 6ebbf2ce43
			
		
	
	
	6ebbf2ce43
	
	
	
		
			
			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>
		
	
			
		
			
				
	
	
		
			225 lines
		
	
	
	
		
			5.2 KiB
			
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			225 lines
		
	
	
	
		
			5.2 KiB
			
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
| /*
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|  *  linux/arch/arm/mm/proc-sa110.S
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|  *
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|  *  Copyright (C) 1997-2002 Russell King
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|  *  hacked for non-paged-MM by Hyok S. Choi, 2003.
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|  *
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|  * This program is free software; you can redistribute it and/or modify
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|  * it under the terms of the GNU General Public License version 2 as
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|  * published by the Free Software Foundation.
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|  *
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|  *  MMU functions for SA110
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|  *
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|  *  These are the low level assembler for performing cache and TLB
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|  *  functions on the StrongARM-110.
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|  */
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| #include <linux/linkage.h>
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| #include <linux/init.h>
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| #include <asm/assembler.h>
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| #include <asm/asm-offsets.h>
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| #include <asm/hwcap.h>
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| #include <mach/hardware.h>
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| #include <asm/pgtable-hwdef.h>
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| #include <asm/pgtable.h>
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| #include <asm/ptrace.h>
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| 
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| #include "proc-macros.S"
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| 
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| /*
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|  * the cache line size of the I and D cache
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|  */
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| #define DCACHELINESIZE	32
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| 
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| 	.text
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| 
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| /*
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|  * cpu_sa110_proc_init()
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|  */
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| ENTRY(cpu_sa110_proc_init)
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| 	mov	r0, #0
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| 	mcr	p15, 0, r0, c15, c1, 2		@ Enable clock switching
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| 	ret	lr
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| 
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| /*
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|  * cpu_sa110_proc_fin()
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|  */
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| ENTRY(cpu_sa110_proc_fin)
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| 	mov	r0, #0
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| 	mcr	p15, 0, r0, c15, c2, 2		@ Disable clock switching
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| 	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
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| 	bic	r0, r0, #0x1000			@ ...i............
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| 	bic	r0, r0, #0x000e			@ ............wca.
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| 	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
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| 	ret	lr
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| 
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| /*
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|  * cpu_sa110_reset(loc)
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|  *
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|  * Perform a soft reset of the system.  Put the CPU into the
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|  * same state as it would be if it had been reset, and branch
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|  * to what would be the reset vector.
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|  *
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|  * loc: location to jump to for soft reset
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|  */
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| 	.align	5
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| 	.pushsection	.idmap.text, "ax"
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| ENTRY(cpu_sa110_reset)
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| 	mov	ip, #0
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| 	mcr	p15, 0, ip, c7, c7, 0		@ invalidate I,D caches
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| 	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
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| #ifdef CONFIG_MMU
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| 	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I & D TLBs
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| #endif
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| 	mrc	p15, 0, ip, c1, c0, 0		@ ctrl register
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| 	bic	ip, ip, #0x000f			@ ............wcam
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| 	bic	ip, ip, #0x1100			@ ...i...s........
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| 	mcr	p15, 0, ip, c1, c0, 0		@ ctrl register
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| 	ret	r0
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| ENDPROC(cpu_sa110_reset)
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| 	.popsection
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| 
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| /*
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|  * cpu_sa110_do_idle(type)
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|  *
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|  * Cause the processor to idle
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|  *
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|  * type: call type:
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|  *   0 = slow idle
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|  *   1 = fast idle
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|  *   2 = switch to slow processor clock
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|  *   3 = switch to fast processor clock
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|  */
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| 	.align	5
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| 
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| ENTRY(cpu_sa110_do_idle)
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| 	mcr	p15, 0, ip, c15, c2, 2		@ disable clock switching
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| 	ldr	r1, =UNCACHEABLE_ADDR		@ load from uncacheable loc
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| 	ldr	r1, [r1, #0]			@ force switch to MCLK
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| 	mov	r0, r0				@ safety
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| 	mov	r0, r0				@ safety
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| 	mov	r0, r0				@ safety
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| 	mcr	p15, 0, r0, c15, c8, 2		@ Wait for interrupt, cache aligned
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| 	mov	r0, r0				@ safety
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| 	mov	r0, r0				@ safety
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| 	mov	r0, r0				@ safety
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| 	mcr	p15, 0, r0, c15, c1, 2		@ enable clock switching
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| 	ret	lr
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| 
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| /* ================================= CACHE ================================ */
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| 
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| /*
