/* * Copyright 2010 Tilera Corporation. All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, version 2. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for * more details. * * Linux interrupt vectors. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define PTREGS_PTR(reg, ptreg) addli reg, sp, C_ABI_SAVE_AREA_SIZE + (ptreg) #define PTREGS_OFFSET_SYSCALL PTREGS_OFFSET_REG(TREG_SYSCALL_NR) #if !CHIP_HAS_WH64() /* By making this an empty macro, we can use wh64 in the code. */ .macro wh64 reg .endm #endif .macro push_reg reg, ptr=sp, delta=-4 { sw \ptr, \reg addli \ptr, \ptr, \delta } .endm .macro pop_reg reg, ptr=sp, delta=4 { lw \reg, \ptr addli \ptr, \ptr, \delta } .endm .macro pop_reg_zero reg, zreg, ptr=sp, delta=4 { move \zreg, zero lw \reg, \ptr addi \ptr, \ptr, \delta } .endm .macro push_extra_callee_saves reg PTREGS_PTR(\reg, PTREGS_OFFSET_REG(51)) push_reg r51, \reg push_reg r50, \reg push_reg r49, \reg push_reg r48, \reg push_reg r47, \reg push_reg r46, \reg push_reg r45, \reg push_reg r44, \reg push_reg r43, \reg push_reg r42, \reg push_reg r41, \reg push_reg r40, \reg push_reg r39, \reg push_reg r38, \reg push_reg r37, \reg push_reg r36, \reg push_reg r35, \reg push_reg r34, \reg, PTREGS_OFFSET_BASE - PTREGS_OFFSET_REG(34) .endm .macro panic str .pushsection .rodata, "a" 1: .asciz "\str" .popsection { moveli r0, lo16(1b) } { auli r0, r0, ha16(1b) jal panic } .endm #ifdef __COLLECT_LINKER_FEEDBACK__ .pushsection .text.intvec_feedback,"ax" intvec_feedback: .popsection #endif /* * Default interrupt handler. * * vecnum is where we'll put this code. * c_routine is the C routine we'll call. * * The C routine is passed two arguments: * - A pointer to the pt_regs state. * - The interrupt vector number. * * The "processing" argument specifies the code for processing * the interrupt. Defaults to "handle_interrupt". */ .macro int_hand vecnum, vecname, c_routine, processing=handle_interrupt .org (\vecnum << 8) intvec_\vecname: .ifc \vecnum, INT_SWINT_1 blz TREG_SYSCALL_NR_NAME, sys_cmpxchg .endif /* Temporarily save a register so we have somewhere to work. */ mtspr SPR_SYSTEM_SAVE_K_1, r0 mfspr r0, SPR_EX_CONTEXT_K_1 /* The cmpxchg code clears sp to force us to reset it here on fault. */ { bz sp, 2f andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ } .ifc \vecnum, INT_DOUBLE_FAULT /* * For double-faults from user-space, fall through to the normal * register save and stack setup path. Otherwise, it's the * hypervisor giving us one last chance to dump diagnostics, and we * branch to the kernel_double_fault routine to do so. */ bz r0, 1f j _kernel_double_fault 1: .else /* * If we're coming from user-space, then set sp to the top of * the kernel stack. Otherwise, assume sp is already valid. */ { bnz r0, 0f move r0, sp } .endif .ifc \c_routine, do_page_fault /* * The page_fault handler may be downcalled directly by the * hypervisor even when Linux is running and has ICS set. * * In this case the contents of EX_CONTEXT_K_1 reflect the * previous fault and can't be relied on to choose whether or * not to reinitialize the stack pointer. So we add a test * to see whether SYSTEM_SAVE_K_2 has the high bit set, * and if so we don't reinitialize sp, since we must be coming * from Linux. (In fact the precise case is !(val & ~1), * but any Linux PC has to have the high bit set.) * * Note that the hypervisor *always* sets SYSTEM_SAVE_K_2 for * any path that turns into a downcall to one of our TLB handlers. */ mfspr r0, SPR_SYSTEM_SAVE_K_2 { blz r0, 0f /* high bit in S_S_1_2 is for a PC to use */ move r0, sp } .endif 2: /* * SYSTEM_SAVE_K_0 holds the cpu number in the low bits, and * the current stack top in the higher bits. So we recover * our stack top by just masking off the low bits, then * point sp at the top aligned address on the actual stack page. */ mfspr r0, SPR_SYSTEM_SAVE_K_0 mm r0, r0, zero, LOG2_THREAD_SIZE, 31 0: /* * Align the stack mod 64 so we can properly predict what * cache lines we need to write-hint to reduce memory fetch * latency as we enter the kernel. The layout of memory is * as follows, with cache line 0 at the lowest VA, and cache * line 4 just below the r0 value this "andi" computes. * Note that we never write to cache line 4, and we skip * cache line 1 for syscalls. * * cache line 4: ptregs padding (two words) * cache line 3: r46...lr, pc, ex1, faultnum, orig_r0, flags, pad * cache line 2: r30...r45 * cache line 1: r14...r29 * cache line 0: 2 x frame, r0..r13 */ andi r0, r0, -64 /* * Push the first four registers on the stack, so that we can set * them to vector-unique values before we jump to the common code. * * Registers are pushed on the stack as a struct pt_regs, * with the sp initially just above the struct, and when we're * done, sp points to the base of the struct, minus * C_ABI_SAVE_AREA_SIZE, so we can directly jal to C code. * * This routine saves just the first four registers, plus the * stack context so we can do proper backtracing right away, * and defers to handle_interrupt to save the rest. * The backtracer needs pc, ex1, lr, sp, r52, and faultnum. */ addli r0, r0, PTREGS_OFFSET_LR - (PTREGS_SIZE + KSTK_PTREGS_GAP) wh64 r0 /* cache line 3 */ { sw r0, lr addli r0, r0, PTREGS_OFFSET_SP - PTREGS_OFFSET_LR } { sw r0, sp addli sp, r0, PTREGS_OFFSET_REG(52) - PTREGS_OFFSET_SP } { sw sp, r52 addli sp, sp, PTREGS_OFFSET_REG(1) - PTREGS_OFFSET_REG(52) } wh64 sp /* cache line 0 */ { sw sp, r1 addli sp, sp, PTREGS_OFFSET_REG(2) - PTREGS_OFFSET_REG(1) } { sw sp, r2 addli sp, sp, PTREGS_OFFSET_REG(3) - PTREGS_OFFSET_REG(2) } { sw sp, r3 addli sp, sp, PTREGS_OFFSET_PC - PTREGS_OFFSET_REG(3) } mfspr r0, SPR_EX_CONTEXT_K_0 .ifc \processing,handle_syscall /* * Bump the saved PC by one bundle so that when we return, we won't * execute the same swint instruction again. We need to do this while * we're in the critical section. */ addi r0, r0, 8 .endif { sw sp, r0 addli sp, sp, PTREGS_OFFSET_EX1 - PTREGS_OFFSET_PC } mfspr r0, SPR_EX_CONTEXT_K_1 { sw sp, r0 addi sp, sp, PTREGS_OFFSET_FAULTNUM - PTREGS_OFFSET_EX1 /* * Use r0 for syscalls so it's a temporary; use r1 for interrupts * so