932 lines
23 KiB
ArmAsm
932 lines
23 KiB
ArmAsm
/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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* Rewritten by Cort Dougan (cort@fsmlabs.com) for PReP
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* Copyright (C) 1996 Cort Dougan <cort@fsmlabs.com>
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* Adapted for Power Macintosh by Paul Mackerras.
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* Low-level exception handlers and MMU support
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* rewritten by Paul Mackerras.
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* Copyright (C) 1996 Paul Mackerras.
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* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
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*
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* This file contains the system call entry code, context switch
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* code, and exception/interrupt return code for PowerPC.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/sys.h>
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#include <linux/threads.h>
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#include <asm/processor.h>
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#include <asm/page.h>
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#include <asm/mmu.h>
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#include <asm/cputable.h>
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#include <asm/thread_info.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/unistd.h>
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#undef SHOW_SYSCALLS
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#undef SHOW_SYSCALLS_TASK
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/*
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* MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE.
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*/
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#if MSR_KERNEL >= 0x10000
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#define LOAD_MSR_KERNEL(r, x) lis r,(x)@h; ori r,r,(x)@l
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#else
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#define LOAD_MSR_KERNEL(r, x) li r,(x)
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#endif
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#ifdef CONFIG_BOOKE
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#include "head_booke.h"
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#define TRANSFER_TO_HANDLER_EXC_LEVEL(exc_level) \
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mtspr exc_level##_SPRG,r8; \
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BOOKE_LOAD_EXC_LEVEL_STACK(exc_level); \
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lwz r0,GPR10-INT_FRAME_SIZE(r8); \
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stw r0,GPR10(r11); \
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lwz r0,GPR11-INT_FRAME_SIZE(r8); \
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stw r0,GPR11(r11); \
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mfspr r8,exc_level##_SPRG
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.globl mcheck_transfer_to_handler
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mcheck_transfer_to_handler:
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TRANSFER_TO_HANDLER_EXC_LEVEL(MCHECK)
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b transfer_to_handler_full
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.globl debug_transfer_to_handler
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debug_transfer_to_handler:
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TRANSFER_TO_HANDLER_EXC_LEVEL(DEBUG)
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b transfer_to_handler_full
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.globl crit_transfer_to_handler
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crit_transfer_to_handler:
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TRANSFER_TO_HANDLER_EXC_LEVEL(CRIT)
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/* fall through */
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#endif
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#ifdef CONFIG_40x
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.globl crit_transfer_to_handler
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crit_transfer_to_handler:
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lwz r0,crit_r10@l(0)
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stw r0,GPR10(r11)
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lwz r0,crit_r11@l(0)
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stw r0,GPR11(r11)
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/* fall through */
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#endif
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/*
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* This code finishes saving the registers to the exception frame
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* and jumps to the appropriate handler for the exception, turning
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* on address translation.
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* Note that we rely on the caller having set cr0.eq iff the exception
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* occurred in kernel mode (i.e. MSR:PR = 0).
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*/
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.globl transfer_to_handler_full
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transfer_to_handler_full:
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SAVE_NVGPRS(r11)
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/* fall through */
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.globl transfer_to_handler
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transfer_to_handler:
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stw r2,GPR2(r11)
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stw r12,_NIP(r11)
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stw r9,_MSR(r11)
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andi. r2,r9,MSR_PR
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mfctr r12
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mfspr r2,SPRN_XER
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stw r12,_CTR(r11)
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stw r2,_XER(r11)
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mfspr r12,SPRN_SPRG3
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addi r2,r12,-THREAD
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tovirt(r2,r2) /* set r2 to current */
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beq 2f /* if from user, fix up THREAD.regs */
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addi r11,r1,STACK_FRAME_OVERHEAD
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stw r11,PT_REGS(r12)
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#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
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/* Check to see if the dbcr0 register is set up to debug. Use the
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single-step bit to do this. */
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lwz r12,THREAD_DBCR0(r12)
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andis. r12,r12,DBCR0_IC@h
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beq+ 3f
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/* From user and task is ptraced - load up global dbcr0 */
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li r12,-1 /* clear all pending debug events */
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mtspr SPRN_DBSR,r12
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lis r11,global_dbcr0@ha
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tophys(r11,r11)
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addi r11,r11,global_dbcr0@l
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lwz r12,0(r11)
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mtspr SPRN_DBCR0,r12
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lwz r12,4(r11)
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addi r12,r12,-1
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stw r12,4(r11)
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#endif
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b 3f
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2: /* if from kernel, check interrupted DOZE/NAP mode and
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* check for stack overflow
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*/
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lwz r9,THREAD_INFO-THREAD(r12)
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cmplw r1,r9 /* if r1 <= current->thread_info */
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ble- stack_ovf /* then the kernel stack overflowed */
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5:
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#ifdef CONFIG_6xx
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tophys(r9,r9) /* check local flags */
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lwz r12,TI_LOCAL_FLAGS(r9)
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mtcrf 0x01,r12
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bt- 31-TLF_NAPPING,4f
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#endif /* CONFIG_6xx */
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.globl transfer_to_handler_cont
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transfer_to_handler_cont:
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3:
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mflr r9
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lwz r11,0(r9) /* virtual address of handler */
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lwz r9,4(r9) /* where to go when done */
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mtspr SPRN_SRR0,r11
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mtspr SPRN_SRR1,r10
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mtlr r9
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SYNC
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RFI /* jump to handler, enable MMU */
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#ifdef CONFIG_6xx
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4: rlwinm r12,r12,0,~_TLF_NAPPING
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stw r12,TI_LOCAL_FLAGS(r9)
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b power_save_6xx_restore
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#endif
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/*
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* On kernel stack overflow, load up an initial stack pointer
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* and call StackOverflow(regs), which should not return.
