| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * PowerPC version |
| * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) |
| * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP |
| * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> |
| * 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 <asm/cache.h> |
| #include <asm/unistd.h> |
| #include <asm/processor.h> |
| #include <asm/page.h> |
| #include <asm/mmu.h> |
| #include <asm/thread_info.h> |
| #include <asm/code-patching-asm.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/cputable.h> |
| #include <asm/firmware.h> |
| #include <asm/bug.h> |
| #include <asm/ptrace.h> |
| #include <asm/irqflags.h> |
| #include <asm/hw_irq.h> |
| #include <asm/context_tracking.h> |
| #include <asm/ppc-opcode.h> |
| #include <asm/barrier.h> |
| #include <asm/export.h> |
| #include <asm/asm-compat.h> |
| #ifdef CONFIG_PPC_BOOK3S |
| #include <asm/exception-64s.h> |
| #else |
| #include <asm/exception-64e.h> |
| #endif |
| #include <asm/feature-fixups.h> |
| #include <asm/kup.h> |
| |
| /* |
| * System calls. |
| */ |
| .section ".text" |
| |
| #ifdef CONFIG_PPC_BOOK3S_64 |
| |
| #define FLUSH_COUNT_CACHE \ |
| 1: nop; \ |
| patch_site 1b, patch__call_flush_branch_caches1; \ |
| 1: nop; \ |
| patch_site 1b, patch__call_flush_branch_caches2; \ |
| 1: nop; \ |
| patch_site 1b, patch__call_flush_branch_caches3 |
| |
| .macro nops number |
| .rept \number |
| nop |
| .endr |
| .endm |
| |
| .balign 32 |
| .global flush_branch_caches |
| flush_branch_caches: |
| /* Save LR into r9 */ |
| mflr r9 |
| |
| // Flush the link stack |
| .rept 64 |
| bl .+4 |
| .endr |
| b 1f |
| nops 6 |
| |
| .balign 32 |
| /* Restore LR */ |
| 1: mtlr r9 |
| |
| // If we're just flushing the link stack, return here |
| 3: nop |
| patch_site 3b patch__flush_link_stack_return |
| |
| li r9,0x7fff |
| mtctr r9 |
| |
| PPC_BCCTR_FLUSH |
| |
| 2: nop |
| patch_site 2b patch__flush_count_cache_return |
| |
| nops 3 |
| |
| .rept 278 |
| .balign 32 |
| PPC_BCCTR_FLUSH |
| nops 7 |
| .endr |
| |
| blr |
| #else |
| #define FLUSH_COUNT_CACHE |
| #endif /* CONFIG_PPC_BOOK3S_64 */ |
| |
| /* |
| * 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, via interrupt_return. |
| * On entry, r3 points to the THREAD for the current task, r4 |
| * points to the THREAD for the new task. |
| * |
| * 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/powerpc/kernel/process.c |
| */ |
| .align 7 |
| _GLOBAL(_switch) |
| mflr r0 |
| std r0,16(r1) |
| stdu r1,-SWITCH_FRAME_SIZE(r1) |
| /* r3-r13 are caller saved -- Cort */ |
| SAVE_NVGPRS(r1) |
| std r0,_NIP(r1) /* Return to switch caller */ |
| mfcr r23 |
| std r23,_CCR(r1) |
| std r1,KSP(r3) /* Set old stack pointer */ |
| |
| kuap_check_amr r9, r10 |
| |
| FLUSH_COUNT_CACHE /* Clobbers r9, ctr */ |
| |
| /* |
| * On SMP kernels, care must be taken because a task may be |
| * scheduled off CPUx and on to CPUy. Memory ordering must be |
| * considered. |
| * |
| * Cacheable stores on CPUx will be visible when the task is |
| * scheduled on CPUy by virtue of the core scheduler barriers |
