/* * 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> #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 = next thread_info pointer * * Called only from the iwmmxt notifier with task preemption disabled. */ ENTRY(iwmmxt_task_switch) mrc p15, 0, r1, c15, c1, 0 tst r1, #0x3 @ CP0 and CP1 accessible? 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? movne pc, lr @ no: leave Concan disabled 1: eor r1, r1, #3 @ flip Concan access mcr p15, 0, r1, c15, c1, 0 mrc p15, 0, r1, c2, c0, 0 sub pc, lr, r1, 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