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linux/arch/arm/mm/proc-arm925.S
Russell King 6ebbf2ce43 ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 
ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls.  Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).

We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.

Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code.  This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.

Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-07-18 12:29:04 +01:00

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/*
* linux/arch/arm/mm/arm925.S: MMU functions for ARM925
*
* Copyright (C) 1999,2000 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd.
* Copyright (C) 2002 RidgeRun, Inc.
* Copyright (C) 2002-2003 MontaVista Software, Inc.
*
* Update for Linux-2.6 and cache flush improvements
* Copyright (C) 2004 Nokia Corporation by Tony Lindgren <tony@atomide.com>
*
* hacked for non-paged-MM by Hyok S. Choi, 2004.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* These are the low level assembler for performing cache and TLB
* functions on the arm925.
*
* CONFIG_CPU_ARM925_CPU_IDLE -> nohlt
*
* Some additional notes based on deciphering the TI TRM on OMAP-5910:
*
* NOTE1: The TI925T Configuration Register bit "D-cache clean and flush
* entry mode" must be 0 to flush the entries in both segments
* at once. This is the default value. See TRM 2-20 and 2-24 for
* more information.
*
* NOTE2: Default is the "D-cache clean and flush entry mode". It looks
* like the "Transparent mode" must be on for partial cache flushes
* to work in this mode. This mode only works with 16-bit external
* memory. See TRM 2-24 for more information.
*
* NOTE3: Write-back cache flushing seems to be flakey with devices using
* direct memory access, such as USB OHCI. The workaround is to use
* write-through cache with CONFIG_CPU_DCACHE_WRITETHROUGH (this is
* the default for OMAP-1510).
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/hwcap.h>
#include <asm/pgtable-hwdef.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include "proc-macros.S"
/*
* The size of one data cache line.
*/
#define CACHE_DLINESIZE 16
/*
* The number of data cache segments.
*/
#define CACHE_DSEGMENTS 2
/*
* The number of lines in a cache segment.
*/
#define CACHE_DENTRIES 256
/*
* This is the size at which it becomes more efficient to
* clean the whole cache, rather than using the individual
* cache line maintenance instructions.
*/
#define CACHE_DLIMIT 8192
.text
/*
* cpu_arm925_proc_init()
*/
ENTRY(cpu_arm925_proc_init)
ret lr
/*
* cpu_arm925_proc_fin()
*/
ENTRY(cpu_arm925_proc_fin)
mrc p15, 0, r0, c1, c0, 0 @ ctrl register
bic r0, r0, #0x1000 @ ...i............
bic r0, r0, #0x000e @ ............wca.
mcr p15, 0, r0, c1, c0, 0 @ disable caches
ret lr
/*
* cpu_arm925_reset(loc)
*
* Perform a soft reset of the system. Put the CPU into the
* same state as it would be if it had been reset, and branch
* to what would be the reset vector.
*
* loc: location to jump to for soft reset
*/
.align 5
.pushsection .idmap.text, "ax"
ENTRY(cpu_arm925_reset)
/* Send software reset to MPU and DSP */
mov ip, #0xff000000
orr ip, ip, #0x00fe0000
orr ip, ip, #0x0000ce00
mov r4, #1
strh r4, [ip, #0x10]
ENDPROC(cpu_arm925_reset)
.popsection
mov ip, #0
mcr p15, 0, ip, c7, c7, 0 @ invalidate I,D caches
mcr p15, 0, ip, c7, c10, 4 @ drain WB
#ifdef CONFIG_MMU
mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
#endif
mrc p15, 0, ip, c1, c0, 0 @ ctrl register
bic ip, ip, #0x000f @ ............wcam
bic ip, ip, #0x1100 @ ...i...s........
mcr p15, 0, ip, c1, c0, 0 @ ctrl register
ret r0
/*
* cpu_arm925_do_idle()
*
* Called with IRQs disabled
*/
.align 10
ENTRY(cpu_arm925_do_idle)
mov r0, #0
mrc p15, 0, r1, c1, c0, 0 @ Read control register
mcr p15, 0, r0, c7, c10, 4 @ Drain write buffer
bic r2, r1, #1 << 12
mcr p15, 0, r2, c1, c0, 0 @ Disable I cache
mcr p15, 0, r0, c7, c0, 4 @ Wait for interrupt
mcr p15, 0, r1, c1, c0, 0 @ Restore ICache enable
ret lr
/*
* flush_icache_all()
*
* Unconditionally clean and invalidate the entire icache.
*/
ENTRY(arm925_flush_icache_all)
mov r0, #0
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
ret lr
ENDPROC(arm925_flush_icache_all)
/*
* flush_user_cache_all()
*
* Clean and invalidate all cache entries in a particular
* address space.
*/
ENTRY(arm925_flush_user_cache_all)
/* FALLTHROUGH */
/*
* flush_kern_cache_all()
*
* Clean and invalidate the entire cache.