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*/
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stack_ovf:
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/* sometimes we use a statically-allocated stack, which is OK. */
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lis r12,_end@h
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ori r12,r12,_end@l
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cmplw r1,r12
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ble 5b /* r1 <= &_end is OK */
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SAVE_NVGPRS(r11)
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addi r3,r1,STACK_FRAME_OVERHEAD
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lis r1,init_thread_union@ha
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addi r1,r1,init_thread_union@l
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addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
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lis r9,StackOverflow@ha
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addi r9,r9,StackOverflow@l
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LOAD_MSR_KERNEL(r10,MSR_KERNEL)
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FIX_SRR1(r10,r12)
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mtspr SPRN_SRR0,r9
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mtspr SPRN_SRR1,r10
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SYNC
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RFI
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/*
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* Handle a system call.
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*/
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.stabs "arch/ppc/kernel/",N_SO,0,0,0f
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.stabs "entry.S",N_SO,0,0,0f
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0:
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_GLOBAL(DoSyscall)
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stw r0,THREAD+LAST_SYSCALL(r2)
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stw r3,ORIG_GPR3(r1)
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li r12,0
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stw r12,RESULT(r1)
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lwz r11,_CCR(r1) /* Clear SO bit in CR */
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rlwinm r11,r11,0,4,2
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stw r11,_CCR(r1)
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#ifdef SHOW_SYSCALLS
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bl do_show_syscall
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#endif /* SHOW_SYSCALLS */
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rlwinm r10,r1,0,0,18 /* current_thread_info() */
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lwz r11,TI_FLAGS(r10)
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andi. r11,r11,_TIF_SYSCALL_T_OR_A
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bne- syscall_dotrace
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syscall_dotrace_cont:
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cmplwi 0,r0,NR_syscalls
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lis r10,sys_call_table@h
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ori r10,r10,sys_call_table@l
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slwi r0,r0,2
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bge- 66f
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lwzx r10,r10,r0 /* Fetch system call handler [ptr] */
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mtlr r10
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addi r9,r1,STACK_FRAME_OVERHEAD
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PPC440EP_ERR42
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blrl /* Call handler */
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.globl ret_from_syscall
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ret_from_syscall:
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#ifdef SHOW_SYSCALLS
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bl do_show_syscall_exit
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#endif
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mr r6,r3
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rlwinm r12,r1,0,0,18 /* current_thread_info() */
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/* disable interrupts so current_thread_info()->flags can't change */
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LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
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SYNC
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MTMSRD(r10)
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lwz r9,TI_FLAGS(r12)
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li r8,-_LAST_ERRNO
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andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
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bne- syscall_exit_work
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cmplw 0,r3,r8
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blt+ syscall_exit_cont
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lwz r11,_CCR(r1) /* Load CR */
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neg r3,r3
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oris r11,r11,0x1000 /* Set SO bit in CR */
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stw r11,_CCR(r1)
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syscall_exit_cont:
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#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
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/* If the process has its own DBCR0 value, load it up. The single
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step bit tells us that dbcr0 should be loaded. */
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lwz r0,THREAD+THREAD_DBCR0(r2)
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andis. r10,r0,DBCR0_IC@h
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bnel- load_dbcr0
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#endif
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stwcx. r0,0,r1 /* to clear the reservation */
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lwz r4,_LINK(r1)
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lwz r5,_CCR(r1)
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mtlr r4
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mtcr r5
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lwz r7,_NIP(r1)
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lwz r8,_MSR(r1)
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FIX_SRR1(r8, r0)
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lwz r2,GPR2(r1)
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lwz r1,GPR1(r1)
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mtspr SPRN_SRR0,r7
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mtspr SPRN_SRR1,r8
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SYNC
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RFI
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66: li r3,-ENOSYS
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b ret_from_syscall
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.globl ret_from_fork
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ret_from_fork:
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REST_NVGPRS(r1)
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bl schedule_tail
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li r3,0
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b ret_from_syscall
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/* Traced system call support */
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syscall_dotrace:
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SAVE_NVGPRS(r1)
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li r0,0xc00
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stw r0,TRAP(r1)
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addi r3,r1,STACK_FRAME_OVERHEAD
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bl do_syscall_trace_enter
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lwz r0,GPR0(r1) /* Restore original registers */
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lwz r3,GPR3(r1)
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lwz r4,GPR4(r1)
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lwz r5,GPR5(r1)
