[tip:x86/fpu] x86/fpu: Add might_fault() to user_insn()

From: tip-bot for Sebastian Andrzej Siewior
Date: Mon Dec 03 2018 - 16:04:37 EST


Commit-ID: 6637401c35b2f327a35d27f44bda05e327f2f017
Gitweb: https://git.kernel.org/tip/6637401c35b2f327a35d27f44bda05e327f2f017
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Wed, 28 Nov 2018 23:20:11 +0100
Committer: Borislav Petkov <bp@xxxxxxx>
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@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: kvm ML <kvm@xxxxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20181128222035.2996-6-bigeasy@xxxxxxxxxxxxx
---
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" \