*/
ENTRY(arm925_flush_kern_cache_all)
mov r2, #VM_EXEC
mov ip, #0
__flush_whole_cache:
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache
#else
/* Flush entries in both segments at once, see NOTE1 above */
mov r3, #(CACHE_DENTRIES - 1) << 4 @ 256 entries in segment
2: mcr p15, 0, r3, c7, c14, 2 @ clean+invalidate D index
subs r3, r3, #1 << 4
bcs 2b @ entries 255 to 0
#endif
tst r2, #VM_EXEC
mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
mcrne p15, 0, ip, c7, c10, 4 @ drain WB
ret lr
/*
* flush_user_cache_range(start, end, flags)
*
* Clean and invalidate a range of cache entries in the
* specified address range.
*
* - start - start address (inclusive)
* - end - end address (exclusive)
* - flags - vm_flags describing address space
*/
ENTRY(arm925_flush_user_cache_range)
mov ip, #0
sub r3, r1, r0 @ calculate total size
cmp r3, #CACHE_DLIMIT
bgt __flush_whole_cache
1: tst r2, #VM_EXEC
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
add r0, r0, #CACHE_DLINESIZE
mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
add r0, r0, #CACHE_DLINESIZE
#else
mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
add r0, r0, #CACHE_DLINESIZE
mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
add r0, r0, #CACHE_DLINESIZE
#endif
cmp r0, r1
blo 1b
tst r2, #VM_EXEC
mcrne p15, 0, ip, c7, c10, 4 @ drain WB
ret lr
/*
* coherent_kern_range(start, end)
*
* Ensure coherency between the Icache and the Dcache in the
* region described by start, end. If you have non-snooping
* Harvard caches, you need to implement this function.
*
* - start - virtual start address
* - end - virtual end address
*/
ENTRY(arm925_coherent_kern_range)
/* FALLTHROUGH */
/*
* coherent_user_range(start, end)
*
* Ensure coherency between the Icache and the Dcache in the
* region described by start, end. If you have non-snooping
* Harvard caches, you need to implement this function.
*
* - start - virtual start address
* - end - virtual end address
*/
ENTRY(arm925_coherent_user_range)
bic r0, r0, #CACHE_DLINESIZE - 1
1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mcr p15, 0, r0, c7, c10, 4 @ drain WB
mov r0, #0
ret lr
/*
* flush_kern_dcache_area(void *addr, size_t size)
*
* Ensure no D cache aliasing occurs, either with itself or
* the I cache
*
* - addr - kernel address
* - size - region size
*/
ENTRY(arm925_flush_kern_dcache_area)
add r1, r0, r1
1: mcr p15, 0, r0, c7, c14, 1 @ clean+invalidate D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
mcr p15, 0, r0, c7, c10, 4 @ drain WB
ret lr
/*
* dma_inv_range(start, end)
*
* Invalidate (discard) the specified virtual address range.
* May not write back any entries. If 'start' or 'end'
* are not cache line aligned, those lines must be written
* back.
*
* - start - virtual start address
* - end - virtual end address
*
* (same as v4wb)
*/
arm925_dma_inv_range:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
tst r0, #CACHE_DLINESIZE - 1
mcrne p15, 0, r0, c7, c10, 1 @ clean D entry
tst r1, #CACHE_DLINESIZE - 1
mcrne p15, 0, r1, c7, c10, 1 @ clean D entry
#endif
bic r0, r0, #CACHE_DLINESIZE - 1
1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mcr p15, 0, r0, c7, c10, 4 @ drain WB
ret lr
/*
* dma_clean_range(start, end)
*
* Clean the specified virtual address range.
*
* - start - virtual start address
* - end - virtual end address
*
* (same as v4wb)
*/
arm925_dma_clean_range:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
bic r0, r0, #CACHE_DLINESIZE - 1
1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
#endif
mcr p15, 0, r0, c7, c10, 4 @ drain WB
ret lr
/*
* dma_flush_range(start, end)
*
* Clean and invalidate the specified virtual address range.
*
* - start - virtual start address
* - end - virtual end address
*/
ENTRY(arm925_dma_flush_range)
bic r0, r0, #CACHE_DLINESIZE - 1
1:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
mcr p15, 0, r0, c7, c14, 1 @ clean+invalidate D entry
#else
mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
#endif
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mcr p15, 0, r0, c7, c10, 4 @ drain WB
ret lr
/*
* dma_map_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
ENTRY(arm925_dma_map_area)
add r1, r1, r0
cmp r2, #DMA_TO_DEVICE
beq arm925_dma_clean_range
bcs arm925_dma_inv_range
b arm925_dma_flush_range
ENDPROC(arm925_dma_map_area)
/*
* dma_unmap_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
ENTRY(arm925_dma_unmap_area)
ret lr
ENDPROC(arm925_dma_unmap_area)
.globl arm925_flush_kern_cache_louis
.equ arm925_flush_kern_cache_louis, arm925_flush_kern_cache_all
@ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
define_cache_functions arm925
ENTRY(cpu_arm925_dcache_clean_area)
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
add r0, r0, #CACHE_DLINESIZE
subs r1, r1, #CACHE_DLINESIZE
bhi 1b
#endif
mcr p15, 0, r0, c7, c10, 4 @ drain WB
ret lr
/* =============================== PageTable ============================== */
/*
* cpu_arm925_switch_mm(pgd)
*
* Set the translation base pointer to be as described by pgd.
