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Diffstat (limited to '')
| -rw-r--r-- | arch/arm/kernel/iwmmxt.S | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S new file mode 100644 index 000000000..d2b4ac06e --- /dev/null +++ b/arch/arm/kernel/iwmmxt.S @@ -0,0 +1,371 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * 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. + */ + +#include <linux/linkage.h> +#include <asm/ptrace.h> +#include <asm/thread_info.h> +#include <asm/asm-offsets.h> +#include <asm/assembler.h> +#include "iwmmxt.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 + .align 2 +concan_owner: + .word 0 + |