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Diffstat (limited to 'arch/arm/kernel/iwmmxt.S')
| -rw-r--r-- | arch/arm/kernel/iwmmxt.S | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S new file mode 100644 index 0000000..8f74e24 --- /dev/null +++ b/arch/arm/kernel/iwmmxt.S @@ -0,0 +1,320 @@ +/* + * 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/constants.h> + +#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 + +/* + * 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 disabled + */ + +ENTRY(iwmmxt_task_enable) + + mrc p15, 0, r2, c15, c1, 0 + tst r2, #0x3 @ CP0 and CP1 accessible? + movne pc, lr @ if so no business here + orr r2, r2, #0x3 @ enable access to CP0 and CP1 + mcr p15, 0, r2, c15, c1, 0 + + 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 + + teq r1, #0 @ test for last ownership + mov lr, r9 @ normal exit from exception + beq concan_load @ no owner, skip save + +concan_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? + moveq pc, lr + +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 + moveq pc, lr + tmcr wCon, r2 + mov pc, lr + +/* + * 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 + + mrc p15, 0, r4, c15, c1, 0 + orr r4, r4, #0x3 @ enable access to CP0 and CP1 + mcr p15, 0, r4, c15, c1, 0 + 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 + + bic r4, r4, #0x3 @ disable access to CP0 and CP1 + mcr p15, 0, r4, c15, c1, 0 + mrc p15, 0, r2, c2, c0, 0 + mov r2, r2 @ cpwait + +1: msr cpsr_c, ip @ restore interrupt mode + ldmfd sp!, {r4, pc} + +/* + * 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 + mov pc, r3 + +/* + * 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 + mov pc, r3 + +/* + * Concan handling on task switch + * + * r0 = previous task_struct pointer (must be preserved) + * r1 = previous thread_info pointer + * r2 = next thread_info.cpu_domain pointer (must be preserved) + * + * Called only from __switch_to with task preemption disabled. + * No need to care about preserving r4 and above. + */ +ENTRY(iwmmxt_task_switch) + + mrc p15, 0, r4, c15, c1, 0 + tst r4, #0x3 @ CP0 and CP1 accessible? + bne 1f @ yes: block them for next task + + ldr r5, =concan_owner + add r6, r2, #(TI_IWMMXT_STATE - TI_CPU_DOMAIN) @ get next task Concan save area + ldr r5, [r5] @ get current Concan owner + teq r5, r6 @ next task owns it? + movne pc, lr @ no: leave Concan disabled + +1: eor r4, r4, #3 @ flip Concan access + mcr p15, 0, r4, c15, c1, 0 + + mrc p15, 0, r4, c2, c0, 0 + sub pc, lr, r4, lsr #32 @ cpwait and return + +/* + * 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 + mov pc, lr + + .data +concan_owner: + .word 0 + |
