From e65f38ed0bb7af367ff919c573cf29643fc5f9e8 Mon Sep 17 00:00:00 2001
From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Sat, 18 Jun 2005 09:33:31 +0100
Subject: [PATCH] ARM SMP: Add support for startup of secondary processors
Create a temporary page table to startup secondary processors. This
page table must have a 1:1 virtual/physical mapping for the kernel
in addition to the standard mappings to ensure that the secondary
CPU can enable its MMU safely.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/kernel/head.S | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
(limited to 'arch/arm/kernel/head.S')
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 4733877296d..bd4823c7464 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -2,6 +2,8 @@
* linux/arch/arm/kernel/head.S
*
* Copyright (C) 1994-2002 Russell King
+ * Copyright (c) 2003 ARM Limited
+ * All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -165,6 +167,48 @@ __mmap_switched:
stmia r6, {r0, r4} @ Save control register values
b start_kernel
+#if defined(CONFIG_SMP)
+ .type secondary_startup, #function
+ENTRY(secondary_startup)
+ /*
+ * Common entry point for secondary CPUs.
+ *
+ * Ensure that we're in SVC mode, and IRQs are disabled. Lookup
+ * the processor type - there is no need to check the machine type
+ * as it has already been validated by the primary processor.
+ */
+ msr cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC
+ bl __lookup_processor_type
+ movs r10, r5 @ invalid processor?
+ moveq r0, #'p' @ yes, error 'p'
+ beq __error
+
+ /*
+ * Use the page tables supplied from __cpu_up.
+ */
+ adr r4, __secondary_data
+ ldmia r4, {r5, r6, r13} @ address to jump to after
+ sub r4, r4, r5 @ mmu has been enabled
+ ldr r4, [r6, r4] @ get secondary_data.pgdir
+ adr lr, __enable_mmu @ return address
+ add pc, r10, #12 @ initialise processor
+ @ (return control reg)
+
+ /*
+ * r6 = &secondary_data
+ */
+ENTRY(__secondary_switched)
+ ldr sp, [r6, #4] @ get secondary_data.stack
+ mov fp, #0
+ b secondary_start_kernel
+
+ .type __secondary_data, %object
+__secondary_data:
+ .long .
+ .long secondary_data
+ .long __secondary_switched
+#endif /* defined(CONFIG_SMP) */
+
/*
--
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