| /* 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- 2f |
| #endif /* CONFIG_PPC_47x */ |
| 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 |
| 2: li r7,0 |
| iccci r0,r0 |
| stw r7,icache_44x_need_flush@l(r4) |
| b 1b |
| #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) */ |