that it gets passed through unchanged to the handler routine. * Note that the .if conditional confusingly spans bundles. */ .ifc \processing,handle_syscall movei r0, \vecnum } { sw sp, r0 .else movei r1, \vecnum } { sw sp, r1 .endif addli sp, sp, PTREGS_OFFSET_REG(0) - PTREGS_OFFSET_FAULTNUM } mfspr r0, SPR_SYSTEM_SAVE_K_1 /* Original r0 */ { sw sp, r0 addi sp, sp, -PTREGS_OFFSET_REG(0) - 4 } { sw sp, zero /* write zero into "Next SP" frame pointer */ addi sp, sp, -4 /* leave SP pointing at bottom of frame */ } .ifc \processing,handle_syscall j handle_syscall .else /* * Capture per-interrupt SPR context to registers. * We overload the meaning of r3 on this path such that if its bit 31 * is set, we have to mask all interrupts including NMIs before * clearing the interrupt critical section bit. * See discussion below at "finish_interrupt_save". */ .ifc \c_routine, do_page_fault mfspr r2, SPR_SYSTEM_SAVE_K_3 /* address of page fault */ mfspr r3, SPR_SYSTEM_SAVE_K_2 /* info about page fault */ .else .ifc \vecnum, INT_DOUBLE_FAULT { mfspr r2, SPR_SYSTEM_SAVE_K_2 /* double fault info from HV */ movei r3, 0 } .else .ifc \c_routine, do_trap { mfspr r2, GPV_REASON movei r3, 0 } .else .ifc \c_routine, op_handle_perf_interrupt { mfspr r2, PERF_COUNT_STS movei r3, -1 /* not used, but set for consistency */ } .else #if CHIP_HAS_AUX_PERF_COUNTERS() .ifc \c_routine, op_handle_aux_perf_interrupt { mfspr r2, AUX_PERF_COUNT_STS movei r3, -1 /* not used, but set for consistency */ } .else #endif movei r3, 0 #if CHIP_HAS_AUX_PERF_COUNTERS() .endif #endif .endif .endif .endif .endif /* Put function pointer in r0 */ moveli r0, lo16(\c_routine) { auli r0, r0, ha16(\c_routine) j \processing } .endif ENDPROC(intvec_\vecname) #ifdef __COLLECT_LINKER_FEEDBACK__ .pushsection .text.intvec_feedback,"ax" .org (\vecnum << 5) FEEDBACK_ENTER_EXPLICIT(intvec_\vecname, .intrpt1, 1 << 8) jrp lr .popsection #endif .endm /* * Save the rest of the registers that we didn't save in the actual * vector itself. We can't use r0-r10 inclusive here. */ .macro finish_interrupt_save, function /* If it's a syscall, save a proper orig_r0, otherwise just zero. */ PTREGS_PTR(r52, PTREGS_OFFSET_ORIG_R0) { .ifc \function,handle_syscall sw r52, r0 .else sw r52, zero .endif PTREGS_PTR(r52, PTREGS_OFFSET_TP) } /* * For ordinary syscalls, we save neither caller- nor callee- * save registers, since the syscall invoker doesn't expect the * caller-saves to be saved, and the called kernel functions will * take care of saving the callee-saves for us. * * For interrupts we save just the caller-save registers. Saving * them is required (since the "caller" can't save them). Again, * the called kernel functions will restore the callee-save * registers for us appropriately. * * On return, we normally restore nothing special for syscalls, * and just the caller-save registers for interrupts. * * However, there are some important caveats to all this: * * - We always save a few callee-save registers to give us * some scratchpad registers to carry across function calls. * * - fork/vfork/etc require us to save all the callee-save * registers, which we do in PTREGS_SYSCALL_ALL_REGS, below. * * - We always save r0..r5 and r10 for syscalls, since we need * to reload them a bit later for the actual kernel call, and * since we might need them for -ERESTARTNOINTR, etc. * * - Before invoking a signal handler, we save the unsaved * callee-save registers so they are visible to the * signal handler or any ptracer. * * - If the unsaved callee-save registers are modified, we set * a bit in pt_regs so we know to reload them from pt_regs * and not just rely on the kernel function unwinding. * (Done for ptrace register writes and SA_SIGINFO handler.) */ { sw r52, tp PTREGS_PTR(r52, PTREGS_OFFSET_REG(33)) } wh64 r52 /* cache line 2 */ push_reg r33, r52 push_reg r32, r52 push_reg r31, r52 .ifc \function,handle_syscall push_reg r30, r52, PTREGS_OFFSET_SYSCALL - PTREGS_OFFSET_REG(30) push_reg TREG_SYSCALL_NR_NAME, r52, \ PTREGS_OFFSET_REG(5) - PTREGS_OFFSET_SYSCALL .else push_reg r30, r52, PTREGS_OFFSET_REG(29) - PTREGS_OFFSET_REG(30) wh64 r52 /* cache line 1 */ push_reg r29, r52 push_reg r28, r52 push_reg r27, r52 push_reg r26, r52 push_reg r25, r52 push_reg r24, r52 push_reg r23, r52 push_reg r22, r52 push_reg r21, r52 push_reg r20, r52 push_reg r19, r52 push_reg r18, r52 push_reg r17, r52 push_reg r16, r52 push_reg r15, r52 push_reg r14, r52 push_reg r13, r52 push_reg r12, r52 push_reg r11, r52 push_reg r10, r52 push_reg r9, r52 push_reg r8, r52 push_reg r7, r52 push_reg r6, r52 .endif push_reg r5, r52 sw r52, r4 /* Load tp with our per-cpu offset. */ #ifdef CONFIG_SMP { mfspr r20, SPR_SYSTEM_SAVE_K_0 moveli r21, lo16(__per_cpu_offset) } { auli r21, r21, ha16(__per_cpu_offset) mm r20, r20, zero, 0, LOG2_THREAD_SIZE-1 } s2a r20, r20, r21 lw tp, r20 #else move tp, zero #endif /* * If we will be returning to the kernel, we will need to * reset the interrupt masks to the state they had before. * Set DISABLE_IRQ in flags iff we came from PL1 with irqs disabled. * We load flags in r32 here so we can jump to .Lrestore_regs * directly after do_page_fault_ics() if necessary. */ mfspr r32, SPR_EX_CONTEXT_K_1 { andi r32, r32, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ PTREGS_PTR(r21, PTREGS_OFFSET_FLAGS) } bzt r32, 1f /* zero if from user space */ IRQS_DISABLED(r32) /* zero if irqs enabled */ #if PT_FLAGS_DISABLE_IRQ != 1 # error Value of IRQS_DISABLED used to set PT_FLAGS_DISABLE_IRQ; fix #endif 1: .ifnc \function,handle_syscall /* Record the fact that we saved the caller-save registers above. */ ori r32, r32, PT_FLAGS_CALLER_SAVES .endif sw r21, r32 #ifdef __COLLECT_LINKER_FEEDBACK__ /* * Notify the feedback routines that we were in the * appropriate fixed interrupt vector area. Note that we * still have ICS set at this point, so we can't invoke any * atomic operations or we will panic. The feedback * routines internally preserve r0..r10 and r30 up. */ .ifnc \function,handle_syscall shli r20, r1, 5 .else moveli r20, INT_SWINT_1 << 5 .endif addli r20, r20, lo16(intvec_feedback) auli