linux-kernel - [tip:x86/fpu] x86/fpu: Inline copy_user_to_fpregs

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Date:   Sat, 13 Apr 2019 14:00:04 -0700
From:   tip-bot for Sebastian Andrzej Siewior <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, pbonzini@...hat.com, Jason@...c4.com,
        luto@...nel.org, mingo@...nel.org, x86@...nel.org,
        dave.hansen@...el.com, tglx@...utronix.de, mingo@...hat.com,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        riel@...riel.com, jannh@...gle.com, bp@...e.de, rkrcmar@...hat.com,
        bigeasy@...utronix.de
Subject: [tip:x86/fpu] x86/fpu: Inline copy_user_to_fpregs_zeroing()

Commit-ID:  e0d3602f933367881bddfff310a744e6e61c284c
Gitweb:     https://git.kernel.org/tip/e0d3602f933367881bddfff310a744e6e61c284c
Author:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Wed, 3 Apr 2019 18:41:49 +0200
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Thu, 11 Apr 2019 20:45:20 +0200

x86/fpu: Inline copy_user_to_fpregs_zeroing()

Start refactoring __fpu__restore_sig() by inlining
copy_user_to_fpregs_zeroing(). The original function remains and will be
used to restore from userland memory if possible.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Dave Hansen <dave.hansen@...el.com>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Jann Horn <jannh@...gle.com>
Cc: "Jason A. Donenfeld" <Jason@...c4.com>
Cc: kvm ML <kvm@...r.kernel.org>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Cc: Rik van Riel <riel@...riel.com>
Cc: x86-ml <x86@...nel.org>
Link: https://lkml.kernel.org/r/20190403164156.19645-21-bigeasy@linutronix.de
---
 arch/x86/kernel/fpu/signal.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 9b9dfdc96285..c2ff43fbbd07 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -337,11 +337,29 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 		kfree(tmp);
 		return err;
 	} else {
+		int ret;
+
 		/*
 		 * For 64-bit frames and 32-bit fsave frames, restore the user
 		 * state to the registers directly (with exceptions handled).
 		 */
-		if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
+		if (use_xsave()) {
+			if ((unsigned long)buf_fx % 64 || fx_only) {
+				u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE;
+				copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+				ret = copy_user_to_fxregs(buf_fx);
+			} else {
+				u64 init_bv = xfeatures_mask & ~xfeatures;
+				if (unlikely(init_bv))
+					copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+				ret = copy_user_to_xregs(buf_fx, xfeatures);
+			}
+		} else if (use_fxsr()) {
+			ret = copy_user_to_fxregs(buf_fx);
+		} else
+			ret = copy_user_to_fregs(buf_fx);
+
+		if (ret) {
 			fpu__clear(fpu);
 			return -1;
 		}