From: "H. Peter Anvin" <hpa@linux.intel.com>
To: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Mario Gzuk <mariogzuk@technikz.de>,
"H. Peter Anvin" <hpa@linux.intel.com>
Subject: [PATCH 8/8] x86, cleanups: Simplify sync_core() in the case of no CPUID
Date: Wed, 28 Nov 2012 11:50:30 -0800 [thread overview]
Message-ID: <1354132230-21854-9-git-send-email-hpa@linux.intel.com> (raw)
In-Reply-To: <1354132230-21854-1-git-send-email-hpa@linux.intel.com>
From: "H. Peter Anvin" <hpa@linux.intel.com>
Simplify the implementation of sync_core() for the case where we may
not have the CPUID instruction available.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
arch/x86/include/asm/processor.h | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 9a4ee46..b381df7 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -673,17 +673,24 @@ static inline void sync_core(void)
int tmp;
#ifdef CONFIG_M486
- if (boot_cpu_data.x86 < 5)
- /* There is no speculative execution.
- * jmp is a barrier to prefetching. */
- asm volatile("jmp 1f\n1:\n" ::: "memory");
- else
+ /*
+ * Do a CPUID if available, otherwise do a jump. The jump
+ * can conveniently enough be the jump around CPUID.
+ */
+ asm volatile("cmpl %2,%1\n\t"
+ "jl 1f\n\t"
+ "cpuid\n"
+ "1:"
+ : "=a" (tmp)
+ : "rm" (boot_cpu_data.cpuid_level), "ri" (0), "0" (1)
+ : "ebx", "ecx", "edx", "memory");
+#else
+ /* cpuid is a barrier to speculative execution.
+ * Prefetched instructions are automatically
+ * invalidated when modified. */
+ asm volatile("cpuid" : "=a" (tmp) : "0" (1)
+ : "ebx", "ecx", "edx", "memory");
#endif
- /* cpuid is a barrier to speculative execution.
- * Prefetched instructions are automatically
- * invalidated when modified. */
- asm volatile("cpuid" : "=a" (tmp) : "0" (1)
- : "ebx", "ecx", "edx", "memory");
}
static inline void __monitor(const void *eax, unsigned long ecx,
--
1.7.11.7
next prev parent reply other threads:[~2012-11-28 19:51 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-28 19:50 [PATCH 0/8] RFC: Remove 386 support H. Peter Anvin
2012-11-28 19:50 ` [PATCH 1/8] x86, 386 removal: Remove CONFIG_M386 from Kconfig H. Peter Anvin
2012-12-01 0:34 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
2012-11-28 19:50 ` [PATCH 2/8] x86, 386 removal: Remove CONFIG_CMPXCHG H. Peter Anvin
2012-12-01 0:35 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
2012-11-28 19:50 ` [PATCH 3/8] x86, 386 removal: Remove CONFIG_XADD H. Peter Anvin
2012-11-28 20:30 ` Borislav Petkov
2012-12-01 0:36 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
2012-11-28 19:50 ` [PATCH 4/8] x86, 386 removal: Remove CONFIG_BSWAP H. Peter Anvin
2012-12-01 0:37 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
2012-11-28 19:50 ` [PATCH 5/8] x86, 386 removal: Remove CONFIG_INVLPG H. Peter Anvin
2012-12-01 0:38 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
2012-11-28 19:50 ` [PATCH 6/8] x86, 386 removal: Remove CONFIG_X86_WP_WORKS_OK H. Peter Anvin
2012-11-28 20:52 ` Alan Cox
2012-11-28 23:11 ` H. Peter Anvin
2012-12-01 0:42 ` [tip:x86/nuke386] x86, 386 removal: Document Nx586 as a 386 and thus unsupported tip-bot for H. Peter Anvin
2012-12-01 0:39 ` [tip:x86/nuke386] x86, 386 removal: Remove CONFIG_X86_WP_WORKS_OK tip-bot for H. Peter Anvin
2012-11-28 19:50 ` [PATCH 7/8] x86, 386 removal: Remove CONFIG_X86_POPAD_OK H. Peter Anvin
2012-12-01 0:40 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
2012-11-28 19:50 ` H. Peter Anvin [this message]
2012-11-28 20:41 ` [PATCH 8/8] x86, cleanups: Simplify sync_core() in the case of no CPUID Borislav Petkov
2012-11-29 0:14 ` H. Peter Anvin
2012-11-29 9:13 ` Borislav Petkov
2012-11-29 21:06 ` H. Peter Anvin
2012-11-29 21:18 ` Borislav Petkov
2012-11-29 21:20 ` H. Peter Anvin
2012-11-29 21:31 ` Borislav Petkov
2012-11-29 21:24 ` H. Peter Anvin
2012-11-29 21:34 ` Borislav Petkov
2012-11-30 17:01 ` Linus Torvalds
2012-11-30 17:28 ` Borislav Petkov
2012-11-30 18:03 ` H. Peter Anvin
2012-11-30 18:10 ` Borislav Petkov
2012-11-30 18:40 ` H. Peter Anvin
2012-12-01 0:41 ` [tip:x86/nuke386] " tip-bot for H. Peter Anvin
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