r20, r20, ha16(intvec_feedback) jalr r20 /* And now notify the feedback routines that we are here. */ FEEDBACK_ENTER(\function) #endif /* * we've captured enough state to the stack (including in * particular our EX_CONTEXT state) that we can now release * the interrupt critical section and replace it with our * standard "interrupts disabled" mask value. This allows * synchronous interrupts (and profile interrupts) to punch * through from this point onwards. * * If bit 31 of r3 is set during a non-NMI interrupt, we know we * are on the path where the hypervisor has punched through our * ICS with a page fault, so we call out to do_page_fault_ics() * to figure out what to do with it. If the fault was in * an atomic op, we unlock the atomic lock, adjust the * saved register state a little, and return "zero" in r4, * falling through into the normal page-fault interrupt code. * If the fault was in a kernel-space atomic operation, then * do_page_fault_ics() resolves it itself, returns "one" in r4, * and as a result goes directly to restoring registers and iret, * without trying to adjust the interrupt masks at all. * The do_page_fault_ics() API involves passing and returning * a five-word struct (in registers) to avoid writing the * save and restore code here. */ .ifc \function,handle_nmi IRQ_DISABLE_ALL(r20) .else .ifnc \function,handle_syscall bgezt r3, 1f { PTREGS_PTR(r0, PTREGS_OFFSET_BASE) jal do_page_fault_ics } FEEDBACK_REENTER(\function) bzt r4, 1f j .Lrestore_regs 1: .endif IRQ_DISABLE(r20, r21) .endif mtspr INTERRUPT_CRITICAL_SECTION, zero #if CHIP_HAS_WH64() /* * Prepare the first 256 stack bytes to be rapidly accessible * without having to fetch the background data. We don't really * know how far to write-hint, but kernel stacks generally * aren't that big, and write-hinting here does take some time. */ addi r52, sp, -64 { wh64 r52 addi r52, r52, -64 } { wh64 r52 addi r52, r52, -64 } { wh64 r52 addi r52, r52, -64 } wh64 r52 #endif #ifdef CONFIG_TRACE_IRQFLAGS .ifnc \function,handle_nmi /* * We finally have enough state set up to notify the irq * tracing code that irqs were disabled on entry to the handler. * The TRACE_IRQS_OFF call clobbers registers r0-r29. * For syscalls, we already have the register state saved away * on the stack, so we don't bother to do any register saves here, * and later we pop the registers back off the kernel stack. * For interrupt handlers, save r0-r3 in callee-saved registers. */ .ifnc \function,handle_syscall { move r30, r0; move r31, r1 } { move r32, r2; move r33, r3 } .endif TRACE_IRQS_OFF .ifnc \function,handle_syscall { move r0, r30; move r1, r31 } { move r2, r32; move r3, r33 } .endif .endif #endif .endm .macro check_single_stepping, kind, not_single_stepping /* * Check for single stepping in user-level priv * kind can be "normal", "ill", or "syscall" * At end, if fall-thru * r29: thread_info->step_state * r28: &pt_regs->pc * r27: pt_regs->pc * r26: thread_info->step_state->buffer */ /* Check for single stepping */ GET_THREAD_INFO(r29) { /* Get pointer to field holding step state */ addi r29, r29, THREAD_INFO_STEP_STATE_OFFSET /* Get pointer to EX1 in register state */ PTREGS_PTR(r27, PTREGS_OFFSET_EX1) } { /* Get pointer to field holding PC */ PTREGS_PTR(r28, PTREGS_OFFSET_PC) /* Load the pointer to the step state */ lw r29, r29 } /* Load EX1 */ lw r27, r27 { /* Points to flags */ addi r23, r29, SINGLESTEP_STATE_FLAGS_OFFSET /* No single stepping if there is no step state structure */ bzt r29, \not_single_stepping } { /* mask off ICS and any other high bits */ andi r27, r27, SPR_EX_CONTEXT_1_1__PL_MASK /* Load pointer to single step instruction buffer */ lw r26, r29 } /* Check priv state */ bnz r27, \not_single_stepping /* Get flags */ lw r22, r23 { /* Branch if single-step mode not enabled */ bbnst r22, \not_single_stepping /* Clear enabled flag */ andi r22, r22, ~SINGLESTEP_STATE_MASK_IS_ENABLED } .ifc \kind,normal { /* Load PC */ lw r27, r28 /* Point to the entry containing the original PC */ addi r24, r29, SINGLESTEP_STATE_ORIG_PC_OFFSET } { /* Disable single stepping flag */ sw r23, r22 } { /* Get the original pc */ lw r24, r24 /* See if the PC is at the start of the single step buffer */ seq r25, r26, r27 } /* * NOTE: it is really expected that the PC be in the single step buffer * at this point */ bzt r25, \not_single_stepping /* Restore the original PC */ sw r28, r24 .else .ifc \kind,syscall { /* Load PC */ lw r27, r28 /* Point to the entry containing the next PC */ addi r24, r29, SINGLESTEP_STATE_NEXT_PC_OFFSET } { /* Increment the stopped PC by the bundle size */ addi r26, r26, 8 /* Disable single stepping flag */ sw r23, r22 } { /* Get the next pc */ lw r24, r24 /* * See if the PC is one bundle past the start of the * single step buffer */ seq r25, r26, r27 } { /* * NOTE: it is really expected that the PC be in the * single step buffer at this point */ bzt r25, \not_single_stepping } /* Set to the next PC */ sw r28, r24 .else { /* Point to 3rd bundle in buffer */ addi r25, r26, 16 /* Load PC */ lw r27, r28 } { /* Disable single stepping flag */ sw r23, r22 /* See if the PC is in the single step buffer */ slte_u r24, r26, r27 } { slte_u r25, r27, r25 /* * NOTE: it is really expected that the PC be in the * single step buffer at this point */ bzt r24, \not_single_stepping } bzt r25, \not_single_stepping .endif .endif .endm /* * Redispatch a downcall. */ .macro dc_dispatch vecnum, vecname .org (\vecnum << 8) intvec_\vecname: j hv_downcall_dispatch ENDPROC(intvec_\vecname) .endm /* * Common code for most interrupts. The C function we're eventually * going to is in r0, and the faultnum is in r1; the original * values for those registers are on the stack. */ .pushsection .text.handle_interrupt,"ax" handle_interrupt: finish_interrupt_save handle_interrupt /* * Check for if we are single stepping in user level. If so, then * we need to restore the PC. */ check_single_stepping normal, .Ldispatch_interrupt .Ldispatch_interrupt: /* Jump to the C routine; it should enable irqs as soon as possible. */ { jalr r0 PTREGS_PTR(r0, PTREGS_OFFSET_BASE) } FEEDBACK_REENTER(handle_interrupt) { movei