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alistair23-linux/arch/arm/kernel/iwmmxt.S
Ard Biesheuvel 13d1b9575a ARM: 8221/1: PJ4: allow building in Thumb-2 mode 
Two files that get included when building the multi_v7_defconfig target
fail to build when selecting THUMB2_KERNEL for this configuration.

In both cases, we can just build the file as ARM code, as none of its
symbols are exported to modules, so there are no interworking concerns.
In the iwmmxt.S case, add ENDPROC() declarations so the symbols are
annotated as functions, resulting in the linker to emit the appropriate
mode switches.

Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-12-03 16:08:00 +00:00

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8.5 KiB
ArmAsm
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/*
* linux/arch/arm/kernel/iwmmxt.S
*
* XScale iWMMXt (Concan) context switching and handling
*
* Initial code:
* Copyright (c) 2003, Intel Corporation
*
* Full lazy switching support, optimizations and more, by Nicolas Pitre
* Copyright (c) 2003-2004, MontaVista Software, Inc.
*
* 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.
*/
#include <linux/linkage.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#if defined(CONFIG_CPU_PJ4) || defined(CONFIG_CPU_PJ4B)
#define PJ4(code...) code
#define XSC(code...)
#elif defined(CONFIG_CPU_MOHAWK) || \
defined(CONFIG_CPU_XSC3) || \
defined(CONFIG_CPU_XSCALE)
#define PJ4(code...)
#define XSC(code...) code
#else
#error "Unsupported iWMMXt architecture"
#endif
#define MMX_WR0 (0x00)
#define MMX_WR1 (0x08)
#define MMX_WR2 (0x10)
#define MMX_WR3 (0x18)
#define MMX_WR4 (0x20)
#define MMX_WR5 (0x28)
#define MMX_WR6 (0x30)
#define MMX_WR7 (0x38)
#define MMX_WR8 (0x40)
#define MMX_WR9 (0x48)
#define MMX_WR10 (0x50)
#define MMX_WR11 (0x58)
#define MMX_WR12 (0x60)
#define MMX_WR13 (0x68)
#define MMX_WR14 (0x70)
#define MMX_WR15 (0x78)
#define MMX_WCSSF (0x80)
#define MMX_WCASF (0x84)
#define MMX_WCGR0 (0x88)
#define MMX_WCGR1 (0x8C)
#define MMX_WCGR2 (0x90)
#define MMX_WCGR3 (0x94)
#define MMX_SIZE (0x98)
.text
.arm
/*
* Lazy switching of Concan coprocessor context
*
* r10 = struct thread_info pointer
* r9 = ret_from_exception
* lr = undefined instr exit
*
* called from prefetch exception handler with interrupts enabled
*/
ENTRY(iwmmxt_task_enable)
inc_preempt_count r10, r3
XSC(mrc p15, 0, r2, c15, c1, 0)
PJ4(mrc p15, 0, r2, c1, c0, 2)
@ CP0 and CP1 accessible?
XSC(tst r2, #0x3)
PJ4(tst r2, #0xf)
bne 4f @ if so no business here
@ enable access to CP0 and CP1
XSC(orr r2, r2, #0x3)
XSC(mcr p15, 0, r2, c15, c1, 0)
PJ4(orr r2, r2, #0xf)
