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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>
313 lines
8.4 KiB
ArmAsm
313 lines
8.4 KiB
ArmAsm
/*
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* arch/arm/kernel/crunch-bits.S
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* Cirrus MaverickCrunch context switching and handling
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*
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* Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
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*
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* Shamelessly stolen from the iWMMXt code by Nicolas Pitre, which is
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* Copyright (c) 2003-2004, MontaVista Software, Inc.
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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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#include <linux/linkage.h>
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#include <asm/ptrace.h>
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#include <asm/thread_info.h>
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#include <asm/asm-offsets.h>
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#include <asm/assembler.h>
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#include <mach/ep93xx-regs.h>
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/*
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* We can't use hex constants here due to a bug in gas.
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*/
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#define CRUNCH_MVDX0 0
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#define CRUNCH_MVDX1 8
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#define CRUNCH_MVDX2 16
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#define CRUNCH_MVDX3 24
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#define CRUNCH_MVDX4 32
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#define CRUNCH_MVDX5 40
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#define CRUNCH_MVDX6 48
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#define CRUNCH_MVDX7 56
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#define CRUNCH_MVDX8 64
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#define CRUNCH_MVDX9 72
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#define CRUNCH_MVDX10 80
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#define CRUNCH_MVDX11 88
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#define CRUNCH_MVDX12 96
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#define CRUNCH_MVDX13 104
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#define CRUNCH_MVDX14 112
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#define CRUNCH_MVDX15 120
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#define CRUNCH_MVAX0L 128
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#define CRUNCH_MVAX0M 132
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#define CRUNCH_MVAX0H 136
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#define CRUNCH_MVAX1L 140
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#define CRUNCH_MVAX1M 144
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#define CRUNCH_MVAX1H 148
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#define CRUNCH_MVAX2L 152
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#define CRUNCH_MVAX2M 156
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#define CRUNCH_MVAX2H 160
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#define CRUNCH_MVAX3L 164
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#define CRUNCH_MVAX3M 168
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#define CRUNCH_MVAX3H 172
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#define CRUNCH_DSPSC 176
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#define CRUNCH_SIZE 184
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.text
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/*
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* Lazy switching of crunch coprocessor context
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*
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* r10 = struct thread_info pointer
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* r9 = ret_from_exception
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* lr = undefined instr exit
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*
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* called from prefetch exception handler with interrupts enabled
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*/
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ENTRY(crunch_task_enable)
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inc_preempt_count r10, r3
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ldr r8, =(EP93XX_APB_VIRT_BASE + 0x00130000) @ syscon addr
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ldr r1, [r8, #0x80]
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tst r1, #0x00800000 @ access to crunch enabled?
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bne 2f @ if so no business here
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mov r3, #0xaa @ unlock syscon swlock
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str r3, [r8, #0xc0]
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orr r1, r1, #0x00800000 @ enable access to crunch
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str r1, [r8, #0x80]
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ldr r3, =crunch_owner
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add r0, r10, #TI_CRUNCH_STATE @ get task crunch save area
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ldr r2, [sp, #60] @ current task pc value
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ldr r1, [r3] @ get current crunch owner
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str r0, [r3] @ this task now owns crunch
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sub r2, r2, #4 @ adjust pc back
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str r2, [sp, #60]
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ldr r2, [r8, #0x80]
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mov r2, r2 @ flush out enable (@@@)
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teq r1, #0 @ test for last ownership
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mov lr, r9 @ normal exit from exception
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beq crunch_load @ no owner, skip save
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crunch_save:
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cfstr64 mvdx0, [r1, #CRUNCH_MVDX0] @ save 64b registers
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cfstr64 mvdx1, [r1, #CRUNCH_MVDX1]
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cfstr64 mvdx2, [r1, #CRUNCH_MVDX2]
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cfstr64 mvdx3, [r1, #CRUNCH_MVDX3]
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cfstr64 mvdx4, [r1, #CRUNCH_MVDX4]
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cfstr64 mvdx5, [r1, #CRUNCH_MVDX5]
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cfstr64 mvdx6, [r1, #CRUNCH_MVDX6]
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cfstr64 mvdx7, [r1, #CRUNCH_MVDX7]
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cfstr64 mvdx8, [r1, #CRUNCH_MVDX8]
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cfstr64 mvdx9, [r1, #CRUNCH_MVDX9]
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cfstr64 mvdx10, [r1, #CRUNCH_MVDX10]
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cfstr64 mvdx11, [r1, #CRUNCH_MVDX11]