r30, 0 /* not an NMI */ j interrupt_return } STD_ENDPROC(handle_interrupt) /* * This routine takes a boolean in r30 indicating if this is an NMI. * If so, we also expect a boolean in r31 indicating whether to * re-enable the oprofile interrupts. * * Note that .Lresume_userspace is jumped to directly in several * places, and we need to make sure r30 is set correctly in those * callers as well. */ STD_ENTRY(interrupt_return) /* If we're resuming to kernel space, don't check thread flags. */ { bnz r30, .Lrestore_all /* NMIs don't special-case user-space */ PTREGS_PTR(r29, PTREGS_OFFSET_EX1) } lw r29, r29 andi r29, r29, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ bzt r29, .Lresume_userspace #ifdef CONFIG_PREEMPT /* Returning to kernel space. Check if we need preemption. */ GET_THREAD_INFO(r29) addli r28, r29, THREAD_INFO_FLAGS_OFFSET { lw r28, r28 addli r29, r29, THREAD_INFO_PREEMPT_COUNT_OFFSET } { andi r28, r28, _TIF_NEED_RESCHED lw r29, r29 } bzt r28, 1f bnz r29, 1f jal preempt_schedule_irq FEEDBACK_REENTER(interrupt_return) 1: #endif /* If we're resuming to _cpu_idle_nap, bump PC forward by 8. */ { PTREGS_PTR(r29, PTREGS_OFFSET_PC) moveli r27, lo16(_cpu_idle_nap) } { lw r28, r29 auli r27, r27, ha16(_cpu_idle_nap) } { seq r27, r27, r28 } { bbns r27, .Lrestore_all addi r28, r28, 8 } sw r29, r28 j .Lrestore_all .Lresume_userspace: FEEDBACK_REENTER(interrupt_return) /* * Use r33 to hold whether we have already loaded the callee-saves * into ptregs. We don't want to do it twice in this loop, since * then we'd clobber whatever changes are made by ptrace, etc. * Get base of stack in r32. */ { GET_THREAD_INFO(r32) movei r33, 0 } .Lretry_work_pending: /* * Disable interrupts so as to make sure we don't * miss an interrupt that sets any of the thread flags (like * need_resched or sigpending) between sampling and the iret. * Routines like schedule() or do_signal() may re-enable * interrupts before returning. */ IRQ_DISABLE(r20, r21) TRACE_IRQS_OFF /* Note: clobbers registers r0-r29 */ /* Check to see if there is any work to do before returning to user. */ { addi r29, r32, THREAD_INFO_FLAGS_OFFSET moveli r1, lo16(_TIF_ALLWORK_MASK) } { lw r29, r29 auli r1, r1, ha16(_TIF_ALLWORK_MASK) } and r1, r29, r1 bzt r1, .Lrestore_all /* * Make sure we have all the registers saved for signal * handling, notify-resume, or single-step. Call out to C * code to figure out exactly what we need to do for each flag bit, * then if necessary, reload the flags and recheck. */ { PTREGS_PTR(r0, PTREGS_OFFSET_BASE) bnz r33, 1f } push_extra_callee_saves r0 movei r33, 1 1: jal do_work_pending bnz r0, .Lretry_work_pending /* * In the NMI case we * omit the call to single_process_check_nohz, which normally checks * to see if we should start or stop the scheduler tick, because * we can't call arbitrary Linux code from an NMI context. * We always call the homecache TLB deferral code to re-trigger * the deferral mechanism. * * The other chunk of responsibility this code has is to reset the * interrupt masks appropriately to reset irqs and NMIs. We have * to call TRACE_IRQS_OFF and TRACE_IRQS_ON to support all the * lockdep-type stuff, but we can't set ICS until afterwards, since * ICS can only be used in very tight chunks of code to avoid * tripping over various assertions that it is off. * * (There is what looks like a window of vulnerability here since * we might take a profile interrupt between the two SPR writes * that set the mask, but since we write the low SPR word first, * and our interrupt entry code checks the low SPR word, any * profile interrupt will actually disable interrupts in both SPRs * before returning, which is OK.) */ .Lrestore_all: PTREGS_PTR(r0, PTREGS_OFFSET_EX1) { lw r0, r0 PTREGS_PTR(r32, PTREGS_OFFSET_FLAGS) } { andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK lw r32, r32 } bnz r0, 1f j 2f #if PT_FLAGS_DISABLE_IRQ != 1 # error Assuming PT_FLAGS_DISABLE_IRQ == 1 so we can use bbnst below #endif 1: bbnst r32, 2f IRQ_DISABLE(r20,r21) TRACE_IRQS_OFF movei r0, 1 mtspr INTERRUPT_CRITICAL_SECTION, r0 bzt r30, .Lrestore_regs j 3f 2: TRACE_IRQS_ON movei r0, 1 mtspr INTERRUPT_CRITICAL_SECTION, r0 IRQ_ENABLE(r20, r21) bzt r30, .Lrestore_regs 3: /* * We now commit to returning from this interrupt, since we will be * doing things like setting EX_CONTEXT SPRs and unwinding the stack * frame. No calls should be made to any other code after this point. * This code should only be entered with ICS set. * r32 must still be set to ptregs.flags. * We launch loads to each cache line separately first, so we can * get some parallelism out of the memory subsystem. * We start zeroing caller-saved registers throughout, since * that will save some cycles if this turns out to be a syscall. */ .Lrestore_regs: FEEDBACK_REENTER(interrupt_return) /* called from elsewhere */ /* * Rotate so we have one high bit and one low bit to test. * - low bit says whether to restore all the callee-saved registers, * or just r30-r33, and r52 up. * - high bit (i.e. sign bit) says whether to restore all the * caller-saved registers, or just r0. */ #if PT_FLAGS_CALLER_SAVES != 2 || PT_FLAGS_RESTORE_REGS != 4 # error Rotate trick does not work :-) #endif { rli r20, r32, 30 PTREGS_PTR(sp, PTREGS_OFFSET_REG(0)) } /* * Load cache lines 0, 2, and 3 in that order, then use * the last loaded value, which makes it likely that the other * cache lines have also loaded, at which point we should be * able to safely read all the remaining words on those cache * lines without waiting for the memory subsystem. */ pop_reg_zero r0, r28, sp, PTREGS_OFFSET_REG(30) - PTREGS_OFFSET_REG(0) pop_reg_zero r30, r2, sp, PTREGS_OFFSET_PC - PTREGS_OFFSET_REG(30) pop_reg_zero r21, r3, sp, PTREGS_OFFSET_EX1 - PTREGS_OFFSET_PC pop_reg_zero lr, r4, sp, PTREGS_OFFSET_REG(52) - PTREGS_OFFSET_EX1 { mtspr SPR_EX_CONTEXT_K_0, r21 move r5, zero } { mtspr SPR_EX_CONTEXT_K_1, lr andi lr, lr, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ } /* Restore callee-saveds that we actually use. */ pop_reg_zero r52, r6, sp, PTREGS_OFFSET_REG(31) - PTREGS_OFFSET_REG(52) pop_reg_zero r31, r7 pop_reg_zero