From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
Borislav Petkov <bp@alien8.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Matthew Whitehead <tedheadster@gmail.com>,
Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH v2 2/6] Revert "x86/boot: Fail the boot if !M486 and CPUID is missing"
Date: Thu, 1 Dec 2016 16:34:58 -0800 [thread overview]
Message-ID: <82acde18a108b8e353180dd6febcc2876df33f24.1480638597.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1480536936.git.luto@kernel.org>
In-Reply-To: <cover.1480638597.git.luto@kernel.org>
This reverts commit ed68d7e9b9cfb64f3045ffbcb108df03c09a0f98.
The patch wasn't quite correct -- there are non-Intel (and hence
non-486) CPUs that we support that don't have CPUID. Since we no
longer require CPUID for sync_core(), just revert the patch.
I think the relevant CPUs are Geode and Elan, but I'm not sure.
In principle, we should try to do better at identifying CPUID-less
CPUs in early boot, but that's more complicated.
Reported-by: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/boot/cpu.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c
index 4224ede43b4e..26240dde081e 100644
--- a/arch/x86/boot/cpu.c
+++ b/arch/x86/boot/cpu.c
@@ -87,12 +87,6 @@ int validate_cpu(void)
return -1;
}
- if (CONFIG_X86_MINIMUM_CPU_FAMILY <= 4 && !IS_ENABLED(CONFIG_M486) &&
- !has_eflag(X86_EFLAGS_ID)) {
- printf("This kernel requires a CPU with the CPUID instruction. Build with CONFIG_M486=y to run on this CPU.\n");
- return -1;
- }
-
if (err_flags) {
puts("This kernel requires the following features "
"not present on the CPU:\n");
--
2.9.3
next prev parent reply other threads:[~2016-12-02 0:36 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 20:34 [PATCH 0/4] CPUID-less CPU fixes and improvements Andy Lutomirski
2016-11-30 20:34 ` [PATCH 1/4] x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels Andy Lutomirski
2016-11-30 20:34 ` [PATCH 2/4] Revert "x86/boot: Fail the boot if !M486 and CPUID is missing" Andy Lutomirski
2016-12-01 5:53 ` Peter Zijlstra
2016-12-01 9:02 ` Borislav Petkov
2016-12-01 10:07 ` Thomas Gleixner
2016-12-01 11:15 ` [PATCH] x86/CPU: Add X86_FEATURE_CPUID Borislav Petkov
2016-12-01 17:00 ` Andy Lutomirski
2016-12-02 0:33 ` [PATCH 2/4] Revert "x86/boot: Fail the boot if !M486 and CPUID is missing" Andy Lutomirski
2016-12-01 17:00 ` Andy Lutomirski
2016-11-30 20:34 ` [PATCH 3/4] x86/microcode/intel: Replace sync_core() with cpuid_eax(1) Andy Lutomirski
2016-12-01 9:11 ` Borislav Petkov
2016-11-30 20:34 ` [PATCH 4/4] x86/asm: Change sync_core() to use MOV to CR2 to serialize Andy Lutomirski
2016-12-01 9:22 ` Borislav Petkov
2016-12-01 17:08 ` Andy Lutomirski
2016-12-01 17:46 ` Andrew Cooper
2016-12-02 7:34 ` Ingo Molnar
2016-12-02 0:34 ` [PATCH v2 0/6] CPUID-less CPU/sync_core fixes and improvements Andy Lutomirski
2016-12-02 0:34 ` [PATCH v2 1/6] x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels Andy Lutomirski
2016-12-02 0:34 ` Andy Lutomirski [this message]
2016-12-02 0:34 ` [PATCH v2 3/6] x86/microcode/intel: Replace sync_core() with cpuid_eax(1) Andy Lutomirski
2016-12-02 0:35 ` [PATCH v2 4/6] x86/paravirt: Make sync_core() be a paravirt op Andy Lutomirski
2016-12-02 0:35 ` [PATCH v2 5/6] x86/xen: Add a Xen-specific sync_core() implementation Andy Lutomirski
2016-12-02 11:44 ` Andrew Cooper
2016-12-02 17:07 ` Andy Lutomirski
2016-12-02 17:16 ` Andrew Cooper
2016-12-02 17:23 ` Andy Lutomirski
2016-12-02 17:26 ` Andrew Cooper
2016-12-02 18:50 ` Boris Ostrovsky
2016-12-02 19:34 ` Andy Lutomirski
2016-12-02 20:09 ` Boris Ostrovsky
2016-12-02 17:32 ` Linus Torvalds
2016-12-02 17:38 ` Andy Lutomirski
2016-12-02 17:53 ` Linus Torvalds
2016-12-02 18:03 ` Borislav Petkov
2016-12-02 18:27 ` Linus Torvalds
2016-12-02 18:50 ` Borislav Petkov
2016-12-02 19:03 ` Linus Torvalds
2016-12-02 19:20 ` Borislav Petkov
2016-12-02 19:24 ` Linus Torvalds
2016-12-02 19:28 ` Borislav Petkov
2016-12-03 15:02 ` [PATCH] x86/alternatives: Do not use sync_core() to serialize I$ Borislav Petkov
2016-12-03 17:05 ` Andy Lutomirski
2016-12-20 7:58 ` [tip:x86/urgent] " tip-bot for Borislav Petkov
2016-12-20 9:35 ` tip-bot for Borislav Petkov
2016-12-02 19:30 ` [PATCH v2 5/6] x86/xen: Add a Xen-specific sync_core() implementation Andy Lutomirski
2016-12-02 19:35 ` Linus Torvalds
2016-12-02 20:41 ` Andy Lutomirski
2016-12-02 21:10 ` Linus Torvalds
2016-12-02 22:55 ` Andy Lutomirski
2016-12-02 23:09 ` Linus Torvalds
2016-12-02 19:23 ` Andy Lutomirski
2016-12-02 19:30 ` Borislav Petkov
2016-12-03 12:44 ` Borislav Petkov
2016-12-02 0:35 ` [PATCH v2 6/6] x86/asm: Change sync_core() to use MOV to CR2 to serialize Andy Lutomirski
2016-12-02 0:36 ` [PATCH 0/4] CPUID-less CPU fixes and improvements Andy Lutomirski
2016-12-02 10:17 ` Ingo Molnar
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