From: Dan Williams <dan.j.williams@intel.com>
To: tglx@linutronix.de
Cc: Andi Kleen <ak@linux.intel.com>,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
luto@kernel.org
Subject: [PATCH 2/3] x86/entry: Clear registers for 64bit exceptions/interrupts
Date: Sat, 03 Feb 2018 15:21:42 -0800 [thread overview]
Message-ID: <151770010215.7213.2691813454732314390.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <151770009169.7213.12476757146099518628.stgit@dwillia2-desk3.amr.corp.intel.com>
From: Andi Kleen <ak@linux.intel.com>
Clear the 'extra' registers on entering the 64bit kernel for exceptions
and interrupts. The common registers are not cleared since they are
likely clobbered well before they can be exploited in a speculative
execution attack.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
arch/x86/entry/entry_64.S | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 46260e951da6..d73eedf1eb47 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -563,6 +563,7 @@ END(irq_entries_start)
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
+ CLEAR_EXTRA_REGS_NOSPEC
ENCODE_FRAME_POINTER
testb $3, CS(%rsp)
@@ -1121,6 +1122,7 @@ ENTRY(xen_failsafe_callback)
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
+ CLEAR_EXTRA_REGS_NOSPEC
ENCODE_FRAME_POINTER
jmp error_exit
END(xen_failsafe_callback)
@@ -1166,6 +1168,7 @@ ENTRY(paranoid_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ CLEAR_EXTRA_REGS_NOSPEC
ENCODE_FRAME_POINTER 8
movl $1, %ebx
movl $MSR_GS_BASE, %ecx
@@ -1218,6 +1221,7 @@ ENTRY(error_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ CLEAR_EXTRA_REGS_NOSPEC
ENCODE_FRAME_POINTER 8
xorl %ebx, %ebx
testb $3, CS+8(%rsp)
@@ -1416,6 +1420,7 @@ ENTRY(nmi)
pushq %r14 /* pt_regs->r14 */
pushq %r15 /* pt_regs->r15 */
UNWIND_HINT_REGS
+ CLEAR_EXTRA_REGS_NOSPEC
ENCODE_FRAME_POINTER
/*
next prev parent reply other threads:[~2018-02-03 23:31 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-03 23:21 [PATCH 0/3] x86/entry: clear registers to sanitize speculative usages Dan Williams
2018-02-03 23:21 ` [PATCH 1/3] x86/entry: Clear extra registers beyond syscall arguments for 64bit kernels Dan Williams
2018-02-04 0:14 ` Andy Lutomirski
2018-02-04 1:25 ` Dan Williams
2018-02-04 1:29 ` Andy Lutomirski
2018-02-04 13:01 ` Brian Gerst
2018-02-04 17:42 ` Dan Williams
2018-02-04 18:40 ` Linus Torvalds
2018-02-05 16:26 ` Ingo Molnar
2018-02-05 16:38 ` Andy Lutomirski
2018-02-05 18:29 ` Ingo Molnar
2018-02-05 18:47 ` Brian Gerst
2018-02-05 19:48 ` Ingo Molnar
2018-02-05 20:25 ` Andy Lutomirski
2018-02-05 20:05 ` Ingo Molnar
2018-02-06 8:48 ` Ingo Molnar
2018-02-03 23:21 ` Dan Williams [this message]
2018-02-03 23:21 ` [PATCH 3/3] x86/entry: Clear registers for compat syscalls Dan Williams
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