linux/arch/arm/kernel/head-nommu.S
Russell King 6fc31d5444 ARM: Defer lookup of machine_type to setup.c
Since the debug macros no longer depend on the machine type information,
the machine type lookup can be deferred to setup_arch() in setup.c which
simplifies the code somewhat.

We also move the __error_a functionality into setup.c for displaying a
message when a bad machine ID is passed to the kernel via the LL debug
code.  We also log this into the kernel ring buffer which makes it
possible to retrieve the message via a debugger.

Original idea from Grant Likely.

Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-02-15 16:36:44 +00:00

91 lines
2.1 KiB
ArmAsm

/*
* linux/arch/arm/kernel/head-nommu.S
*
* Copyright (C) 1994-2002 Russell King
* Copyright (C) 2003-2006 Hyok S. Choi
*
* 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
* published by the Free Software Foundation.
*
* Common kernel startup code (non-paged MM)
*
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/ptrace.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/system.h>
/*
* Kernel startup entry point.
* ---------------------------
*
* This is normally called from the decompressor code. The requirements
* are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
* r1 = machine nr.
*
* See linux/arch/arm/tools/mach-types for the complete list of machine
* numbers for r1.
*
*/
__HEAD
ENTRY(stext)
setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
@ and irqs disabled
#ifndef CONFIG_CPU_CP15
ldr r9, =CONFIG_PROCESSOR_ID
#else
mrc p15, 0, r9, c0, c0 @ get processor id
#endif
bl __lookup_processor_type @ r5=procinfo r9=cpuid
movs r10, r5 @ invalid processor (r5=0)?
beq __error_p @ yes, error 'p'
adr lr, BSYM(__after_proc_init) @ return (PIC) address
ARM( add pc, r10, #PROCINFO_INITFUNC )
THUMB( add r12, r10, #PROCINFO_INITFUNC )
THUMB( mov pc, r12 )
ENDPROC(stext)
/*
* Set the Control Register and Read the process ID.
*/
__after_proc_init:
#ifdef CONFIG_CPU_CP15
/*
* CP15 system control register value returned in r0 from
* the CPU init function.
*/
#ifdef CONFIG_ALIGNMENT_TRAP
orr r0, r0, #CR_A
#else
bic r0, r0, #CR_A
#endif
#ifdef CONFIG_CPU_DCACHE_DISABLE
bic r0, r0, #CR_C
#endif
#ifdef CONFIG_CPU_BPREDICT_DISABLE
bic r0, r0, #CR_Z
#endif
#ifdef CONFIG_CPU_ICACHE_DISABLE
bic r0, r0, #CR_I
#endif
#ifdef CONFIG_CPU_HIGH_VECTOR
orr r0, r0, #CR_V
#else
bic r0, r0, #CR_V
#endif
mcr p15, 0, r0, c1, c0, 0 @ write control reg
#endif /* CONFIG_CPU_CP15 */
b __mmap_switched @ clear the BSS and jump
@ to start_kernel
ENDPROC(__after_proc_init)
.ltorg
#include "head-common.S"