linux/arch/arm/mm/tlb-v7.S
Russell King f00ec48fad ARM: Allow SMP kernels to boot on UP systems
UP systems do not implement all the instructions that SMP systems have,
so in order to boot a SMP kernel on a UP system, we need to rewrite
parts of the kernel.

Do this using an 'alternatives' scheme, where the kernel code and data
is modified prior to initialization to replace the SMP instructions,
thereby rendering the problematical code ineffectual.  We use the linker
to generate a list of 32-bit word locations and their replacement values,
and run through these replacements when we detect a UP system.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-10-04 20:23:36 +01:00

95 lines
2.6 KiB
ArmAsm

/*
* linux/arch/arm/mm/tlb-v7.S
*
* Copyright (C) 1997-2002 Russell King
* Modified for ARMv7 by Catalin Marinas
*
* 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.
*
* ARM architecture version 6 TLB handling functions.
* These assume a split I/D TLB.
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/page.h>
#include <asm/tlbflush.h>
#include "proc-macros.S"
/*
* v7wbi_flush_user_tlb_range(start, end, vma)
*
* Invalidate a range of TLB entries in the specified address space.
*
* - start - start address (may not be aligned)
* - end - end address (exclusive, may not be aligned)
* - vma - vma_struct describing address range
*
* It is assumed that:
* - the "Invalidate single entry" instruction will invalidate
* both the I and the D TLBs on Harvard-style TLBs
*/
ENTRY(v7wbi_flush_user_tlb_range)
vma_vm_mm r3, r2 @ get vma->vm_mm
mmid r3, r3 @ get vm_mm->context.id
dsb
mov r0, r0, lsr #PAGE_SHIFT @ align address
mov r1, r1, lsr #PAGE_SHIFT
asid r3, r3 @ mask ASID
orr r0, r3, r0, lsl #PAGE_SHIFT @ Create initial MVA
mov r1, r1, lsl #PAGE_SHIFT
1:
ALT_SMP(mcr p15, 0, r0, c8, c3, 1) @ TLB invalidate U MVA (shareable)
ALT_UP(mcr p15, 0, r0, c8, c7, 1) @ TLB invalidate U MVA
add r0, r0, #PAGE_SZ
cmp r0, r1
blo 1b
mov ip, #0
ALT_SMP(mcr p15, 0, ip, c7, c1, 6) @ flush BTAC/BTB Inner Shareable
ALT_UP(mcr p15, 0, ip, c7, c5, 6) @ flush BTAC/BTB
dsb
mov pc, lr
ENDPROC(v7wbi_flush_user_tlb_range)
/*
* v7wbi_flush_kern_tlb_range(start,end)
*
* Invalidate a range of kernel TLB entries
*
* - start - start address (may not be aligned)
* - end - end address (exclusive, may not be aligned)
*/
ENTRY(v7wbi_flush_kern_tlb_range)
dsb
mov r0, r0, lsr #PAGE_SHIFT @ align address
mov r1, r1, lsr #PAGE_SHIFT
mov r0, r0, lsl #PAGE_SHIFT
mov r1, r1, lsl #PAGE_SHIFT
1:
ALT_SMP(mcr p15, 0, r0, c8, c3, 1) @ TLB invalidate U MVA (shareable)
ALT_UP(mcr p15, 0, r0, c8, c7, 1) @ TLB invalidate U MVA
add r0, r0, #PAGE_SZ
cmp r0, r1
blo 1b
mov r2, #0
ALT_SMP(mcr p15, 0, r2, c7, c1, 6) @ flush BTAC/BTB Inner Shareable
ALT_UP(mcr p15, 0, r2, c7, c5, 6) @ flush BTAC/BTB
dsb
isb
mov pc, lr
ENDPROC(v7wbi_flush_kern_tlb_range)
__INIT
.type v7wbi_tlb_fns, #object
ENTRY(v7wbi_tlb_fns)
.long v7wbi_flush_user_tlb_range
.long v7wbi_flush_kern_tlb_range
ALT_SMP(.long v7wbi_tlb_flags_smp)
ALT_UP(.long v7wbi_tlb_flags_up)
.size v7wbi_tlb_fns, . - v7wbi_tlb_fns