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 V2 8/9] x86/speculation: Add unwind hint to trampoline return
Date: Tue, 7 Apr 2020 09:31:41 +0200 [thread overview]
Message-ID: <20200407073142.20659-9-alexandre.chartre@oracle.com> (raw)
In-Reply-To: <20200407073142.20659-1-alexandre.chartre@oracle.com>
With retpoline, the address to branch to is pushed on the stack and
the return instruction (ret) is used to jump to that address. Use the
UNWIND_HINT_RET_OFFSET directive to inform objtool that the stack
should be adjusted.
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
replace RETPOLINE_RET with UNWIND_HINT_RET_OFFSET
---
arch/x86/include/asm/nospec-branch.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index a345c6fa0541..5ce2a40a26da 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -10,6 +10,7 @@
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
+#include <asm/unwind_hints.h>
/*
* This should be used immediately before a retpoline alternative. It tells
@@ -100,6 +101,7 @@
jmp .Lspec_trap_\@
.Ldo_rop_\@:
mov \reg, (%_ASM_SP)
+ UNWIND_HINT_RET_OFFSET
ret
.endm
--
2.18.2
next prev parent reply other threads:[~2020-04-07 7:28 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 7:31 [PATCH V2 0/9] objtool changes to remove all ANNOTATE_NOSPEC_ALTERNATIVE Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 1/9] objtool: Introduce HINT_RET_OFFSET Alexandre Chartre
2020-04-07 12:53 ` Peter Zijlstra
2020-04-07 13:17 ` Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 2/9] objtool: UNWIND_HINT_RET_OFFSET should not check registers Alexandre Chartre
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 3/9] objtool: is_fentry_call() crashes if call has no destination Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 4/9] objtool: Allow branches within the same alternative Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 5/9] objtool: Add support for intra-function calls Alexandre Chartre
2020-04-07 13:07 ` Peter Zijlstra
2020-04-07 13:28 ` Alexandre Chartre
2020-04-08 14:06 ` Alexandre Chartre
2020-04-08 14:19 ` Julien Thierry
2020-04-08 16:03 ` Alexandre Chartre
2020-04-08 16:04 ` Julien Thierry
2020-04-08 17:06 ` Alexandre Chartre
2020-04-08 17:07 ` Julien Thierry
2020-04-07 7:31 ` [PATCH V2 6/9] x86/speculation: Change __FILL_RETURN_BUFFER to work with objtool Alexandre Chartre
2020-04-07 13:27 ` Josh Poimboeuf
2020-04-07 7:31 ` [PATCH V2 7/9] x86/speculation: Annotate intra-function calls Alexandre Chartre
2020-04-07 7:31 ` Alexandre Chartre [this message]
2020-04-07 7:31 ` [PATCH V2 9/9] x86/speculation: Remove all ANNOTATE_NOSPEC_ALTERNATIVE directives Alexandre Chartre
2020-04-07 13:28 ` Peter Zijlstra
2020-04-07 13:34 ` Josh Poimboeuf
2020-04-07 14:32 ` Alexandre Chartre
2020-04-07 16:18 ` Alexandre Chartre
2020-04-07 16:28 ` Josh Poimboeuf
2020-04-07 17:01 ` Alexandre Chartre
2020-04-07 17:26 ` Peter Zijlstra
2020-04-07 17:27 ` Peter Zijlstra
2020-04-08 21:35 ` Peter Zijlstra
2020-04-09 8:18 ` Alexandre Chartre
2020-04-09 10:34 ` Peter Zijlstra
2020-04-09 10:40 ` Peter Zijlstra
2020-04-07 16:41 ` Peter Zijlstra
2020-04-07 17:04 ` Alexandre Chartre
2020-04-07 13:52 ` Peter Zijlstra
2020-04-07 13:59 ` Peter Zijlstra
2020-04-07 13:35 ` [PATCH V2 0/9] objtool changes to remove all ANNOTATE_NOSPEC_ALTERNATIVE Josh Poimboeuf
2020-04-07 14:02 ` Alexandre Chartre
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