[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>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 4733877296d4..bd4823c74645 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) */
+
 
 
 /*