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linux/arch/arm/mm/proc-arm720.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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5.9 KiB
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/*
* linux/arch/arm/mm/proc-arm720.S: MMU functions for ARM720
*
* Copyright (C) 2000 Steve Hill (sjhill@cotw.com)
* Rob Scott (rscott@mtrob.fdns.net)
* Copyright (C) 2000 ARM Limited, Deep Blue Solutions Ltd.
* 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 ARM720T. The ARM720T has a writethrough IDC
* cache, so we don't need to clean it.
*
* Changelog:
* 05-09-2000 SJH Created by moving 720 specific functions
* out of 'proc-arm6,7.S' per RMK discussion
* 07-25-2000 SJH Added idle function.
* 08-25-2000 DBS Updated for integration of ARM Ltd version.
* 04-20-2004 HSC modified for non-paged memory management mode.
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/hwcap.h>
#include <asm/pgtable-hwdef.h>
#include <asm/pgtable.h>
#include <asm/ptrace.h>
#include "proc-macros.S"
/*
* Function: arm720_proc_init (void)
* : arm720_proc_fin (void)
*
* Notes : This processor does not require these
*/
ENTRY(cpu_arm720_dcache_clean_area)
ENTRY(cpu_arm720_proc_init)
ret lr
ENTRY(cpu_arm720_proc_fin)
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #0x1000 @ ...i............
bic r0, r0, #0x000e @ ............wca.
mcr p15, 0, r0, c1, c0, 0 @ disable caches
ret lr
/*
* Function: arm720_proc_do_idle(void)
* Params : r0 = unused
* Purpose : put the processor in proper idle mode
*/
ENTRY(cpu_arm720_do_idle)
ret lr
/*
* Function: arm720_switch_mm(unsigned long pgd_phys)
* Params : pgd_phys Physical address of page table
* Purpose : Perform a task switch, saving the old process' state and restoring
* the new.
*/
ENTRY(cpu_arm720_switch_mm)
#ifdef CONFIG_MMU
mov r1, #0
mcr p15, 0, r1, c7, c7, 0 @ invalidate cache
mcr p15, 0, r0, c2, c0, 0 @ update page table ptr
mcr p15, 0, r1, c8, c7, 0 @ flush TLB (v4)
#endif
ret lr
/*
* Function: arm720_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext)
* Params : r0 = Address to set
* : r1 = value to set
* Purpose : Set a PTE and flush it out of any WB cache
*/
.align 5
ENTRY(cpu_arm720_set_pte_ext)
#ifdef CONFIG_MMU
armv3_set_pte_ext wc_disable=0
#endif
ret lr
/*
* Function: arm720_reset
* Params : r0 = address to jump to
* Notes : This sets up everything for a reset
*/
.pushsection .idmap.text, "ax"
ENTRY(cpu_arm720_reset)
mov ip, #0
mcr p15, 0, ip, c7, c7, 0 @ invalidate cache
#ifdef CONFIG_MMU
mcr p15, 0, ip, c8, c7, 0 @ flush TLB (v4)
#endif
mrc p15, 0, ip, c1, c0, 0 @ get ctrl register
bic ip, ip, #0x000f @ ............wcam
bic ip, ip, #0x2100 @ ..v....s........
mcr p15, 0, ip, c1, c0, 0 @ ctrl register
ret r0
ENDPROC(cpu_arm720_reset)
.popsection
.type __arm710_setup, #function
__arm710_setup:
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 @ invalidate caches
#ifdef CONFIG_MMU
mcr p15, 0, r0, c8, c7, 0 @ flush TLB (v4)
#endif
mrc p15, 0, r0, c1, c0 @ get control register
ldr r5, arm710_cr1_clear
bic r0, r0, r5
ldr r5, arm710_cr1_set
orr r0, r0, r5
ret lr @ __ret (head.S)
.size __arm710_setup, . - __arm710_setup
/*
* R
* .RVI ZFRS BLDP WCAM
* .... 0001 ..11 1101
*
*/
.type arm710_cr1_clear, #object
.type arm710_cr1_set, #object
arm710_cr1_clear:
.word 0x0f3f
arm710_cr1_set:
.word 0x013d
.type __arm720_setup, #function
__arm720_setup:
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 @ invalidate caches
#ifdef CONFIG_MMU
mcr p15, 0, r0, c8, c7, 0 @ flush TLB (v4)
#endif
adr r5, arm720_crval
ldmia r5, {r5, r6}
mrc p15, 0, r0, c1, c0 @ get control register
bic r0, r0, r5
orr r0, r0, r6
ret lr @ __ret (head.S)
.size __arm720_setup, . - __arm720_setup
/*
* R
* .RVI ZFRS BLDP WCAM
* ..1. 1001 ..11 1101
*
*/
.type arm720_crval, #object
arm720_crval:
crval clear=0x00002f3f, mmuset=0x0000213d, ucset=0x00000130
__INITDATA
@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
define_processor_functions arm720, dabort=v4t_late_abort, pabort=legacy_pabort
.section ".rodata"
string cpu_arch_name, "armv4t"
string cpu_elf_name, "v4"
string cpu_arm710_name, "ARM710T"
string cpu_arm720_name, "ARM720T"
.align
/*
* See <asm/procinfo.h> for a definition of this structure.
*/
.section ".proc.info.init", #alloc, #execinstr
.macro arm720_proc_info name:req, cpu_val:req, cpu_mask:req, cpu_name:req, cpu_flush:req
.type __\name\()_proc_info,#object
__\name\()_proc_info:
.long \cpu_val
.long \cpu_mask
.long PMD_TYPE_SECT | \
PMD_SECT_BUFFERABLE | \
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 \cpu_flush @ cpu_flush
.long cpu_arch_name @ arch_name
.long cpu_elf_name @ elf_name
.long HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB @ elf_hwcap
.long \cpu_name
.long arm720_processor_functions
.long v4_tlb_fns
.long v4wt_user_fns
.long v4_cache_fns
.size __\name\()_proc_info, . - __\name\()_proc_info
.endm
arm720_proc_info arm710, 0x41807100, 0xffffff00, cpu_arm710_name, __arm710_setup
arm720_proc_info arm720, 0x41807200, 0xffffff00, cpu_arm720_name, __arm720_setup
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