diff options
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 487 |
1 files changed, 117 insertions, 370 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 29949bbe857b..5d782acb86d4 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -16,6 +16,7 @@ #include <linux/errno.h> #include <linux/err.h> +#include <asm/cache.h> #include <asm/unistd.h> #include <asm/processor.h> #include <asm/page.h> @@ -228,6 +229,7 @@ _GLOBAL(ret_from_kernel_thread) 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) @@ -238,6 +240,7 @@ _GLOBAL(save_nvgprs) std r0,_TRAP(r1) blr _ASM_NOKPROBE_SYMBOL(save_nvgprs); +#endif #ifdef CONFIG_PPC_BOOK3S_64 @@ -301,7 +304,7 @@ flush_count_cache: * 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 ret_from_except. + * 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. * @@ -453,408 +456,152 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) addi r1,r1,SWITCH_FRAME_SIZE blr - .align 7 -_GLOBAL(ret_from_except) - ld r11,_TRAP(r1) - andi. r0,r11,1 - bne ret_from_except_lite - REST_NVGPRS(r1) - -_GLOBAL(ret_from_except_lite) +#ifdef CONFIG_PPC_BOOK3S /* - * Disable interrupts so that current_thread_info()->flags - * can't change between when we test it and when we return - * from the interrupt. - */ -#ifdef CONFIG_PPC_BOOK3E - wrteei 0 -#else - li r10,MSR_RI - mtmsrd r10,1 /* Update machine state */ -#endif /* CONFIG_PPC_BOOK3E */ + * If MSR EE/RI was never enabled, IRQs not reconciled, NVGPRs not + * touched, AMR not set, 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) + ld r4,_MSR(r1) + andi. r0,r4,MSR_PR + bne .Lfast_user_interrupt_return + andi. r0,r4,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 */ - ld r9, PACA_THREAD_INFO(r13) - ld r3,_MSR(r1) -#ifdef CONFIG_PPC_BOOK3E - ld r10,PACACURRENT(r13) -#endif /* CONFIG_PPC_BOOK3E */ - ld r4,TI_FLAGS(r9) - andi. r3,r3,MSR_PR - beq resume_kernel -#ifdef CONFIG_PPC_BOOK3E - lwz r3,(THREAD+THREAD_DBCR0)(r10) -#endif /* CONFIG_PPC_BOOK3E */ + .balign IFETCH_ALIGN_BYTES + .globl interrupt_return +interrupt_return: +_ASM_NOKPROBE_SYMBOL(interrupt_return) + REST_NVGPRS(r1) - /* Check current_thread_info()->flags */ - andi. r0,r4,_TIF_USER_WORK_MASK - bne 1f -#ifdef CONFIG_PPC_BOOK3E - /* - * Check to see if the dbcr0 register is set up to debug. - * Use the internal debug mode bit to do this. - */ - andis. r0,r3,DBCR0_IDM@h - beq restore - mfmsr r0 - rlwinm r0,r0,0,~MSR_DE /* Clear MSR.DE */ - mtmsr r0 - mtspr SPRN_DBCR0,r3 - li r10, -1 - mtspr SPRN_DBSR,r10 - b restore -#else - addi r3,r1,STACK_FRAME_OVERHEAD - bl restore_math - b restore -#endif -1: andi. r0,r4,_TIF_NEED_RESCHED - beq 2f - bl restore_interrupts - SCHEDULE_USER - b ret_from_except_lite -2: -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM - andi. r0,r4,_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM - bne 3f /* only restore TM if nothing else to do */ + .balign IFETCH_ALIGN_BYTES + .globl interrupt_return_lite +interrupt_return_lite: +_ASM_NOKPROBE_SYMBOL(interrupt_return_lite) + ld r4,_MSR(r1) + andi. r0,r4,MSR_PR + beq .Lkernel_interrupt_return addi r3,r1,STACK_FRAME_OVERHEAD - bl restore_tm_state - b restore -3: -#endif - bl save_nvgprs - /* - * Use a non volatile GPR to save and restore our thread_info flags - * across the call to restore_interrupts. - */ - mr r30,r4 - bl restore_interrupts - mr r4,r30 - addi r3,r1,STACK_FRAME_OVERHEAD - bl do_notify_resume - b ret_from_except - -resume_kernel: - /* check current_thread_info, _TIF_EMULATE_STACK_STORE */ - andis. r8,r4,_TIF_EMULATE_STACK_STORE@h - beq+ 1f + bl interrupt_exit_user_prepare + cmpdi r3,0 + bne- .Lrestore_nvgprs - addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */ +.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 - ld r3,GPR1(r1) - subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception frame */ - mr r4,r1 /* src: current exception frame */ - mr r1,r3 /* Reroute the trampoline frame to r1 */ +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) - /* Copy from the original to the trampoline. */ - li r5,INT_FRAME_SIZE/8 /* size: INT_FRAME_SIZE */ - li r6,0 /* start offset: 0 */ - mtctr r5 -2: ldx r0,r6,r4 - stdx r0,r6,r3 - addi r6,r6,8 - bdnz 2b - - /* Do real store operation to complete stdu */ - ld r5,GPR1(r1) - std r8,0(r5) - - /* Clear _TIF_EMULATE_STACK_STORE flag */ - lis r11,_TIF_EMULATE_STACK_STORE@h - addi r5,r9,TI_FLAGS -0: ldarx r4,0,r5 - andc r4,r4,r11 - stdcx. r4,0,r5 - bne- 0b -1: - -#ifdef CONFIG_PREEMPTION - /* Check if we need to preempt */ - andi. r0,r4,_TIF_NEED_RESCHED - beq+ restore - /* Check that preempt_count() == 0 and interrupts are enabled */ - lwz r8,TI_PREEMPT(r9) - cmpwi cr0,r8,0 - bne restore - ld r0,SOFTE(r1) - andi. r0,r0,IRQS_DISABLED - bne restore + ld r3,_CCR(r1) + ld r4,_LINK(r1) + ld r5,_CTR(r1) + ld r6,_XER(r1) + li r0,0 - /* - * Here we are preempting the current task. We want to make - * sure we are soft-disabled first and reconcile irq state. - */ - RECONCILE_IRQ_STATE(r3,r4) - bl preempt_schedule_irq + REST_4GPRS(7, r1) + REST_2GPRS(11, r1) + REST_GPR(13, r1) - /* - * arch_local_irq_restore() from preempt_schedule_irq above may - * enable hard interrupt but we really should disable interrupts - * when we return from the interrupt, and so that we don't get - * interrupted after loading SRR0/1. - */ -#ifdef CONFIG_PPC_BOOK3E - wrteei 0 -#else - li r10,MSR_RI - mtmsrd r10,1 /* Update machine state */ -#endif /* CONFIG_PPC_BOOK3E */ -#endif /* CONFIG_PREEMPTION */ + mtcr r3 + mtlr r4 + mtctr r5 + mtspr SPRN_XER,r6 - .globl fast_exc_return_irq -fast_exc_return_irq: -restore: - /* - * This is the main kernel exit path. First we check if we - * are about to re-enable interrupts - */ - ld r5,SOFTE(r1) - lbz r6,PACAIRQSOFTMASK(r13) - andi. r5,r5,IRQS_DISABLED - bne .Lrestore_irq_off + REST_4GPRS(2, r1) + REST_GPR(6, r1) + REST_GPR(0, r1) + REST_GPR(1, r1) + RFI_TO_USER + b . /* prevent speculative execution */ - /* We are enabling, were we already enabled ? Yes, just return */ - andi. r6,r6,IRQS_DISABLED - beq cr0,.Ldo_restore +.Lrestore_nvgprs: + REST_NVGPRS(r1) + b .Lfast_user_interrupt_return - /* - * We are about to soft-enable interrupts (we are hard disabled - * at this point). We check if there's anything that needs to - * be replayed