xsave, xfeatures);
-
-		} else if (use_fxsr()) {
-			ret = __copy_from_user(&state->fxsave, buf_fx, state_size);
-			if (ret)
-				goto err_out;
-
-			if (use_xsave()) {
-				u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE;
-				copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
-			}
-			state->fxsave.mxcsr &= mxcsr_feature_mask;
-
-			ret = copy_users_to_fxregs(&state->fxsave);
-		} else {
-			ret = __copy_from_user(&state->fsave, buf_fx, state_size);
-			if (ret)
-				goto err_out;
-			ret = copy_users_to_fregs(buf_fx);
-		}
-
-err_out:
-		kfree(tmp);
-		if (ret) {
-			fpu__clear(fpu);
-			return -1;
-		}
+		ret = __copy_from_user(&env, buf, sizeof(env));
+		if (ret)
+			goto err_out;
+		envp = &env;
 	}
 
-	return 0;
+	if (use_xsave() && !fx_only) {
+		u64 init_bv = xfeatures_mask & ~xfeatures;
+
+		if (using_compacted_format()) {
+			ret = copy_user_to_xstate(&state->xsave, buf_fx);
+		} else {
+			ret = __copy_from_user(&state->xsave, buf_fx, state_size);
+
+			if (!ret && state_size > offsetof(struct xregs_state, header))
+				ret = validate_xstate_header(&state->xsave.header);
+		}
+		if (ret)
+			goto err_out;
+
+		sanitize_restored_xstate(state, envp, xfeatures, fx_only);
+
+		if (unlikely(init_bv))
+			copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+		ret = copy_users_to_xregs(&state->xsave, xfeatures);
+
+	} else if (use_fxsr()) {
+		ret = __copy_from_user(&state->fxsave, buf_fx, state_size);
+		if (ret)
+			goto err_out;
+
+		sanitize_restored_xstate(state, envp, xfeatures, fx_only);
+		if (use_xsave()) {
+			u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE;
+			copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+		}
+
+		ret = copy_users_to_fxregs(&state->fxsave);
+	} else {
+		ret = __copy_from_user(&state->fsave, buf_fx, state_size);
+		if (ret)
+			goto err_out;
+		ret = copy_users_to_fregs(buf_fx);
+	}
+
+err_out:
+	kfree(tmp);
+	if (ret)
+		fpu__clear(fpu);
+	return ret;
 }
 
 static inline int xstate_sigframe_size(void)
-- 
2.20.0.rc1


  parent reply	other threads:[~2018-11-28 22:21 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-28 22:20 [PATCH v5] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 01/29] x86/fpu: Use ULL for shift in xfeature_uncompacted_offset() Sebastian Andrzej Siewior
2018-11-29  1:52   ` Rik van Riel
2018-12-03 21:00   ` [tip:x86/fpu] x86/fpu: Use unsigned long long " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 02/29] x86/entry/32: Remove asm/math_emu.h include Sebastian Andrzej Siewior
2018-11-29  1:52   ` Rik van Riel
2018-12-03 21:01   ` [tip:x86/fpu] x86/process/32: " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 03/29] x86/entry: Remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-11-29  1:53   ` Rik van Riel
2018-12-03 21:02   ` [tip:x86/fpu] x86/thread_info: " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 04/29] x86/pkeys: Make init_pkru_value static Sebastian Andrzej Siewior
2018-11-29  1:53   ` Rik van Riel
2018-12-03 21:02   ` [tip:x86/fpu] " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 05/29] x86/fpu: add might_fault() to user_insn() Sebastian Andrzej Siewior
2018-11-29  1:54   ` Rik van Riel
2018-12-03 21:03   ` [tip:x86/fpu] x86/fpu: Add " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 06/29] x86/fpu: Update comment for __raw_xsave_addr() Sebastian Andrzej Siewior
2018-11-29  1:56   ` Rik van Riel
2018-12-03 21:03   ` [tip:x86/fpu] " tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 07/29] x86/fpu: don't export __kernel_fpu_{begin|end}() Sebastian Andrzej Siewior
2018-11-29  2:00   ` Rik van Riel
2018-11-29 15:02     ` [PATCH 07/29 v2] " Sebastian Andrzej Siewior
2018-12-03 21:04       ` [tip:x86/fpu] x86/fpu: Don't export __kernel_fpu_{begin,end}() tip-bot for Sebastian Andrzej Siewior
2018-12-03 21:12         ` Ard Biesheuvel
2018-12-03 22:08           ` Borislav Petkov
2018-12-04 11:39             ` Borislav Petkov
2018-12-04 12:15             ` Sebastian Andrzej Siewior
2018-12-04 12:33               ` Borislav Petkov
2018-12-04 11:45       ` tip-bot for Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 08/29] x86/fpu: Remove fpu->initialized usage in __fpu__restore_sig() Sebastian Andrzej Siewior
2018-12-06 20:07   ` Borislav Petkov
2018-12-07  8:17     ` Sebastian Andrzej Siewior
2018-12-07 10:19       ` Borislav Petkov
2018-11-28 22:20 ` [PATCH 09/29] x86/fpu: Remove fpu__restore() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 10/29] x86/fpu: Remove preempt_disable() in fpu__clear() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 11/29] x86/fpu: Always init the `state' " Sebastian Andrzej Siewior
2018-12-12 17:11   ` Borislav Petkov
2018-12-13 14:35     ` Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 12/29] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 13/29] x86/fpu: Don't save fxregs for ia32 frames " Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 14/29] x86/fpu: Remove fpu->initialized Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 15/29] x86/fpu: Remove user_fpu_begin() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 16/29] x86/fpu: Add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 17/29] x86/fpu: Make __raw_xsave_addr() use feature number instead of mask Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 18/29] x86/fpu: Make get_xsave_field_ptr() and get_xsave_addr() " Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 19/29] x86/fpu: Only write PKRU if it is different from current Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 20/29] x86/pkeys: Don't check if PKRU is zero before writting it Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 21/29] x86/fpu: Eager switch PKRU state Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 22/29] x86/entry: Add TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 23/29] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 24/29] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 25/29] x86/fpu: Update xstate's PKRU value on write_pkru() Sebastian Andrzej Siewior
2018-11-28 22:20 ` [PATCH 26/29] x86/fpu: Inline copy_user_to_fpregs_zeroing() Sebastian Andrzej Siewior
2018-11-28 23:09   ` Joey Pabalinas
2018-11-28 22:20 ` [PATCH 27/29] x86/fpu: Let __fpu__restore_sig() restore the !32bit+fxsr frame from kernel memory Sebastian Andrzej Siewior
2018-11-28 22:20 ` Sebastian Andrzej Siewior [this message]
2018-11-28 22:20 ` [PATCH 29/29] x86/fpu: Defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-11-29 15:00   ` Sebastian Andrzej Siewior
2018-12-10 14:41   ` Sebastian Andrzej Siewior
2018-11-30 11:52 ` [PATCH v5] x86: load FPU registers on return to userland Sebastian Andrzej Siewior

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