linux-kernel - [tip:x86/fpu] x86/fpu: Add might_fault() to user

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Date:   Mon, 3 Dec 2018 13:03:14 -0800
From:   tip-bot for Sebastian Andrzej Siewior <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     jannh@...gle.com, hpa@...or.com, bigeasy@...utronix.de,
        x86@...nel.org, tglx@...utronix.de, linux-kernel@...r.kernel.org,
        mingo@...hat.com, bp@...e.de, riel@...riel.com,
        dave.hansen@...ux.intel.com, mingo@...nel.org, Jason@...c4.com,
        rkrcmar@...hat.com, kvm@...r.kernel.org, luto@...nel.org,
        pbonzini@...hat.com
Subject: [tip:x86/fpu] x86/fpu: Add might_fault() to user_insn()

Commit-ID:  6637401c35b2f327a35d27f44bda05e327f2f017
Gitweb:     https://git.kernel.org/tip/6637401c35b2f327a35d27f44bda05e327f2f017
Author:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Wed, 28 Nov 2018 23:20:11 +0100
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Mon, 3 Dec 2018 19:15:32 +0100

x86/fpu: Add might_fault() to user_insn()

Every user of user_insn() passes an user memory pointer to this macro.

Add might_fault() to user_insn() so we can spot users which are using
this macro in sections where page faulting is not allowed.

 [ bp: Space it out to make it more visible. ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Rik van Riel <riel@...riel.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: "Jason A. Donenfeld" <Jason@...c4.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Jann Horn <jannh@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: kvm ML <kvm@...r.kernel.org>
Cc: x86-ml <x86@...nel.org>
Link: https://lkml.kernel.org/r/20181128222035.2996-6-bigeasy@linutronix.de
---
 arch/x86/include/asm/fpu/internal.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 69dcdf195b61..fa2c93cb42a2 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -106,6 +106,9 @@ extern void fpstate_sanitize_xstate(struct fpu *fpu);
 #define user_insn(insn, output, input...)				\
 ({									\
 	int err;							\
+									\
+	might_fault();							\
+									\
 	asm volatile(ASM_STAC "\n"					\
 		     "1:" #insn "\n\t"					\
 		     "2: " ASM_CLAC "\n"				\