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From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andi Kleen <ak@linux.intel.com>,
	Arjan Van De Ven <arjan.van.de.ven@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	Asit Mallick <asit.k.mallick@intel.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH v2 05/10] x86: Annotate static_cpu_has alternative
Date: Tue, 16 Jan 2018 15:28:30 +0100	[thread overview]
Message-ID: <20180116143241.176728634@infradead.org> (raw)
In-Reply-To: 20180116142825.376986833@infradead.org

[-- Attachment #1: peterz-x86-static_cpu_has-annotate.patch --]
[-- Type: text/plain, Size: 1696 bytes --]

In order to recognise static_cpu_has() alternatives from any other
alternative without dodgy heuristics, we need to explicitly mark them.
Use the new type field for this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/include/asm/alternative.h |    1 +
 arch/x86/include/asm/cpufeature.h  |    5 +++--
 2 files changed, 4 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -46,6 +46,7 @@
 #endif
 
 #define ALT_TYPE_DEFAULT	0
+#define ALT_TYPE_STATIC_CPU_HAS	1 /* objtool, static_cpu_has */
 
 struct alt_instr {
 	s32 instr_offset;	/* original instruction */
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -157,7 +157,7 @@ static __always_inline __pure bool _stat
 		 " .byte 3b - 1b\n"		/* src len */
 		 " .byte 5f - 4f\n"		/* repl len */
 		 " .byte 3b - 2b\n"		/* pad len */
-		 " .byte 0\n"			/* type */
+		 " .byte %P[type]\n"		/* type */
 		 ".previous\n"
 		 ".section .altinstr_replacement,\"ax\"\n"
 		 "4: jmp %l[t_no]\n"
@@ -170,7 +170,7 @@ static __always_inline __pure bool _stat
 		 " .byte 3b - 1b\n"		/* src len */
 		 " .byte 0\n"			/* repl len */
 		 " .byte 0\n"			/* pad len */
-		 " .byte 0\n"			/* type */
+		 " .byte %P[type]\n"		/* type */
 		 ".previous\n"
 		 ".section .altinstr_aux,\"ax\"\n"
 		 "6:\n"
@@ -181,6 +181,7 @@ static __always_inline __pure bool _stat
 		 : : [feature]  "i" (bit),
 		     [always]   "i" (X86_FEATURE_ALWAYS),
 		     [bitnum]   "i" (1 << (bit & 7)),
+		     [type]	"i" (ALT_TYPE_STATIC_CPU_HAS),
 		     [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
 		 : : t_yes, t_no);
 t_yes:

  parent reply	other threads:[~2018-01-16 14:37 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-16 14:28 [PATCH v2 00/10] objtool validation of static branches and retpoline Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 01/10] x86: Reindent _static_cpu_has Peter Zijlstra
2018-01-16 15:48   ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 02/10] x86: Update _static_cpu_has to use all named variables Peter Zijlstra
2018-01-18 11:21   ` Borislav Petkov
2018-01-18 15:09     ` Peter Zijlstra
2018-01-18 15:24       ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 03/10] x86: Add a type field to alt_instr Peter Zijlstra
2018-01-16 22:49   ` Josh Poimboeuf
2018-01-16 22:53     ` Borislav Petkov
2018-01-16 23:06       ` Josh Poimboeuf
2018-01-18 11:32   ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 04/10] objtool: Implement base jump_assert support Peter Zijlstra
2018-01-16 14:28 ` Peter Zijlstra [this message]
2018-01-18 13:15   ` [PATCH v2 05/10] x86: Annotate static_cpu_has alternative Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 06/10] objtool: Implement jump_assert for _static_cpu_has() Peter Zijlstra
2018-01-16 23:02   ` Josh Poimboeuf
2018-01-17  9:19     ` Peter Zijlstra
2018-01-17 14:27       ` Josh Poimboeuf
2018-01-17 14:30         ` Josh Poimboeuf
2018-01-17 16:30           ` Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 07/10] x86/jump_label: Implement arch_static_assert() Peter Zijlstra
2018-01-18 13:33   ` Borislav Petkov
2018-01-18 15:31     ` Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 08/10] objtool: Add retpoline validation Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 09/10] x86: Annotate dynamic jump in head_64.S Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 10/10] objtool: More complex static jump implementation Peter Zijlstra
2018-01-16 15:20   ` Peter Zijlstra
2018-01-17  3:05   ` Josh Poimboeuf
2018-01-17  8:18     ` Peter Zijlstra
2018-01-16 19:49 ` [PATCH v2 11/10] objtool: Even more complex static block checks Peter Zijlstra
2018-01-17  3:12   ` Josh Poimboeuf
2018-01-17  8:13     ` Peter Zijlstra
2018-01-17 14:13       ` Josh Poimboeuf

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