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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: [PATCH v6.5 02/26] x86/alt: Introduce ALTERNATIVE{, _2} macros
Date: Thu, 4 Jan 2018 00:15:31 +0000	[thread overview]
Message-ID: <1515024955-13390-3-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1515024955-13390-1-git-send-email-andrew.cooper3@citrix.com>

To help creating alternative frames in assembly.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
v3:
 * Drop the now-unused ALTERNATIVE_2
 * Use .L\@ rather than opencoded numbers
v4:
 * Extra @progbits
 * Reinstate ALTERNATIVE_2
---
 xen/include/asm-x86/alternative-asm.h | 46 +++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/xen/include/asm-x86/alternative-asm.h b/xen/include/asm-x86/alternative-asm.h
index bf0332e..6640e85 100644
--- a/xen/include/asm-x86/alternative-asm.h
+++ b/xen/include/asm-x86/alternative-asm.h
@@ -17,6 +17,52 @@
     .byte \alt_len
 .endm
 
+.macro ALTERNATIVE oldinstr, newinstr, feature
+.Lold_start_\@:
+    \oldinstr
+.Lold_end_\@:
+
+    .pushsection .altinstructions, "a", @progbits
+    altinstruction_entry .Lold_start_\@, .Lnew_start_\@, \feature, \
+        (.Lold_end_\@ - .Lold_start_\@), (.Lnew_end_\@ - .Lnew_start_\@)
+
+    .section .discard, "a", @progbits
+    /* Assembler-time check that \newinstr isn't longer than \oldinstr. */
+    .byte 0xff + (.Lnew_end_\@ - .Lnew_start_\@) - (.Lold_end_\@ - .Lold_start_\@)
+
+    .section .altinstr_replacement, "ax", @progbits
+.Lnew_start_\@:
+    \newinstr
+.Lnew_end_\@:
+    .popsection
+.endm
+
+.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
+.Lold_start_\@:
+    \oldinstr
+.Lold_end_\@:
+
+    .pushsection .altinstructions, "a", @progbits
+    altinstruction_entry .Lold_start_\@, .Lnew1_start_\@, \feature1, \
+        (.Lold_end_\@ - .Lold_start_\@), (.Lnew1_end_\@ - .Lnew1_start_\@)
+    altinstruction_entry .Lold_start_\@, .Lnew2_start_\@, \feature2, \
+        (.Lold_end_\@ - .Lold_start_\@), (.Lnew2_end_\@ - .Lnew2_start_\@)
+
+    .section .discard, "a", @progbits
+    /* Assembler-time check that \newinstr{1,2} aren't longer than \oldinstr. */
+    .byte 0xff + (.Lnew1_end_\@ - .Lnew1_start_\@) - (.Lold_end_\@ - .Lold_start_\@)
+    .byte 0xff + (.Lnew2_end_\@ - .Lnew2_start_\@) - (.Lold_end_\@ - .Lold_start_\@)
+
+    .section .altinstr_replacement, "ax", @progbits
+.Lnew1_start_\@:
+    \newinstr1
+.Lnew1_end_\@:
+.Lnew2_start_\@:
+    \newinstr2
+.Lnew2_end_\@:
+    .popsection
+.endm
+
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_X86_ALTERNATIVE_ASM_H_ */
 