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lwz r6,GPR6(r1)
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lwz r7,GPR7(r1)
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lwz r8,GPR8(r1)
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REST_NVGPRS(r1)
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b syscall_dotrace_cont
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syscall_exit_work:
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andi. r0,r9,_TIF_RESTOREALL
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beq+ 0f
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REST_NVGPRS(r1)
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b 2f
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0: cmplw 0,r3,r8
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blt+ 1f
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andi. r0,r9,_TIF_NOERROR
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bne- 1f
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lwz r11,_CCR(r1) /* Load CR */
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neg r3,r3
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oris r11,r11,0x1000 /* Set SO bit in CR */
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stw r11,_CCR(r1)
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1: stw r6,RESULT(r1) /* Save result */
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stw r3,GPR3(r1) /* Update return value */
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2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
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beq 4f
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/* Clear per-syscall TIF flags if any are set. */
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li r11,_TIF_PERSYSCALL_MASK
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addi r12,r12,TI_FLAGS
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3: lwarx r8,0,r12
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andc r8,r8,r11
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#ifdef CONFIG_IBM405_ERR77
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dcbt 0,r12
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#endif
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stwcx. r8,0,r12
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bne- 3b
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subi r12,r12,TI_FLAGS
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4: /* Anything which requires enabling interrupts? */
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andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
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beq ret_from_except
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/* Re-enable interrupts */
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ori r10,r10,MSR_EE
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SYNC
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MTMSRD(r10)
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/* Save NVGPRS if they're not saved already */
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lwz r4,TRAP(r1)
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andi. r4,r4,1
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beq 5f
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SAVE_NVGPRS(r1)
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li r4,0xc00
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stw r4,TRAP(r1)
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5:
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addi r3,r1,STACK_FRAME_OVERHEAD
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bl do_syscall_trace_leave
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b ret_from_except_full
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#ifdef SHOW_SYSCALLS
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do_show_syscall:
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#ifdef SHOW_SYSCALLS_TASK
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lis r11,show_syscalls_task@ha
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lwz r11,show_syscalls_task@l(r11)
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cmp 0,r2,r11
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bnelr
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#endif
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stw r31,GPR31(r1)
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mflr r31
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lis r3,7f@ha
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addi r3,r3,7f@l
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lwz r4,GPR0(r1)
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lwz r5,GPR3(r1)
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lwz r6,GPR4(r1)
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lwz r7,GPR5(r1)
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lwz r8,GPR6(r1)
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lwz r9,GPR7(r1)
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bl printk
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lis r3,77f@ha
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addi r3,r3,77f@l
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lwz r4,GPR8(r1)
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mr r5,r2
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bl printk
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lwz r0,GPR0(r1)
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lwz r3,GPR3(r1)
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lwz r4,GPR4(r1)
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lwz r5,GPR5(r1)
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lwz r6,GPR6(r1)
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lwz r7,GPR7(r1)
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lwz r8,GPR8(r1)
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mtlr r31
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lwz r31,GPR31(r1)
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blr
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do_show_syscall_exit:
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#ifdef SHOW_SYSCALLS_TASK
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lis r11,show_syscalls_task@ha
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lwz r11,show_syscalls_task@l(r11)
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cmp 0,r2,r11
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bnelr
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#endif
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stw r31,GPR31(r1)
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mflr r31
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stw r3,RESULT(r1) /* Save result */
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mr r4,r3
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lis r3,79f@ha
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addi r3,r3,79f@l
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bl printk
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lwz r3,RESULT(r1)
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mtlr r31
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lwz r31,GPR31(r1)
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blr
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7: .string "syscall %d(%x, %x, %x, %x, %x, "
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77: .string "%x), current=%p\n"
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79: .string " -> %x\n"
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.align 2,0
|
|
|
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#ifdef SHOW_SYSCALLS_TASK
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.data
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.globl show_syscalls_task
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show_syscalls_task:
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.long -1
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.text
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#endif
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#endif /* SHOW_SYSCALLS */
|
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|
|
/*
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* The fork/clone functions need to copy the full register set into
|
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* the child process. Therefore we need to save all the nonvolatile
|
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* registers (r13 - r31) before calling the C code.
