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Commit 0eb0511d authored by Russell King's avatar Russell King
Browse files

ARM: SMP: use more sane register allocation for __fixup_smp_on_up 



Use r0,r3-r6 rather than r0,r3,r4,r6,r7, which makes it easier to
understand which registers can be modified.  Also document which
registers hold values which must be preserved.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent b54992fe

arch/arm/kernel/head.S

+22 −17
Original line number Diff line number Diff line
@@ -89,6 +89,11 @@ ENTRY(stext) 
	bl	__lookup_machine_type		@ r5=machinfo

	movs	r8, r5				@ invalid machine (r5=0)?

	beq	__error_a			@ yes, error 'a'



	/*

	 * r1 = machine no, r2 = atags,

	 * r8 = machinfo, r9 = cpuid, r10 = procinfo

	 */

	bl	__vet_atags

#ifdef CONFIG_SMP_ON_UP

	bl	__fixup_smp
@@ -381,19 +386,19 @@ ENDPROC(__turn_mmu_on) 


#ifdef CONFIG_SMP_ON_UP

__fixup_smp:

	mov	r7, #0x00070000

	orr	r6, r7, #0xff000000	@ mask 0xff070000

	orr	r7, r7, #0x41000000	@ val 0x41070000

	and	r0, r9, r6

	teq	r0, r7			@ ARM CPU and ARMv6/v7?

	mov	r4, #0x00070000

	orr	r3, r4, #0xff000000	@ mask 0xff070000

	orr	r4, r4, #0x41000000	@ val 0x41070000

	and	r0, r9, r3

	teq	r0, r4			@ ARM CPU and ARMv6/v7?

	bne	__fixup_smp_on_up	@ no, assume UP



	orr	r6, r6, #0x0000ff00

	orr	r6, r6, #0x000000f0	@ mask 0xff07fff0

	orr	r7, r7, #0x0000b000

	orr	r7, r7, #0x00000020	@ val 0x4107b020

	and	r0, r9, r6

	teq	r0, r7			@ ARM 11MPCore?

	orr	r3, r3, #0x0000ff00

	orr	r3, r3, #0x000000f0	@ mask 0xff07fff0

	orr	r4, r4, #0x0000b000

	orr	r4, r4, #0x00000020	@ val 0x4107b020

	and	r0, r9, r3

	teq	r0, r4			@ ARM 11MPCore?

	moveq	pc, lr			@ yes, assume SMP



	mrc	p15, 0, r0, c0, c0, 5	@ read MPIDR
@@ -402,13 +407,13 @@ __fixup_smp: 


__fixup_smp_on_up:

	adr	r0, 1f

	ldmia	r0, {r3, r6, r7}

	ldmia	r0, {r3 - r5}

	sub	r3, r0, r3

	add	r6, r6, r3

	add	r7, r7, r3

2:	cmp	r6, r7

	ldmia	r6!, {r0, r4}

	strlo	r4, [r0, r3]

	add	r4, r4, r3

	add	r5, r5, r3

2:	cmp	r4, r5

	ldmia	r4!, {r0, r6}

	strlo	r6, [r0, r3]

	blo	2b

	mov	pc, lr

ENDPROC(__fixup_smp)