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cfstr64 mvdx12, [r1, #CRUNCH_MVDX12]
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cfstr64 mvdx13, [r1, #CRUNCH_MVDX13]
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cfstr64 mvdx14, [r1, #CRUNCH_MVDX14]
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cfstr64 mvdx15, [r1, #CRUNCH_MVDX15]
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#ifdef __ARMEB__
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#error fix me for ARMEB
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#endif
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cfmv32al mvfx0, mvax0 @ save 72b accumulators
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX0L]
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cfmv32am mvfx0, mvax0
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX0M]
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cfmv32ah mvfx0, mvax0
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX0H]
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cfmv32al mvfx0, mvax1
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX1L]
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cfmv32am mvfx0, mvax1
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX1M]
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cfmv32ah mvfx0, mvax1
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX1H]
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cfmv32al mvfx0, mvax2
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX2L]
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cfmv32am mvfx0, mvax2
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX2M]
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cfmv32ah mvfx0, mvax2
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX2H]
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cfmv32al mvfx0, mvax3
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX3L]
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cfmv32am mvfx0, mvax3
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX3M]
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cfmv32ah mvfx0, mvax3
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cfstr32 mvfx0, [r1, #CRUNCH_MVAX3H]
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cfmv32sc mvdx0, dspsc @ save status word
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cfstr64 mvdx0, [r1, #CRUNCH_DSPSC]
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teq r0, #0 @ anything to load?
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cfldr64eq mvdx0, [r1, #CRUNCH_MVDX0] @ mvdx0 was clobbered
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beq 1f
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crunch_load:
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cfldr64 mvdx0, [r0, #CRUNCH_DSPSC] @ load status word
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cfmvsc32 dspsc, mvdx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX0L] @ load 72b accumulators
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cfmval32 mvax0, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX0M]
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cfmvam32 mvax0, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX0H]
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cfmvah32 mvax0, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX1L]
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cfmval32 mvax1, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX1M]
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cfmvam32 mvax1, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX1H]
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cfmvah32 mvax1, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX2L]
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cfmval32 mvax2, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX2M]
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cfmvam32 mvax2, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX2H]
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cfmvah32 mvax2, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX3L]
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cfmval32 mvax3, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX3M]
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cfmvam32 mvax3, mvfx0
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cfldr32 mvfx0, [r0, #CRUNCH_MVAX3H]
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cfmvah32 mvax3, mvfx0
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cfldr64 mvdx0, [r0, #CRUNCH_MVDX0] @ load 64b registers
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cfldr64 mvdx1, [r0, #CRUNCH_MVDX1]
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cfldr64 mvdx2, [r0, #CRUNCH_MVDX2]
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cfldr64 mvdx3, [r0, #CRUNCH_MVDX3]
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cfldr64 mvdx4, [r0, #CRUNCH_MVDX4]
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cfldr64 mvdx5, [r0, #CRUNCH_MVDX5]
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cfldr64 mvdx6, [r0, #CRUNCH_MVDX6]
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cfldr64 mvdx7, [r0, #CRUNCH_MVDX7]
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cfldr64 mvdx8, [r0, #CRUNCH_MVDX8]
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cfldr64 mvdx9, [r0, #CRUNCH_MVDX9]
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cfldr64 mvdx10, [r0, #CRUNCH_MVDX10]
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cfldr64 mvdx11, [r0, #CRUNCH_MVDX11]
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cfldr64 mvdx12, [r0, #CRUNCH_MVDX12]
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cfldr64 mvdx13, [r0, #CRUNCH_MVDX13]
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cfldr64 mvdx14, [r0, #CRUNCH_MVDX14]
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cfldr64 mvdx15, [r0, #CRUNCH_MVDX15]
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1:
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#ifdef CONFIG_PREEMPT_COUNT
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get_thread_info r10
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#endif
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2: dec_preempt_count r10, r3
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ret lr
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/*
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* Back up crunch regs to save area and disable access to them
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* (mainly for gdb or sleep mode usage)
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*
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* r0 = struct thread_info pointer of target task or NULL for any
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*/
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ENTRY(crunch_task_disable)
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stmfd sp!, {r4, r5, lr}
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mrs ip, cpsr
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orr r2, ip, #PSR_I_BIT @ disable interrupts
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msr cpsr_c, r2
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ldr r4, =(EP93XX_APB_VIRT_BASE + 0x00130000) @ syscon addr
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ldr r3, =crunch_owner
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add r2, r0, #TI_CRUNCH_STATE @ get task crunch save area
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ldr r1, [r3] @ get current crunch owner
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teq r1, #0 @ any current owner?