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*/
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.globl ppc_fork
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ppc_fork:
|
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SAVE_NVGPRS(r1)
|
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lwz r0,TRAP(r1)
|
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rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
|
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stw r0,TRAP(r1) /* register set saved */
|
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b sys_fork
|
|
|
|
.globl ppc_vfork
|
|
ppc_vfork:
|
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SAVE_NVGPRS(r1)
|
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lwz r0,TRAP(r1)
|
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rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
|
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stw r0,TRAP(r1) /* register set saved */
|
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b sys_vfork
|
|
|
|
.globl ppc_clone
|
|
ppc_clone:
|
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SAVE_NVGPRS(r1)
|
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lwz r0,TRAP(r1)
|
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rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
|
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stw r0,TRAP(r1) /* register set saved */
|
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b sys_clone
|
|
|
|
.globl ppc_swapcontext
|
|
ppc_swapcontext:
|
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SAVE_NVGPRS(r1)
|
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lwz r0,TRAP(r1)
|
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rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
|
|
stw r0,TRAP(r1) /* register set saved */
|
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b sys_swapcontext
|
|
|
|
/*
|
|
* Top-level page fault handling.
|
|
* This is in assembler because if do_page_fault tells us that
|
|
* it is a bad kernel page fault, we want to save the non-volatile
|
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* registers before calling bad_page_fault.
|
|
*/
|
|
.globl handle_page_fault
|
|
handle_page_fault:
|
|
stw r4,_DAR(r1)
|
|
addi r3,r1,STACK_FRAME_OVERHEAD
|
|
bl do_page_fault
|
|
cmpwi r3,0
|
|
beq+ ret_from_except
|
|
SAVE_NVGPRS(r1)
|
|
lwz r0,TRAP(r1)
|
|
clrrwi r0,r0,1
|
|
stw r0,TRAP(r1)
|
|
mr r5,r3
|
|
addi r3,r1,STACK_FRAME_OVERHEAD
|
|
lwz r4,_DAR(r1)
|
|
bl bad_page_fault
|
|
b ret_from_except_full
|
|
|
|
/*
|
|
* This routine switches between two different tasks. The process
|
|
* state of one is saved on its kernel stack. Then the state
|
|
* of the other is restored from its kernel stack. The memory
|
|
* management hardware is updated to the second process's state.
|
|
* Finally, we can return to the second process.
|
|
* On entry, r3 points to the THREAD for the current task, r4
|
|
* points to the THREAD for the new task.
|
|
*
|
|
* This routine is always called with interrupts disabled.
|
|
*
|
|
* Note: there are two ways to get to the "going out" portion
|
|
* of this code; either by coming in via the entry (_switch)
|
|
* or via "fork" which must set up an environment equivalent
|
|
* to the "_switch" path. If you change this , you'll have to
|
|
* change the fork code also.
|
|
*
|
|
* The code which creates the new task context is in 'copy_thread'
|
|
* in arch/ppc/kernel/process.c
|
|
*/
|
|
_GLOBAL(_switch)
|
|
stwu r1,-INT_FRAME_SIZE(r1)
|
|
mflr r0
|
|
stw r0,INT_FRAME_SIZE+4(r1)
|
|
/* r3-r12 are caller saved -- Cort */
|
|
SAVE_NVGPRS(r1)
|
|
stw r0,_NIP(r1) /* Return to switch caller */
|
|
mfmsr r11
|
|
li r0,MSR_FP /* Disable floating-point */
|
|
#ifdef CONFIG_ALTIVEC
|
|
BEGIN_FTR_SECTION
|
|
oris r0,r0,MSR_VEC@h /* Disable altivec */
|
|
mfspr r12,SPRN_VRSAVE /* save vrsave register value */
|
|
stw r12,THREAD+THREAD_VRSAVE(r2)
|
|
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
|
|
#endif /* CONFIG_ALTIVEC */
|
|
#ifdef CONFIG_SPE
|
|
oris r0,r0,MSR_SPE@h /* Disable SPE */
|
|
mfspr r12,SPRN_SPEFSCR /* save spefscr register value */
|
|
stw r12,THREAD+THREAD_SPEFSCR(r2)
|
|
#endif /* CONFIG_SPE */
|
|
and. r0,r0,r11 /* FP or altivec or SPE enabled? */
|
|
beq+ 1f
|
|
andc r11,r11,r0
|
|
MTMSRD(r11)
|
|
isync
|
|
1: stw r11,_MSR(r1)
|
|
mfcr r10
|
|
stw r10,_CCR(r1)
|
|
stw r1,KSP(r3) /* Set old stack pointer */
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* We need a sync somewhere here to make sure that if the
|
|
* previous task gets rescheduled on another CPU, it sees all
|
|
* stores it has performed on this one.