r32, r8 pop_reg_zero r33, r9, sp, PTREGS_OFFSET_REG(29) - PTREGS_OFFSET_REG(33) /* * If we modified other callee-saveds, restore them now. * This is rare, but could be via ptrace or signal handler. */ { move r10, zero bbs r20, .Lrestore_callees } .Lcontinue_restore_regs: /* Check if we're returning from a syscall. */ { move r11, zero blzt r20, 1f /* no, so go restore callee-save registers */ } /* * Check if we're returning to userspace. * Note that if we're not, we don't worry about zeroing everything. */ { addli sp, sp, PTREGS_OFFSET_LR - PTREGS_OFFSET_REG(29) bnz lr, .Lkernel_return } /* * On return from syscall, we've restored r0 from pt_regs, but we * clear the remainder of the caller-saved registers. We could * restore the syscall arguments, but there's not much point, * and it ensures user programs aren't trying to use the * caller-saves if we clear them, as well as avoiding leaking * kernel pointers into userspace. */ pop_reg_zero lr, r12, sp, PTREGS_OFFSET_TP - PTREGS_OFFSET_LR pop_reg_zero tp, r13, sp, PTREGS_OFFSET_SP - PTREGS_OFFSET_TP { lw sp, sp move r14, zero move r15, zero } { move r16, zero; move r17, zero } { move r18, zero; move r19, zero } { move r20, zero; move r21, zero } { move r22, zero; move r23, zero } { move r24, zero; move r25, zero } { move r26, zero; move r27, zero } /* Set r1 to errno if we are returning an error, otherwise zero. */ { moveli r29, 4096 sub r1, zero, r0 } slt_u r29, r1, r29 { mnz r1, r29, r1 move r29, zero } iret /* * Not a syscall, so restore caller-saved registers. * First kick off a load for cache line 1, which we're touching * for the first time here. */ .align 64 1: pop_reg r29, sp, PTREGS_OFFSET_REG(1) - PTREGS_OFFSET_REG(29) pop_reg r1 pop_reg r2 pop_reg r3 pop_reg r4 pop_reg r5 pop_reg r6 pop_reg r7 pop_reg r8 pop_reg r9 pop_reg r10 pop_reg r11 pop_reg r12 pop_reg r13 pop_reg r14 pop_reg r15 pop_reg r16 pop_reg r17 pop_reg r18 pop_reg r19 pop_reg r20 pop_reg r21 pop_reg r22 pop_reg r23 pop_reg r24 pop_reg r25 pop_reg r26 pop_reg r27 pop_reg r28, sp, PTREGS_OFFSET_LR - PTREGS_OFFSET_REG(28) /* r29 already restored above */ bnz lr, .Lkernel_return pop_reg lr, sp, PTREGS_OFFSET_TP - PTREGS_OFFSET_LR pop_reg tp, sp, PTREGS_OFFSET_SP - PTREGS_OFFSET_TP lw sp, sp iret /* * We can't restore tp when in kernel mode, since a thread might * have migrated from another cpu and brought a stale tp value. */ .Lkernel_return: pop_reg lr, sp, PTREGS_OFFSET_SP - PTREGS_OFFSET_LR lw sp, sp iret /* Restore callee-saved registers from r34 to r51. */ .Lrestore_callees: addli sp, sp, PTREGS_OFFSET_REG(34) - PTREGS_OFFSET_REG(29) pop_reg r34 pop_reg r35 pop_reg r36 pop_reg r37 pop_reg r38 pop_reg r39 pop_reg r40 pop_reg r41 pop_reg r42 pop_reg r43 pop_reg r44 pop_reg r45 pop_reg r46 pop_reg r47 pop_reg r48 pop_reg r49 pop_reg r50 pop_reg r51, sp, PTREGS_OFFSET_REG(29) - PTREGS_OFFSET_REG(51) j .Lcontinue_restore_regs STD_ENDPROC(interrupt_return) /* * Some interrupts don't check for single stepping */ .pushsection .text.handle_interrupt_no_single_step,"ax" handle_interrupt_no_single_step: finish_interrupt_save handle_interrupt_no_single_step { jalr r0 PTREGS_PTR(r0, PTREGS_OFFSET_BASE) } FEEDBACK_REENTER(handle_interrupt_no_single_step) { movei r30, 0 /* not an NMI */ j interrupt_return } STD_ENDPROC(handle_interrupt_no_single_step) /* * "NMI" interrupts mask ALL interrupts before calling the * handler, and don't check thread flags, etc., on the way * back out. In general, the only things we do here for NMIs * are the register save/restore, fixing the PC if we were * doing single step, and the dataplane kernel-TLB management. * We don't (for example) deal with start/stop of the sched tick. */ .pushsection .text.handle_nmi,"ax" handle_nmi: finish_interrupt_save handle_nmi check_single_stepping normal, .Ldispatch_nmi .Ldispatch_nmi: { jalr r0 PTREGS_PTR(r0, PTREGS_OFFSET_BASE) } FEEDBACK_REENTER(handle_nmi) j interrupt_return STD_ENDPROC(handle_nmi) /* * Parallel code for syscalls to handle_interrupt. */ .pushsection .text.handle_syscall,"ax" handle_syscall: finish_interrupt_save handle_syscall /* * Check for if we are single stepping in user level. If so, then * we need to restore the PC. */ check_single_stepping syscall, .Ldispatch_syscall .Ldispatch_syscall: /* Enable irqs. */ TRACE_IRQS_ON IRQ_ENABLE(r20, r21) /* Bump the counter for syscalls made on this tile. */ moveli r20, lo16(irq_stat + IRQ_CPUSTAT_SYSCALL_COUNT_OFFSET) auli r20, r20, ha16(irq_stat + IRQ_CPUSTAT_SYSCALL_COUNT_OFFSET) add r20, r20, tp lw r21, r20 addi r21, r21, 1 { sw r20, r21 GET_THREAD_INFO(r31) } /* Trace syscalls, if requested. */ addi r31, r31, THREAD_INFO_FLAGS_OFFSET lw r30, r31 andi r30, r30, _TIF_SYSCALL_TRACE bzt r30, .Lrestore_syscall_regs { PTREGS_PTR(r0, PTREGS_OFFSET_BASE) jal do_syscall_trace_enter } FEEDBACK_REENTER(handle_syscall) /* * We always reload our registers from the stack at this * point. They might be valid, if we didn't build with * TRACE_IRQFLAGS, and this isn't a dataplane tile, and we're not * doing syscall tracing, but there are enough cases now that it * seems simplest just to do the reload unconditionally. */ .Lrestore_syscall_regs: PTREGS_PTR(r11, PTREGS_OFFSET_REG(0)) pop_reg r0, r11 pop_reg r1, r11 pop_reg r2, r11 pop_reg r3, r11 pop_reg r4, r11 pop_reg r5, r11, PTREGS_OFFSET_SYSCALL - PTREGS_OFFSET_REG(5) pop_reg TREG_SYSCALL_NR_NAME, r11 /* Ensure that the syscall number is within the legal range. */ moveli r21, __NR_syscalls { slt_u r21, TREG_SYSCALL_NR_NAME, r21 moveli r20, lo16(sys_call_table) } { bbns r21, .Linvalid_syscall auli r20, r20, ha16(sys_call_table) } s2a r20, TREG_SYSCALL_NR_NAME, r20 lw r20, r20 /* Jump to syscall handler. */ jalr r20 .Lhandle_syscall_link: /* value of "lr" after "jalr r20" above */ /* * Write our r0 onto the stack so it gets restored instead * of whatever the user had there before. */ PTREGS_PTR(r29, PTREGS_OFFSET_REG(0)) sw r29, r0 .Lsyscall_sigreturn_skip: FEEDBACK_REENTER(handle_syscall) /* Do syscall trace again, if requested. */ lw r30, r31 andi r30, r30, _TIF_SYSCALL_TRACE bzt r30, 1f { PTREGS_PTR(r0, PTREGS_OFFSET_BASE) jal