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Diffstat (limited to 'arch/tile/kernel/intvec_64.S')
| -rw-r--r-- | arch/tile/kernel/intvec_64.S | 1289 |
1 files changed, 1289 insertions, 0 deletions
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S new file mode 100644 index 00000000..30ae76e5 --- /dev/null +++ b/arch/tile/kernel/intvec_64.S @@ -0,0 +1,1289 @@ +/* + * Copyright 2011 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 <linux/linkage.h> +#include <linux/errno.h> +#include <linux/unistd.h> +#include <asm/ptrace.h> +#include <asm/thread_info.h> +#include <asm/irqflags.h> +#include <asm/asm-offsets.h> +#include <asm/types.h> +#include <asm/signal.h> +#include <hv/hypervisor.h> +#include <arch/abi.h> +#include <arch/interrupts.h> +#include <arch/spr_def.h> + +#ifdef CONFIG_PREEMPT +# error "No support for kernel preemption currently" +#endif + +#define PTREGS_PTR(reg, ptreg) addli reg, sp, C_ABI_SAVE_AREA_SIZE + (ptreg) + +#define PTREGS_OFFSET_SYSCALL PTREGS_OFFSET_REG(TREG_SYSCALL_NR) + + + .macro push_reg reg, ptr=sp, delta=-8 + { + st \ptr, \reg + addli \ptr, \ptr, \delta + } + .endm + + .macro pop_reg reg, ptr=sp, delta=8 + { + ld \reg, \ptr + addli \ptr, \ptr, \delta + } + .endm + + .macro pop_reg_zero reg, zreg, ptr=sp, delta=8 + { + move \zreg, zero + ld \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, hw2_last(1b) + } + { + shl16insli r0, r0, hw1(1b) + } + { + shl16insli r0, r0, hw0(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: + /* Temporarily save a register so we have somewhere to work. */ + + mtspr SPR_SYSTEM_SAVE_K_1, r0 + mfspr r0, SPR_EX_CONTEXT_K_1 + + 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. + */ + beqz 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. + */ + { + bnez 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. + * + * FIXME: if we end up never using this path, perhaps we should + * prevent the hypervisor from generating downcalls in this case. + * The advantage of getting a downcall is we can panic in Linux. + */ + mfspr r0, SPR_SYSTEM_SAVE_K_2 + { + bltz r0, 0f /* high bit in S_S_1_2 is for a PC to use */ + move r0, sp + } + .endif + + + /* + * 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, zero, LOG2_THREAD_SIZE, 63 + +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 8 just below the r0 value this "andi" computes. + * Note that we never write to cache line 8, and we skip + * cache lines 1-3 for syscalls. + * + * cache line 8: ptregs padding (two words) + * cache line 7: sp, lr, pc, ex1, faultnum, orig_r0, flags, cmpexch + * cache line 6: r46...r53 (tp) + * cache line 5: r38...r45 + * cache line 4: r30...r37 + * cache line 3: r22...r29 + * cache line 2: r14...r21 + * cache line 1: r6...r13 + * cache line 0: 2 x frame, r0..r5 + */ + 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 7 */ + { + st r0, lr + addli r0, r0, PTREGS_OFFSET_SP - PTREGS_OFFSET_LR + } + { + st r0, sp + addli sp, r0, PTREGS_OFFSET_REG(52) - PTREGS_OFFSET_SP + } + wh64 sp /* cache line 6 */ + { + st sp, r52 + addli sp, sp, PTREGS_OFFSET_REG(1) - PTREGS_OFFSET_REG(52) + } + wh64 sp /* cache line 0 */ + { + st sp, r1 + addli sp, sp, PTREGS_OFFSET_REG(2) - PTREGS_OFFSET_REG(1) + } + { + st sp, r2 + addli sp, sp, PTREGS_OFFSET_REG(3) - PTREGS_OFFSET_REG(2) + } + { + st 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 + { + st sp, r0 + addli sp, sp, PTREGS_OFFSET_EX1 - PTREGS_OFFSET_PC + } + mfspr r0, SPR_EX_CONTEXT_K_1 + { + st 