|
|
*/
|
|
sync
|
|
#endif /* CONFIG_SMP */
|
|
|
|
tophys(r0,r4)
|
|
CLR_TOP32(r0)
|
|
mtspr SPRN_SPRG3,r0 /* Update current THREAD phys addr */
|
|
lwz r1,KSP(r4) /* Load new stack pointer */
|
|
|
|
/* save the old current 'last' for return value */
|
|
mr r3,r2
|
|
addi r2,r4,-THREAD /* Update current */
|
|
|
|
#ifdef CONFIG_ALTIVEC
|
|
BEGIN_FTR_SECTION
|
|
lwz r0,THREAD+THREAD_VRSAVE(r2)
|
|
mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */
|
|
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
|
|
#endif /* CONFIG_ALTIVEC */
|
|
#ifdef CONFIG_SPE
|
|
lwz r0,THREAD+THREAD_SPEFSCR(r2)
|
|
mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */
|
|
#endif /* CONFIG_SPE */
|
|
|
|
lwz r0,_CCR(r1)
|
|
mtcrf 0xFF,r0
|
|
/* r3-r12 are destroyed -- Cort */
|
|
REST_NVGPRS(r1)
|
|
|
|
lwz r4,_NIP(r1) /* Return to _switch caller in new task */
|
|
mtlr r4
|
|
addi r1,r1,INT_FRAME_SIZE
|
|
blr
|
|
|
|
.globl fast_exception_return
|
|
fast_exception_return:
|
|
#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
|
|
andi. r10,r9,MSR_RI /* check for recoverable interrupt */
|
|
beq 1f /* if not, we've got problems */
|
|
#endif
|
|
|
|
2: REST_4GPRS(3, r11)
|
|
lwz r10,_CCR(r11)
|
|
REST_GPR(1, r11)
|
|
mtcr r10
|
|
lwz r10,_LINK(r11)
|
|
mtlr r10
|
|
REST_GPR(10, r11)
|
|
mtspr SPRN_SRR1,r9
|
|
mtspr SPRN_SRR0,r12
|
|
REST_GPR(9, r11)
|
|
REST_GPR(12, r11)
|
|
lwz r11,GPR11(r11)
|
|
SYNC
|
|
RFI
|
|
|
|
#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
|
|
/* check if the exception happened in a restartable section */
|
|
1: lis r3,exc_exit_restart_end@ha
|
|
addi r3,r3,exc_exit_restart_end@l
|
|
cmplw r12,r3
|
|
bge 3f
|
|
lis r4,exc_exit_restart@ha
|
|
addi r4,r4,exc_exit_restart@l
|
|
cmplw r12,r4
|
|
blt 3f
|
|
lis r3,fee_restarts@ha
|
|
tophys(r3,r3)
|
|
lwz r5,fee_restarts@l(r3)
|
|
addi r5,r5,1
|
|
stw r5,fee_restarts@l(r3)
|
|
mr r12,r4 /* restart at exc_exit_restart */
|
|
b 2b
|
|
|
|
.comm fee_restarts,4
|
|
|
|
/* aargh, a nonrecoverable interrupt, panic */
|
|
/* aargh, we don't know which trap this is */
|
|
/* but the 601 doesn't implement the RI bit, so assume it's OK */
|
|
3:
|
|
BEGIN_FTR_SECTION
|
|
b 2b
|
|
END_FTR_SECTION_IFSET(CPU_FTR_601)
|
|
li r10,-1
|
|
stw r10,TRAP(r11)
|
|
addi r3,r1,STACK_FRAME_OVERHEAD
|
|
lis r10,MSR_KERNEL@h
|
|
ori r10,r10,MSR_KERNEL@l
|
|
bl transfer_to_handler_full
|
|
.long nonrecoverable_exception
|
|
.long ret_from_except
|
|
#endif
|
|
|
|
.globl ret_from_except_full
|
|
ret_from_except_full:
|
|
REST_NVGPRS(r1)
|
|
/* fall through */
|
|
|
|
.globl ret_from_except
|
|
ret_from_except:
|
|
/* Hard-disable interrupts so that current_thread_info()->flags
|
|
* can't change between when we test it and when we return
|
|
* from the interrupt. */
|
|
LOAD_MSR_KERNEL(r10,MSR_KERNEL)
|
|
SYNC /* Some chip revs have problems here... */
|
|
MTMSRD(r10) /* disable interrupts */
|
|
