linux-kernel - [PATCH 05/29] x86/fpu: add might_fault() to user

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Date:   Wed, 28 Nov 2018 23:20:11 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     x86@...nel.org, Andy Lutomirski <luto@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        kvm@...r.kernel.org, "Jason A. Donenfeld" <Jason@...c4.com>,
        Rik van Riel <riel@...riel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 05/29] 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.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 arch/x86/include/asm/fpu/internal.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 69dcdf195b611..978a1633c0698 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -106,6 +106,7 @@ 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"				\
-- 
2.20.0.rc1