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From: Alexandre Chartre <alexandre.chartre@oracle.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, jpoimboe@redhat.com,
	peterz@infradead.org, jthierry@redhat.com, tglx@linutronix.de,
	alexandre.chartre@oracle.com
Subject: [PATCH V3 7/9] x86/speculation: Change __FILL_RETURN_BUFFER to work with objtool
Date: Tue, 14 Apr 2020 12:36:16 +0200	[thread overview]
Message-ID: <20200414103618.12657-8-alexandre.chartre@oracle.com> (raw)
In-Reply-To: <20200414103618.12657-1-alexandre.chartre@oracle.com>

Change __FILL_RETURN_BUFFER so that the stack state is deterministically
defined for each iteration and that objtool can have an accurate view
of the stack.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
 arch/x86/include/asm/nospec-branch.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 07e95dcb40ad..b0db793fd083 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -59,8 +59,8 @@
 	jmp	775b;				\
 774:						\
 	dec	reg;				\
-	jnz	771b;				\
-	add	$(BITS_PER_LONG/8) * nr, sp;
+	add	$(BITS_PER_LONG/8) * 2, sp;	\
+	jnz	771b;
 
 #ifdef __ASSEMBLY__
 
-- 
2.18.2


  parent reply	other threads:[~2020-04-14 10:57 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-14 10:36 [PATCH V3 0/9] objtool changes to check retpoline code Alexandre Chartre
2020-04-14 10:36 ` [PATCH V3 1/9] objtool: is_fentry_call() crashes if call has no destination Alexandre Chartre
2020-05-01 18:22   ` [tip: objtool/core] " tip-bot2 for Alexandre Chartre
2020-04-14 10:36 ` [PATCH V3 2/9] objtool: Allow branches within the same alternative Alexandre Chartre
2020-04-14 10:36 ` [PATCH V3 3/9] objtool: Add support for intra-function calls Alexandre Chartre
2020-04-14 12:07   ` Julien Thierry
2020-04-16 12:12   ` Miroslav Benes
2020-05-01 18:22   ` [tip: objtool/core] " tip-bot2 for Alexandre Chartre
2020-04-14 10:36 ` [PATCH V3 4/9] objtool: Handle return instruction with intra-function call Alexandre Chartre
2020-04-14 13:44   ` Julien Thierry
2020-04-14 10:36 ` [PATCH V3 5/9] objtool: Add return address unwind hints Alexandre Chartre
2020-04-14 16:16   ` Peter Zijlstra
2020-04-14 16:40     ` Alexandre Chartre
2020-04-14 17:56       ` Peter Zijlstra
2020-04-14 18:31         ` Alexandre Chartre
2020-04-14 18:42           ` Peter Zijlstra
2020-04-14 19:27             ` Alexandre Chartre
2020-04-14 19:48               ` Peter Zijlstra
2020-04-14 10:36 ` [PATCH V3 6/9] objtool: Report inconsistent stack changes in alternative Alexandre Chartre
2020-04-14 15:35   ` Julien Thierry
2020-04-14 22:41   ` kbuild test robot
2020-04-14 22:41     ` kbuild test robot
2020-04-14 23:09   ` kbuild test robot
2020-04-14 23:09     ` kbuild test robot
2020-04-16 14:18   ` Peter Zijlstra
2020-04-16 14:43     ` Alexandre Chartre
2020-04-14 10:36 ` Alexandre Chartre [this message]
2020-04-14 10:36 ` [PATCH V3 8/9] x86/speculation: Add return address unwind hints to retpoline and RSB stuffing Alexandre Chartre
2020-04-14 10:36 ` [PATCH V3 9/9] x86/speculation: Annotate intra-function calls Alexandre Chartre

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