| * (see "Notes on Program-Order guarantees on SMP systems." in |
| * kernel/sched/core.c). |
| * |
| * Uncacheable stores in the case of involuntary preemption must |
| * be taken care of. The smp_mb__after_spinlock() in __schedule() |
| * is implemented as hwsync on powerpc, which orders MMIO too. So |
| * long as there is an hwsync in the context switch path, it will |
| * be executed on the source CPU after the task has performed |
| * all MMIO ops on that CPU, and on the destination CPU before the |
| * task performs any MMIO ops there. |
| */ |
| |
| /* |
| * The kernel context switch path must contain a spin_lock, |
| * which contains larx/stcx, which will clear any reservation |
| * of the task being switched. |
| */ |
| #ifdef CONFIG_PPC_BOOK3S |
| /* Cancel all explict user streams as they will have no use after context |
| * switch and will stop the HW from creating streams itself |
| */ |
| DCBT_BOOK3S_STOP_ALL_STREAM_IDS(r6) |
| #endif |
| |
| addi r6,r4,-THREAD /* Convert THREAD to 'current' */ |
| std r6,PACACURRENT(r13) /* Set new 'current' */ |
| #if defined(CONFIG_STACKPROTECTOR) |
| ld r6, TASK_CANARY(r6) |
| std r6, PACA_CANARY(r13) |
| #endif |
| |
| ld r8,KSP(r4) /* new stack pointer */ |
| #ifdef CONFIG_PPC_BOOK3S_64 |
| BEGIN_MMU_FTR_SECTION |
| b 2f |
| END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) |
| BEGIN_FTR_SECTION |
| clrrdi r6,r8,28 /* get its ESID */ |
| clrrdi r9,r1,28 /* get current sp ESID */ |
| FTR_SECTION_ELSE |
| clrrdi r6,r8,40 /* get its 1T ESID */ |
| clrrdi r9,r1,40 /* get current sp 1T ESID */ |
| ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_1T_SEGMENT) |
| clrldi. r0,r6,2 /* is new ESID c00000000? */ |
| cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */ |
| cror eq,4*cr1+eq,eq |
| beq 2f /* if yes, don't slbie it */ |
| |
| /* Bolt in the new stack SLB entry */ |
| ld r7,KSP_VSID(r4) /* Get new stack's VSID */ |
| oris r0,r6,(SLB_ESID_V)@h |
| ori r0,r0,(SLB_NUM_BOLTED-1)@l |
| BEGIN_FTR_SECTION |
| li r9,MMU_SEGSIZE_1T /* insert B field */ |
| oris r6,r6,(MMU_SEGSIZE_1T << SLBIE_SSIZE_SHIFT)@h |
| rldimi r7,r9,SLB_VSID_SSIZE_SHIFT,0 |
| END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT) |
| |
| /* Update the last bolted SLB. No write barriers are needed |
| * here, provided we only update the current CPU's SLB shadow |
| * buffer. |
| */ |
| ld r9,PACA_SLBSHADOWPTR(r13) |
| li r12,0 |
| std r12,SLBSHADOW_STACKESID(r9) /* Clear ESID */ |
| li r12,SLBSHADOW_STACKVSID |
| STDX_BE r7,r12,r9 /* Save VSID */ |
| li r12,SLBSHADOW_STACKESID |
| STDX_BE r0,r12,r9 /* Save ESID */ |
| |
| /* No need to check for MMU_FTR_NO_SLBIE_B here, since when |
| * we have 1TB segments, the only CPUs known to have the errata |
| * only support less than 1TB of system memory and we'll never |
| * actually hit this code path. |
| */ |
| |
| isync |
| slbie r6 |
| BEGIN_FTR_SECTION |
| slbie r6 /* Workaround POWER5 < DD2.1 issue */ |
| END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) |
| slbmte r7,r0 |
| isync |
| 2: |
| #endif /* CONFIG_PPC_BOOK3S_64 */ |
| |
| clrrdi r7, r8, THREAD_SHIFT /* base of new stack */ |
