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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 43/75] ARM: bugs: add support for per-processor bug checking
Date:   Fri,  8 Nov 2019 19:50:00 +0100
Message-Id: <20191108174749.716102119@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 9d3a04925deeabb97c8e26d940b501a2873e8af3 upstream.

Add support for per-processor bug checking - each processor function
descriptor gains a function pointer for this check, which must not be
an __init function.  If non-NULL, this will be called whenever a CPU
enters the kernel via which ever path (boot CPU, secondary CPU startup,
CPU resuming, etc.)

This allows processor specific bug checks to validate that workaround
bits are properly enabled by firmware via all entry paths to 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/proc-fns.h |    4 ++++
 arch/arm/kernel/bugs.c          |    4 ++++
 arch/arm/mm/proc-macros.S       |    3 ++-
 3 files changed, 10 insertions(+), 1 deletion(-)

--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -37,6 +37,10 @@ extern struct processor {
 	 */
 	void (*_proc_init)(void);
 	/*
+	 * Check for processor bugs
+	 */
+	void (*check_bugs)(void);
+	/*
 	 * Disable any processor specifics
 	 */
 	void (*_proc_fin)(void);
--- a/arch/arm/kernel/bugs.c
+++ b/arch/arm/kernel/bugs.c
@@ -5,6 +5,10 @@
 
 void check_other_bugs(void)
 {
+#ifdef MULTI_CPU
+	if (processor.check_bugs)
+		processor.check_bugs();
+#endif
 }
 
 void __init check_bugs(void)
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -258,13 +258,14 @@
 	mcr	p15, 0, ip, c7, c10, 4		@ data write barrier
 	.endm
 
-.macro define_processor_functions name:req, dabort:req, pabort:req, nommu=0, suspend=0
+.macro define_processor_functions name:req, dabort:req, pabort:req, nommu=0, suspend=0, bugs=0
 	.type	\name\()_processor_functions, #object
 	.align 2
 ENTRY(\name\()_processor_functions)
 	.word	\dabort
 	.word	\pabort
 	.word	cpu_\name\()_proc_init
+	.word	\bugs
 	.word	cpu_\name\()_proc_fin
 	.word	cpu_\name\()_reset
 	.word	cpu_\name\()_do_idle