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 + } + { + st sp, r0 + .else + movei r1, \vecnum + } + { + st sp, r1 + .endif + addli sp, sp, PTREGS_OFFSET_REG(0) - PTREGS_OFFSET_FAULTNUM + } + mfspr r0, SPR_SYSTEM_SAVE_K_1 /* Original r0 */ + { + st sp, r0 + addi sp, sp, -PTREGS_OFFSET_REG(0) - 8 + } + { + st sp, zero /* write zero into "Next SP" frame pointer */ + addi sp, sp, -8 /* leave SP pointing at bottom of frame */ + } + .ifc \processing,handle_syscall + j handle_syscall + .else + /* Capture per-interrupt SPR context to registers. */ + .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_ILL_TRANS + mfspr r2, ILL_TRANS_REASON + .else + .ifc \vecnum, INT_DOUBLE_FAULT + mfspr r2, SPR_SYSTEM_SAVE_K_2 /* double fault info from HV */ + .else + .ifc \c_routine, do_trap + mfspr r2, GPV_REASON + .else + .ifc \c_routine, op_handle_perf_interrupt + mfspr r2, PERF_COUNT_STS +#if CHIP_HAS_AUX_PERF_COUNTERS() + .else + .ifc \c_routine, op_handle_aux_perf_interrupt + mfspr r2, AUX_PERF_COUNT_STS + .endif +#endif + .endif + .endif + .endif + .endif + .endif + /* Put function pointer in r0 */ + moveli r0, hw2_last(\c_routine) + shl16insli r0, r0, hw1(\c_routine) + { + shl16insli r0, r0, hw0(\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 + st r52, r0 + .else + st r52, zero + .endif + PTREGS_PTR(r52, PTREGS_OFFSET_TP) + } + st r52, tp + { + mfspr tp, CMPEXCH_VALUE + PTREGS_PTR(r52, PTREGS_OFFSET_CMPEXCH) + } + + /* + * 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.) + */ + { + st r52, tp + PTREGS_PTR(r52, PTREGS_OFFSET_REG(33)) + } + wh64 r52 /* cache line 4 */ + 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 3 */ + 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 + wh64 r52 /* cache line 2 */ + 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 + wh64 r52 /* cache line 1 */ + 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 + st r52, r4 + + /* Load tp with our per-cpu offset. */ +#ifdef CONFIG_SMP + { + mfspr r20, SPR_SYSTEM_SAVE_K_0 + moveli r21, hw2_last(__per_cpu_offset) + } + { + shl16insli r21, r21, hw1(__per_cpu_offset) + bfextu r20, r20, 0, LOG2_THREAD_SIZE-1 + } + shl16insli r21, r21, hw0(__per_cpu_offset) + shl3add r20, r20, r21 + ld 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. + */ + 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) + } + beqzt 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 + st 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 + moveli r21, hw2_last(intvec_feedback) + shl16insli r21, r21, hw1(intvec_feedback) + shl16insli r21, r21, hw0(intvec_feedback) + add r20, r20, r21 + 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. + */ + .ifc \function,handle_nmi + IRQ_DISABLE_ALL(r20) + .else + IRQ_DISABLE(r20, r21) + .endif + mtspr INTERRUPT_CRITICAL_SECTION, zero + + /* + * Prepare the first 256 stack bytes to be rapidly accessible + * without having to fetch the background data. + */ + addi r52, sp, -64 + { + wh64 r52 + addi r52, r52, -64 + } + { + wh64 r52 + addi r52, r52, -64 + } + { + wh64 r52 + addi r52, r52, -64 + } + wh64 r52 + +#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 + + /* + * 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 + + /* 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. */ + { + bnez r30, .Lrestore_all /* NMIs don't special-case user-space */ + PTREGS_PTR(r29, PTREGS_OFFSET_EX1) + } + ld r29, r29 + andi r29, r29, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ + { + beqzt r29, .Lresume_userspace + PTREGS_PTR(r29, PTREGS_OFFSET_PC) + } + + /* If we're resuming to _cpu_idle_nap, bump PC forward by 8. */ + moveli r27, hw2_last(_cpu_idle_nap) + { + ld r28, r29 + shl16insli r27, r27, hw1(_cpu_idle_nap) + } + { + shl16insli r27, r27, hw0(_cpu_idle_nap) + } + { + cmpeq r27, r27, r28 + } + { + blbc r27, .Lrestore_all + addi r28, r28, 8 + } + st 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. + */ + { + movei r33, 0 + move r32, sp + } + + /* Get base of stack in r32. */ + EXTRACT_THREAD_INFO(r32) + +.