| /* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE |
| because we don't need to leave the 288-byte ABI gap at the |
| top of the kernel stack. */ |
| addi r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE |
| |
| /* |
| * PMU interrupts in radix may come in here. They will use r1, not |
| * PACAKSAVE, so this stack switch will not cause a problem. They |
| * will store to the process stack, which may then be migrated to |
| * another CPU. However the rq lock release on this CPU paired with |
| * the rq lock acquire on the new CPU before the stack becomes |
| * active on the new CPU, will order those stores. |
| */ |
| mr r1,r8 /* start using new stack pointer */ |
| std r7,PACAKSAVE(r13) |
| |
| ld r6,_CCR(r1) |
| mtcrf 0xFF,r6 |
| |
| /* r3-r13 are destroyed -- Cort */ |
| REST_NVGPRS(r1) |
| |
| /* convert old thread to its task_struct for return value */ |
| addi r3,r3,-THREAD |
| ld r7,_NIP(r1) /* Return to _switch caller in new task */ |
| mtlr r7 |
| addi r1,r1,SWITCH_FRAME_SIZE |
| blr |
| |
| #ifdef CONFIG_PPC_RTAS |
| /* |
| * On CHRP, the Run-Time Abstraction Services (RTAS) have to be |
| * called with the MMU off. |
| * |
| * In addition, we need to be in 32b mode, at least for now. |
| * |
| * Note: r3 is an input parameter to rtas, so don't trash it... |
| */ |
| _GLOBAL(enter_rtas) |
| mflr r0 |
| std r0,16(r1) |
| stdu r1,-SWITCH_FRAME_SIZE(r1) /* Save SP and create stack space. */ |
| |
| /* Because RTAS is running in 32b mode, it clobbers the high order half |
| * of all registers that it saves. We therefore save those registers |
| * RTAS might touch to the stack. (r0, r3-r13 are caller saved) |
| */ |
| SAVE_GPR(2, r1) /* Save the TOC */ |
| SAVE_GPR(13, r1) /* Save paca */ |
| SAVE_NVGPRS(r1) /* Save the non-volatiles */ |
| |
| mfcr r4 |
| std r4,_CCR(r1) |
| mfctr r5 |
| std r5,_CTR(r1) |
| mfspr r6,SPRN_XER |
| std r6,_XER(r1) |
| mfdar r7 |
| std r7,_DAR(r1) |
| mfdsisr r8 |
| std r8,_DSISR(r1) |
| |
| /* Temporary workaround to clear CR until RTAS can be modified to |
| * ignore all bits. |
| */ |
| li r0,0 |
| mtcr r0 |
| |
| #ifdef CONFIG_BUG |
| /* There is no way it is acceptable to get here with interrupts enabled, |
| * check it with the asm equivalent of WARN_ON |
| */ |
| lbz r0,PACAIRQSOFTMASK(r13) |
| 1: tdeqi r0,IRQS_ENABLED |
| EMIT_WARN_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING |
| #endif |
| |
| /* Hard-disable interrupts */ |
| mfmsr r6 |
| rldicl r7,r6,48,1 |
| rotldi r7,r7,16 |
| mtmsrd r7,1 |
| |
| /* Unfortunately, the stack pointer and the MSR are also clobbered, |
| * so they are saved in the PACA which allows us to restore |
| * our original state after RTAS returns. |
| */ |
| std r1,PACAR1(r13) |
| std r6,PACASAVEDMSR(r13) |
| |
| /* Setup our real return addr */ |
| LOAD_REG_ADDR(r4,rtas_return_loc) |
| clrldi r4,r4,2 /* convert to realmode address */ |
| mtlr r4 |
| |
| li r0,0 |
| ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI |
| andc r0,r6,r0 |
| |
| li r9,1 |
| rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) |
| ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE |
| andc r6,r0,r9 |
