From: tip-bot for David Woodhouse <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org,
dwmw2@infradead.org, dan.j.williams@intel.com,
gregkh@linuxfoundation.org, luto@kernel.org, dwmw@amazon.co.uk,
jpoimboe@redhat.com, torvalds@linux-foundation.org,
dave.hansen@linux.intel.com, bp@alien8.de, peterz@infradead.org,
tglx@linutronix.de, arjan@linux.intel.com
Subject: [tip:x86/pti] Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()"
Date: Tue, 13 Feb 2018 00:58:21 -0800 [thread overview]
Message-ID: <tip-f208820a321f9b23d77d7eed89945d862d62a3ed@git.kernel.org> (raw)
In-Reply-To: <1518305967-31356-3-git-send-email-dwmw@amazon.co.uk>
Commit-ID: f208820a321f9b23d77d7eed89945d862d62a3ed
Gitweb: https://git.kernel.org/tip/f208820a321f9b23d77d7eed89945d862d62a3ed
Author: David Woodhouse <dwmw@amazon.co.uk>
AuthorDate: Sat, 10 Feb 2018 23:39:23 +0000
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Feb 2018 08:59:00 +0100
Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()"
This reverts commit 64e16720ea0879f8ab4547e3b9758936d483909b.
We cannot call C functions like that, without marking all the
call-clobbered registers as, well, clobbered. We might have got away
with it for now because the __ibp_barrier() function was *fairly*
unlikely to actually use any other registers. But no. Just no.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
Cc: arjan.van.de.ven@intel.com
Cc: dave.hansen@intel.com
Cc: jmattson@google.com
Cc: karahmed@amazon.de
Cc: kvm@vger.kernel.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: sironi@amazon.de
Link: http://lkml.kernel.org/r/1518305967-31356-3-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/nospec-branch.h | 13 +++++++++----
arch/x86/include/asm/processor.h | 3 ---
arch/x86/kernel/cpu/bugs.c | 6 ------
3 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 4d57894..300cc15 100644
--- 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)
{
- alternative_input("",
- "call __ibp_barrier",
- X86_FEATURE_USE_IBPB,
- ASM_NO_INPUT_CLOBBER("eax", "ecx", "edx", "memory"));
+ 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");
}
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 513f960..99799fb 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -969,7 +969,4 @@ bool xen_set_default_idle(void);
void stop_this_cpu(void *dummy);
void df_debug(struct pt_regs *regs, long error_code);
-
-void __ibp_barrier(void);
-
#endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 71949bf..61152aa 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -337,9 +337,3 @@ ssize_t cpu_show_spectre_v2(struct device *dev,
spectre_v2_module_string());
}
#endif
-
-void __ibp_barrier(void)
-{
- __wrmsr(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, 0);
-}
-EXPORT_SYMBOL_GPL(__ibp_barrier);
next prev parent reply other threads:[~2018-02-13 8:58 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 [this message]
2018-02-13 9:41 ` Peter Zijlstra
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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