From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Thu, 19 Jul 2018 10:59:56 +0000 (+0100)
Subject: ARM: split out processor lookup
X-Git-Tag: v5.15~7477^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=65987a8553061515b5851b472081aedb9837a391;p=platform%2Fkernel%2Flinux-starfive.git

ARM: split out processor lookup

Split out the lookup of the processor type and associated error handling
from the rest of setup_processor() - we will need to use this in the
secondary CPU bringup path for big.Little Spectre variant 2 mitigation.

Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---

diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index 2602198..f6df4bb4 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -107,6 +107,7 @@
 #define ARM_CPU_PART_SCORPION		0x510002d0
 
 extern unsigned int processor_id;
+struct proc_info_list *lookup_processor(u32 midr);
 
 #ifdef CONFIG_CPU_CP15
 #define read_cpuid(reg)							\
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index fc40a2b..05a4eb6 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -667,22 +667,29 @@ static void __init smp_build_mpidr_hash(void)
 }
 #endif
 
-static void __init setup_processor(void)
+/*
+ * locate processor in the list of supported processor types.  The linker
+ * builds this table for us from the entries in arch/arm/mm/proc-*.S
+ */
+struct proc_info_list *lookup_processor(u32 midr)
 {
-	struct proc_info_list *list;
+	struct proc_info_list *list = lookup_processor_type(midr);
 
-	/*
-	 * locate processor in the list of supported processor
-	 * types.  The linker builds this table for us from the
-	 * entries in arch/arm/mm/proc-*.S
-	 */
-	list = lookup_processor_type(read_cpuid_id());
 	if (!list) {
-		pr_err("CPU configuration botched (ID %08x), unable to continue.\n",
-		       read_cpuid_id());
-		while (1);
+		pr_err("CPU%u: configuration botched (ID %08x), CPU halted\n",
+		       smp_processor_id(), midr);
+		while (1)
+		/* can't use cpu_relax() here as it may require MMU setup */;
 	}
 
+	return list;
+}
+
+static void __init setup_processor(void)
+{
+	unsigned int midr = read_cpuid_id();
+	struct proc_info_list *list = lookup_processor(midr);
+
 	cpu_name = list->cpu_name;
 	__cpu_architecture = __get_cpu_architecture();
 
@@ -700,7 +707,7 @@ static void __init setup_processor(void)
 #endif
 
 	pr_info("CPU: %s [%08x] revision %d (ARMv%s), cr=%08lx\n",
-		cpu_name, read_cpuid_id(), read_cpuid_id() & 15,
+		list->cpu_name, midr, midr & 15,
 		proc_arch[cpu_architecture()], get_cr());
 
 	snprintf(init_utsname()->machine, __NEW_UTS_LEN + 1, "%s%c",