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Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 999 |
1 files changed, 999 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S new file mode 100644 index 000000000..2831b0aa9 --- /dev/null +++ b/arch/powerpc/kernel/entry_64.S @@ -0,0 +1,999 @@ +/* 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/tm.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 ".toc","aw" +SYS_CALL_TABLE: + .tc sys_call_table[TC],sys_call_table + +#ifdef CONFIG_COMPAT +COMPAT_SYS_CALL_TABLE: + .tc compat_sys_call_table[TC],compat_sys_call_table +#endif + +/* This value is used to mark exception frames on the stack. */ +exception_marker: + .tc ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER + + .section ".text" + .align 7 + +#ifdef CONFIG_PPC_BOOK3S +.macro system_call_vectored name trapnr + .globl system_call_vectored_\name +system_call_vectored_\name: +_ASM_NOKPROBE_SYMBOL(system_call_vectored_\name) +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +BEGIN_FTR_SECTION + extrdi. r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */ + bne .Ltabort_syscall +END_FTR_SECTION_IFSET(CPU_FTR_TM) +#endif + SCV_INTERRUPT_TO_KERNEL + mr r10,r1 + ld r1,PACAKSAVE(r13) + std r10,0(r1) + std r11,_NIP(r1) + std r12,_MSR(r1) + std r0,GPR0(r1) + std r10,GPR1(r1) + std r2,GPR2(r1) + ld r2,PACATOC(r13) + mfcr r12 + li r11,0 + /* Can we avoid saving r3-r8 in common case? */ + std r3,GPR3(r1) + std r4,GPR4(r1) + std r5,GPR5(r1) + std r6,GPR6(r1) + std r7,GPR7(r1) + std r8,GPR8(r1) + /* Zero r9-r12, this should only be required when restoring all GPRs */ + std r11,GPR9(r1) + std r11,GPR10(r1) + std r11,GPR11(r1) + std r11,GPR12(r1) + std r9,GPR13(r1) + SAVE_NVGPRS(r1) + std r11,_XER(r1) + std r11,_LINK(r1) + std r11,_CTR(r1) + + li r11,\trapnr + std r11,_TRAP(r1) + std r12,_CCR(r1) + std r3,ORIG_GPR3(r1) + addi r10,r1,STACK_FRAME_OVERHEAD + ld r11,exception_marker@toc(r2) + std r11,-16(r10) /* "regshere" marker */ + +BEGIN_FTR_SECTION + HMT_MEDIUM +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + /* + * RECONCILE_IRQ_STATE without calling trace_hardirqs_off(), which + * would clobber syscall parameters. Also we always enter with IRQs + * enabled and nothing pending. system_call_exception() will call + * trace_hardirqs_off(). + * + * scv enters with MSR[EE]=1, so don't set PACA_IRQ_HARD_DIS. The + * entry vector already sets PACAIRQSOFTMASK to IRQS_ALL_DISABLED. + */ + + /* Calling convention has r9 = orig r0, r10 = regs */ + mr r9,r0 + bl system_call_exception + +.Lsyscall_vectored_\name\()_exit: + addi r4,r1,STACK_FRAME_OVERHEAD + li r5,1 /* scv */ + bl syscall_exit_prepare + + ld r2,_CCR(r1) + ld r4,_NIP(r1) + ld r5,_MSR(r1) + +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + +BEGIN_FTR_SECTION + HMT_MEDIUM_LOW +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + cmpdi r3,0 + bne .Lsyscall_vectored_\name\()_restore_regs + + /* rfscv returns with LR->NIA and CTR->MSR */ + mtlr r4 + mtctr r5 + + /* Could zero these as per ABI, but we may consider a