diff options
Diffstat (limited to 'arch/sh/kernel/traps.c')
| -rw-r--r-- | arch/sh/kernel/traps.c | 712 |
1 files changed, 712 insertions, 0 deletions
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c new file mode 100644 index 000000000000..7eb06719d844 --- /dev/null +++ b/arch/sh/kernel/traps.c @@ -0,0 +1,712 @@ +/* $Id: traps.c,v 1.17 2004/05/02 01:46:30 sugioka Exp $ + * + * linux/arch/sh/traps.c + * + * SuperH version: Copyright (C) 1999 Niibe Yutaka + * Copyright (C) 2000 Philipp Rumpf + * Copyright (C) 2000 David Howells + * Copyright (C) 2002, 2003 Paul Mundt + */ + +/* + * 'Traps.c' handles hardware traps and faults after we have saved some + * state in 'entry.S'. + */ +#include <linux/config.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/ptrace.h> +#include <linux/timer.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/smp_lock.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/spinlock.h> +#include <linux/module.h> +#include <linux/kallsyms.h> + +#include <asm/system.h> +#include <asm/uaccess.h> +#include <asm/io.h> +#include <asm/atomic.h> +#include <asm/processor.h> +#include <asm/sections.h> + +#ifdef CONFIG_SH_KGDB +#include <asm/kgdb.h> +#define CHK_REMOTE_DEBUG(regs) \ +{ \ + if ((kgdb_debug_hook != (kgdb_debug_hook_t *) NULL) && (!user_mode(regs))) \ + { \ + (*kgdb_debug_hook)(regs); \ + } \ +} +#else +#define CHK_REMOTE_DEBUG(regs) +#endif + +#define DO_ERROR(trapnr, signr, str, name, tsk) \ +asmlinkage void do_##name(unsigned long r4, unsigned long r5, \ + unsigned long r6, unsigned long r7, \ + struct pt_regs regs) \ +{ \ + unsigned long error_code; \ + \ + /* Check if it's a DSP instruction */ \ + if (is_dsp_inst(®s)) { \ + /* Enable DSP mode, and restart instruction. */ \ + regs.sr |= SR_DSP; \ + return; \ + } \ + \ + asm volatile("stc r2_bank, %0": "=r" (error_code)); \ + local_irq_enable(); \ + tsk->thread.error_code = error_code; \ + tsk->thread.trap_no = trapnr; \ + CHK_REMOTE_DEBUG(®s); \ + force_sig(signr, tsk); \ + die_if_no_fixup(str,®s,error_code); \ +} + +#ifdef CONFIG_CPU_SH2 +#define TRAP_RESERVED_INST 4 +#define TRAP_ILLEGAL_SLOT_INST 6 +#else +#define TRAP_RESERVED_INST 12 +#define TRAP_ILLEGAL_SLOT_INST 13 +#endif + +/* + * These constants are for searching for possible module text + * segments. VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is + * a guess of how much space is likely to be vmalloced. + */ +#define VMALLOC_OFFSET (8*1024*1024) +#define MODULE_RANGE (8*1024*1024) + +spinlock_t die_lock; + +void die(const char * str, struct pt_regs * regs, long err) +{ + static int die_counter; + + console_verbose(); + spin_lock_irq(&die_lock); + printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter); + CHK_REMOTE_DEBUG(regs); + show_regs(regs); + spin_unlock_irq(&die_lock); + do_exit(SIGSEGV); +} + +static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err) +{ + if (!user_mode(regs)) + die(str, regs, err); +} + +static int handle_unaligned_notify_count = 10; + +/* + * try and fix up kernelspace address errors + * - userspace errors just cause EFAULT to be returned, resulting in SEGV + * - kernel/userspace interfaces cause a jump to an appropriate handler + * - other kernel errors are bad + * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault + */ +static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err) +{ + if (!user_mode(regs)) + { + const struct exception_table_entry *fixup; + fixup = search_exception_tables(regs->pc); + if (fixup) { + regs->pc = fixup->fixup; + return 0; + } + die(str, regs, err); + } + return -EFAULT; +} + +/* + * handle an instruction that does an unaligned memory access by emulating the + * desired behaviour + * - note that PC _may not_ point to the faulting instruction + * (if that instruction is in a branch delay slot) + * - return 0 if emulation okay, -EFAULT on existential error + */ +static int handle_unaligned_ins(u16 instruction, struct pt_regs *regs) +{ + int ret, index, count; + unsigned long *rm, *rn; + unsigned char *src, *dst; + + index = (instruction>>8)&15; /* 0x0F00 */ + rn = ®s->regs[index]; + + index = (instruction>>4)&15; /* 0x00F0 */ + rm = ®s->regs[index]; + + count = 1<<(instruction&3); + + ret = -EFAULT; + switch (instruction>>12) { + case 0: /* mov.