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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Borislav Petkov <bp@suse.de>, Rik van Riel <riel@surriel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>, Jann Horn <jannh@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        kvm ML <kvm@vger.kernel.org>, x86-ml <x86@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.20 104/352] x86/fpu: Add might_fault() to user_insn()
Date:   Mon, 11 Feb 2019 15:15:31 +0100
Message-Id: <20190211141852.406612757@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 6637401c35b2f327a35d27f44bda05e327f2f017 ]

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@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rik van Riel <riel@surriel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20181128222035.2996-6-bigeasy@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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"				\
-- 
2.19.1