|
|
lwz r3,_MSR(r1) /* Returning to user mode? */
|
|
andi. r0,r3,MSR_PR
|
|
beq resume_kernel
|
|
|
|
user_exc_return: /* r10 contains MSR_KERNEL here */
|
|
/* Check current_thread_info()->flags */
|
|
rlwinm r9,r1,0,0,18
|
|
lwz r9,TI_FLAGS(r9)
|
|
andi. r0,r9,(_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK|_TIF_NEED_RESCHED)
|
|
bne do_work
|
|
|
|
restore_user:
|
|
#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
|
|
/* Check whether this process has its own DBCR0 value. The single
|
|
step bit tells us that dbcr0 should be loaded. */
|
|
lwz r0,THREAD+THREAD_DBCR0(r2)
|
|
andis. r10,r0,DBCR0_IC@h
|
|
bnel- load_dbcr0
|
|
#endif
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
b restore
|
|
|
|
/* N.B. the only way to get here is from the beq following ret_from_except. */
|
|
resume_kernel:
|
|
/* check current_thread_info->preempt_count */
|
|
rlwinm r9,r1,0,0,18
|
|
lwz r0,TI_PREEMPT(r9)
|
|
cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
|
|
bne restore
|
|
lwz r0,TI_FLAGS(r9)
|
|
andi. r0,r0,_TIF_NEED_RESCHED
|
|
beq+ restore
|
|
andi. r0,r3,MSR_EE /* interrupts off? */
|
|
beq restore /* don't schedule if so */
|
|
1: bl preempt_schedule_irq
|
|
rlwinm r9,r1,0,0,18
|
|
lwz r3,TI_FLAGS(r9)
|
|
andi. r0,r3,_TIF_NEED_RESCHED
|
|
bne- 1b
|
|
#else
|
|
resume_kernel:
|
|
#endif /* CONFIG_PREEMPT */
|
|
|
|
/* interrupts are hard-disabled at this point */
|
|
restore:
|
|
lwz r0,GPR0(r1)
|
|
lwz r2,GPR2(r1)
|
|
REST_4GPRS(3, r1)
|
|
REST_2GPRS(7, r1)
|
|
|
|
lwz r10,_XER(r1)
|
|
lwz r11,_CTR(r1)
|
|
mtspr SPRN_XER,r10
|
|
mtctr r11
|
|
|
|
PPC405_ERR77(0,r1)
|
|
stwcx. r0,0,r1 /* to clear the reservation */
|
|
|
|
#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
|
|
lwz r9,_MSR(r1)
|
|
andi. r10,r9,MSR_RI /* check if this exception occurred */
|
|
beql nonrecoverable /* at a bad place (MSR:RI = 0) */
|
|
|
|
lwz r10,_CCR(r1)
|
|
lwz r11,_LINK(r1)
|
|
mtcrf 0xFF,r10
|
|
mtlr r11
|
|
|
|
/*
|
|
* Once we put values in SRR0 and SRR1, we are in a state
|
|
* where exceptions are not recoverable, since taking an
|
|
* exception will trash SRR0 and SRR1. Therefore we clear the
|
|
* MSR:RI bit to indicate this. If we do take an exception,
|
|
* we can't return to the point of the exception but we
|
|
* can restart the exception exit path at the label
|
|
* exc_exit_restart below. -- paulus
|
|
*/
|
|
LOAD_MSR_KERNEL(r10,MSR_KERNEL & ~MSR_RI)
|
|
SYNC
|
|
MTMSRD(r10) /* clear the RI bit */
|
|
.globl exc_exit_restart
|
|
exc_exit_restart:
|
|
lwz r9,_MSR(r1)
|
|
lwz r12,_NIP(r1)
|
|
FIX_SRR1(r9,r10)
|
|
mtspr SPRN_SRR0,r12
|
|
mtspr SPRN_SRR1,r9
|
|
REST_4GPRS(9, r1)
|
|
lwz r1,GPR1(r1)
|
|
.globl exc_exit_restart_end
|
|
exc_exit_restart_end:
|
|
SYNC
|
|
RFI
|
|
|
|
#else /* !(CONFIG_4xx || CONFIG_BOOKE) */
|
|
/*
|
|
* This is a bit different on 4xx/Book-E because it doesn't have
|
|
* the RI bit in the MSR.