first. - */ - lbz r0,PACAIRQHAPPENED(r13) - cmpwi cr0,r0,0 - bne- .Lrestore_check_irq_replay + .balign IFETCH_ALIGN_BYTES +.Lkernel_interrupt_return: + addi r3,r1,STACK_FRAME_OVERHEAD + bl interrupt_exit_kernel_prepare - /* - * Get here when nothing happened while soft-disabled, just - * soft-enable and move-on. We will hard-enable as a side - * effect of rfi - */ -.Lrestore_no_replay: - TRACE_ENABLE_INTS - li r0,IRQS_ENABLED - stb r0,PACAIRQSOFTMASK(r13); +.Lfast_kernel_interrupt_return: + cmpdi cr1,r3,0 + ld r11,_NIP(r1) + ld r12,_MSR(r1) + mtspr SPRN_SRR0,r11 + mtspr SPRN_SRR1,r12 - /* - * Final return path. BookE is handled in a different file - */ -.Ldo_restore: -#ifdef CONFIG_PPC_BOOK3E - b exception_return_book3e -#else - /* - * Clear the reservation. If we know the CPU tracks the address of - * the reservation then we can potentially save some cycles and use - * a larx. On POWER6 and POWER7 this is significantly faster. - */ BEGIN_FTR_SECTION stdcx. r0,0,r1 /* to clear the reservation */ FTR_SECTION_ELSE - ldarx r4,0,r1 + ldarx r0,0,r1 ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) - /* - * Some code path such as load_up_fpu or altivec return directly - * here. They run entirely hard disabled and do not alter the - * interrupt state. They also don't use lwarx/stwcx. and thus - * are known not to leave dangling reservations. - */ - .globl fast_exception_return -fast_exception_return: - ld r3,_MSR(r1) + ld r3,_LINK(r1) ld r4,_CTR(r1) - ld r0,_LINK(r1) - mtctr r4 - mtlr r0 - ld r4,_XER(r1) - mtspr SPRN_XER,r4 - - kuap_check_amr r5, r6 - - REST_8GPRS(5, r1) - - andi. r0,r3,MSR_RI - beq- .Lunrecov_restore - - /* - * Clear RI before restoring r13. If we are returning to - * userspace and we take an exception after restoring r13, - * we end up corrupting the userspace r13 value. - */ - li r4,0 - mtmsrd r4,1 - -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM - /* TM debug */ - std r3, PACATMSCRATCH(r13) /* Stash returned-to MSR */ -#endif - /* - * r13 is our per cpu area, only restore it if we are returning to - * userspace the value stored in the stack frame may belong to - * another CPU. - */ - andi. r0,r3,MSR_PR - beq 1f -BEGIN_FTR_SECTION - /* Restore PPR */ - ld r2,_PPR(r1) - mtspr SPRN_PPR,r2 -END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) - ACCOUNT_CPU_USER_EXIT(r13, r2, r4) - REST_GPR(13, r1) - - /* - * 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. - */ - mtspr SPRN_SRR1,r3 - - ld r2,_CCR(r1) - mtcrf 0xFF,r2 - ld r2,_NIP(r1) - mtspr SPRN_SRR0,r2 - - ld r0,GPR0(r1) - ld r2,GPR2(r1) - ld r3,GPR3(r1) - ld r4,GPR4(r1) - ld r1,GPR1(r1) - RFI_TO_USER - b . /* prevent speculative execution */ + ld r5,_XER(r1) + ld r6,_CCR(r1) + li r0,0 -1: mtspr SPRN_SRR1,r3 + REST_4GPRS(7, r1) + REST_2GPRS(11, r1) - ld r2,_CCR(r1) - mtcrf 0xFF,r2 - ld r2,_NIP(r1) - mtspr SPRN_SRR0,r2 + 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. */ - li r2,0 - std r2,STACK_FRAME_OVERHEAD-16(r1) + std r0,STACK_FRAME_OVERHEAD-16(r1) - ld r0,GPR0(r1) - ld r2,GPR2(r1) - ld r3,GPR3(r1) + REST_4GPRS(2, r1) - kuap_restore_amr r4 - - ld r4,GPR4(r1) - ld