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, hw1_last(_TIF_ALLWORK_MASK) + } + { + ld r29, r29 + shl16insli r1, r1, hw0(_TIF_ALLWORK_MASK) + } + and r1, r29, r1 + beqzt r1, .Lrestore_all + + /* + * Make sure we have all the registers saved for signal + * handling or notify-resume. 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) + bnez r33, 1f + } + push_extra_callee_saves r0 + movei r33, 1 +1: jal do_work_pending + bnez 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. + */ +.Lrestore_all: + PTREGS_PTR(r0, PTREGS_OFFSET_EX1) + { + ld r0, r0 + PTREGS_PTR(r32, PTREGS_OFFSET_FLAGS) + } + { + andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK + ld r32, r32 + } + bnez r0, 1f + j 2f +#if PT_FLAGS_DISABLE_IRQ != 1 +# error Assuming PT_FLAGS_DISABLE_IRQ == 1 so we can use blbct below +#endif +1: blbct r32, 2f + IRQ_DISABLE(r20,r21) + TRACE_IRQS_OFF + movei r0, 1 + mtspr INTERRUPT_CRITICAL_SECTION, r0 + beqzt r30, .Lrestore_regs + j 3f +2: TRACE_IRQS_ON + movei r0, 1 + mtspr INTERRUPT_CRITICAL_SECTION, r0 + IRQ_ENABLE(r20, r21) + beqzt 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 + { + rotli r20, r32, 62 + PTREGS_PTR(sp, PTREGS_OFFSET_REG(0)) + } + + /* + * Load cache lines 0, 4, 6 and 7, 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 r0, sp, PTREGS_OFFSET_REG(30) - PTREGS_OFFSET_REG(0) + pop_reg r30, sp, PTREGS_OFFSET_REG(52) - PTREGS_OFFSET_REG(30) + pop_reg_zero r52, r3, sp, PTREGS_OFFSET_CMPEXCH - PTREGS_OFFSET_REG(52) + pop_reg_zero r21, r27, sp, PTREGS_OFFSET_EX1 - PTREGS_OFFSET_CMPEXCH + pop_reg_zero lr, r2, sp, PTREGS_OFFSET_PC - PTREGS_OFFSET_EX1 + { + mtspr CMPEXCH_VALUE, r21 + move r4, zero + } + pop_reg r21, sp, PTREGS_OFFSET_REG(31) - PTREGS_OFFSET_PC + { + mtspr SPR_EX_CONTEXT_K_1, lr + andi lr, lr, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */ + } + { + mtspr SPR_EX_CONTEXT_K_0, r21 + move r5, zero + } + + /* Restore callee-saveds that we actually use. */ + pop_reg_zero r31, r6 + pop_reg_zero r32, r7 + pop_reg_zero r33, r8, 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 r9, zero + blbs r20, .Lrestore_callees + } +.Lcontinue_restore_regs: + + /* Check if we're returning from a syscall. */ + { + move r10, zero + bltzt 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) + bnez 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, r11, sp, PTREGS_OFFSET_TP - PTREGS_OFFSET_LR + pop_reg_zero tp, r12, sp, PTREGS_OFFSET_SP - PTREGS_OFFSET_TP + { + ld sp, sp + move r13, zero + 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 } + + /* Set r1 to errno if we are returning an error, otherwise zero. */ + { + moveli r29, 4096 + sub r1, zero, r0 + } + { + move r28, zero + cmpltu r29, r1, r29 + } + { + mnz r1, r29, r1 + move r29, zero + } + iret + + /* + * Not a syscall, so restore caller-saved registers. + * First kick off loads for cache lines 1-3, which we're touching + * for the first time here. + */ + .align 64 +1: pop_reg r29, sp, PTREGS_OFFSET_REG(21) - PTREGS_OFFSET_REG(29) + pop_reg