|
|
* The TLB miss handler checks if we have interrupted
|
|
* the exception exit path and restarts it if so
|
|
* (well maybe one day it will... :).
|
|
*/
|
|
lwz r11,_LINK(r1)
|
|
mtlr r11
|
|
lwz r10,_CCR(r1)
|
|
mtcrf 0xff,r10
|
|
REST_2GPRS(9, r1)
|
|
.globl exc_exit_restart
|
|
exc_exit_restart:
|
|
lwz r11,_NIP(r1)
|
|
lwz r12,_MSR(r1)
|
|
exc_exit_start:
|
|
mtspr SPRN_SRR0,r11
|
|
mtspr SPRN_SRR1,r12
|
|
REST_2GPRS(11, r1)
|
|
lwz r1,GPR1(r1)
|
|
.globl exc_exit_restart_end
|
|
exc_exit_restart_end:
|
|
PPC405_ERR77_SYNC
|
|
rfi
|
|
b . /* prevent prefetch past rfi */
|
|
|
|
/*
|
|
* Returning from a critical interrupt in user mode doesn't need
|
|
* to be any different from a normal exception. For a critical
|
|
* interrupt in the kernel, we just return (without checking for
|
|
* preemption) since the interrupt may have happened at some crucial
|
|
* place (e.g. inside the TLB miss handler), and because we will be
|
|
* running with r1 pointing into critical_stack, not the current
|
|
* process's kernel stack (and therefore current_thread_info() will
|
|
* give the wrong answer).
|
|
* We have to restore various SPRs that may have been in use at the
|
|
* time of the critical interrupt.
|
|
*
|
|
*/
|
|
#ifdef CONFIG_40x
|
|
#define PPC_40x_TURN_OFF_MSR_DR \
|
|
/* avoid any possible TLB misses here by turning off MSR.DR, we \
|
|
* assume the instructions here are mapped by a pinned TLB entry */ \
|
|
li r10,MSR_IR; \
|
|
mtmsr r10; \
|
|
isync; \
|
|
tophys(r1, r1);
|
|
#else
|
|
#define PPC_40x_TURN_OFF_MSR_DR
|
|
#endif
|
|
|
|
#define RET_FROM_EXC_LEVEL(exc_lvl_srr0, exc_lvl_srr1, exc_lvl_rfi) \
|
|
REST_NVGPRS(r1); \
|
|
lwz r3,_MSR(r1); \
|
|
andi. r3,r3,MSR_PR; \
|
|
LOAD_MSR_KERNEL(r10,MSR_KERNEL); \
|
|
bne user_exc_return; \
|
|
lwz r0,GPR0(r1); \
|
|
lwz r2,GPR2(r1); \
|
|
REST_4GPRS(3, r1); \
|
|
REST_2GPRS(7, r1); \
|
|
lwz r10,_XER(r1); \
|
|
lwz r11,_CTR(r1); \
|
|
mtspr SPRN_XER,r10; \
|
|
mtctr r11; \
|
|
PPC405_ERR77(0,r1); \
|
|
stwcx. r0,0,r1; /* to clear the reservation */ \
|
|
lwz r11,_LINK(r1); \
|
|
mtlr r11; \
|
|
lwz r10,_CCR(r1); \
|
|
mtcrf 0xff,r10; \
|
|
PPC_40x_TURN_OFF_MSR_DR; \
|
|
lwz r9,_DEAR(r1); \
|
|
lwz r10,_ESR(r1); \
|
|
mtspr SPRN_DEAR,r9; \
|
|
mtspr SPRN_ESR,r10; \
|
|
lwz r11,_NIP(r1); \
|
|
lwz r12,_MSR(r1); \
|
|
mtspr exc_lvl_srr0,r11; \
|
|
mtspr exc_lvl_srr1,r12; \
|
|
lwz r9,GPR9(r1); \
|
|
lwz r12,GPR12(r1); \
|
|
lwz r10,GPR10(r1); \
|
|
lwz r11,GPR11(r1); \
|
|
lwz r1,GPR1(r1); \
|
|
PPC405_ERR77_SYNC; \
|
|
exc_lvl_rfi; \
|
|
b .; /* prevent prefetch past exc_lvl_rfi */
|
|
|
|
.globl ret_from_crit_exc
|
|
ret_from_crit_exc:
|
|
RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, RFCI)
|
|
|
|
#ifdef CONFIG_BOOKE
|
|
.globl ret_from_debug_exc
|
|
ret_from_debug_exc:
|
|
RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, RFDI)
|
|
|
|
.globl ret_from_mcheck_exc
|
|
ret_from_mcheck_exc:
|
|
RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, RFMCI)
|
|
#endif /* CONFIG_BOOKE */
|
|
|
|
/*
|
|
* Load the DBCR0 value for a task that is being ptraced,
|
|
* having first saved away the global DBCR0. Note that r0
|
|
* has the dbcr0 value to set upon entry to this.
