From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, dave.hansen@linux.intel.com,
bp@alien8.de, tglx@linutronix.de, arjan@linux.intel.com,
mingo@kernel.org, linux-kernel@vger.kernel.org,
dwmw2@infradead.org, hpa@zytor.com, gregkh@linuxfoundation.org,
dan.j.williams@intel.com, dwmw@amazon.co.uk, luto@kernel.org,
jpoimboe@redhat.com
Cc: linux-tip-commits@vger.kernel.org, Joe Konno <joe.konno@linux.intel.com>
Subject: Re: [tip:x86/pti] Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()"
Date: Tue, 13 Feb 2018 10:41:32 +0100 [thread overview]
Message-ID: <20180213094132.GF25201@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <tip-f208820a321f9b23d77d7eed89945d862d62a3ed@git.kernel.org>
On Tue, Feb 13, 2018 at 12:58:21AM -0800, tip-bot for David Woodhouse wrote:
> --- a/arch/x86/include/asm/nospec-branch.h
> +++ b/arch/x86/include/asm/nospec-branch.h
> @@ -164,10 +164,15 @@ static inline void vmexit_fill_RSB(void)
>
> static inline void indirect_branch_prediction_barrier(void)
> {
> + asm volatile(ALTERNATIVE("",
> + "movl %[msr], %%ecx\n\t"
> + "movl %[val], %%eax\n\t"
> + "movl $0, %%edx\n\t"
> + "wrmsr",
> + X86_FEATURE_USE_IBPB)
> + : : [msr] "i" (MSR_IA32_PRED_CMD),
> + [val] "i" (PRED_CMD_IBPB)
> + : "eax", "ecx", "edx", "memory");
> }
Joe Konno pointed out that we now need the below line too, because we're
using MSR_IA32_PRED_CMD in this header.
With the existing code that's not a problem per-se, but my objtool
retpoline annotation things did do stumble over this.
Do we want to fold it into the objtool annotation patch or have it
separate?
---
arch/x86/include/asm/nospec-branch.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 300cc159b4a0..76b058533e47 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -6,6 +6,7 @@
#include <asm/alternative.h>
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
+#include <asm/msr-index.h>
#ifdef __ASSEMBLY__
next prev parent reply other threads:[~2018-02-13 9:41 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-10 23:39 [PATCH v2 0/6] Spectre v2 updates David Woodhouse
2018-02-10 23:39 ` [PATCH v2 1/6] x86/speculation: Update Speculation Control microcode blacklist David Woodhouse
2018-02-11 12:08 ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-02-12 9:50 ` [PATCH v2 1/6] " Darren Kenny
2018-02-12 14:16 ` David Woodhouse
2018-02-12 14:32 ` Thomas Gleixner
2018-02-10 23:39 ` [PATCH v2 2/6] Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()" David Woodhouse
2018-02-11 12:09 ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-02-13 8:58 ` tip-bot for David Woodhouse
2018-02-13 9:41 ` Peter Zijlstra [this message]
2018-02-13 11:28 ` Ingo Molnar
2018-02-13 13:28 ` Peter Zijlstra
2018-02-13 13:38 ` Ingo Molnar
2018-02-13 15:26 ` [tip:x86/pti] x86/speculation: Add <asm/msr-index.h> dependency tip-bot for Peter Zijlstra
2018-02-15 0:28 ` tip-bot for Peter Zijlstra
2018-02-10 23:39 ` [PATCH v2 3/6] KVM: x86: Reduce retpoline performance impact in slot_handle_level_range() David Woodhouse
2018-02-11 12:09 ` [tip:x86/pti] KVM/x86: Reduce retpoline performance impact in slot_handle_level_range(), by always inlining iterator helper methods tip-bot for David Woodhouse
2018-02-13 8:58 ` tip-bot for David Woodhouse
2018-02-10 23:39 ` [PATCH v2 4/6] X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs David Woodhouse
2018-02-11 12:10 ` [tip:x86/pti] " tip-bot for KarimAllah Ahmed
2018-02-13 8:59 ` tip-bot for KarimAllah Ahmed
2018-02-10 23:39 ` [PATCH v2 5/6] KVM/nVMX: Set the CPU_BASED_USE_MSR_BITMAPS if we have a valid L02 MSR bitmap David Woodhouse
2018-02-11 10:19 ` Ingo Molnar
[not found] ` <1518345844.3677.365.camel@amazon.co.uk>
2018-02-11 10:55 ` Ingo Molnar
2018-02-11 12:10 ` [tip:x86/pti] " tip-bot for KarimAllah Ahmed
2018-02-13 8:59 ` tip-bot for KarimAllah Ahmed
2018-02-10 23:39 ` [PATCH v2 6/6] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-11 11:46 ` Ingo Molnar
2018-02-11 10:41 ` [PATCH v2 0/6] Spectre v2 updates Ingo Molnar
2018-02-11 15:19 ` [PATCH v2.1] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-11 18:50 ` [PATCH] x86/speculation: Clean up various Spectre related details Ingo Molnar
2018-02-11 19:25 ` David Woodhouse
2018-02-11 19:43 ` Ingo Molnar
2018-02-12 15:30 ` David Woodhouse
2018-02-13 8:04 ` Ingo Molnar
2018-02-11 19:19 ` [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware tip-bot for David Woodhouse
2018-02-12 5:59 ` afzal mohammed
2018-02-12 16:30 ` David Woodhouse
2018-02-12 10:22 ` Ingo Molnar
2018-02-12 11:50 ` Peter Zijlstra
2018-02-12 12:27 ` David Woodhouse
2018-02-12 13:06 ` Peter Zijlstra
2018-02-13 7:58 ` Ingo Molnar
2018-02-12 12:28 ` Peter Zijlstra
2018-02-12 16:13 ` Dave Hansen
2018-02-12 16:58 ` Peter Zijlstra
2018-02-13 7:55 ` Ingo Molnar
2018-02-14 1:49 ` Tim Chen
2018-02-14 8:56 ` Peter Zijlstra
2018-02-14 8:57 ` Peter Zijlstra
2018-02-14 19:20 ` Tim Chen
2018-02-14 23:19 ` Ingo Molnar
2018-02-15 2:01 ` Tim Chen
2018-02-14 9:31 ` [PATCH] watchdog: hpwdt: Remove spinlock acquire and BIOS calls from NMI context Ingo Molnar
2018-02-14 9:38 ` Peter Zijlstra
2018-02-14 10:39 ` Ingo Molnar
2018-02-14 9:44 ` Borislav Petkov
2018-02-14 18:13 ` Jerry Hoemann
2018-02-14 23:17 ` Ingo Molnar
2018-02-15 17:44 ` Jerry Hoemann
2018-02-15 19:02 ` Ingo Molnar
2018-02-15 19:48 ` Peter Zijlstra
2018-02-16 18:44 ` [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware Tim Chen
2018-02-16 19:16 ` David Woodhouse
2018-02-16 23:46 ` Tim Chen
2018-02-17 10:26 ` Ingo Molnar
2018-02-19 9:20 ` Peter Zijlstra
2018-02-19 9:29 ` David Woodhouse
2018-02-19 9:39 ` Ingo Molnar
2018-02-19 9:44 ` David Woodhouse
2018-02-19 10:08 ` Peter Zijlstra
2018-02-19 9:36 ` Ingo Molnar
2018-02-12 8:27 ` [PATCH v2 0/6] Spectre v2 updates Paolo Bonzini
2018-02-13 7:59 ` Ingo Molnar
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