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linux/arch/powerpc/kernel/entry_32.S
Becky Bruce b64f87c16f [POWERPC] Avoid unpaired stwcx. on some processors 
The context switch code in the kernel issues a dummy stwcx. to clear the
reservation, as recommended by the architecture.  However, some processors
can have issues if this stwcx to address A occurs while the reservation
is already held to a different address B.  To avoid this problem, the dummy
stwcx. needs to be paired with a dummy lwarx to the same address.

This adds the dummy lwarx, and creates a cpu feature bit to indicate
which cpus are affected.  Tested on mpc8641_hpcn_defconfig in
arch/powerpc; build tested in arch/ppc.

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-11-13 16:22:43 +11:00

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/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Rewritten by Cort Dougan (cort@fsmlabs.com) for PReP
* Copyright (C) 1996 Cort Dougan <cort@fsmlabs.com>
* Adapted for Power Macintosh by Paul Mackerras.
* Low-level exception handlers and MMU support
* rewritten by Paul Mackerras.
* Copyright (C) 1996 Paul Mackerras.
* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
*
* This file contains the system call entry code, context switch
* code, and exception/interrupt return code for PowerPC.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/errno.h>
#include <linux/sys.h>
#include <linux/threads.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
#undef SHOW_SYSCALLS
#undef SHOW_SYSCALLS_TASK
/*
* MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE.
*/
#if MSR_KERNEL >= 0x10000
#define LOAD_MSR_KERNEL(r, x) lis r,(x)@h; ori r,r,(x)@l
#else
#define LOAD_MSR_KERNEL(r, x) li r,(x)
#endif
#ifdef CONFIG_BOOKE
#include "head_booke.h"
#define TRANSFER_TO_HANDLER_EXC_LEVEL(exc_level) \
mtspr exc_level##_SPRG,r8; \
BOOKE_LOAD_EXC_LEVEL_STACK(exc_level); \
lwz r0,GPR10-INT_FRAME_SIZE(r8); \
stw r0,GPR10(r11); \
lwz r0,GPR11-INT_FRAME_SIZE(r8); \
stw r0,GPR11(r11); \
mfspr r8,exc_level##_SPRG
.globl mcheck_transfer_to_handler
mcheck_transfer_to_handler:
TRANSFER_TO_HANDLER_EXC_LEVEL(MCHECK)
b transfer_to_handler_full
.globl debug_transfer_to_handler
debug_transfer_to_handler:
TRANSFER_TO_HANDLER_EXC_LEVEL(DEBUG)
b transfer_to_handler_full
.globl crit_transfer_to_handler
crit_transfer_to_handler:
TRANSFER_TO_HANDLER_EXC_LEVEL(CRIT)
/* fall through */
#endif
#ifdef CONFIG_40x
.globl crit_transfer_to_handler
crit_transfer_to_handler:
lwz r0,crit_r10@l(0)
stw r0,GPR10(r11)
lwz r0,crit_r11@l(0)
stw r0,GPR11(r11)
/* fall through */
#endif
/*
* This code finishes saving the registers to the exception frame
* and jumps to the appropriate handler for the exception, turning
* on address translation.
* Note that we rely on the caller having set cr0.eq iff the exception
* occurred in kernel mode (i.e. MSR:PR = 0).
