linux-kernel - [PATCH 3.16 04/76] x86/cpufeatures: Make CPU bugs sticky

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Message-ID: <lsq.1520823972.893939599@decadent.org.uk>
Date:   Mon, 12 Mar 2018 03:06:12 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Ingo Molnar" <mingo@...nel.org>,
        "Borislav Petkov" <bp@...en8.de>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        "Dave Hansen" <dave.hansen@...ux.intel.com>,
        "Eduardo Valentin" <eduval@...zon.com>,
        "Juergen Gross" <jgross@...e.com>,
        "Peter Zijlstra" <peterz@...radead.org>,
        "Denys Vlasenko" <dvlasenk@...hat.com>,
        "Josh Poimboeuf" <jpoimboe@...hat.com>,
        "David Laight" <David.Laight@...lab.com>,
        "Rik van Riel" <riel@...hat.com>,
        "Brian Gerst" <brgerst@...il.com>, keescook@...gle.com,
        "Dave Hansen" <dave.hansen@...el.com>,
        "David Woodhouse" <dwmw@...zon.co.uk>,
        "H. Peter Anvin" <hpa@...or.com>,
        "Will Deacon" <will.deacon@....com>,
        "Borislav Petkov" <bp@...e.de>, daniel.gruss@...k.tugraz.at,
        "Borislav Petkov" <bpetkov@...e.de>,
        "Linus Torvalds" <torvalds@...ux-foundation.org>,
        "Greg KH" <gregkh@...uxfoundation.org>, hughd@...gle.com,
        aliguori@...zon.com,
        "Boris Ostrovsky" <boris.ostrovsky@...cle.com>,
        "Andy Lutomirski" <luto@...nel.org>
Subject: [PATCH 3.16 04/76] x86/cpufeatures: Make CPU bugs sticky

3.16.56-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@...utronix.de>

commit 6cbd2171e89b13377261d15e64384df60ecb530e upstream.

There is currently no way to force CPU bug bits like CPU feature bits. That
makes it impossible to set a bug bit once at boot and have it stick for all
upcoming CPUs.

Extend the force set/clear arrays to handle bug bits as well.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Borislav Petkov <bpetkov@...e.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: David Laight <David.Laight@...lab.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: Eduardo Valentin <eduval@...zon.com>
Cc: Greg KH <gregkh@...uxfoundation.org>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rik van Riel <riel@...hat.com>
Cc: Will Deacon <will.deacon@....com>
Cc: aliguori@...zon.com
Cc: daniel.gruss@...k.tugraz.at
Cc: hughd@...gle.com
Cc: keescook@...gle.com
Link: https://lkml.kernel.org/r/20171204150606.992156574@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/include/asm/cpufeature.h | 2 ++
 arch/x86/include/asm/processor.h  | 4 ++--
 arch/x86/kernel/cpu/common.c      | 6 +++---
 3 files changed, 7 insertions(+), 5 deletions(-)

--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -286,6 +286,8 @@ extern const char * const x86_power_flag
 	set_bit(bit, (unsigned long *)cpu_caps_set);	\
 } while (0)
 
+#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
+
 #define cpu_has_fpu		boot_cpu_has(X86_FEATURE_FPU)
 #define cpu_has_vme		boot_cpu_has(X86_FEATURE_VME)
 #define cpu_has_de		boot_cpu_has(X86_FEATURE_DE)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -147,8 +147,8 @@ extern struct cpuinfo_x86	boot_cpu_data;
 extern struct cpuinfo_x86	new_cpu_data;
 
 extern struct tss_struct	doublefault_tss;
-extern __u32			cpu_caps_cleared[NCAPINTS];
-extern __u32			cpu_caps_set[NCAPINTS];
+extern __u32			cpu_caps_cleared[NCAPINTS + NBUGINTS];
+extern __u32			cpu_caps_set[NCAPINTS + NBUGINTS];
 
 #ifdef CONFIG_SMP
 DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -441,8 +441,8 @@ static const char *table_lookup_model(st
 	return NULL;		/* Not found */
 }
 
-__u32 cpu_caps_cleared[NCAPINTS];
-__u32 cpu_caps_set[NCAPINTS];
+__u32 cpu_caps_cleared[NCAPINTS + NBUGINTS];
+__u32 cpu_caps_set[NCAPINTS + NBUGINTS];
 
 void load_percpu_segment(int cpu)
 {
@@ -674,7 +674,7 @@ static void apply_forced_caps(struct cpu
 {
 	int i;
 
-	for (i = 0; i < NCAPINTS; i++) {
+	for (i = 0; i < NCAPINTS + NBUGINTS; i++) {
 		c->x86_capability[i] &= ~cpu_caps_cleared[i];
 		c->x86_capability[i] |= cpu_caps_set[i];
 	}