PJ4(mcr p15, 0, r2, c1, c0, 2)
ldr r3, =concan_owner
add r0, r10, #TI_IWMMXT_STATE @ get task Concan save area
ldr r2, [sp, #60] @ current task pc value
ldr r1, [r3] @ get current Concan owner
str r0, [r3] @ this task now owns Concan regs
sub r2, r2, #4 @ adjust pc back
str r2, [sp, #60]
mrc p15, 0, r2, c2, c0, 0
mov r2, r2 @ cpwait
bl concan_save
#ifdef CONFIG_PREEMPT_COUNT
get_thread_info r10
#endif
4: dec_preempt_count r10, r3
ret r9 @ normal exit from exception
concan_save:
teq r1, #0 @ test for last ownership
beq concan_load @ no owner, skip save
tmrc r2, wCon
@ CUP? wCx
tst r2, #0x1
beq 1f
concan_dump:
wstrw wCSSF, [r1, #MMX_WCSSF]
wstrw wCASF, [r1, #MMX_WCASF]
wstrw wCGR0, [r1, #MMX_WCGR0]
wstrw wCGR1, [r1, #MMX_WCGR1]
wstrw wCGR2, [r1, #MMX_WCGR2]
wstrw wCGR3, [r1, #MMX_WCGR3]
1: @ MUP? wRn
tst r2, #0x2
beq 2f
wstrd wR0, [r1, #MMX_WR0]
wstrd wR1, [r1, #MMX_WR1]
wstrd wR2, [r1, #MMX_WR2]
wstrd wR3, [r1, #MMX_WR3]
wstrd wR4, [r1, #MMX_WR4]
wstrd wR5, [r1, #MMX_WR5]
wstrd wR6, [r1, #MMX_WR6]
wstrd wR7, [r1, #MMX_WR7]
wstrd wR8, [r1, #MMX_WR8]
wstrd wR9, [r1, #MMX_WR9]
wstrd wR10, [r1, #MMX_WR10]
wstrd wR11, [r1, #MMX_WR11]
wstrd wR12, [r1, #MMX_WR12]
wstrd wR13, [r1, #MMX_WR13]
wstrd wR14, [r1, #MMX_WR14]
wstrd wR15, [r1, #MMX_WR15]
2: teq r0, #0 @ anything to load?
reteq lr @ if not, return
concan_load:
@ Load wRn
wldrd wR0, [r0, #MMX_WR0]
wldrd wR1, [r0, #MMX_WR1]
wldrd wR2, [r0, #MMX_WR2]
wldrd wR3, [r0, #MMX_WR3]
wldrd wR4, [r0, #MMX_WR4]
wldrd wR5, [r0, #MMX_WR5]
wldrd wR6, [r0, #MMX_WR6]
wldrd wR7, [r0, #MMX_WR7]
wldrd wR8, [r0, #MMX_WR8]
wldrd wR9, [r0, #MMX_WR9]
wldrd wR10, [r0, #MMX_WR10]
wldrd wR11, [r0, #MMX_WR11]
wldrd wR12, [r0, #MMX_WR12]
wldrd wR13, [r0, #MMX_WR13]
wldrd wR14, [r0, #MMX_WR14]
wldrd wR15, [r0, #MMX_WR15]
@ Load wCx
wldrw wCSSF, [r0, #MMX_WCSSF]
wldrw wCASF, [r0, #MMX_WCASF]
wldrw wCGR0, [r0, #MMX_WCGR0]
wldrw wCGR1, [r0, #MMX_WCGR1]
wldrw wCGR2, [r0, #MMX_WCGR2]
wldrw wCGR3, [r0, #MMX_WCGR3]
@ clear CUP/MUP (only if r1 != 0)
teq r1, #0
mov r2, #0
reteq lr
tmcr wCon, r2
ret lr
ENDPROC(iwmmxt_task_enable)
/*
* Back up Concan regs to save area and disable access to them
* (mainly for gdb or sleep mode usage)
*
* r0 = struct thread_info pointer of target task or NULL for any
*/
ENTRY(iwmmxt_task_disable)
stmfd sp!, {r4, lr}
mrs ip, cpsr
orr r2, ip, #PSR_I_BIT @ disable interrupts
msr cpsr_c, r2
ldr r3, =concan_owner
add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r1, [r3] @ get current Concan owner
teq r1, #0 @ any current owner?
beq 1f @ no: quit
teq r0, #0 @ any owner?
teqne r1, r2 @ or specified one?