|
|
*/
|
|
load_dbcr0:
|
|
mfmsr r10 /* first disable debug exceptions */
|
|
rlwinm r10,r10,0,~MSR_DE
|
|
mtmsr r10
|
|
isync
|
|
mfspr r10,SPRN_DBCR0
|
|
lis r11,global_dbcr0@ha
|
|
addi r11,r11,global_dbcr0@l
|
|
stw r10,0(r11)
|
|
mtspr SPRN_DBCR0,r0
|
|
lwz r10,4(r11)
|
|
addi r10,r10,1
|
|
stw r10,4(r11)
|
|
li r11,-1
|
|
mtspr SPRN_DBSR,r11 /* clear all pending debug events */
|
|
blr
|
|
|
|
.comm global_dbcr0,8
|
|
#endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
|
|
|
|
do_work: /* r10 contains MSR_KERNEL here */
|
|
andi. r0,r9,_TIF_NEED_RESCHED
|
|
beq do_user_signal
|
|
|
|
do_resched: /* r10 contains MSR_KERNEL here */
|
|
ori r10,r10,MSR_EE
|
|
SYNC
|
|
MTMSRD(r10) /* hard-enable interrupts */
|
|
bl schedule
|
|
recheck:
|
|
LOAD_MSR_KERNEL(r10,MSR_KERNEL)
|
|
SYNC
|
|
MTMSRD(r10) /* disable interrupts */
|
|
rlwinm r9,r1,0,0,18
|
|
lwz r9,TI_FLAGS(r9)
|
|
andi. r0,r9,_TIF_NEED_RESCHED
|
|
bne- do_resched
|
|
andi. r0,r9,_TIF_SIGPENDING
|
|
beq restore_user
|
|
do_user_signal: /* r10 contains MSR_KERNEL here */
|
|
ori r10,r10,MSR_EE
|
|
SYNC
|
|
MTMSRD(r10) /* hard-enable interrupts */
|
|
/* save r13-r31 in the exception frame, if not already done */
|
|
lwz r3,TRAP(r1)
|
|
andi. r0,r3,1
|
|
beq 2f
|
|
SAVE_NVGPRS(r1)
|
|
rlwinm r3,r3,0,0,30
|
|
stw r3,TRAP(r1)
|
|
2: li r3,0
|
|
addi r4,r1,STACK_FRAME_OVERHEAD
|
|
bl do_signal
|
|
REST_NVGPRS(r1)
|
|
b recheck
|
|
|
|
/*
|
|
* We come here when we are at the end of handling an exception
|
|
* that occurred at a place where taking an exception will lose
|
|
* state information, such as the contents of SRR0 and SRR1.
|
|
*/
|
|
nonrecoverable:
|
|
lis r10,exc_exit_restart_end@ha
|
|
addi r10,r10,exc_exit_restart_end@l
|
|
cmplw r12,r10
|
|
bge 3f
|
|
lis r11,exc_exit_restart@ha
|
|
addi r11,r11,exc_exit_restart@l
|
|
cmplw r12,r11
|
|
blt 3f
|
|
lis r10,ee_restarts@ha
|
|
lwz r12,ee_restarts@l(r10)
|
|
addi r12,r12,1
|
|
stw r12,ee_restarts@l(r10)
|
|
mr r12,r11 /* restart at exc_exit_restart */
|
|
blr
|
|
3: /* OK, we can't recover, kill this process */
|
|
/* but the 601 doesn't implement the RI bit, so assume it's OK */
|
|
BEGIN_FTR_SECTION
|
|
blr
|
|
END_FTR_SECTION_IFSET(CPU_FTR_601)
|
|
lwz r3,TRAP(r1)
|
|
andi. r0,r3,1
|
|
beq 4f
|
|
SAVE_NVGPRS(r1)
|
|
rlwinm r3,r3,0,0,30
|
|
stw r3,TRAP(r1)
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4: addi r3,r1,STACK_FRAME_OVERHEAD
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bl nonrecoverable_exception
|
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/* shouldn't return */
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|
b 4b
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|
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.comm ee_restarts,4
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