r1,GPR1(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 */ -#endif /* CONFIG_PPC_BOOK3E */ - - /* - * We are returning to a context with interrupts soft disabled. - * - * However, we may also about to hard enable, so we need to - * make sure that in this case, we also clear PACA_IRQ_HARD_DIS - * or that bit can get out of sync and bad things will happen - */ -.Lrestore_irq_off: - ld r3,_MSR(r1) - lbz r7,PACAIRQHAPPENED(r13) - andi. r0,r3,MSR_EE - beq 1f - rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS - stb r7,PACAIRQHAPPENED(r13) -1: -#if defined(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG) && defined(CONFIG_BUG) - /* The interrupt should not have soft enabled. */ - lbz r7,PACAIRQSOFTMASK(r13) -1: tdeqi r7,IRQS_ENABLED - EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING -#endif - b .Ldo_restore - - /* - * Something did happen, check if a re-emit is needed - * (this also clears paca->irq_happened) - */ -.Lrestore_check_irq_replay: - /* XXX: We could implement a fast path here where we check - * for irq_happened being just 0x01, in which case we can - * clear it and return. That means that we would potentially - * miss a decrementer having wrapped all the way around. - * - * Still, this might be useful for things like hash_page - */ - bl __check_irq_replay - cmpwi cr0,r3,0 - beq .Lrestore_no_replay - - /* - * We need to re-emit an interrupt. We do so by re-using our - * existing exception frame. We first change the trap value, - * but we need to ensure we preserve the low nibble of it - */ - ld r4,_TRAP(r1) - clrldi r4,r4,60 - or r4,r4,r3 - std r4,_TRAP(r1) - - /* - * PACA_IRQ_HARD_DIS won't always be set here, so set it now - * to reconcile the IRQ state. Tracing is already accounted for. - */ - lbz r4,PACAIRQHAPPENED(r13) - ori r4,r4,PACA_IRQ_HARD_DIS - stb r4,PACAIRQHAPPENED(r13) - - /* - * Then find the right handler and call it. Interrupts are - * still soft-disabled and we keep them that way. - */ - cmpwi cr0,r3,0x500 - bne 1f - addi r3,r1,STACK_FRAME_OVERHEAD; - bl do_IRQ - b ret_from_except -1: cmpwi cr0,r3,0xf00 - bne 1f - addi r3,r1,STACK_FRAME_OVERHEAD; - bl performance_monitor_exception - b ret_from_except -1: cmpwi cr0,r3,0xe60 - bne 1f - addi r3,r1,STACK_FRAME_OVERHEAD; - bl handle_hmi_exception - b ret_from_except -1: cmpwi cr0,r3,0x900 - bne 1f - addi r3,r1,STACK_FRAME_OVERHEAD; - bl timer_interrupt - b ret_from_except -#ifdef CONFIG_PPC_DOORBELL -1: -#ifdef CONFIG_PPC_BOOK3E - cmpwi cr0,r3,0x280 -#else - cmpwi cr0,r3,0xa00 -#endif /* CONFIG_PPC_BOOK3E */ - bne 1f - addi r3,r1,STACK_FRAME_OVERHEAD; - bl doorbell_exception -#endif /* CONFIG_PPC_DOORBELL */ -1: b ret_from_except /* What else to do here ? */ - -.Lunrecov_restore: - addi r3,r1,STACK_FRAME_OVERHEAD - bl unrecoverable_exception - b .Lunrecov_restore - -_ASM_NOKPROBE_SYMBOL(ret_from_except); -_ASM_NOKPROBE_SYMBOL(ret_from_except_lite); -_ASM_NOKPROBE_SYMBOL(resume_kernel); -_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq); -_ASM_NOKPROBE_SYMBOL(restore); -_ASM_NOKPROBE_SYMBOL(fast_exception_return); +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 /* |