*/
.globl transfer_to_handler_full
transfer_to_handler_full:
SAVE_NVGPRS(r11)
/* fall through */
.globl transfer_to_handler
transfer_to_handler:
stw r2,GPR2(r11)
stw r12,_NIP(r11)
stw r9,_MSR(r11)
andi. r2,r9,MSR_PR
mfctr r12
mfspr r2,SPRN_XER
stw r12,_CTR(r11)
stw r2,_XER(r11)
mfspr r12,SPRN_SPRG3
addi r2,r12,-THREAD
tovirt(r2,r2) /* set r2 to current */
beq 2f /* if from user, fix up THREAD.regs */
addi r11,r1,STACK_FRAME_OVERHEAD
stw r11,PT_REGS(r12)
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
/* Check to see if the dbcr0 register is set up to debug. Use the
single-step bit to do this. */
lwz r12,THREAD_DBCR0(r12)
andis. r12,r12,DBCR0_IC@h
beq+ 3f
/* From user and task is ptraced - load up global dbcr0 */
li r12,-1 /* clear all pending debug events */
mtspr SPRN_DBSR,r12
lis r11,global_dbcr0@ha
tophys(r11,r11)
addi r11,r11,global_dbcr0@l
lwz r12,0(r11)
mtspr SPRN_DBCR0,r12
lwz r12,4(r11)
addi r12,r12,-1
stw r12,4(r11)
#endif
b 3f
2: /* if from kernel, check interrupted DOZE/NAP mode and
* check for stack overflow
*/
lwz r9,THREAD_INFO-THREAD(r12)
cmplw r1,r9 /* if r1 <= current->thread_info */
ble- stack_ovf /* then the kernel stack overflowed */
5:
#ifdef CONFIG_6xx
tophys(r9,r9) /* check local flags */
lwz r12,TI_LOCAL_FLAGS(r9)
mtcrf 0x01,r12
bt- 31-TLF_NAPPING,4f
#endif /* CONFIG_6xx */
.globl transfer_to_handler_cont
transfer_to_handler_cont:
3:
mflr r9
lwz r11,0(r9) /* virtual address of handler */
lwz r9,4(r9) /* where to go when done */
mtspr SPRN_SRR0,r11
mtspr SPRN_SRR1,r10
mtlr r9
SYNC
RFI /* jump to handler, enable MMU */
#ifdef CONFIG_6xx
4: rlwinm r12,r12,0,~_TLF_NAPPING
stw r12,TI_LOCAL_FLAGS(r9)
b power_save_6xx_restore
#endif
/*
* On kernel stack overflow, load up an initial stack pointer
* and call StackOverflow(regs), which should not return.
*/
stack_ovf:
/* sometimes we use a statically-allocated stack, which is OK. */
lis r12,_end@h
ori r12,r12,_end@l
cmplw r1,r12
ble 5b /* r1 <= &_end is OK */
SAVE_NVGPRS(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
lis r1,init_thread_union@ha
addi r1,r1,init_thread_union@l
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
lis r9,StackOverflow@ha
addi r9,r9,StackOverflow@l
LOAD_MSR_KERNEL(r10,MSR_KERNEL)
FIX_SRR1(r10,r12)
mtspr SPRN_SRR0,r9
mtspr SPRN_SRR1,r10
SYNC
RFI
/*
* Handle a system call.
*/
.stabs "arch/powerpc/kernel/",N_SO,0,0,0f
.stabs "entry_32.S",N_SO,0,0,0f
0:
_GLOBAL(DoSyscall)
stw r3,ORIG_GPR3(r1)
li r12,0
stw r12,RESULT(r1)
lwz r11,_CCR(r1) /* Clear SO bit in CR */
rlwinm r11,r11,0,4,2
stw r11,_CCR(r1)
#ifdef SHOW_SYSCALLS
bl do_show_syscall
#endif /* SHOW_SYSCALLS */
rlwinm r10,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */
lwz r11,TI_FLAGS(r10)
andi. r11,r11,_TIF_SYSCALL_T_OR_A
bne- syscall_dotrace
syscall_dotrace_cont:
cmplwi 0,r0,NR_syscalls
lis r10,sys_call_table@h
ori r10,r10,sys_call_table@l
slwi r0,r0,2
bge- 66f
lwzx r10,r10,r0 /* Fetch system call handler [ptr] */
mtlr r10
addi r9,r1,STACK_FRAME_OVERHEAD
PPC440EP_ERR42
blrl /* Call handler */
.globl ret_from_syscall
ret_from_syscall:
#ifdef SHOW_SYSCALLS
bl do_show_syscall_exit
#endif
mr r6,r3
rlwinm r12,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */
/* disable interrupts so current_thread_info()->flags can't change */
LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */
SYNC
MTMSRD(r10)
lwz r9,TI_FLAGS(r12)
li r8,-_LAST_ERRNO
andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
bne- syscall_exit_work
cmplw 0,r3,r8
blt+ syscall_exit_cont
lwz r11,_CCR(r1) /* Load CR */
neg r3,r3
