/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas ([email protected])
* Rewritten by Cort Dougan ([email protected]) for PReP
* Copyright (C) 1996 Cort Dougan <[email protected]>
* 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 ([email protected]).
*
* This file contains the system call entry code, context switch
* code, and exception/interrupt return code for PowerPC.
*/
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/sys.h>
#include <linux/threads.h>
#include <linux/linkage.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>
#include <asm/ptrace.h>
#include <asm/feature-fixups.h>
#include <asm/barrier.h>
#include <asm/kup.h>
#include <asm/bug.h>
#include <asm/interrupt.h>
#include "head_32.h"
/*
* powerpc relies on return from interrupt/syscall being context synchronising
* (which rfi is) to support ARCH_HAS_MEMBARRIER_SYNC_CORE without additional
* synchronisation instructions.
*/
/*
* Align to 4k in order to ensure that all functions modyfing srr0/srr1
* fit into one page in order to not encounter a TLB miss between the
* modification of srr0/srr1 and the associated rfi.
*/
.align 12
#if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_PPC_E500)
.globl prepare_transfer_to_handler
prepare_transfer_to_handler:
/* if from kernel, check interrupted DOZE/NAP mode */
lwz r12,TI_LOCAL_FLAGS(r2)
mtcrf 0x01,r12
bt- 31-TLF_NAPPING,4f
bt- 31-TLF_SLEEPING,7f
blr
4: rlwinm r12,r12,0,~_TLF_NAPPING
stw r12,TI_LOCAL_FLAGS(r2)
b power_save_ppc32_restore
7: rlwinm r12,r12,0,~_TLF_SLEEPING
stw r12,TI_LOCAL_FLAGS(r2)
lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */
rlwinm r9,r9,0,~MSR_EE
lwz r12,_LINK(r11) /* and return to address in LR */
REST_GPR(2, r11)
b fast_exception_return
_ASM_NOKPROBE_SYMBOL(prepare_transfer_to_handler)
#endif /* CONFIG_PPC_BOOK3S_32 || CONFIG_PPC_E500 */
#if defined(CONFIG_PPC_KUEP) && defined(CONFIG_PPC_BOOK3S_32)
SYM_FUNC_START(__kuep_lock)
lwz r9, THREAD+THSR0(r2)
update_user_segments_by_4 r9, r10, r11, r12
blr
SYM_FUNC_END(__kuep_lock)
SYM_FUNC_START_LOCAL(__kuep_unlock)
lwz r9, THREAD+THSR0(r2)
rlwinm r9,r9,0,~SR_NX
update_user_segments_by_4 r9, r10, r11, r12
blr
SYM_FUNC_END(__kuep_unlock)
.macro kuep_lock
bl __kuep_lock
.endm
.macro kuep_unlock
bl __kuep_unlock
.endm
#else
.macro kuep_lock
.endm
.macro kuep_unlock
.endm
#endif
.globl transfer_to_syscall
transfer_to_syscall:
stw r3, ORIG_GPR3(r1)
stw r11, GPR1(r1)
stw r11, 0(r1)
mflr r12
stw r12, _LINK(r1)
#ifdef CONFIG_BOOKE
rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */
#endif
lis r12,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */
SAVE_GPR(2, r1)
addi r12,r12,STACK_FRAME_REGS_MARKER@l
stw r9,_MSR(r1)
li r2, INTERRUPT_SYSCALL
stw r12,STACK_INT_FRAME_MARKER(r1)
stw r2,_TRAP(r1)
SAVE_GPR(0, r1)
SAVE_GPRS(3, 8, r1)
addi r2,r10,-THREAD
SAVE_NVGPRS(r1)
kuep_lock
/* Calling convention has r3 = regs, r4 = orig r0 */
addi r3,r1,STACK_INT_FRAME_REGS
mr r4,r0
bl system_call_exception
ret_from_syscall:
addi r4,r1,STACK_INT_FRAME_REGS
li r5,0
bl syscall_exit_prepare
#ifdef CONFIG_PPC_47x
lis r4,icache_44x_need_flush@ha
lwz r5,icache_44x_need_flush@l(r4)
cmplwi cr0,r5,0
bne- .L44x_icache_flush
#endif /* CONFIG_PPC_47x */
.L44x_icache_flush_return:
kuep_unlock
lwz r4,_LINK(r1)
lwz r5,_CCR(r1)
mtlr r4
lwz r7,_NIP(r1)
lwz r8,_MSR(r1)
cmpwi r3,0
REST_GPR(3, r1)
syscall_exit_finish:
mtspr SPRN_SRR0,r7
mtspr SPRN_SRR1,r8
bne 3f
mtcr r5
1: REST_GPR(2, r1)
REST_GPR(1, r1)
rfi
3: mtcr r5
lwz r4,_CTR(r1)
lwz r5,_XER(r1)
REST_NVGPRS(r1)
mtctr r4
mtxer r5
REST_GPR(0, r1)
REST_GPRS(3, 12, r1)
b 1b
#ifdef CONFIG_44x
.L44x_icache_flush:
li r7,0
iccci r0,r0
stw r7,icache_44x_need_flush@l(r4)
b .L44x_icache_flush_return
#endif /* CONFIG_44x */
.globl ret_from_fork
ret_from_fork:
REST_NVGPRS(r1)
bl schedule_tail
li r3,0 /* fork() return value */
b ret_from_syscall
.globl ret_from_kernel_user_thread
ret_from_kernel_user_thread:
bl schedule_tail
mtctr r14
mr r3,r15
PPC440EP_ERR42
bctrl
li r3,0
b ret_from_syscall
.globl start_kernel_thread
start_kernel_thread:
bl schedule_tail
mtctr r14
mr r3,r15
PPC440EP_ERR42
bctrl
/*
* This must not return. We actually want to BUG here, not WARN,
* because BUG will exit the process which is what the kernel thread
* should have done, which may give some hope of continuing.
