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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linus.walleij@linaro.org, rmk+kernel@armlinux.org.uk, Ard Biesheuvel" 
        <ardb@kernel.org>, Russell King <rmk+kernel@armlinux.org.uk>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Tony Lindgren <tony@atomide.com>,
        Marc Zyngier <marc.zyngier@arm.com>,
        "David A. Long" <dave.long@linaro.org>,
        Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 4.4 42/75] ARM: bugs: hook processor bug checking into SMP and suspend paths
Date:   Fri,  8 Nov 2019 19:49:59 +0100
Message-Id: <20191108174749.313487476@linuxfoundation.org>
In-Reply-To: <20191108174708.135680837@linuxfoundation.org>
References: <20191108174708.135680837@linuxfoundation.org>
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From: Russell King <rmk+kernel@armlinux.org.uk>

Commit 26602161b5ba795928a5a719fe1d5d9f2ab5c3ef upstream.

Check for CPU bugs when secondary processors are being brought online,
and also when CPUs are resuming from a low power mode.  This gives an
opportunity to check that processor specific bug workarounds are
correctly enabled for all paths that a CPU re-enters the kernel.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm/include/asm/bugs.h |    2 ++
 arch/arm/kernel/bugs.c      |    5 +++++
 arch/arm/kernel/smp.c       |    4 ++++
 arch/arm/kernel/suspend.c   |    2 ++
 4 files changed, 13 insertions(+)

--- a/arch/arm/include/asm/bugs.h
+++ b/arch/arm/include/asm/bugs.h
@@ -14,8 +14,10 @@ extern void check_writebuffer_bugs(void)
 
 #ifdef CONFIG_MMU
 extern void check_bugs(void);
+extern void check_other_bugs(void);
 #else
 #define check_bugs() do { } while (0)
+#define check_other_bugs() do { } while (0)
 #endif
 
 #endif
--- a/arch/arm/kernel/bugs.c
+++ b/arch/arm/kernel/bugs.c
@@ -3,7 +3,12 @@
 #include <asm/bugs.h>
 #include <asm/proc-fns.h>
 
+void check_other_bugs(void)
+{
+}
+
 void __init check_bugs(void)
 {
 	check_writebuffer_bugs();
+	check_other_bugs();
 }
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -29,6 +29,7 @@
 #include <linux/irq_work.h>
 
 #include <linux/atomic.h>
+#include <asm/bugs.h>
 #include <asm/smp.h>
 #include <asm/cacheflush.h>
 #include <asm/cpu.h>
@@ -396,6 +397,9 @@ asmlinkage void secondary_start_kernel(v
 	 * before we continue - which happens after __cpu_up returns.
 	 */
 	set_cpu_online(cpu, true);
+
+	check_other_bugs();
+
 	complete(&cpu_running);
 
 	local_irq_enable();
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -1,6 +1,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 
+#include <asm/bugs.h>
 #include <asm/cacheflush.h>
 #include <asm/idmap.h>
 #include <asm/pgalloc.h>
@@ -34,6 +35,7 @@ int cpu_suspend(unsigned long arg, int (
 		cpu_switch_mm(mm->pgd, mm);
 		local_flush_bp_all();
 		local_flush_tlb_all();
+		check_other_bugs();
 	}
 
 	return ret;