bne 1f @ no: quit
@ enable access to CP0 and CP1
XSC(mrc p15, 0, r4, c15, c1, 0)
XSC(orr r4, r4, #0x3)
XSC(mcr p15, 0, r4, c15, c1, 0)
PJ4(mrc p15, 0, r4, c1, c0, 2)
PJ4(orr r4, r4, #0xf)
PJ4(mcr p15, 0, r4, c1, c0, 2)
mov r0, #0 @ nothing to load
str r0, [r3] @ no more current owner
mrc p15, 0, r2, c2, c0, 0
mov r2, r2 @ cpwait
bl concan_save
@ disable access to CP0 and CP1
XSC(bic r4, r4, #0x3)
XSC(mcr p15, 0, r4, c15, c1, 0)
PJ4(bic r4, r4, #0xf)
PJ4(mcr p15, 0, r4, c1, c0, 2)
mrc p15, 0, r2, c2, c0, 0
mov r2, r2 @ cpwait
1: msr cpsr_c, ip @ restore interrupt mode
ldmfd sp!, {r4, pc}
ENDPROC(iwmmxt_task_disable)
/*
* Copy Concan state to given memory address
*
* r0 = struct thread_info pointer of target task
* r1 = memory address where to store Concan state
*
* this is called mainly in the creation of signal stack frames
*/
ENTRY(iwmmxt_task_copy)
mrs ip, cpsr
orr r2, ip, #PSR_I_BIT @ disable interrupts
msr cpsr_c, r2
ldr r3, =concan_owner
add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r3, [r3] @ get current Concan owner
teq r2, r3 @ does this task own it...
beq 1f
@ current Concan values are in the task save area
msr cpsr_c, ip @ restore interrupt mode
mov r0, r1
mov r1, r2
mov r2, #MMX_SIZE
b memcpy
1: @ this task owns Concan regs -- grab a copy from there
mov r0, #0 @ nothing to load
mov r2, #3 @ save all regs
mov r3, lr @ preserve return address
bl concan_dump
msr cpsr_c, ip @ restore interrupt mode
ret r3
ENDPROC(iwmmxt_task_copy)
/*
* Restore Concan state from given memory address
*
* r0 = struct thread_info pointer of target task
* r1 = memory address where to get Concan state from
*
* this is used to restore Concan state when unwinding a signal stack frame
*/
ENTRY(iwmmxt_task_restore)
mrs ip, cpsr
orr r2, ip, #PSR_I_BIT @ disable interrupts
msr cpsr_c, r2
ldr r3, =concan_owner
add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r3, [r3] @ get current Concan owner
bic r2, r2, #0x7 @ 64-bit alignment
teq r2, r3 @ does this task own it...
beq 1f
@ this task doesn't own Concan regs -- use its save area
msr cpsr_c, ip @ restore interrupt mode
mov r0, r2
mov r2, #MMX_SIZE
b memcpy
1: @ this task owns Concan regs -- load them directly
mov r0, r1
mov r1, #0 @ don't clear CUP/MUP
mov r3, lr @ preserve return address
bl concan_load
msr cpsr_c, ip @ restore interrupt mode
ret r3
ENDPROC(iwmmxt_task_restore)
/*
* Concan handling on task switch
*
* r0 = next thread_info pointer
*
* Called only from the iwmmxt notifier with task preemption disabled.
*/
ENTRY(iwmmxt_task_switch)
XSC(mrc p15, 0, r1, c15, c1, 0)
PJ4(mrc p15, 0, r1, c1, c0, 2)
@ CP0 and CP1 accessible?
XSC(tst r1, #0x3)
PJ4(tst r1, #0xf)
bne 1f @ yes: block them for next task
ldr r2, =concan_owner
add r3, r0, #TI_IWMMXT_STATE @ get next task Concan save area
ldr r2, [r2] @ get current Concan owner
teq r2, r3 @ next task owns it?
retne lr @ no: leave Concan disabled
1: @ flip Concan access
XSC(eor r1, r1, #0x3)
XSC(mcr p15, 0, r1, c15, c1, 0)
PJ4(eor r1, r1, #0xf)
PJ4(mcr p15, 0, r1, c1, c0, 2)
mrc p15, 0, r1, c2, c0, 0
sub pc, lr, r1, lsr #32 @ cpwait and return
ENDPROC(iwmmxt_task_switch)
/*
* Remove Concan ownership of given task
*
* r0 = struct thread_info pointer
*/
ENTRY(iwmmxt_task_release)
mrs r2, cpsr
orr ip, r2, #PSR_I_BIT @ disable interrupts
msr cpsr_c, ip
ldr r3, =concan_owner
add r0, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r1, [r3] @ get current Concan owner
eors r0, r0, r1 @ if equal...
streq r0, [r3] @ then clear ownership
msr cpsr_c, r2 @ restore interrupts
ret lr
ENDPROC(iwmmxt_task_release)
.data
concan_owner:
.word 0
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