*/
100: trap
EMIT_BUG_ENTRY 100b,__FILE__,__LINE__,0
.globl fast_exception_return
fast_exception_return:
#ifndef CONFIG_BOOKE
andi. r10,r9,MSR_RI /* check for recoverable interrupt */
beq 3f /* if not, we've got problems */
#endif
2: lwz r10,_CCR(r11)
REST_GPRS(1, 6, r11)
mtcr r10
lwz r10,_LINK(r11)
mtlr r10
/* Clear the exception marker on the stack to avoid confusing stacktrace */
li r10, 0
stw r10, 8(r11)
REST_GPR(10, r11)
#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS)
mtspr SPRN_NRI, r0
#endif
mtspr SPRN_SRR1,r9
mtspr SPRN_SRR0,r12
REST_GPR(9, r11)
REST_GPR(12, r11)
REST_GPR(11, r11)
rfi
_ASM_NOKPROBE_SYMBOL(fast_exception_return)
/* aargh, a nonrecoverable interrupt, panic */
/* aargh, we don't know which trap this is */
3:
li r10,-1
stw r10,_TRAP(r11)
prepare_transfer_to_handler
bl unrecoverable_exception
trap /* should not get here */
.globl interrupt_return
interrupt_return:
lwz r4,_MSR(r1)
addi r3,r1,STACK_INT_FRAME_REGS
andi. r0,r4,MSR_PR
beq .Lkernel_interrupt_return
bl interrupt_exit_user_prepare
cmpwi r3,0
kuep_unlock
bne- .Lrestore_nvgprs
.Lfast_user_interrupt_return:
lwz r11,_NIP(r1)
lwz r12,_MSR(r1)
mtspr SPRN_SRR0,r11
mtspr SPRN_SRR1,r12
BEGIN_FTR_SECTION
stwcx. r0,0,r1 /* to clear the reservation */
FTR_SECTION_ELSE
lwarx r0,0,r1
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
lwz r3,_CCR(r1)
lwz r4,_LINK(r1)
lwz r5,_CTR(r1)
lwz r6,_XER(r1)
li r0,0
/*
* Leaving a stale exception marker on the stack can confuse
* the reliable stack unwinder later on. Clear it.
*/
stw r0,8(r1)
REST_GPRS(7, 12, r1)
mtcr r3
mtlr r4
mtctr r5
mtspr SPRN_XER,r6
REST_GPRS(2, 6, r1)
REST_GPR(0, r1)
REST_GPR(1, r1)
rfi
.Lrestore_nvgprs:
REST_NVGPRS(r1)
b .Lfast_user_interrupt_return
.Lkernel_interrupt_return:
bl interrupt_exit_kernel_prepare
.Lfast_kernel_interrupt_return:
cmpwi cr1,r3,0
lwz r11,_NIP(r1)
lwz r12,_MSR(r1)
mtspr SPRN_SRR0,r11
mtspr SPRN_SRR1,r12
BEGIN_FTR_SECTION
stwcx. r0,0,r1 /* to clear the reservation */
FTR_SECTION_ELSE
lwarx r0,0,r1
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
lwz r3,_LINK(r1)
lwz r4,_CTR(r1)
lwz r5,_XER(r1)
lwz r6,_CCR(r1)
li r0,0
REST_GPRS(7, 12, r1)
mtlr r3
mtctr r4
mtspr SPRN_XER,r5
/*
* Leaving a stale exception marker on the stack can confuse
* the reliable stack unwinder later on. Clear it.