stricter ABI + * which preserves these if libc implementations can benefit, so + * restore them for now until further measurement is done. */ + ld r0,GPR0(r1) + ld r4,GPR4(r1) + ld r5,GPR5(r1) + ld r6,GPR6(r1) + ld r7,GPR7(r1) + ld r8,GPR8(r1) + /* Zero volatile regs that may contain sensitive kernel data */ + li r9,0 + li r10,0 + li r11,0 + li r12,0 + mtspr SPRN_XER,r0 + + /* + * We don't need to restore AMR on the way back to userspace for KUAP. + * The value of AMR only matters while we're in the kernel. + */ + mtcr r2 + ld r2,GPR2(r1) + ld r3,GPR3(r1) + ld r13,GPR13(r1) + ld r1,GPR1(r1) + RFSCV_TO_USER + b . /* prevent speculative execution */ + +.Lsyscall_vectored_\name\()_restore_regs: + li r3,0 + mtmsrd r3,1 + mtspr SPRN_SRR0,r4 + mtspr SPRN_SRR1,r5 + + ld r3,_CTR(r1) + ld r4,_LINK(r1) + ld r5,_XER(r1) + + REST_NVGPRS(r1) + ld r0,GPR0(r1) + mtcr r2 + mtctr r3 + mtlr r4 + mtspr SPRN_XER,r5 + REST_10GPRS(2, r1) + REST_2GPRS(12, r1) + ld r1,GPR1(r1) + RFI_TO_USER +.endm + +system_call_vectored common 0x3000 +/* + * We instantiate another entry copy for the SIGILL variant, with TRAP=0x7ff0 + * which is tested by system_call_exception when r0 is -1 (as set by vector + * entry code). + */ +system_call_vectored sigill 0x7ff0 + + +/* + * Entered via kernel return set up by kernel/sstep.c, must match entry regs + */ + .globl system_call_vectored_emulate +system_call_vectored_emulate: +_ASM_NOKPROBE_SYMBOL(system_call_vectored_emulate) + li r10,IRQS_ALL_DISABLED + stb r10,PACAIRQSOFTMASK(r13) + b system_call_vectored_common +#endif + + .balign IFETCH_ALIGN_BYTES + .globl system_call_common +system_call_common: +_ASM_NOKPROBE_SYMBOL(system_call_common) +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +BEGIN_FTR_SECTION + extrdi. r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */ + bne .Ltabort_syscall +END_FTR_SECTION_IFSET(CPU_FTR_TM) +#endif + mr r10,r1 + ld r1,PACAKSAVE(r13) + std r10,0(r1) + std r11,_NIP(r1) + std r12,_MSR(r1) + std r0,GPR0(r1) + std r10,GPR1(r1) + std r2,GPR2(r1) +#ifdef CONFIG_PPC_FSL_BOOK3E +START_BTB_FLUSH_SECTION + BTB_FLUSH(r10) +END_BTB_FLUSH_SECTION +#endif + ld r2,PACATOC(r13) + mfcr r12 + li r11,0 + /* Can we avoid saving r3-r8 in common case? */ + std r3,GPR3(r1) + std r4,GPR4(r1) + std r5,GPR5(r1) + std r6,GPR6(r1) + std r7,GPR7(r1) + std r8,GPR8(r1) + /* Zero r9-r12, this should only be required when restoring all GPRs */ + std r11,GPR9(r1) + std r11,GPR10(r1) + std r11,GPR11(r1) + std r11,GPR12(r1) + std r9,GPR13(r1) + SAVE_NVGPRS(r1) + std r11,_XER(r1) + std r11,_CTR(r1) + mflr r10 + + /* + * This clears CR0.SO (bit 28), which is the error indication on + * return from this system call. + */ + rldimi r12,r11,28,(63-28) + li r11,0xc00 + std r10,_LINK(r1) + std r11,_TRAP(r1) + std r12,_CCR(r1) + std r3,ORIG_GPR3(r1) + addi r10,r1,STACK_FRAME_OVERHEAD + ld r11,exception_marker@toc(r2) + std r11,-16(r10) /* "regshere" marker */ + + /* + * RECONCILE_IRQ_STATE without calling trace_hardirqs_off(), which + * would clobber syscall parameters. Also we always enter