*
* pgd: new page tables
*/
.align 5
ENTRY(cpu_arm925_switch_mm)
#ifdef CONFIG_MMU
mov ip, #0
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache
#else
/* Flush entries in bothe segments at once, see NOTE1 above */
mov r3, #(CACHE_DENTRIES - 1) << 4 @ 256 entries in segment
2: mcr p15, 0, r3, c7, c14, 2 @ clean & invalidate D index
subs r3, r3, #1 << 4
bcs 2b @ entries 255 to 0
#endif
mcr p15, 0, ip, c7, c5, 0 @ invalidate I cache
mcr p15, 0, ip, c7, c10, 4 @ drain WB
mcr p15, 0, r0, c2, c0, 0 @ load page table pointer
mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
#endif
ret lr
/*
* cpu_arm925_set_pte_ext(ptep, pte, ext)
*
* Set a PTE and flush it out
*/
.align 5
ENTRY(cpu_arm925_set_pte_ext)
#ifdef CONFIG_MMU
armv3_set_pte_ext
mov r0, r0
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
mcr p15, 0, r0, c7, c10, 1 @ clean D entry
#endif
mcr p15, 0, r0, c7, c10, 4 @ drain WB
#endif /* CONFIG_MMU */
ret lr
.type __arm925_setup, #function
__arm925_setup:
mov r0, #0
#if defined(CONFIG_CPU_ICACHE_STREAMING_DISABLE)
orr r0,r0,#1 << 7
#endif
/* Transparent on, D-cache clean & flush mode. See NOTE2 above */
orr r0,r0,#1 << 1 @ transparent mode on
mcr p15, 0, r0, c15, c1, 0 @ write TI config register
mov r0, #0
mcr p15, 0, r0, c7, c7 @ invalidate I,D caches on v4
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer on v4
#ifdef CONFIG_MMU
mcr p15, 0, r0, c8, c7 @ invalidate I,D TLBs on v4
#endif
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
mov r0, #4 @ disable write-back on caches explicitly
mcr p15, 7, r0, c15, c0, 0
#endif
adr r5, arm925_crval
ldmia r5, {r5, r6}
mrc p15, 0, r0, c1, c0 @ get control register v4
bic r0, r0, r5
orr r0, r0, r6
#ifdef CONFIG_CPU_CACHE_ROUND_ROBIN
orr r0, r0, #0x4000 @ .1.. .... .... ....
#endif
ret lr
.size __arm925_setup, . - __arm925_setup
/*
* R
* .RVI ZFRS BLDP WCAM
* .011 0001 ..11 1101
*
*/
.type arm925_crval, #object
arm925_crval:
crval clear=0x00007f3f, mmuset=0x0000313d, ucset=0x00001130
__INITDATA
@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
define_processor_functions arm925, dabort=v4t_early_abort, pabort=legacy_pabort
.section ".rodata"
string cpu_arch_name, "armv4t"
string cpu_elf_name, "v4"
string cpu_arm925_name, "ARM925T"
.align
.section ".proc.info.init", #alloc, #execinstr
.macro arm925_proc_info name:req, cpu_val:req, cpu_mask:req, cpu_name:req, cache
.type __\name\()_proc_info,#object
__\name\()_proc_info:
.long \cpu_val
.long \cpu_mask
.long PMD_TYPE_SECT | \
PMD_SECT_CACHEABLE | \
PMD_BIT4 | \
PMD_SECT_AP_WRITE | \
PMD_SECT_AP_READ
.long PMD_TYPE_SECT | \
PMD_BIT4 | \
PMD_SECT_AP_WRITE | \
PMD_SECT_AP_READ
b __arm925_setup
.long cpu_arch_name
.long cpu_elf_name
.long HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB
.long cpu_arm925_name
.long arm925_processor_functions
.long v4wbi_tlb_fns
.long v4wb_user_fns
.long arm925_cache_fns
.size __\name\()_proc_info, . - __\name\()_proc_info
.endm
arm925_proc_info arm925, 0x54029250, 0xfffffff0, cpu_arm925_name
arm925_proc_info arm915, 0x54029150, 0xfffffff0, cpu_arm925_name
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