r21, sp, PTREGS_OFFSET_REG(13) - PTREGS_OFFSET_REG(21) + pop_reg r13, sp, PTREGS_OFFSET_REG(1) - PTREGS_OFFSET_REG(13) + 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, sp, 16 + /* r13 already restored above */ + pop_reg r14 + pop_reg r15 + pop_reg r16 + pop_reg r17 + pop_reg r18 + pop_reg r19 + pop_reg r20, sp, 16 + /* r21 already restored above */ + 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 */ + bnez lr, .Lkernel_return + pop_reg lr, sp, PTREGS_OFFSET_TP - PTREGS_OFFSET_LR + pop_reg tp, sp, PTREGS_OFFSET_SP - PTREGS_OFFSET_TP + ld 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 + ld 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) + + /* + * "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 register save/restore and 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 + { + jalr r0 + PTREGS_PTR(r0, PTREGS_OFFSET_BASE) + } + FEEDBACK_REENTER(handle_nmi) + { + movei r30, 1 + move r31, r0 + } + 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 + + /* Enable irqs. */ + TRACE_IRQS_ON + IRQ_ENABLE(r20, r21) + + /* Bump the counter for syscalls made on this tile. */ + moveli r20, hw2_last(irq_stat + IRQ_CPUSTAT_SYSCALL_COUNT_OFFSET) + shl16insli r20, r20, hw1(irq_stat + IRQ_CPUSTAT_SYSCALL_COUNT_OFFSET) + shl16insli r20, r20, hw0(irq_stat + IRQ_CPUSTAT_SYSCALL_COUNT_OFFSET) + add r20, r20, tp + ld4s r21, r20 + { + addi r21, r21, 1 + move r31, sp + } + { + st4 r20, r21 + EXTRACT_THREAD_INFO(r31) + } + + /* Trace syscalls, if requested. */ + addi r31, r31, THREAD_INFO_FLAGS_OFFSET + ld r30, r31 + andi r30, r30, _TIF_SYSCALL_TRACE + { + addi r30, r31, THREAD_INFO_STATUS_OFFSET - THREAD_INFO_FLAGS_OFFSET + beqzt r30, .Lrestore_syscall_regs + } + jal do_syscall_trace + 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: + { + ld r30, r30 + 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) + { + ld TREG_SYSCALL_NR_NAME, r11 + moveli r21, __NR_syscalls + } + + /* Ensure that the syscall number is within the legal range. */ + { + moveli r20, hw2(sys_call_table) + blbs r30, .Lcompat_syscall + } + { + cmpltu r21, TREG_SYSCALL_NR_NAME, r21 + shl16insli r20, r20, hw1(sys_call_table) + } + { + blbc r21, .Linvalid_syscall + shl16insli r20, r20, hw0(sys_call_table) + } +.Lload_syscall_pointer: + shl3add r20, TREG_SYSCALL_NR_NAME, r20 + ld 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. + * In compat mode, sign-extend r0 before storing it. + */ + { + PTREGS_PTR(r29, PTREGS_OFFSET_REG(0)) + blbct r30, 1f + } + addxi r0, r0, 0 +1: st r29, r0 + +.Lsyscall_sigreturn_skip: + FEEDBACK_REENTER(handle_syscall) + + /* Do syscall trace again, if requested. */ + ld r30, r31 + andi r0, r30, _TIF_SYSCALL_TRACE + { + andi r0, r30, _TIF_SINGLESTEP + beqzt r0, 1f + } + jal do_syscall_trace + FEEDBACK_REENTER(handle_syscall) + andi r0, r30, _TIF_SINGLESTEP + +1: beqzt r0, 2f + + /* Single stepping -- notify ptrace. */ + { + movei r0, SIGTRAP + jal ptrace_notify + } + FEEDBACK_REENTER(handle_syscall) + +2: { + movei r30, 0 /* not an NMI */ + j .Lresume_userspace /* jump into middle of interrupt_return */ + } + +.Lcompat_syscall: + /* + * Load the base of the compat syscall table in r20, and + * range-check the syscall number (duplicated from 64-bit path). + * Sign-extend all the user's passed arguments to make them consistent. + * Also save the original "r(n)" values away in "r(11+n)" in + * case the syscall table entry wants to validate them. + */ + moveli