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Diffstat (limited to 'arch/tile/kernel/traps.c')
| -rw-r--r-- | arch/tile/kernel/traps.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c new file mode 100644 index 000000000000..12cb10f38527 --- /dev/null +++ b/arch/tile/kernel/traps.c @@ -0,0 +1,237 @@ +/* + * 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. + */ + +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/kprobes.h> +#include <linux/module.h> +#include <linux/reboot.h> +#include <linux/uaccess.h> +#include <linux/ptrace.h> +#include <asm/opcode-tile.h> + +#include <arch/interrupts.h> +#include <arch/spr_def.h> + +void __init trap_init(void) +{ + /* Nothing needed here since we link code at .intrpt1 */ +} + +int unaligned_fixup = 1; + +static int __init setup_unaligned_fixup(char *str) +{ + /* + * Say "=-1" to completely disable it. If you just do "=0", we + * will still parse the instruction, then fire a SIGBUS with + * the correct address from inside the single_step code. + */ + long val; + if (strict_strtol(str, 0, &val) != 0) + return 0; + unaligned_fixup = val; + printk("Fixups for unaligned data accesses are %s\n", + unaligned_fixup >= 0 ? + (unaligned_fixup ? "enabled" : "disabled") : + "completely disabled"); + return 1; +} +__setup("unaligned_fixup=", setup_unaligned_fixup); + +#if CHIP_HAS_TILE_DMA() + +static int dma_disabled; + +static int __init nodma(char *str) +{ + printk("User-space DMA is disabled\n"); + dma_disabled = 1; + return 1; +} +__setup("nodma", nodma); + +/* How to decode SPR_GPV_REASON */ +#define IRET_ERROR (1U << 31) +#define MT_ERROR (1U << 30) +#define MF_ERROR (1U << 29) +#define SPR_INDEX ((1U << 15) - 1) +#define SPR_MPL_SHIFT 9 /* starting bit position for MPL encoded in SPR */ + +/* + * See if this GPV is just to notify the kernel of SPR use and we can + * retry the user instruction after adjusting some MPLs suitably. + */ +static int retry_gpv(unsigned int gpv_reason) +{ + int mpl; + + if (gpv_reason & IRET_ERROR) + return 0; + + BUG_ON((gpv_reason & (MT_ERROR|MF_ERROR)) == 0); + mpl = (gpv_reason & SPR_INDEX) >> SPR_MPL_SHIFT; + if (mpl == INT_DMA_NOTIFY && !dma_disabled) { + /* User is turning on DMA. Allow it and retry. */ + printk(KERN_DEBUG "Process %d/%s is now enabled for DMA\n", + current->pid, current->comm); + BUG_ON(current->thread.tile_dma_state.enabled); + current->thread.tile_dma_state.enabled = 1; + grant_dma_mpls(); + return 1; + } + + return 0; +} + +#endif /* CHIP_HAS_TILE_DMA() */ + +/* Defined inside do_trap(), below. */ +#ifdef __tilegx__ +extern tilegx_bundle_bits bpt_code; +#else +extern tile_bundle_bits bpt_code; +#endif + +void __kprobes do_trap(struct pt_regs *regs, int fault_num, + unsigned long reason) +{ + siginfo_t info = { 0 }; + int signo, code; + unsigned long address; + __typeof__(bpt_code) instr; + + /* Re-enable interrupts. */ + local_irq_enable(); + + /* + * If it hits in kernel mode and we can't fix it up, just exit the + * current process and hope for the best. + */ + if (!user_mode(regs)) { + if (fixup_exception(regs)) /* only UNALIGN_DATA in practice */ + return; + printk(KERN_ALERT "Kernel took bad trap %d at PC %#lx\n", + fault_num, regs->pc); + if (fault_num == INT_GPV) + printk(KERN_ALERT "GPV_REASON is %#lx\n", reason); + show_regs(regs); + do_exit(SIGKILL); /* FIXME: implement i386 die() */ + return; + } + + switch (fault_num) { + case INT_ILL: + asm(".pushsection .rodata.bpt_code,\"a\";" + ".align 8;" + "bpt_code: bpt;" + ".size bpt_code,.-bpt_code;" + ".popsection"); + + if (copy_from_user(&instr, (void *)regs->pc, sizeof(instr))) { + printk(KERN_ERR "Unreadable instruction for INT_ILL:" + " %#lx\n", regs->pc); + do_exit(SIGKILL); + return; + } + if (instr == bpt_code) { + signo = SIGTRAP; + code = TRAP_BRKPT; + } else { + signo = SIGILL; + code = ILL_ILLOPC; + } + address = regs->pc; + break; + case INT_GPV: +#if CHIP_HAS_TILE_DMA() + if (retry_gpv(reason)) + return; +#endif + /*FALLTHROUGH*/ + case INT_UDN_ACCESS: + case INT_IDN_ACCESS: +#if CHIP_HAS_SN() + case INT_SN_ACCESS: +#endif + signo = SIGILL; + code = ILL_PRVREG; + address = regs->pc; + break; + case INT_SWINT_3: + case INT_SWINT_2: + case INT_SWINT_0: + signo = SIGILL; + code = ILL_ILLTRP; + address = regs->pc; + break; + case INT_UNALIGN_DATA: +#ifndef __tilegx__ /* FIXME: GX: no single-step yet */ + if (unaligned_fixup >= 0) { + struct single_step_state *state = + current_thread_info()->step_state; + if (!state || (void *)(regs->pc) != state->buffer) { + single_step_once(regs); + return; + } + } +#endif + signo = SIGBUS; + code = BUS_ADRALN; + address = 0; + break; + case INT_DOUBLE_FAULT: + /* + * For double fault, "reason" is actually passed as + * SYSTEM_SAVE_1_2, the hypervisor's double-fault info, so + * we can provide the original fault number rather than + * the uninteresting "INT_DOUBLE_FAULT" so the user can + * learn what actually struck while PL0 ICS was set. + */ + fault_num = reason; + signo = SIGILL; + code = ILL_DBLFLT; + address = regs->pc; + break; +#ifdef __tilegx__ + case INT_ILL_TRANS: + signo = SIGSEGV; + code = SEGV_MAPERR; + if (reason & SPR_ILL_TRANS_REASON__I_STREAM_VA_RMASK) + address = regs->pc; + else + address = 0; /* FIXME: GX: single-step for address */ + break; +#endif + default: + panic("Unexpected do_trap interrupt number %d", fault_num); + return; + } + + info.si_signo = signo; + info.si_code = code; + info.si_addr = (void *)address; + if (signo == SIGILL) + info.si_trapno = fault_num; + force_sig_info(signo, &info, current); +} + +extern void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52); + +void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52) +{ + _dump_stack(dummy, pc, lr, sp, r52); + printk("Double fault: exiting\n"); + machine_halt(); +} |