oris r11,r11,0x1000 /* Set SO bit in CR */
stw r11,_CCR(r1)
syscall_exit_cont:
#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
/* If the process has its own DBCR0 value, load it up. 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_44x
lis r4,icache_44x_need_flush@ha
lwz r5,icache_44x_need_flush@l(r4)
cmplwi cr0,r5,0
bne- 2f
1:
#endif /* CONFIG_44x */
BEGIN_FTR_SECTION
lwarx r7,0,r1
END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
stwcx. r0,0,r1 /* to clear the reservation */
lwz r4,_LINK(r1)
lwz r5,_CCR(r1)
mtlr r4
mtcr r5
lwz r7,_NIP(r1)
lwz r8,_MSR(r1)
FIX_SRR1(r8, r0)
lwz r2,GPR2(r1)
lwz r1,GPR1(r1)
mtspr SPRN_SRR0,r7
mtspr SPRN_SRR1,r8
SYNC
RFI
#ifdef CONFIG_44x
2: li r7,0
iccci r0,r0
stw r7,icache_44x_need_flush@l(r4)
b 1b
#endif /* CONFIG_44x */
66: li r3,-ENOSYS
b ret_from_syscall
.globl ret_from_fork
ret_from_fork:
REST_NVGPRS(r1)
bl schedule_tail
li r3,0
b ret_from_syscall
/* Traced system call support */
syscall_dotrace:
SAVE_NVGPRS(r1)
li r0,0xc00
stw r0,_TRAP(r1)
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_syscall_trace_enter
lwz r0,GPR0(r1) /* Restore original registers */
lwz r3,GPR3(r1)
lwz r4,GPR4(r1)
lwz r5,GPR5(r1)
lwz r6,GPR6(r1)
lwz r7,GPR7(r1)
lwz r8,GPR8(r1)
REST_NVGPRS(r1)
b syscall_dotrace_cont
syscall_exit_work:
andi. r0,r9,_TIF_RESTOREALL
beq+ 0f
REST_NVGPRS(r1)
b 2f
0: cmplw 0,r3,r8
blt+ 1f
andi. r0,r9,_TIF_NOERROR
bne- 1f
lwz r11,_CCR(r1) /* Load CR */
neg r3,r3
oris r11,r11,0x1000 /* Set SO bit in CR */
stw r11,_CCR(r1)
1: stw r6,RESULT(r1) /* Save result */
stw r3,GPR3(r1) /* Update return value */
2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
beq 4f
/* Clear per-syscall TIF flags if any are set. */
li r11,_TIF_PERSYSCALL_MASK
addi r12,r12,TI_FLAGS
3: lwarx r8,0,r12
andc r8,r8,r11
#ifdef CONFIG_IBM405_ERR77
dcbt 0,r12
#endif
stwcx. r8,0,r12
bne- 3b
subi r12,r12,TI_FLAGS
4: /* Anything which requires enabling interrupts? */
andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
beq ret_from_except
/* Re-enable interrupts */
ori r10,r10,MSR_EE
SYNC
MTMSRD(r10)
/* Save NVGPRS if they're not saved already */
lwz r4,_TRAP(r1)
andi. r4,r4,1
beq 5f
SAVE_NVGPRS(r1)
li r4,0xc00
stw r4,_TRAP(r1)
5:
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_syscall_trace_leave
b ret_from_except_full
#ifdef SHOW_SYSCALLS
do_show_syscall:
#ifdef SHOW_SYSCALLS_TASK
lis r11,show_syscalls_task@ha
lwz r11,show_syscalls_task@l(r11)
cmp 0,r2,r11
bnelr
#endif
stw r31,GPR31(r1)
mflr r31
lis r3,7f@ha
addi r3,r3,7f@l
lwz r4,GPR0(r1)
lwz r5,GPR3(r1)
lwz r6,GPR4(r1)
lwz r7,GPR5(r1)
lwz r8,GPR6(r1)
lwz r9,GPR7(r1)
bl printk
lis r3,77f@ha
addi r3,r3,77f@l
lwz r4,GPR8(r1)
mr r5,r2
bl printk
lwz r0,GPR0(r1)
lwz r3,GPR3(r1)
lwz r4,GPR4(r1)
lwz r5,GPR5(r1)
lwz r6,GPR6(r1)
lwz r7,GPR7(r1)
lwz r8,GPR8(r1)
mtlr r31
lwz r31,GPR31(r1)
blr
do_show_syscall_exit:
#ifdef SHOW_SYSCALLS_TASK
lis r11,show_syscalls_task@ha
lwz r11,show_syscalls_task@l(r11)
cmp 0,r2,r11
bnelr
#endif
stw r31,GPR31(r1)
mflr r31
stw r3,RESULT(r1) /* Save result */
mr r4,r3
lis r3,79f@ha
addi r3,r3,79f@l
bl printk
lwz r3,RESULT(r1)
mtlr r31
lwz r31,GPR31(r1)
blr
7: .string "syscall %d(%x, %x, %x, %x, %x, "
77: .string "%x), current=%p\n"
79: .string " -> %x\n"
.align 2,0
#ifdef SHOW_SYSCALLS_TASK
.data
.globl show_syscalls_task
show_syscalls_task:
.long -1
.text
#endif
#endif /* SHOW_SYSCALLS */
/*
* The fork/clone functions need to copy the full register set into
* the child process. Therefore we need to save all the nonvolatile
* registers (r13 - r31) before calling the C code.