| |
| __enter_rtas: |
| sync /* disable interrupts so SRR0/1 */ |
| mtmsrd r0 /* don't get trashed */ |
| |
| LOAD_REG_ADDR(r4, rtas) |
| ld r5,RTASENTRY(r4) /* get the rtas->entry value */ |
| ld r4,RTASBASE(r4) /* get the rtas->base value */ |
| |
| mtspr SPRN_SRR0,r5 |
| mtspr SPRN_SRR1,r6 |
| RFI_TO_KERNEL |
| b . /* prevent speculative execution */ |
| |
| rtas_return_loc: |
| FIXUP_ENDIAN |
| |
| /* |
| * Clear RI and set SF before anything. |
| */ |
| mfmsr r6 |
| li r0,MSR_RI |
| andc r6,r6,r0 |
| sldi r0,r0,(MSR_SF_LG - MSR_RI_LG) |
| or r6,r6,r0 |
| sync |
| mtmsrd r6 |
| |
| /* relocation is off at this point */ |
| GET_PACA(r4) |
| clrldi r4,r4,2 /* convert to realmode address */ |
| |
| bcl 20,31,$+4 |
| 0: mflr r3 |
| ld r3,(1f-0b)(r3) /* get &rtas_restore_regs */ |
| |
| ld r1,PACAR1(r4) /* Restore our SP */ |
| ld r4,PACASAVEDMSR(r4) /* Restore our MSR */ |
| |
| mtspr SPRN_SRR0,r3 |
| mtspr SPRN_SRR1,r4 |
| RFI_TO_KERNEL |
| b . /* prevent speculative execution */ |
| _ASM_NOKPROBE_SYMBOL(__enter_rtas) |
| _ASM_NOKPROBE_SYMBOL(rtas_return_loc) |
| |
| .align 3 |
| 1: .8byte rtas_restore_regs |
| |
| rtas_restore_regs: |
| /* relocation is on at this point */ |
| REST_GPR(2, r1) /* Restore the TOC */ |
| REST_GPR(13, r1) /* Restore paca */ |
| REST_NVGPRS(r1) /* Restore the non-volatiles */ |
| |
| GET_PACA(r13) |
| |
| ld r4,_CCR(r1) |
| mtcr r4 |
| ld r5,_CTR(r1) |
| mtctr r5 |
| ld r6,_XER(r1) |
| mtspr SPRN_XER,r6 |
| ld r7,_DAR(r1) |
| mtdar r7 |
| ld r8,_DSISR(r1) |
| mtdsisr r8 |
| |
| addi r1,r1,SWITCH_FRAME_SIZE /* Unstack our frame */ |
| ld r0,16(r1) /* get return address */ |
| |
| mtlr r0 |
| blr /* return to caller */ |
| |
| #endif /* CONFIG_PPC_RTAS */ |
| |
| _GLOBAL(enter_prom) |
| mflr r0 |
| std r0,16(r1) |
| stdu r1,-SWITCH_FRAME_SIZE(r1) /* Save SP and create stack space */ |
| |
| /* Because PROM is running in 32b mode, it clobbers the high order half |
| * of all registers that it saves. We therefore save those registers |
| * PROM might touch to the stack. (r0, r3-r13 are caller saved) |
| */ |
| SAVE_GPR(2, r1) |
| SAVE_GPR(13, r1) |
| SAVE_NVGPRS(r1) |
| mfcr r10 |
| mfmsr r11 |
| std r10,_CCR(r1) |
| std r11,_MSR(r1) |
| |
| /* Put PROM address in SRR0 */ |
| mtsrr0 r4 |
| |
| /* Setup our trampoline return addr in LR */ |
| bcl 20,31,$+4 |
| 0: mflr r4 |
| addi r4,r4,(1f - 0b) |
| mtlr r4 |
| |
| /* Prepare a 32-bit mode big endian MSR |
| */ |
| #ifdef CONFIG_PPC_BOOK3E |
| rlwinm r11,r11,0,1,31 |
| mtsrr1 r11 |
| rfi |
| #else /* CONFIG_PPC_BOOK3E */ |
| LOAD_REG_IMMEDIATE(r12, MSR_SF | MSR_LE) |
| andc r11,r11,r12 |
| mtsrr1 r11 |
| RFI_TO_KERNEL |
| #endif /* CONFIG_PPC_BOOK3E */ |
| |
| 1: /* Return from OF */ |
| FIXUP_ENDIAN |
| |
| /* Just make sure that r1 top 32 bits didn't get |
| * corrupt by OF |
| */ |
| rldicl r1,r1,0,32 |
| |
| /* Restore the MSR (back to 64 bits) */ |
| ld r0,_MSR(r1) |
| MTMSRD(r0) |
| isync |
| |
| /* Restore other registers */ |
| REST_GPR(2, r1) |
| REST_GPR(13, r1) |
| REST_NVGPRS(r1) |
| ld r4,_CCR(r1) |
| mtcr r4 |
| |
| addi r1,r1,SWITCH_FRAME_SIZE |
| ld r0,16(r1) |
| mtlr r0 |
| blr |