with IRQs + * enabled and nothing pending. system_call_exception() will call + * trace_hardirqs_off(). + */ + li r11,IRQS_ALL_DISABLED + li r12,PACA_IRQ_HARD_DIS + stb r11,PACAIRQSOFTMASK(r13) + stb r12,PACAIRQHAPPENED(r13) + + /* Calling convention has r9 = orig r0, r10 = regs */ + mr r9,r0 + bl system_call_exception + +.Lsyscall_exit: + addi r4,r1,STACK_FRAME_OVERHEAD + li r5,0 /* !scv */ + bl syscall_exit_prepare + + ld r2,_CCR(r1) + ld r4,_NIP(r1) + ld r5,_MSR(r1) + ld r6,_LINK(r1) + +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + + mtspr SPRN_SRR0,r4 + mtspr SPRN_SRR1,r5 + mtlr r6 + + cmpdi r3,0 + bne .Lsyscall_restore_regs + /* Zero volatile regs that may contain sensitive kernel data */ + li r0,0 + li r4,0 + li r5,0 + li r6,0 + li r7,0 + li r8,0 + li r9,0 + li r10,0 + li r11,0 + li r12,0 + mtctr r0 + mtspr SPRN_XER,r0 +.Lsyscall_restore_regs_cont: + +BEGIN_FTR_SECTION + HMT_MEDIUM_LOW +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + /* + * We don't need to restore AMR on the way back to userspace for KUAP. + * The value of AMR only matters while we're in the kernel. + */ + mtcr r2 + ld r2,GPR2(r1) + ld r3,GPR3(r1) + ld r13,GPR13(r1) + ld r1,GPR1(r1) + RFI_TO_USER + b . /* prevent speculative execution */ + +.Lsyscall_restore_regs: + ld r3,_CTR(r1) + ld r4,_XER(r1) + REST_NVGPRS(r1) + mtctr r3 + mtspr SPRN_XER,r4 + ld r0,GPR0(r1) + REST_8GPRS(4, r1) + ld r12,GPR12(r1) + b .Lsyscall_restore_regs_cont + +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +.Ltabort_syscall: + /* Firstly we need to enable TM in the kernel */ + mfmsr r10 + li r9, 1 + rldimi r10, r9, MSR_TM_LG, 63-MSR_TM_LG + mtmsrd r10, 0 + + /* tabort, this dooms the transaction, nothing else */ + li r9, (TM_CAUSE_SYSCALL|TM_CAUSE_PERSISTENT) + TABORT(R9) + + /* + * Return directly to userspace. We have corrupted user register state, + * but userspace will never see that register state. Execution will + * resume after the tbegin of the aborted transaction with the + * checkpointed register state. + */ + li r9, MSR_RI + andc r10, r10, r9 + mtmsrd r10, 1 + mtspr SPRN_SRR0, r11 + mtspr SPRN_SRR1, r12 + RFI_TO_USER + b . /* prevent speculative execution */ +#endif + +#ifdef CONFIG_PPC_BOOK3S +_GLOBAL(ret_from_fork_scv) + bl schedule_tail + REST_NVGPRS(r1) + li r3,0 /* fork() return value */ + b .Lsyscall_vectored_common_exit +#endif + +_GLOBAL(ret_from_fork) + bl schedule_tail + REST_NVGPRS(r1) + li r3,0 /* fork() return value */ + b .Lsyscall_exit + +_GLOBAL(ret_from_kernel_thread) + bl schedule_tail + REST_NVGPRS(r1) + mtctr r14 + mr r3,r15 +#ifdef PPC64_ELF_ABI_v2 + mr r12,r14 +#endif + bctrl + li r3,0 + b .Lsyscall_exit + +#ifdef CONFIG_PPC_BOOK3E +/* Save non-volatile GPRs, if not already saved. */ +_GLOBAL(save_nvgprs) + ld r11,_TRAP(r1) + andi. r0,r11,1 + beqlr- + SAVE_NVGPRS(r1) + clrrdi r0,r11,1 + std r0,_TRAP(r1) + blr +_ASM_NOKPROBE_SYMBOL(save_nvgprs); +#endif + +#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_BOOK3S + /* + * If MSR EE/RI was never enabled, IRQs not reconciled, NVGPRs not + * touched, no