[bwl] to/from memory via r0+rn */ + if (instruction & 8) { + /* from memory */ + src = (unsigned char*) *rm; + src += regs->regs[0]; + dst = (unsigned char*) rn; + *(unsigned long*)dst = 0; + +#ifdef __LITTLE_ENDIAN__ + if (copy_from_user(dst, src, count)) + goto fetch_fault; + + if ((count == 2) && dst[1] & 0x80) { + dst[2] = 0xff; + dst[3] = 0xff; + } +#else + dst += 4-count; + + if (__copy_user(dst, src, count)) + goto fetch_fault; + + if ((count == 2) && dst[2] & 0x80) { + dst[0] = 0xff; + dst[1] = 0xff; + } +#endif + } else { + /* to memory */ + src = (unsigned char*) rm; +#if !defined(__LITTLE_ENDIAN__) + src += 4-count; +#endif + dst = (unsigned char*) *rn; + dst += regs->regs[0]; + + if (copy_to_user(dst, src, count)) + goto fetch_fault; + } + ret = 0; + break; + + case 1: /* mov.l Rm,@(disp,Rn) */ + src = (unsigned char*) rm; + dst = (unsigned char*) *rn; + dst += (instruction&0x000F)<<2; + + if (copy_to_user(dst,src,4)) + goto fetch_fault; + ret = 0; + break; + + case 2: /* mov.[bwl] to memory, possibly with pre-decrement */ + if (instruction & 4) + *rn -= count; + src = (unsigned char*) rm; + dst = (unsigned char*) *rn; +#if !defined(__LITTLE_ENDIAN__) + src += 4-count; +#endif + if (copy_to_user(dst, src, count)) + goto fetch_fault; + ret = 0; + break; + + case 5: /* mov.l @(disp,Rm),Rn */ + src = (unsigned char*) *rm; + src += (instruction&0x000F)<<2; + dst = (unsigned char*) rn; + *(unsigned long*)dst = 0; + + if (copy_from_user(dst,src,4)) + goto fetch_fault; + ret = 0; + break; + + case 6: /* mov.[bwl] from memory, possibly with post-increment */ + src = (unsigned char*) *rm; + if (instruction & 4) + *rm += count; + dst = (unsigned char*) rn; + *(unsigned long*)dst = 0; + +#ifdef __LITTLE_ENDIAN__ + if (copy_from_user(dst, src, count)) + goto fetch_fault; + + if ((count == 2) && dst[1] & 0x80) { + dst[2] = 0xff; + dst[3] = 0xff; + } +#else + dst += 4-count; + + if (copy_from_user(dst, src, count)) + goto fetch_fault; + + if ((count == 2) && dst[2] & 0x80) { + dst[0] = 0xff; + dst[1] = 0xff; + } +#endif + ret = 0; + break; + + case 8: + switch ((instruction&0xFF00)>>8) { + case 0x81: /* mov.w R0,@(disp,Rn) */ + src = (unsigned char*) ®s->regs[0]; +#if !defined(__LITTLE_ENDIAN__) + src += 2; +#endif + dst = (unsigned char*) *rm; /* called Rn in the spec */ + dst += (instruction&0x000F)<<1; + + if (copy_to_user(dst, src, 2)) + goto fetch_fault; + ret = 0; + break; + + case 0x85: /* mov.w @(disp,Rm),R0 */ + src = (unsigned char*) *rm; + src += (instruction&0x000F)<<1; + dst = (unsigned char*) ®s->regs[0]; + *(unsigned long*)dst = 0; + +#if !defined(__LITTLE_ENDIAN__) + dst += 2; +#endif + + if (copy_from_user(dst, src, 2)) + goto fetch_fault; + +#ifdef __LITTLE_ENDIAN__ + if (dst[1] & 0x80) { + dst[2] = 0xff; + dst[3] = 0xff; + } +#else + if (dst[2] & 0x80) { + dst[0] = 0xff; + dst[1] = 0xff; + } +#endif + ret = 0; + break; + } + break; + } + return ret; + + fetch_fault: + /* Argh. Address not only misaligned but also non-existent. + * Raise an EFAULT and see if it's trapped + */ + return die_if_no_fixup("Fault in unaligned fixup", regs, 0); +} + +/* + * emulate the instruction in the delay slot + * - fetches the instruction from PC+2 + */ +static inline int handle_unaligned_delayslot(struct pt_regs *regs) +{ + u16 instruction; + + if (copy_from_user(&instruction, (u16 *)(regs->pc+2), 2)) { + /* the instruction-fetch faulted */ + if (user_mode(regs)) + return -EFAULT; + + /* kernel */ + die("delay-slot-insn faulting in handle_unaligned_delayslot", regs, 0); + } + + return handle_unaligned_ins(instruction,regs); +} + +/* + * handle an instruction that does an unaligned memory access + * - have to be careful of branch delay-slot instructions that fault + * SH3: + * - if the branch would be taken PC points to the branch + * - if the branch would not be taken, PC points to delay-slot + * SH4: + * - PC always points to delayed branch + * - return 0 if handled, -EFAULT if failed (may not return if in kernel) + */ + +/* Macros to determine offset from current PC for branch instructions */ +/* Explicit type coercion is used to force sign extension where needed */ +#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4) +#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4) + +static int handle_unaligned_access(u16 instruction, struct pt_regs *regs) +{ + u_int rm; + int ret, index; + + index = (instruction>>8)&15; /* 0x0F00 */ + rm = regs->regs[index]; + + /* shout about the first ten userspace fixups */ + if (user_mode(regs) && handle_unaligned_notify_count>0) { + handle_unaligned_notify_count--; + + printk("Fixing up unaligned userspace access in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n", + current->comm,current->pid,(u16*)regs->pc,instruction); + } + + ret = -EFAULT; + switch (instruction&0xF000) { + case 0x0000: + if (instruction==0x000B) { + /* rts */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) + regs->pc = regs->pr; + } + else if ((instruction&0x00FF)==0x0023) { + /* braf @Rm */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) + regs->pc += rm + 4; + } + else if ((instruction&0x00FF)==0x0003) { + /* bsrf @Rm */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) { + regs->pr = regs->pc + 4; + regs->pc += rm + 4; + } + } + else { + /* mov.[bwl] to/from memory via r0+rn */ + goto simple; + } + break; + + case 0x1000: /* mov.l Rm,@(disp,Rn) */ + goto simple; + + case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */ + goto simple; + + case 0x4000: + if ((instruction&0x00FF)==0x002B) { + /* jmp @Rm */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) + regs->pc = rm; + } + else if ((instruction&0x00FF)==0x000B) { + /* jsr @Rm */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) { + regs->pr = regs->pc + 4; + regs->pc = rm; + } + } + else { + /* mov.[bwl] to/from memory via r0+rn */ + goto simple; + } + break; + + case 0x5000: /* mov.l @(disp,Rm),Rn */ + goto simple; + + case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */ + goto simple; + + case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */ + switch (instruction&0x0F00) { + case 0x0100: /* mov.w R0,@(disp,Rm) */ + goto simple; + case 0x0500: /* mov.w @(disp,Rm),R0 */ + goto simple; + case 0x0B00: /* bf lab - no delayslot*/ + break; + case 0x0F00: /* bf/s lab */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) { +#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB) + if ((regs->sr & 0x00000001) != 0) + regs->pc += 4; /* next after slot */ + else +#endif + regs->pc += SH_PC_8BIT_OFFSET(instruction); + } + break; + case 0x0900: /* bt lab - no delayslot */ + break; + case 0x0D00: /* bt/s lab */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) { +#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB) + if ((regs->sr & 0x00000001) == 0) + regs->pc += 4; /* next after slot */ + else +#endif + regs->pc += SH_PC_8BIT_OFFSET(instruction); + } + break; + } + break; + + case 0xA000: /* bra label */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) + regs->pc += SH_PC_12BIT_OFFSET(instruction); + break; + + case 0xB000: /* bsr label */ + ret = handle_unaligned_delayslot(regs); + if (ret==0) { + regs->pr = regs->pc + 4; + regs->pc += SH_PC_12BIT_OFFSET(instruction); + } + break; + } + return ret; + + /* handle non-delay-slot instruction */ + simple: + ret = handle_unaligned_ins(instruction,regs); + if (ret==0) + regs->pc += 2; + return ret; +} + +/* + * Handle various address error exceptions + */ +asmlinkage void do_address_error(struct pt_regs *regs, + unsigned long writeaccess, + unsigned long address) +{ + unsigned long error_code; + mm_segment_t oldfs; + u16 instruction; + int tmp; + + asm volatile("stc r2_bank,%0": "=r" (error_code)); + + oldfs = get_fs(); + + if (user_mode(regs)) { + local_irq_enable(); + current->thread.error_code = error_code; + current->thread.trap_no = (writeaccess) ? 