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beq 1f @ no: quit
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teq r0, #0 @ any owner?
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teqne r1, r2 @ or specified one?
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bne 1f @ no: quit
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ldr r5, [r4, #0x80] @ enable access to crunch
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mov r2, #0xaa
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str r2, [r4, #0xc0]
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orr r5, r5, #0x00800000
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str r5, [r4, #0x80]
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mov r0, #0 @ nothing to load
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str r0, [r3] @ no more current owner
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ldr r2, [r4, #0x80] @ flush out enable (@@@)
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mov r2, r2
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bl crunch_save
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mov r2, #0xaa @ disable access to crunch
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str r2, [r4, #0xc0]
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bic r5, r5, #0x00800000
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str r5, [r4, #0x80]
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ldr r5, [r4, #0x80] @ flush out enable (@@@)
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mov r5, r5
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1: msr cpsr_c, ip @ restore interrupt mode
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ldmfd sp!, {r4, r5, pc}
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/*
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* Copy crunch state to given memory address
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*
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* r0 = struct thread_info pointer of target task
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* r1 = memory address where to store crunch state
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*
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* this is called mainly in the creation of signal stack frames
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*/
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ENTRY(crunch_task_copy)
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mrs ip, cpsr
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orr r2, ip, #PSR_I_BIT @ disable interrupts
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msr cpsr_c, r2
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ldr r3, =crunch_owner
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add r2, r0, #TI_CRUNCH_STATE @ get task crunch save area
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ldr r3, [r3] @ get current crunch owner
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teq r2, r3 @ does this task own it...
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beq 1f
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@ current crunch values are in the task save area
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msr cpsr_c, ip @ restore interrupt mode
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mov r0, r1
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mov r1, r2
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mov r2, #CRUNCH_SIZE
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b memcpy
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1: @ this task owns crunch regs -- grab a copy from there
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mov r0, #0 @ nothing to load
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mov r3, lr @ preserve return address
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bl crunch_save
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msr cpsr_c, ip @ restore interrupt mode
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ret r3
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/*
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* Restore crunch state from given memory address
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*
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* r0 = struct thread_info pointer of target task
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* r1 = memory address where to get crunch state from
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*
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* this is used to restore crunch state when unwinding a signal stack frame
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*/
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ENTRY(crunch_task_restore)
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mrs ip, cpsr
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orr r2, ip, #PSR_I_BIT @ disable interrupts
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msr cpsr_c, r2
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ldr r3, =crunch_owner
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add r2, r0, #TI_CRUNCH_STATE @ get task crunch save area
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ldr r3, [r3] @ get current crunch owner
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teq r2, r3 @ does this task own it...
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beq 1f
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@ this task doesn't own crunch regs -- use its save area
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msr cpsr_c, ip @ restore interrupt mode
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mov r0, r2
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mov r2, #CRUNCH_SIZE
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b memcpy
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1: @ this task owns crunch regs -- load them directly
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mov r0, r1
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mov r1, #0 @ nothing to save
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mov r3, lr @ preserve return address
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bl crunch_load
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msr cpsr_c, ip @ restore interrupt mode
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ret r3
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