r20, hw2(compat_sys_call_table) + { + cmpltu r21, TREG_SYSCALL_NR_NAME, r21 + shl16insli r20, r20, hw1(compat_sys_call_table) + } + { + blbc r21, .Linvalid_syscall + shl16insli r20, r20, hw0(compat_sys_call_table) + } + { move r11, r0; addxi r0, r0, 0 } + { move r12, r1; addxi r1, r1, 0 } + { move r13, r2; addxi r2, r2, 0 } + { move r14, r3; addxi r3, r3, 0 } + { move r15, r4; addxi r4, r4, 0 } + { move r16, r5; addxi r5, r5, 0 } + j .Lload_syscall_pointer + +.Linvalid_syscall: + /* Report an invalid syscall back to the user program */ + { + PTREGS_PTR(r29, PTREGS_OFFSET_REG(0)) + movei r28, -ENOSYS + } + st 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) + +/* 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) + +/* Put address of pt_regs in reg and jump. */ +#define PTREGS_SYSCALL(x, reg) \ + STD_ENTRY(_##x); \ + { \ + PTREGS_PTR(reg, PTREGS_OFFSET_BASE); \ + j x \ + }; \ + STD_ENDPROC(_##x) + +/* + * 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(sys_execve, r3) +PTREGS_SYSCALL(sys_sigaltstack, r2) +PTREGS_SYSCALL_SIGRETURN(sys_rt_sigreturn, r0) +#ifdef CONFIG_COMPAT +PTREGS_SYSCALL(compat_sys_execve, r3) +PTREGS_SYSCALL(compat_sys_sigaltstack, r2) +PTREGS_SYSCALL_SIGRETURN(compat_sys_rt_sigreturn, r0) +#endif + +/* Save additional callee-saves to pt_regs, put address in r4 and jump. */ +STD_ENTRY(_sys_clone) + push_extra_callee_saves r4 + j sys_clone + STD_ENDPROC(_sys_clone) + +/* The single-step support may need to read all the registers. */ +int_unalign: + push_extra_callee_saves r0 + j do_trap + +/* Fill the return address stack with nonzero entries. */ +STD_ENTRY(fill_ra_stack) + { + move r0, lr + jal 1f + } +1: jal 2f +2: jal 3f +3: jal 4f +4: jrp r0 + STD_ENDPROC(fill_ra_stack) + +/* 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_MEM_ERROR, MEM_ERROR, do_trap + int_hand INT_SINGLE_STEP_3, SINGLE_STEP_3, bad_intr +#if CONFIG_KERNEL_PL == 2 + int_hand INT_SINGLE_STEP_2, SINGLE_STEP_2, gx_singlestep_handle + int_hand INT_SINGLE_STEP_1, SINGLE_STEP_1, bad_intr +#else + int_hand INT_SINGLE_STEP_2, SINGLE_STEP_2, bad_intr + int_hand INT_SINGLE_STEP_1, SINGLE_STEP_1, gx_singlestep_handle +#endif + int_hand INT_SINGLE_STEP_0, SINGLE_STEP_0, bad_intr + int_hand INT_IDN_COMPLETE, IDN_COMPLETE, bad_intr + int_hand INT_UDN_COMPLETE, UDN_COMPLETE, bad_intr + int_hand INT_ITLB_MISS, ITLB_MISS, do_page_fault + int_hand INT_ILL, ILL, do_trap + int_hand INT_GPV, GPV, do_trap + int_hand INT_IDN_ACCESS, IDN_ACCESS, do_trap + int_hand INT_UDN_ACCESS, UDN_ACCESS, do_trap + 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_ILL_TRANS, ILL_TRANS, 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_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_IDN_AVAIL, IDN_AVAIL, bad_intr + int_hand INT_UDN_AVAIL, UDN_AVAIL, bad_intr + int_hand INT_IPI_3, IPI_3, bad_intr +#if CONFIG_KERNEL_PL == 2 + int_hand INT_IPI_2, IPI_2, tile_dev_intr + int_hand INT_IPI_1, IPI_1, bad_intr +#else + int_hand INT_IPI_2, IPI_2, bad_intr + int_hand INT_IPI_1, IPI_1, tile_dev_intr +#endif + int_hand INT_IPI_0, IPI_0, bad_intr + int_hand INT_PERF_COUNT, PERF_COUNT, \ + op_handle_perf_interrupt, handle_nmi + int_hand INT_AUX_PERF_COUNT, AUX_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, bad_intr + int_hand INT_I_ASID, I_ASID, bad_intr + int_hand INT_D_ASID, D_ASID, bad_intr + int_hand INT_DOUBLE_FAULT, DOUBLE_FAULT, do_trap + + /* Synthetic interrupt delivered only by the simulator */ + int_hand INT_BREAKPOINT, BREAKPOINT, do_breakpoint |