*/
stw r0,8(r1)
REST_GPRS(2, 5, r1)
bne- cr1,1f /* emulate stack store */
mtcr r6
REST_GPR(6, r1)
REST_GPR(0, r1)
REST_GPR(1, r1)
rfi
1: /*
* Emulate stack store with update. New r1 value was already calculated
* and updated in our interrupt regs by emulate_loadstore, but we can't
* store the previous value of r1 to the stack before re-loading our
* registers from it, otherwise they could be clobbered. Use
* SPRG Scratch0 as temporary storage to hold the store
* data, as interrupts are disabled here so it won't be clobbered.
*/
mtcr r6
#ifdef CONFIG_BOOKE
mtspr SPRN_SPRG_WSCRATCH0, r9
#else
mtspr SPRN_SPRG_SCRATCH0, r9
#endif
addi r9,r1,INT_FRAME_SIZE /* get original r1 */
REST_GPR(6, r1)
REST_GPR(0, r1)
REST_GPR(1, r1)
stw r9,0(r1) /* perform store component of stwu */
#ifdef CONFIG_BOOKE
mfspr r9, SPRN_SPRG_RSCRATCH0
#else
mfspr r9, SPRN_SPRG_SCRATCH0
#endif
rfi
_ASM_NOKPROBE_SYMBOL(interrupt_return)
#ifdef CONFIG_BOOKE
/*
* 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.
*
*/
#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; \
bne interrupt_return; \
REST_GPR(0, r1); \
REST_GPRS(2, 8, r1); \
lwz r10,_XER(r1); \
lwz r11,_CTR(r1); \
mtspr SPRN_XER,r10; \
mtctr r11; \
stwcx. r0,0,r1; /* to clear the reservation */ \
lwz r11,_LINK(r1); \
mtlr r11; \
lwz r10,_CCR(r1); \
mtcrf 0xff,r10; \
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; \
REST_GPRS(9, 12, r1); \
REST_GPR(1, r1); \
exc_lvl_rfi; \
b .; /* prevent prefetch past exc_lvl_rfi */
#define RESTORE_xSRR(exc_lvl_srr0, exc_lvl_srr1) \
lwz r9,_##exc_lvl_srr0(r1); \
lwz r10,_##exc_lvl_srr1(r1); \
mtspr SPRN_##exc_lvl_srr0,r9; \
mtspr SPRN_##exc_lvl_srr1,r10;
#if defined(CONFIG_PPC_E500)
#ifdef CONFIG_PHYS_64BIT
#define RESTORE_MAS7 \
lwz r11,MAS7(r1); \
mtspr SPRN_MAS7,r11;
#else
#define RESTORE_MAS7
#endif /* CONFIG_PHYS_64BIT */
#define RESTORE_MMU_REGS \
lwz r9,MAS0(r1); \
lwz r10,MAS1(r1); \
lwz r11,MAS2(r1); \
mtspr SPRN_MAS0,r9; \
lwz r9,MAS3(r1); \
mtspr SPRN_MAS1,r10; \
lwz r10,MAS6(r1); \
mtspr SPRN_MAS2,r11; \
mtspr SPRN_MAS3,r9; \
mtspr SPRN_MAS6,r10; \
RESTORE_MAS7;
#elif defined(CONFIG_44x)
#define RESTORE_MMU_REGS \
lwz r9,MMUCR(r1); \
mtspr SPRN_MMUCR,r9;
#else
#define RESTORE_MMU_REGS
#endif
.globl ret_from_crit_exc
ret_from_crit_exc:
RESTORE_xSRR(SRR0,SRR1);
RESTORE_MMU_REGS;
RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI)
_ASM_NOKPROBE_SYMBOL(ret_from_crit_exc)
.globl ret_from_debug_exc
ret_from_debug_exc:
RESTORE_xSRR(SRR0,SRR1);
RESTORE_xSRR(CSRR0,CSRR1);
RESTORE_MMU_REGS;
RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, PPC_RFDI)
_ASM_NOKPROBE_SYMBOL(ret_from_debug_exc)
.globl ret_from_mcheck_exc
ret_from_mcheck_exc:
RESTORE_xSRR(SRR0,SRR1);
RESTORE_xSRR(CSRR0,CSRR1);
RESTORE_xSRR(DSRR0,DSRR1);
RESTORE_MMU_REGS;
RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, PPC_RFMCI)
_ASM_NOKPROBE_SYMBOL(ret_from_mcheck_exc)
#endif /* CONFIG_BOOKE */
Codebase Browser
linux