-- 
2.1.4


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  parent reply	other threads:[~2018-01-04  0:15 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-04  0:15 [PATCH v6.5 00/26] x86: Mitigations for SP2/CVE-2017-5715/Branch Target Injection Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 01/26] x86/alt: Break out alternative-asm into a separate header file Andrew Cooper
2018-01-04  0:15 ` Andrew Cooper [this message]
2018-01-04  0:15 ` [PATCH v6.5 03/26] x86/hvm: Rename update_guest_vendor() callback to cpuid_policy_changed() Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 04/26] x86: Introduce a common cpuid_policy_updated() Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 05/26] x86/entry: Remove support for partial cpu_user_regs frames Andrew Cooper
2018-01-04  8:51   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 06/26] x86/entry: Rearrange RESTORE_ALL to restore register in stack order Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 07/26] x86/hvm: Use SAVE_ALL to construct the cpu_user_regs frame after VMExit Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 08/26] x86/entry: Erase guest GPR state on entry to Xen Andrew Cooper
2018-01-22 10:04   ` David Woodhouse
2018-01-22 10:18     ` Andrew Cooper
2018-01-22 10:27       ` David Woodhouse
2018-01-04  0:15 ` [PATCH v6.5 09/26] x86: Support compiling with indirect branch thunks Andrew Cooper
2018-01-04  9:02   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 10/26] common/wait: Clarifications to wait infrastructure Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 11/26] x86: Support indirect thunks from assembly code Andrew Cooper
2018-01-04  9:23   ` Jan Beulich
2018-01-08 18:24     ` Andrew Cooper
2018-01-09  8:36       ` Jan Beulich
2018-01-09 11:23         ` Andrew Cooper
2018-01-09 13:18           ` Jan Beulich
2018-01-11 13:03   ` David Woodhouse
2018-01-11 13:41     ` Andrew Cooper
2018-01-11 13:46       ` David Woodhouse
2018-01-04  0:15 ` [PATCH v6.5 12/26] x86/boot: Report details of speculative mitigations Andrew Cooper
2018-01-04  9:29   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 13/26] x86/amd: Try to set lfence as being Dispatch Serialising Andrew Cooper
2018-01-04  9:32   ` Jan Beulich
2018-01-08 19:01     ` Andrew Cooper
2018-01-09  8:38       ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 14/26] x86: Introduce alternative indirect thunks Andrew Cooper
2018-01-04  9:40   ` Jan Beulich
2018-01-09 11:44     ` Andrew Cooper
2018-01-09 13:24       ` Jan Beulich
2018-01-09 13:30         ` Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 15/26] x86/feature: Definitions for Indirect Branch Controls Andrew Cooper
2018-01-04  1:14   ` Doug Goldstein
2018-01-04  1:16     ` Andrew Cooper
2018-01-04  4:05     ` Anthony Liguori
2018-01-04  9:42   ` Jan Beulich
2018-01-04 18:51   ` Wei Liu
2018-01-04  0:15 ` [PATCH v6.5 16/26] x86/cmdline: Introduce a command line option to disable IBRS/IBPB, STIBP and IBPB Andrew Cooper
2018-01-04  9:43   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 17/26] x86/msr: Emulation of MSR_{SPEC_CTRL, PRED_CMD} for guests Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 18/26] x86/migrate: Move MSR_SPEC_CTRL on migrate Andrew Cooper
2018-01-04  0:15 ` [PATCH v6.5 19/26] x86/hvm: Permit guests direct access to MSR_{SPEC_CTRL, PRED_CMD} Andrew Cooper
2018-01-04  9:52   ` Jan Beulich
2018-01-09 12:03     ` Andrew Cooper
2018-01-09 13:28       ` Jan Beulich
2018-01-09 13:34         ` Andrew Cooper
2018-01-09 13:58           ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 20/26] x86: Protect unaware domains from meddling hyperthreads Andrew Cooper
2018-01-04  9:59   ` Jan Beulich
2018-01-09 14:21     ` Andrew Cooper
2018-01-09 14:29       ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 21/26] x86/entry: Use MSR_SPEC_CTRL at each entry/exit point Andrew Cooper
2018-01-04 10:14   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 22/26] x86/boot: Calculate the most appropriate BTI mitigation to use Andrew Cooper
2018-01-04 10:17   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 23/26] x86/entry: Clobber the Return Stack Buffer on entry to Xen Andrew Cooper
2018-01-04 10:22   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 24/26] x86/ctxt: Issue a speculation barrier between vcpu contexts Andrew Cooper
2018-01-04 10:25   ` Jan Beulich
2018-01-04  0:15 ` [PATCH v6.5 25/26] x86/cpuid: Offer Indirect Branch Controls to guests Andrew Cooper
2018-01-09 11:44   ` Wei Liu
2018-01-04  0:15 ` [PATCH v6.5 26/26] x86/idle: Clear SPEC_CTRL while idle Andrew Cooper
2018-01-04 10:29   ` Jan Beulich
2018-01-04 10:41   ` Jan Beulich

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