linux-kernel - [PATCH v2] x86/speculation/mds: Eliminate leaks by trace_hardirqs

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Date:   Sun, 23 Jun 2019 11:35:04 +0800
From:   Zhenzhong Duan <zhenzhong.duan@...cle.com>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, mingo@...nel.org, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, jgross@...e.com, ndesaulniers@...gle.com,
        gregkh@...uxfoundation.org,
        Zhenzhong Duan <zhenzhong.duan@...cle.com>
Subject: [PATCH v2] x86/speculation/mds: Eliminate leaks by trace_hardirqs_on()

Move mds_idle_clear_cpu_buffers() after trace_hardirqs_on() to ensure
all store buffer entries are flushed.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
---
-v2: remove pointless changes which made a double flush

 arch/x86/include/asm/mwait.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
index eb0f80c..e28f8b7 100644
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -86,9 +86,9 @@ static inline void __mwaitx(unsigned long eax, unsigned long ebx,
 
 static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
 {
-	mds_idle_clear_cpu_buffers();
-
 	trace_hardirqs_on();
+
+	mds_idle_clear_cpu_buffers();
 	/* "mwait %eax, %ecx;" */
 	asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
 		     :: "a" (eax), "c" (ecx));
-- 
1.8.3.1