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Commit 0f44ba1d authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[ARM] Move read of processor ID out of lookup_processor_type() 



Read the processor ID at boot, and save it in "processor_id" as we
did before.  Later, when we re-parse the CPU type in the setup.c code,
re-use the value stored in "processor_id".

This allows a cleaner work-around for noMMU devices without CP#15.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent fb1c7762

arch/arm/kernel/head.S

+9 −6
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ 
ENTRY(stext)

	msr	cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC @ ensure svc mode

						@ and irqs disabled

	mrc	p15, 0, r9, c0, c0		@ get processor id

	bl	__lookup_processor_type		@ r5=procinfo r9=cpuid

	movs	r10, r5				@ invalid processor (r5=0)?

	beq	__error_p			@ yes, error 'p'
@@ -156,6 +157,7 @@ ENTRY(secondary_startup) 
	 * as it has already been validated by the primary processor.

	 */

	msr	cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC

	mrc	p15, 0, r9, c0, c0		@ get processor id

	bl	__lookup_processor_type

	movs	r10, r5				@ invalid processor?

	moveq	r0, #'p'			@ yes, error 'p'
@@ -450,19 +452,19 @@ __error: 
 * (and therefore, we are not in the correct address space).  We have to

 * calculate the offset.

 *

 *	r9 = cpuid

 * Returns:

 *	r3, r4, r6 corrupted

 *	r5 = proc_info pointer in physical address space

 *	r9 = cpuid

 *	r9 = cpuid (preserved)

 */

	.type	__lookup_processor_type, %function

__lookup_processor_type:

	adr	r3, 3f

	ldmda	r3, {r5, r6, r9}

	sub	r3, r3, r9			@ get offset between virt&phys

	ldmda	r3, {r5 - r7}

	sub	r3, r3, r7			@ get offset between virt&phys

	add	r5, r5, r3			@ convert virt addresses to

	add	r6, r6, r3			@ physical address space

	mrc	p15, 0, r9, c0, c0		@ get processor id

1:	ldmia	r5, {r3, r4}			@ value, mask

	and	r4, r4, r9			@ mask wanted bits

	teq	r3, r4
@@ -477,10 +479,11 @@ __lookup_processor_type: 
 * This provides a C-API version of the above function.

 */

ENTRY(lookup_processor_type)

	stmfd	sp!, {r4 - r6, r9, lr}

	stmfd	sp!, {r4 - r7, r9, lr}

	mov	r9, r0

	bl	__lookup_processor_type

	mov	r0, r5

	ldmfd	sp!, {r4 - r6, r9, pc}

	ldmfd	sp!, {r4 - r7, r9, pc}



/*

 * Look in include/asm-arm/procinfo.h and arch/arm/kernel/arch.[ch] for

arch/arm/kernel/setup.c

+2 −2
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ int cpu_architecture(void) 
 * These functions re-use the assembly code in head.S, which

 * already provide the required functionality.

 */

extern struct proc_info_list *lookup_processor_type(void);

extern struct proc_info_list *lookup_processor_type(unsigned int);

extern struct machine_desc *lookup_machine_type(unsigned int);



static void __init setup_processor(void)
@@ -290,7 +290,7 @@ static void __init setup_processor(void) 
	 * types.  The linker builds this table for us from the

	 * entries in arch/arm/mm/proc-*.S

	 */

	list = lookup_processor_type();

	list = lookup_processor_type(processor_id);

	if (!list) {

		printk("CPU configuration botched (ID %08x), unable "

		       "to continue.\n", processor_id);