8 : 7; + + /* bad PC is not something we can fix */ + if (regs->pc & 1) + goto uspace_segv; + + set_fs(USER_DS); + if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) { + /* Argh. Fault on the instruction itself. + This should never happen non-SMP + */ + set_fs(oldfs); + goto uspace_segv; + } + + tmp = handle_unaligned_access(instruction, regs); + set_fs(oldfs); + + if (tmp==0) + return; /* sorted */ + + uspace_segv: + printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm); + force_sig(SIGSEGV, current); + } else { + if (regs->pc & 1) + die("unaligned program counter", regs, error_code); + + set_fs(KERNEL_DS); + if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) { + /* Argh. Fault on the instruction itself. + This should never happen non-SMP + */ + set_fs(oldfs); + die("insn faulting in do_address_error", regs, 0); + } + + handle_unaligned_access(instruction, regs); + set_fs(oldfs); + } +} + +#ifdef CONFIG_SH_DSP +/* + * SH-DSP support gerg@snapgear.com. + */ +int is_dsp_inst(struct pt_regs *regs) +{ + unsigned short inst; + + /* + * Safe guard if DSP mode is already enabled or we're lacking + * the DSP altogether. + */ + if (!(cpu_data->flags & CPU_HAS_DSP) || (regs->sr & SR_DSP)) + return 0; + + get_user(inst, ((unsigned short *) regs->pc)); + + inst &= 0xf000; + + /* Check for any type of DSP or support instruction */ + if ((inst == 0xf000) || (inst == 0x4000)) + return 1; + + return 0; +} +#else +#define is_dsp_inst(regs) (0) +#endif /* CONFIG_SH_DSP */ + +DO_ERROR(TRAP_RESERVED_INST, SIGILL, "reserved instruction", reserved_inst, current) +DO_ERROR(TRAP_ILLEGAL_SLOT_INST, SIGILL, "illegal slot instruction", illegal_slot_inst, current) + +asmlinkage void do_exception_error(unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7, + struct pt_regs regs) +{ + long ex; + asm volatile("stc r2_bank, %0" : "=r" (ex)); + die_if_kernel("exception", ®s, ex); +} + +#if defined(CONFIG_SH_STANDARD_BIOS) +void *gdb_vbr_vector; + +static inline void __init gdb_vbr_init(void) +{ + register unsigned long vbr; + + /* + * Read the old value of the VBR register to initialise + * the vector through which debug and BIOS traps are + * delegated by the Linux trap handler. + */ + asm volatile("stc vbr, %0" : "=r" (vbr)); + + gdb_vbr_vector = (void *)(vbr + 0x100); + printk("Setting GDB trap vector to 0x%08lx\n", + (unsigned long)gdb_vbr_vector); +} +#endif + +void __init per_cpu_trap_init(void) +{ + extern void *vbr_base; + +#ifdef CONFIG_SH_STANDARD_BIOS + gdb_vbr_init(); +#endif + + /* NOTE: The VBR value should be at P1 + (or P2, virtural "fixed" address space). + It's definitely should not in physical address. */ + + asm volatile("ldc %0, vbr" + : /* no output */ + : "r" (&vbr_base) + : "memory"); +} + +void __init trap_init(void) +{ + extern void *exception_handling_table[]; + + exception_handling_table[TRAP_RESERVED_INST] + = (void *)do_reserved_inst; + exception_handling_table[TRAP_ILLEGAL_SLOT_INST] + = (void *)do_illegal_slot_inst; + +#ifdef CONFIG_CPU_SH4 + if (!(cpu_data->flags & CPU_HAS_FPU)) { + /* For SH-4 lacking an FPU, treat floating point instructions + as reserved. */ + /* entry 64 corresponds to EXPEVT=0x800 */ + exception_handling_table[64] = (void *)do_reserved_inst; + exception_handling_table[65] = (void *)do_illegal_slot_inst; + } +#endif + + /* Setup VBR for boot cpu */ + per_cpu_trap_init(); +} + +void show_stack(struct task_struct *tsk, unsigned long *sp) +{ + unsigned long *stack, addr; + unsigned long module_start = VMALLOC_START; + unsigned long module_end = VMALLOC_END; + int i = 1; + + if (tsk && !sp) { + sp = (unsigned long *)tsk->thread.sp; + } + + if (!sp) { + __asm__ __volatile__ ( + "mov r15, %0\n\t" + "stc r7_bank, %1\n\t" + : "=r" (module_start), + "=r" (module_end) + ); + + sp = (unsigned long *)module_start; + } + + stack = sp; + + printk("\nCall trace: "); +#ifdef CONFIG_KALLSYMS + printk("\n"); +#endif + + while (!kstack_end(stack)) { + addr = *stack++; + if (((addr >= (unsigned long)_text) && + (addr <= (unsigned long)_etext)) || + ((addr >= module_start) && (addr <= module_end))) { + /* + * For 80-columns display, 6 entry is maximum. + * NOTE: '[<8c00abcd>] ' consumes 13 columns . + */ +#ifndef CONFIG_KALLSYMS + if (i && ((i % 6) == 0)) + printk("\n "); +#endif + printk("[<%08lx>] ", addr); + print_symbol("%s\n", addr); + i++; + } + } + + printk("\n"); +} + +void show_task(unsigned long *sp) +{ + show_stack(NULL, sp); +} + +void dump_stack(void) +{ + show_stack(NULL, NULL); +} +EXPORT_SYMBOL(dump_stack); |