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Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 512 |
1 files changed, 512 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S new file mode 100644 index 000000000..7eda33a24 --- /dev/null +++ b/arch/powerpc/kernel/entry_32.S @@ -0,0 +1,512 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * 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. + */ + +#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_OR_40x + 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 +#ifdef CONFIG_40x + b . /* Prevent prefetch past rfi */ +#endif + +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: +#if !(defined(CONFIG_4xx) || defined(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 +#ifdef CONFIG_40x + b . /* Prevent prefetch past rfi */ +#endif +_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 +#ifdef CONFIG_40x + b . /* Prevent prefetch past rfi */ +#endif + +.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 +#ifdef CONFIG_40x + b . /* Prevent prefetch past rfi */ +#endif + +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 +#ifdef CONFIG_40x + b . /* Prevent prefetch past rfi */ +#endif +_ASM_NOKPROBE_SYMBOL(interrupt_return) + +#if defined(CONFIG_4xx) || defined(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. + * + */ +#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; \ + 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; \ + 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; \ + 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 + +#ifdef CONFIG_40x + .globl ret_from_crit_exc +ret_from_crit_exc: + lis r9,crit_srr0@ha; + lwz r9,crit_srr0@l(r9); + lis r10,crit_srr1@ha; + lwz r10,crit_srr1@l(r10); + mtspr SPRN_SRR0,r9; + mtspr SPRN_SRR1,r10; + RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI) +_ASM_NOKPROBE_SYMBOL(ret_from_crit_exc) +#endif /* CONFIG_40x */ + +#ifdef CONFIG_BOOKE + .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 */ +#endif /* !(CONFIG_4xx || CONFIG_BOOKE) */ |