*/
.globl ppc_fork
ppc_fork:
SAVE_NVGPRS(r1)
lwz r0,_TRAP(r1)
rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
stw r0,_TRAP(r1) /* register set saved */
b sys_fork
.globl ppc_vfork
ppc_vfork:
SAVE_NVGPRS(r1)
lwz r0,_TRAP(r1)
rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
stw r0,_TRAP(r1) /* register set saved */
b sys_vfork
.globl ppc_clone
ppc_clone:
SAVE_NVGPRS(r1)
lwz r0,_TRAP(r1)
rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
stw r0,_TRAP(r1) /* register set saved */
b sys_clone
.globl ppc_swapcontext
ppc_swapcontext:
SAVE_NVGPRS(r1)
lwz r0,_TRAP(r1)
rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
stw r0,_TRAP(r1) /* register set saved */
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
* 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
BEGIN_FTR_SECTION
oris r0,r0,MSR_SPE@h /* Disable SPE */
mfspr r12,SPRN_SPEFSCR /* save spefscr register value */
stw r12,THREAD+THREAD_SPEFSCR(r2)
END_FTR_SECTION_IFSET(CPU_FTR_SPE)
#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
BEGIN_FTR_SECTION
lwz r0,THREAD+THREAD_SPEFSCR(r2)
mtspr SPRN_SPEFSCR,r0 /* restore SPEFSCR reg */
END_FTR_SECTION_IFSET(CPU_FTR_SPE)
#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
.section .bss
.align 2
fee_restarts:
.space 4
.previous
/* 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,(31-THREAD_SHIFT)
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,(31-THREAD_SHIFT)
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,(31-THREAD_SHIFT)
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:
#ifdef CONFIG_44x
lis r4,icache_44x_need_flush@ha
lwz r5,icache_44x_need_flush@l(r4)
cmplwi cr0,r5,0
beq+ 1f
li r6,0
iccci r0,r0
stw r6,icache_44x_need_flush@l(r4)
1:
#endif /* CONFIG_44x */
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)
BEGIN_FTR_SECTION
lwarx r11,0,r1
END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
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
.section .bss
.align 4
global_dbcr0:
.space 8
.previous
#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,(31-THREAD_SHIFT)
lwz r9,TI_FLAGS(r9)
andi. r0,r9,_TIF_NEED_RESCHED
bne- do_resched
andi. r0,r9,_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK
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)
4: addi r3,r1,STACK_FRAME_OVERHEAD
bl nonrecoverable_exception
/* shouldn't return */
b 4b
.section .bss
.align 2
ee_restarts:
.space 4
.previous
/*
* PROM code for specific machines follows. Put it
* here so it's easy to add arch-specific sections later.
* -- Cort
*/
#ifdef CONFIG_PPC_RTAS
/*
* On CHRP, the Run-Time Abstraction Services (RTAS) have to be
* called with the MMU off.
*/
_GLOBAL(enter_rtas)
stwu r1,-INT_FRAME_SIZE(r1)
mflr r0
stw r0,INT_FRAME_SIZE+4(r1)
LOAD_REG_ADDR(r4, rtas)
lis r6,1f@ha /* physical return address for rtas */
addi r6,r6,1f@l
tophys(r6,r6)
tophys(r7,r1)
lwz r8,RTASENTRY(r4)
lwz r4,RTASBASE(r4)
mfmsr r9
stw r9,8(r1)
LOAD_MSR_KERNEL(r0,MSR_KERNEL)
SYNC /* disable interrupts so SRR0/1 */
MTMSRD(r0) /* don't get trashed */
li r9,MSR_KERNEL & ~(MSR_IR|MSR_DR)
mtlr r6
mtspr SPRN_SPRG2,r7
mtspr SPRN_SRR0,r8
mtspr SPRN_SRR1,r9
RFI
1: tophys(r9,r1)
lwz r8,INT_FRAME_SIZE+4(r9) /* get return address */
lwz r9,8(r9) /* original msr value */
FIX_SRR1(r9,r0)
addi r1,r1,INT_FRAME_SIZE
li r0,0
mtspr SPRN_SPRG2,r0
mtspr SPRN_SRR0,r8
mtspr SPRN_SRR1,r9
RFI /* return to caller */
.globl machine_check_in_rtas
machine_check_in_rtas:
twi 31,0,0
/* XXX load up BATs and panic */
#endif /* CONFIG_PPC_RTAS */
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