From: Peter Zijlstra <peterz@infradead.org>
To: jpoimboe@redhat.com, alexandre.chartre@oracle.com
Cc: linux-kernel@vger.kernel.org, jthierry@redhat.com,
tglx@linutronix.de, x86@kernel.org, mbenes@suse.cz,
peterz@infradead.org
Subject: [PATCH v2 11/14] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool
Date: Tue, 28 Apr 2020 21:11:12 +0200 [thread overview]
Message-ID: <20200428191700.032079304@infradead.org> (raw)
In-Reply-To: 20200428191101.886208539@infradead.org
Change FILL_RETURN_BUFFER so that objtool groks it and can generate
correct ORC unwind information.
- Since ORC is alternative invariant; that is, all alternatives
should have the same ORC entries, the __FILL_RETURN_BUFFER body
can not be part of an alternative.
Therefore, move it out of the alternative and keep the alternative
as a sort of jump_label around it.
- Use the ANNOTATE_INTRA_FUNCTION_CALL annotation to white-list
these 'funny' call instructions to nowhere.
- Use UNWIND_HINT_EMPTY to 'fill' the speculation traps, otherwise
objtool will consider them unreachable.
- Move the RSP adjustment into the loop, such that the loop has a
deterministic stack layout.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
arch/x86/include/asm/nospec-branch.h | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -4,11 +4,13 @@
#define _ASM_X86_NOSPEC_BRANCH_H_
#include <linux/static_key.h>
+#include <linux/frame.h>
#include <asm/alternative.h>
#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
@@ -46,21 +48,25 @@
#define __FILL_RETURN_BUFFER(reg, nr, sp) \
mov $(nr/2), reg; \
771: \
+ ANNOTATE_INTRA_FUNCTION_CALL; \
call 772f; \
773: /* speculation trap */ \
+ UNWIND_HINT_EMPTY; \
pause; \
lfence; \
jmp 773b; \
772: \
+ ANNOTATE_INTRA_FUNCTION_CALL; \
call 774f; \
775: /* speculation trap */ \
+ UNWIND_HINT_EMPTY; \
pause; \
lfence; \
jmp 775b; \
774: \
+ add $(BITS_PER_LONG/8) * 2, sp; \
dec reg; \
- jnz 771b; \
- add $(BITS_PER_LONG/8) * nr, sp;
+ jnz 771b;
#ifdef __ASSEMBLY__
@@ -137,10 +143,8 @@
*/
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
#ifdef CONFIG_RETPOLINE
- ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE "jmp .Lskip_rsb_\@", \
- __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \
- \ftr
+ ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
+ __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
.Lskip_rsb_\@:
#endif
.endm
next prev parent reply other threads:[~2020-04-28 19:20 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 19:11 [PATCH v2 00/14] objtool vs retpoline Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 01/14] objtool: Allow branches within the same alternative Peter Zijlstra
2020-04-28 19:53 ` Josh Poimboeuf
2020-04-28 19:11 ` [PATCH v2 02/14] objtool: Fix ORC vs alternatives Peter Zijlstra
2020-04-28 19:55 ` Josh Poimboeuf
2020-04-29 14:33 ` Miroslav Benes
2020-04-29 15:51 ` Peter Zijlstra
2020-04-29 16:41 ` Miroslav Benes
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 03/14] x86,smap: Fix smap_{save,restore}() alternatives Peter Zijlstra
2020-04-29 0:54 ` Brian Gerst
2020-04-29 8:30 ` Peter Zijlstra
2020-04-29 10:18 ` Peter Zijlstra
2020-04-29 12:12 ` Brian Gerst
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 04/14] objtool: is_fentry_call() crashes if call has no destination Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 05/14] objtool: UNWIND_HINT_RET_OFFSET should not check registers Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 06/14] objtool: Rework allocating stack_ops on decode Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 07/14] objtool: Make handle_insn_ops() unconditional Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-05-07 12:38 ` Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 08/14] objtool: Remove INSN_STACK Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 09/14] objtool: Move the IRET hack into the arch decoder Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Miroslav Benes
2020-04-28 19:11 ` [PATCH v2 10/14] objtool: Add support for intra-function calls Peter Zijlstra
2020-04-28 19:11 ` Peter Zijlstra [this message]
2020-05-01 18:22 ` [tip: objtool/core] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 12/14] x86: Simplify retpoline declaration Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 13/14] x86: Change {JMP,CALL}_NOSPEC argument Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 19:11 ` [PATCH v2 14/14] x86/retpoline: Fix retpoline unwind Peter Zijlstra
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2020-04-28 20:17 ` [PATCH v2 00/14] objtool vs retpoline Josh Poimboeuf
2020-04-29 10:19 ` [PATCH v2.1 01-A/14] objtool: Remove check preventing branches within alternative Peter Zijlstra
2020-04-29 10:21 ` [PATCH v2.1 01-B/14] objtool: Uniquely identify alternative instruction groups Peter Zijlstra
2020-04-29 16:46 ` [PATCH v2 00/14] objtool vs retpoline Miroslav Benes
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200428191700.032079304@infradead.org \
--to=peterz@infradead.org \
--cc=alexandre.chartre@oracle.com \
--cc=jpoimboe@redhat.com \
--cc=jthierry@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).