do_syscall_trace_exit } FEEDBACK_REENTER(handle_syscall) 1: { movei r30, 0 /* not an NMI */ j .Lresume_userspace /* jump into middle of interrupt_return */ } .Linvalid_syscall: /* Report an invalid syscall back to the user program */ { PTREGS_PTR(r29, PTREGS_OFFSET_REG(0)) movei r28, -ENOSYS } sw r29, r28 { movei r30, 0 /* not an NMI */ j .Lresume_userspace /* jump into middle of interrupt_return */ } STD_ENDPROC(handle_syscall) /* Return the address for oprofile to suppress in backtraces. */ STD_ENTRY_SECTION(handle_syscall_link_address, .text.handle_syscall) lnk r0 { addli r0, r0, .Lhandle_syscall_link - . jrp lr } STD_ENDPROC(handle_syscall_link_address) STD_ENTRY(ret_from_fork) jal sim_notify_fork jal schedule_tail FEEDBACK_REENTER(ret_from_fork) { movei r30, 0 /* not an NMI */ j .Lresume_userspace /* jump into middle of interrupt_return */ } STD_ENDPROC(ret_from_fork) STD_ENTRY(ret_from_kernel_thread) jal sim_notify_fork jal schedule_tail FEEDBACK_REENTER(ret_from_fork) { move r0, r31 jalr r30 } FEEDBACK_REENTER(ret_from_kernel_thread) { movei r30, 0 /* not an NMI */ j .Lresume_userspace /* jump into middle of interrupt_return */ } STD_ENDPROC(ret_from_kernel_thread) /* * Code for ill interrupt. */ .pushsection .text.handle_ill,"ax" handle_ill: finish_interrupt_save handle_ill /* * Check for if we are single stepping in user level. If so, then * we need to restore the PC. */ check_single_stepping ill, .Ldispatch_normal_ill { /* See if the PC is the 1st bundle in the buffer */ seq r25, r27, r26 /* Point to the 2nd bundle in the buffer */ addi r26, r26, 8 } { /* Point to the original pc */ addi r24, r29, SINGLESTEP_STATE_ORIG_PC_OFFSET /* Branch if the PC is the 1st bundle in the buffer */ bnz r25, 3f } { /* See if the PC is the 2nd bundle of the buffer */ seq r25, r27, r26 /* Set PC to next instruction */ addi r24, r29, SINGLESTEP_STATE_NEXT_PC_OFFSET } { /* Point to flags */ addi r25, r29, SINGLESTEP_STATE_FLAGS_OFFSET /* Branch if PC is in the second bundle */ bz r25, 2f } /* Load flags */ lw r25, r25 { /* * Get the offset for the register to restore * Note: the lower bound is 2, so we have implicit scaling by 4. * No multiplication of the register number by the size of a register * is needed. */ mm r27, r25, zero, SINGLESTEP_STATE_TARGET_LB, \ SINGLESTEP_STATE_TARGET_UB /* Mask Rewrite_LR */ andi r25, r25, SINGLESTEP_STATE_MASK_UPDATE } { addi r29, r29, SINGLESTEP_STATE_UPDATE_VALUE_OFFSET /* Don't rewrite temp register */ bz r25, 3f } { /* Get the temp value */ lw r29, r29 /* Point to where the register is stored */ add r27, r27, sp } /* Add in the C ABI save area size to the register offset */ addi r27, r27, C_ABI_SAVE_AREA_SIZE /* Restore the user's register with the temp value */ sw r27, r29 j 3f 2: /* Must be in the third bundle */ addi r24, r29, SINGLESTEP_STATE_BRANCH_NEXT_PC_OFFSET 3: /* set PC and continue */ lw r26, r24 { sw r28, r26 GET_THREAD_INFO(r0) } /* * Clear TIF_SINGLESTEP to prevent recursion if we execute an ill. * The normal non-arch flow redundantly clears TIF_SINGLESTEP, but we * need to clear it here and can't really impose on all other arches. * So what's another write between friends? */ addi r1, r0, THREAD_INFO_FLAGS_OFFSET { lw r2, r1 addi r0, r0, THREAD_INFO_TASK_OFFSET /* currently a no-op */ } andi r2, r2, ~_TIF_SINGLESTEP sw r1, r2 /* Issue a sigtrap */ { lw r0, r0 /* indirect thru thread_info to get task_info*/ addi r1, sp, C_ABI_SAVE_AREA_SIZE /* put ptregs pointer into r1 */ } jal send_sigtrap /* issue a SIGTRAP */ FEEDBACK_REENTER(handle_ill) { movei r30, 0 /* not an NMI */ j .Lresume_userspace /* jump into middle of interrupt_return */ } .Ldispatch_normal_ill: { jalr r0 PTREGS_PTR(r0, PTREGS_OFFSET_BASE) } FEEDBACK_REENTER(handle_ill) { movei r30, 0 /* not an NMI */ j interrupt_return } STD_ENDPROC(handle_ill) /* Various stub interrupt handlers and syscall handlers */ STD_ENTRY_LOCAL(_kernel_double_fault) mfspr r1, SPR_EX_CONTEXT_K_0 move r2, lr move r3, sp move r4, r52 addi sp, sp, -C_ABI_SAVE_AREA_SIZE j kernel_double_fault STD_ENDPROC(_kernel_double_fault) STD_ENTRY_LOCAL(bad_intr) mfspr r2, SPR_EX_CONTEXT_K_0 panic "Unhandled interrupt %#x: PC %#lx" STD_ENDPROC(bad_intr) /* * Special-case sigreturn to not write r0 to the stack on return. * This is technically more efficient, but it also avoids difficulties * in the 64-bit OS when handling 32-bit compat code, since we must not * sign-extend r0 for the sigreturn return-value case. */ #define PTREGS_SYSCALL_SIGRETURN(x, reg) \ STD_ENTRY(_##x); \ addli lr, lr, .Lsyscall_sigreturn_skip - .Lhandle_syscall_link; \ { \ PTREGS_PTR(reg, PTREGS_OFFSET_BASE); \ j x \ }; \ STD_ENDPROC(_##x) PTREGS_SYSCALL_SIGRETURN(sys_rt_sigreturn, r0) /* Save additional callee-saves to pt_regs and jump to standard function. */ STD_ENTRY(_sys_clone) push_extra_callee_saves r4 j sys_clone STD_ENDPROC(_sys_clone) /* * This entrypoint is taken for the cmpxchg and atomic_update fast * swints. We may wish to generalize it to other fast swints at some * point, but for now there are just two very similar ones, which * makes it faster. * * The fast swint code is designed to have a small footprint. It does * not save or restore any GPRs, counting on the caller-save registers * to be available to it on entry. It does not modify any callee-save * registers (including "lr"). It does not check what PL it is being * called at, so you'd better not call it other than at PL0. * The wrapper assumes it only clobbers r20-r29, so if * it ever is necessary to use more registers, be aware. * * It does not use the stack, but since it might be re-interrupted by * a page fault which would assume the stack was valid, it does * save/restore the stack pointer and zero it out to make sure it gets reset. * Since we always keep interrupts disabled, the hypervisor won't * clobber our EX_CONTEXT_K_x registers, so we don't save/restore them * (other than to advance the PC on return). * * We have to manually validate the user vs kernel address range * (since at PL1 we can read/write both), and for performance reasons * we don't allow cmpxchg on the fc000000 memory region, since we only * validate that the user address is below PAGE_OFFSET. * * We place it in the __HEAD section to ensure it is relatively * near to the intvec_SWINT_1 code (reachable by a conditional branch). * * Our use of ATOMIC_LOCK_REG here must match do_page_fault_ics(). * * As we do in lib/atomic_asm_32.S, we bypass a store if the value we * would store is the same as the value we just loaded. */ __HEAD .align 64 /* Align much later jump on the start of a cache line. */ #if !ATOMIC_LOCKS_FOUND_VIA_TABLE() nop #if PAGE_SIZE >= 0x10000 nop #endif #endif ENTRY(sys_cmpxchg) /* * Save "sp" and set it zero for any possible page fault. * * HACK: We want to both zero sp and check r0's alignment, * so we do both at once. If "sp" becomes nonzero we * know r0 is unaligned and branch to the error handler that * restores sp, so this is OK. * * ICS is disabled right now so having a garbage but nonzero * sp is OK, since we won't execute any faulting instructions * when it is nonzero. */ { move r27, sp andi sp, r0, 3 } /* * Get the lock address in ATOMIC_LOCK_REG, and also validate that the * address is less than PAGE_OFFSET, since that won't trap at PL1. * We only use bits less than PAGE_SHIFT to avoid having to worry * about aliasing among multiple mappings of the same physical page, * and we ignore the low 3 bits so we have one lock that covers * both a cmpxchg64() and a cmpxchg() on either its low or high word. * NOTE: this must match __atomic_hashed_lock() in lib/atomic_32.c. */ #if (PAGE_OFFSET & 0xffff) != 0 # error Code here assumes PAGE_OFFSET can be loaded with just hi16() #endif #if ATOMIC_LOCKS_FOUND_VIA_TABLE() { /* Check for unaligned input. */ bnz sp, .Lcmpxchg_badaddr mm r25, r0, zero, 3, PAGE_SHIFT-1 } { crc32_32 r25, zero, r25 moveli r21, lo16(atomic_lock_ptr) } { auli r21, r21, ha16(atomic_lock_ptr) auli r23, zero, hi16(PAGE_OFFSET) /* hugepage-aligned */ } { shri r20, r25, 32 - ATOMIC_HASH_L1_SHIFT slt_u r23, r0, r23 lw r26, r0 /* see comment in the "#else" for the "lw r26". */ } { s2a r21, r20, r21 bbns r23, .Lcmpxchg_badaddr } { lw r21, r21 seqi r23, TREG_SYSCALL_NR_NAME, __NR_FAST_cmpxchg64 andi r25, r25, ATOMIC_HASH_L2_SIZE - 1 } { /* Branch away at this point if we're doing a 64-bit cmpxchg. */ bbs r23, .Lcmpxchg64 andi r23, r0, 7 /* Precompute alignment for cmpxchg64. */ } { s2a ATOMIC_LOCK_REG_NAME, r25, r21 j .Lcmpxchg32_tns /* see comment in the #else for the jump. */ } #else /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */ { /* Check for unaligned input. */ bnz sp, .Lcmpxchg_badaddr auli r23, zero, hi16(PAGE_OFFSET) /* hugepage-aligned */ } { /* * Slide bits into position for 'mm'. We want to ignore * the low 3 bits of r0, and consider only the next * ATOMIC_HASH_SHIFT bits. * Because of C pointer arithmetic, we want to compute this: * * ((char*)atomic_locks + * (((r0 >> 3) & ((1 << ATOMIC_HASH_SHIFT) - 1)) << 2)) * * Instead of two shifts we just ">> 1", and use 'mm' * to ignore the low and high bits we don't want. */ shri r25, r0, 1 slt_u r23, r0, r23 /* * Ensure that the TLB is loaded before we take out the lock. * On tilepro, this will start fetching the value all the way * into our L1 as well (and if it gets modified before we * grab the lock, it will be invalidated from our cache * before we reload it). On tile64, we'll start fetching it * into our L1 if we're the home, and if we're not, we'll * still at least start fetching it into the home's L2. */ lw r26, r0 } { auli r21, zero, ha16(atomic_locks) bbns r23, .Lcmpxchg_badaddr } #if PAGE_SIZE < 0x10000 /* atomic_locks is page-aligned so for big pages we don't need this. */ addli r21, r21, lo16(atomic_locks) #endif { /* * Insert the hash bits into the page-aligned pointer. * ATOMIC_HASH_SHIFT is so big that we don't actually hash * the unmasked address bits, as that may cause unnecessary * collisions. */ mm ATOMIC_LOCK_REG_NAME, r25, r21, 2, (ATOMIC_HASH_SHIFT + 2) - 1 seqi r23, TREG_SYSCALL_NR_NAME, __NR_FAST_cmpxchg64 } { /* Branch away at this point if we're doing a 64-bit cmpxchg. */ bbs r23, .Lcmpxchg64 andi r23, r0, 7 /* Precompute alignment for cmpxchg64. */ } { /* * We very carefully align the code that actually runs with * the lock held (twelve bundles) so that we know it is all in * the icache when we start. This instruction (the jump) is * at the start of the first cache line, address zero mod 64; * we jump to the very end of the second cache line to get that * line loaded in the icache, then fall through to issue the tns * in the third cache line, at which point it's all cached. * Note that is for performance, not correctness. */ j .Lcmpxchg32_tns } #endif /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */ /* Symbol for do_page_fault_ics() to use to compare against the PC. */ .global __sys_cmpxchg_grab_lock __sys_cmpxchg_grab_lock: /* * Perform the actual cmpxchg or atomic_update. */ .Ldo_cmpxchg32: { lw r21, r0 seqi r23, TREG_SYSCALL_NR_NAME, __NR_FAST_atomic_update move r24, r2 } { seq r22, r21, r1 /* See if cmpxchg matches. */ and r25, r21, r1 /* If atomic_update, compute (*mem & mask) */ } { or r22, r22, r23 /* Skip compare branch for atomic_update. */ add r25, r25, r2 /* Compute (*mem & mask) + addend. */ } { mvnz r24, r23, r25 /* Use atomic_update value if appropriate. */ bbns r22, .Lcmpxchg32_nostore } seq r22, r24, r21 /* Are we storing the value we loaded? */ bbs r22, .Lcmpxchg32_nostore sw r0, r24 /* The following instruction is the start of the second cache line. */ /* Do slow mtspr here so the following "mf" waits less. */ { move sp, r27 mtspr SPR_EX_CONTEXT_K_0, r28 } mf { move r0, r21 sw ATOMIC_LOCK_REG_NAME, zero } iret /* Duplicated code here in the case where we don't overlap "mf" */ .Lcmpxchg32_nostore: { move r0, r21 sw ATOMIC_LOCK_REG_NAME, zero } { move sp, r27 mtspr SPR_EX_CONTEXT_K_0, r28 } iret /* * The locking code is the same for 32-bit cmpxchg/atomic_update, * and for 64-bit cmpxchg. We provide it as a macro and put * it into both versions. We can't share the code literally * since it depends on having the right branch-back address. */ .macro cmpxchg_lock, bitwidth /* Lock; if we succeed, jump back