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|  * cpu_sa110_dcache_clean_area(addr,sz)
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|  *
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|  * Clean the specified entry of any caches such that the MMU
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|  * translation fetches will obtain correct data.
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|  *
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|  * addr: cache-unaligned virtual address
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|  */
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| 	.align	5
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| ENTRY(cpu_sa110_dcache_clean_area)
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| 1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
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| 	add	r0, r0, #DCACHELINESIZE
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| 	subs	r1, r1, #DCACHELINESIZE
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| 	bhi	1b
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| 	ret	lr
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| 
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| /* =============================== PageTable ============================== */
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| 
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| /*
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|  * cpu_sa110_switch_mm(pgd)
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|  *
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|  * Set the translation base pointer to be as described by pgd.
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|  *
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|  * pgd: new page tables
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|  */
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| 	.align	5
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| ENTRY(cpu_sa110_switch_mm)
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| #ifdef CONFIG_MMU
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| 	str	lr, [sp, #-4]!
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| 	bl	v4wb_flush_kern_cache_all	@ clears IP
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| 	mcr	p15, 0, r0, c2, c0, 0		@ load page table pointer
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| 	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I & D TLBs
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| 	ldr	pc, [sp], #4
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| #else
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| 	ret	lr
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| #endif
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| 
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| /*
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|  * cpu_sa110_set_pte_ext(ptep, pte, ext)
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|  *
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|  * Set a PTE and flush it out
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|  */
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| 	.align	5
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| ENTRY(cpu_sa110_set_pte_ext)
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| #ifdef CONFIG_MMU
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| 	armv3_set_pte_ext wc_disable=0
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| 	mov	r0, r0
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| 	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
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| 	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
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| #endif
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| 	ret	lr
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| 
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| 	.type	__sa110_setup, #function
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| __sa110_setup:
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| 	mov	r10, #0
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| 	mcr	p15, 0, r10, c7, c7		@ invalidate I,D caches on v4
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| 	mcr	p15, 0, r10, c7, c10, 4		@ drain write buffer on v4
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| #ifdef CONFIG_MMU
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| 	mcr	p15, 0, r10, c8, c7		@ invalidate I,D TLBs on v4
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| #endif
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| 
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| 	adr	r5, sa110_crval
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| 	ldmia	r5, {r5, r6}
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| 	mrc	p15, 0, r0, c1, c0		@ get control register v4
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| 	bic	r0, r0, r5
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| 	orr	r0, r0, r6
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| 	ret	lr
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| 	.size	__sa110_setup, . - __sa110_setup
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| 
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| 	/*
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| 	 *  R
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| 	 * .RVI ZFRS BLDP WCAM
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| 	 * ..01 0001 ..11 1101
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| 	 * 
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| 	 */
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| 	.type	sa110_crval, #object
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| sa110_crval:
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| 	crval	clear=0x00003f3f, mmuset=0x0000113d, ucset=0x00001130
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| 
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| 	__INITDATA
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| 
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| 	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
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| 	define_processor_functions sa110, dabort=v4_early_abort, pabort=legacy_pabort
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| 
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| 	.section ".rodata"
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| 
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| 	string	cpu_arch_name, "armv4"
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| 	string	cpu_elf_name, "v4"
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| 	string	cpu_sa110_name, "StrongARM-110"
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| 
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| 	.align
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| 
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| 	.section ".proc.info.init", #alloc, #execinstr
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| 
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| 	.type	__sa110_proc_info,#object
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| __sa110_proc_info:
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| 	.long	0x4401a100
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| 	.long	0xfffffff0
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| 	.long   PMD_TYPE_SECT | \
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| 		PMD_SECT_BUFFERABLE | \
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| 		PMD_SECT_CACHEABLE | \
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| 		PMD_SECT_AP_WRITE | \
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| 		PMD_SECT_AP_READ
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| 	.long   PMD_TYPE_SECT | \
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| 		PMD_SECT_AP_WRITE | \
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| 		PMD_SECT_AP_READ
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| 	b	__sa110_setup
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| 	.long	cpu_arch_name
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| 	.long	cpu_elf_name
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| 	.long	HWCAP_SWP | HWCAP_HALF | HWCAP_26BIT | HWCAP_FAST_MULT
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| 	.long	cpu_sa110_name
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| 	.long	sa110_processor_functions
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| 	.long	v4wb_tlb_fns
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| 	.long	v4wb_user_fns
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| 	.long	v4wb_cache_fns
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| 	.size	__sa110_proc_info, . - __sa110_proc_info
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