From: Jeremy Fitzhardinge <jeremy@goop.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
"David S. Miller" <davem@davemloft.net>,
David Daney <david.daney@cavium.com>,
Michael Ellerman <michael@ellerman.id.au>,
Jan Glauber <jang@linux.vnet.ibm.com>,
Jason Baron <jbaron@redhat.com>,
the arch/x86 maintainers <x86@kernel.org>,
Xen Devel <xen-devel@lists.xensource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Subject: Re: [PATCH RFC V4 09/10] x86/jump_label: use GENERIC_NOP5_ATOMIC instead of jmp5 +0
Date: Thu, 13 Oct 2011 09:57:46 -0700 [thread overview]
Message-ID: <4E97188A.6040400@goop.org> (raw)
In-Reply-To: <4E97067A.2070305@zytor.com>
On 10/13/2011 08:40 AM, H. Peter Anvin wrote:
> On 10/12/2011 05:08 PM, Jeremy Fitzhardinge wrote:
>> From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
>>
>> GENERIC_NOP5_ATOMIC should make a better nop.
>>
> On 32 bits, yes. On 64 bits you should use P6_NOP5_ATOMIC.
Something like this?
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Thu, 13 Oct 2011 09:55:25 -0700
Subject: [PATCH] x86/nop: we can use P6 as generic NOP on 64-bit
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/include/asm/nops.h b/arch/x86/include/asm/nops.h
index 405b403..f9fead9 100644
--- a/arch/x86/include/asm/nops.h
+++ b/arch/x86/include/asm/nops.h
@@ -19,15 +19,15 @@
6: leal 0x00000000(%esi),%esi
7: leal 0x00000000(,%esi,1),%esi
*/
-#define GENERIC_NOP1 0x90
-#define GENERIC_NOP2 0x89,0xf6
-#define GENERIC_NOP3 0x8d,0x76,0x00
-#define GENERIC_NOP4 0x8d,0x74,0x26,0x00
-#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4
-#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00
-#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
-#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7
-#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4
+#define GAS_NOP1 0x90
+#define GAS_NOP2 0x89,0xf6
+#define GAS_NOP3 0x8d,0x76,0x00
+#define GAS_NOP4 0x8d,0x74,0x26,0x00
+#define GAS_NOP5 GENERIC_NOP1,GENERIC_NOP4
+#define GAS_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00
+#define GAS_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
+#define GAS_NOP8 GENERIC_NOP1,GENERIC_NOP7
+#define GAS_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4
/* Opteron 64bit nops
1: nop
@@ -87,6 +87,28 @@
#define P6_NOP8 0x0f,0x1f,0x84,0x00,0,0,0,0
#define P6_NOP5_ATOMIC P6_NOP5
+#ifdef CONFIG_X86_32
+#define GENERIC_NOP1 GAS_NOP1
+#define GENERIC_NOP2 GAS_NOP2
+#define GENERIC_NOP3 GAS_NOP3
+#define GENERIC_NOP4 GAS_NOP4
+#define GENERIC_NOP5 GAS_NOP5
+#define GENERIC_NOP6 GAS_NOP6
+#define GENERIC_NOP7 GAS_NOP7
+#define GENERIC_NOP8 GAS_NOP8
+#define GENERIC_NOP5_ATOMIC GAS_NOP5_ATOMIC
+#else
+#define GENERIC_NOP1 P6_NOP1
+#define GENERIC_NOP2 P6_NOP2
+#define GENERIC_NOP3 P6_NOP3
+#define GENERIC_NOP4 P6_NOP4
+#define GENERIC_NOP5 P6_NOP5
+#define GENERIC_NOP6 P6_NOP6
+#define GENERIC_NOP7 P6_NOP7
+#define GENERIC_NOP8 P6_NOP8
+#define GENERIC_NOP5_ATOMIC P6_NOP5_ATOMIC
+#endif
+
#define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n"
#if defined(CONFIG_MK7)
next prev parent reply other threads:[~2011-10-13 18:21 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-13 0:08 [PATCH RFC V4 00/10] jump-label: allow early jump_label_enable() Jeremy Fitzhardinge
[not found] ` <cover.1318464413.git.jeremy.fitzhardinge@citrix.com>
2011-10-13 0:08 ` [PATCH RFC V4 01/10] jump_label: use proper atomic_t initializer Jeremy Fitzhardinge
2011-10-13 0:08 ` [PATCH RFC V4 02/10] stop_machine: make stop_machine safe and efficient to call early Jeremy Fitzhardinge
2011-10-13 0:08 ` [PATCH RFC V4 03/10] jump_label: if a key has already been initialized, don't nop it out Jeremy Fitzhardinge
2011-10-13 0:08 ` [PATCH RFC V4 04/10] x86/jump_label: drop arch_jump_label_text_poke_early() Jeremy Fitzhardinge
2011-10-13 10:15 ` Peter Zijlstra
2011-10-13 0:08 ` [PATCH RFC V4 05/10] sparc/jump_label: " Jeremy Fitzhardinge
2011-10-13 0:08 ` [PATCH RFC V4 06/10] jump_label: add arch_jump_label_transform_static() to optimise non-live code updates Jeremy Fitzhardinge
2011-10-13 10:32 ` Peter Zijlstra
2011-10-13 13:54 ` Jason Baron
2011-10-13 15:29 ` Peter Zijlstra
2011-10-13 15:55 ` Jason Baron
2011-10-13 16:32 ` Peter Zijlstra
2011-10-13 0:08 ` [PATCH RFC V4 07/10] s390/jump-label: add arch_jump_label_transform_static() Jeremy Fitzhardinge
2011-10-13 0:08 ` [PATCH RFC V4 08/10] x86/jump_label: " Jeremy Fitzhardinge
2011-10-13 10:36 ` Peter Zijlstra
2011-10-13 0:08 ` [PATCH RFC V4 09/10] x86/jump_label: use GENERIC_NOP5_ATOMIC instead of jmp5 +0 Jeremy Fitzhardinge
2011-10-13 15:40 ` H. Peter Anvin
2011-10-13 16:50 ` Jeremy Fitzhardinge
2011-10-14 21:52 ` H. Peter Anvin
2011-10-13 16:57 ` Jeremy Fitzhardinge [this message]
2011-10-13 18:37 ` Steven Rostedt
2011-10-14 21:53 ` H. Peter Anvin
2011-10-15 0:22 ` Steven Rostedt
2011-10-14 21:53 ` H. Peter Anvin
2011-10-13 0:08 ` [PATCH RFC V4 10/10] jump-label: initialize jump-label subsystem much earlier Jeremy Fitzhardinge
2011-10-13 10:43 ` Peter Zijlstra
2011-10-13 13:59 ` Jason Baron
2011-10-13 16:56 ` Jeremy Fitzhardinge
2011-10-14 21:51 ` Jeremy Fitzhardinge
2011-10-15 8:42 ` Peter Zijlstra
2011-10-16 1:52 ` Jeremy Fitzhardinge
2011-10-18 11:02 ` Peter Zijlstra
2011-10-25 17:56 ` Jeremy Fitzhardinge
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