exit work created, then this can be used. + */ + .balign IFETCH_ALIGN_BYTES + .globl fast_interrupt_return +fast_interrupt_return: +_ASM_NOKPROBE_SYMBOL(fast_interrupt_return) + kuap_check_amr r3, r4 + ld r5,_MSR(r1) + andi. r0,r5,MSR_PR + bne .Lfast_user_interrupt_return + kuap_restore_amr r3, r4 + andi. r0,r5,MSR_RI + li r3,0 /* 0 return value, no EMULATE_STACK_STORE */ + bne+ .Lfast_kernel_interrupt_return + addi r3,r1,STACK_FRAME_OVERHEAD + bl unrecoverable_exception + b . /* should not get here */ + + .balign IFETCH_ALIGN_BYTES + .globl interrupt_return +interrupt_return: +_ASM_NOKPROBE_SYMBOL(interrupt_return) + ld r4,_MSR(r1) + andi. r0,r4,MSR_PR + beq .Lkernel_interrupt_return + addi r3,r1,STACK_FRAME_OVERHEAD + bl interrupt_exit_user_prepare + cmpdi r3,0 + bne- .Lrestore_nvgprs + +.Lfast_user_interrupt_return: + ld r11,_NIP(r1) + ld r12,_MSR(r1) +BEGIN_FTR_SECTION + ld r10,_PPR(r1) + mtspr SPRN_PPR,r10 +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + mtspr SPRN_SRR0,r11 + mtspr SPRN_SRR1,r12 + +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +FTR_SECTION_ELSE + ldarx r0,0,r1 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + + ld r3,_CCR(r1) + ld r4,_LINK(r1) + ld r5,_CTR(r1) + ld r6,_XER(r1) + li r0,0 + + REST_4GPRS(7, r1) + REST_2GPRS(11, r1) + REST_GPR(13, r1) + + mtcr r3 + mtlr r4 + mtctr r5 + mtspr SPRN_XER,r6 + + REST_4GPRS(2, r1) + REST_GPR(6, r1) + REST_GPR(0, r1) + REST_GPR(1, r1) + RFI_TO_USER + b . /* prevent speculative execution */ + +.Lrestore_nvgprs: + REST_NVGPRS(r1) + b .Lfast_user_interrupt_return + + .balign IFETCH_ALIGN_BYTES +.Lkernel_interrupt_return: + addi r3,r1,STACK_FRAME_OVERHEAD + bl interrupt_exit_kernel_prepare + +.Lfast_kernel_interrupt_return: + cmpdi cr1,r3,0 + ld r11,_NIP(r1) + ld r12,_MSR(r1) + mtspr SPRN_SRR0,r11 + mtspr SPRN_SRR1,r12 + +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +FTR_SECTION_ELSE + ldarx r0,0,r1 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + + ld r3,_LINK(r1) + ld r4,_CTR(r1) + ld r5,_XER(r1) + ld r6,_CCR(r1) + li r0,0 + + REST_4GPRS(7, r1) + REST_2GPRS(11, 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. + */ + std r0,STACK_FRAME_OVERHEAD-16(r1) + + REST_4GPRS(2, r1) + + bne- cr1,1f /* emulate stack store */ + mtcr r6 + REST_GPR(6, r1) + REST_GPR(0, r1) + REST_GPR(1, r1) + RFI_TO_KERNEL + b . /* prevent speculative execution */ + +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 + * PACA_EXGEN as temporary storage to hold the store data, as + * interrupts are disabled here so it won't be clobbered. + */ + mtcr r6 + std r9,PACA_EXGEN+0(r13) + addi r9,r1,INT_FRAME_SIZE /* get original r1 */ + REST_GPR(6, r1) + REST_GPR(0, r1) + REST_GPR(1, r1) + std r9,0(r1) /* perform store component of stdu */ + ld r9,PACA_EXGEN+0(r13) + + RFI_TO_KERNEL + b . /* prevent speculative execution */ +#endif /* CONFIG_PPC_BOOK3S */ + +#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_BUG_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_ISF | 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 |