up to the read-modify-write. */ #ifdef CONFIG_SMP tns r21, ATOMIC_LOCK_REG_NAME #else /* * Non-SMP preserves all the lock infrastructure, to keep the * code simpler for the interesting (SMP) case. However, we do * one small optimization here and in atomic_asm.S, which is * to fake out acquiring the actual lock in the atomic_lock table. */ movei r21, 0 #endif /* Issue the slow SPR here while the tns result is in flight. */ mfspr r28, SPR_EX_CONTEXT_K_0 { addi r28, r28, 8 /* return to the instruction after the swint1 */ bzt r21, .Ldo_cmpxchg\bitwidth } /* * The preceding instruction is the last thing that must be * hot in the icache before we do the "tns" above. */ #ifdef CONFIG_SMP /* * We failed to acquire the tns lock on our first try. Now use * bounded exponential backoff to retry, like __atomic_spinlock(). */ { moveli r23, 2048 /* maximum backoff time in cycles */ moveli r25, 32 /* starting backoff time in cycles */ } 1: mfspr r26, CYCLE_LOW /* get start point for this backoff */ 2: mfspr r22, CYCLE_LOW /* test to see if we've backed off enough */ sub r22, r22, r26 slt r22, r22, r25 bbst r22, 2b { shli r25, r25, 1 /* double the backoff; retry the tns */ tns r21, ATOMIC_LOCK_REG_NAME } slt r26, r23, r25 /* is the proposed backoff too big? */ { mvnz r25, r26, r23 bzt r21, .Ldo_cmpxchg\bitwidth } j 1b #endif /* CONFIG_SMP */ .endm .Lcmpxchg32_tns: /* * This is the last instruction on the second cache line. * The nop here loads the second line, then we fall through * to the tns to load the third line before we take the lock. */ nop cmpxchg_lock 32 /* * This code is invoked from sys_cmpxchg after most of the * preconditions have been checked. We still need to check * that r0 is 8-byte aligned, since if it's not we won't * actually be atomic. However, ATOMIC_LOCK_REG has the atomic * lock pointer and r27/r28 have the saved SP/PC. * r23 is holding "r0 & 7" so we can test for alignment. * The compare value is in r2/r3; the new value is in r4/r5. * On return, we must put the old value in r0/r1. */ .align 64 .Lcmpxchg64: { #if ATOMIC_LOCKS_FOUND_VIA_TABLE() s2a ATOMIC_LOCK_REG_NAME, r25, r21 #endif bzt r23, .Lcmpxchg64_tns } j .Lcmpxchg_badaddr .Ldo_cmpxchg64: { lw r21, r0 addi r25, r0, 4 } { lw r1, r25 } seq r26, r21, r2 { bz r26, .Lcmpxchg64_mismatch seq r26, r1, r3 } { bz r26, .Lcmpxchg64_mismatch } sw r0, r4 sw r25, r5 /* * The 32-bit path provides optimized "match" and "mismatch" * iret paths, but we don't have enough bundles in this cache line * to do that, so we just make even the "mismatch" path do an "mf". */ .Lcmpxchg64_mismatch: { move sp, r27 mtspr SPR_EX_CONTEXT_K_0, r28 } mf { move r0, r21 sw ATOMIC_LOCK_REG_NAME, zero } iret .Lcmpxchg64_tns: cmpxchg_lock 64 /* * Reset sp and revector to sys_cmpxchg_badaddr(), which will * just raise the appropriate signal and exit. Doing it this * way means we don't have to duplicate the code in intvec.S's * int_hand macro that locates the top of the stack. */ .Lcmpxchg_badaddr: { moveli TREG_SYSCALL_NR_NAME, __NR_cmpxchg_badaddr move sp, r27 } j intvec_SWINT_1 ENDPROC(sys_cmpxchg) ENTRY(__sys_cmpxchg_end) /* The single-step support may need to read all the registers. */ int_unalign: push_extra_callee_saves r0 j do_trap /* Include .intrpt1 array of interrupt vectors */ .section ".intrpt1", "ax" #define op_handle_perf_interrupt bad_intr #define op_handle_aux_perf_interrupt bad_intr #ifndef CONFIG_HARDWALL #define do_hardwall_trap bad_intr #endif int_hand INT_ITLB_MISS, ITLB_MISS, \ do_page_fault, handle_interrupt_no_single_step int_hand INT_MEM_ERROR, MEM_ERROR, bad_intr int_hand INT_ILL, ILL, do_trap, handle_ill int_hand INT_GPV, GPV, do_trap int_hand INT_SN_ACCESS, SN_ACCESS, do_trap int_hand INT_IDN_ACCESS, IDN_ACCESS, do_trap int_hand INT_UDN_ACCESS, UDN_ACCESS, do_trap int_hand INT_IDN_REFILL, IDN_REFILL, bad_intr int_hand INT_UDN_REFILL, UDN_REFILL, bad_intr int_hand INT_IDN_COMPLETE, IDN_COMPLETE, bad_intr int_hand INT_UDN_COMPLETE, UDN_COMPLETE, bad_intr int_hand INT_SWINT_3, SWINT_3, do_trap int_hand INT_SWINT_2, SWINT_2, do_trap int_hand INT_SWINT_1, SWINT_1, SYSCALL, handle_syscall int_hand INT_SWINT_0, SWINT_0, do_trap int_hand INT_UNALIGN_DATA, UNALIGN_DATA, int_unalign int_hand INT_DTLB_MISS, DTLB_MISS, do_page_fault int_hand INT_DTLB_ACCESS, DTLB_ACCESS, do_page_fault int_hand INT_DMATLB_MISS, DMATLB_MISS, do_page_fault int_hand INT_DMATLB_ACCESS, DMATLB_ACCESS, do_page_fault int_hand INT_SNITLB_MISS, SNITLB_MISS, do_page_fault int_hand INT_SN_NOTIFY, SN_NOTIFY, bad_intr int_hand INT_SN_FIREWALL, SN_FIREWALL, do_hardwall_trap int_hand INT_IDN_FIREWALL, IDN_FIREWALL, bad_intr int_hand INT_UDN_FIREWALL, UDN_FIREWALL, do_hardwall_trap int_hand INT_TILE_TIMER, TILE_TIMER, do_timer_interrupt int_hand INT_IDN_TIMER, IDN_TIMER, bad_intr int_hand INT_UDN_TIMER, UDN_TIMER, bad_intr int_hand INT_DMA_NOTIFY, DMA_NOTIFY, bad_intr int_hand INT_IDN_CA, IDN_CA, bad_intr int_hand INT_UDN_CA, UDN_CA, bad_intr int_hand INT_IDN_AVAIL, IDN_AVAIL, bad_intr int_hand INT_UDN_AVAIL, UDN_AVAIL, bad_intr int_hand INT_PERF_COUNT, PERF_COUNT, \ op_handle_perf_interrupt, handle_nmi int_hand INT_INTCTRL_3, INTCTRL_3, bad_intr #if CONFIG_KERNEL_PL == 2 dc_dispatch INT_INTCTRL_2, INTCTRL_2 int_hand INT_INTCTRL_1, INTCTRL_1, bad_intr #else int_hand INT_INTCTRL_2, INTCTRL_2, bad_intr dc_dispatch INT_INTCTRL_1, INTCTRL_1 #endif int_hand INT_INTCTRL_0, INTCTRL_0, bad_intr int_hand INT_MESSAGE_RCV_DWNCL, MESSAGE_RCV_DWNCL, \ hv_message_intr int_hand INT_DEV_INTR_DWNCL, DEV_INTR_DWNCL, \ tile_dev_intr int_hand INT_I_ASID, I_ASID, bad_intr int_hand INT_D_ASID, D_ASID, bad_intr int_hand INT_DMATLB_MISS_DWNCL, DMATLB_MISS_DWNCL, \ do_page_fault int_hand INT_SNITLB_MISS_DWNCL, SNITLB_MISS_DWNCL, \ do_page_fault int_hand INT_DMATLB_ACCESS_DWNCL, DMATLB_ACCESS_DWNCL, \ do_page_fault int_hand INT_SN_CPL, SN_CPL, bad_intr int_hand INT_DOUBLE_FAULT, DOUBLE_FAULT, do_trap #if CHIP_HAS_AUX_PERF_COUNTERS() int_hand INT_AUX_PERF_COUNT, AUX_PERF_COUNT, \ op_handle_aux_perf_interrupt, handle_nmi #endif /* Synthetic interrupt delivered only by the simulator */ int_hand INT_BREAKPOINT, BREAKPOINT, do_breakpoint