/* $Id: traps.c,v 1.14 2001/07/24 08:07:10 gniibe Exp $ * * linux/arch/sh/traps.c * * SuperH version: Copyright (C) 1999 Niibe Yutaka * Copyright (C) 2000 Philipp Rumpf * Copyright (C) 2000 David Howells */ /* * 'Traps.c' handles hardware traps and faults after we have saved some * state in 'entry.S'. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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; \ \ asm volatile("stc r2_bank, %0": "=r" (error_code)); \ sti(); \ tsk->thread.error_code = error_code; \ tsk->thread.trap_no = trapnr; \ force_sig(signr, tsk); \ die_if_no_fixup(str,®s,error_code); \ } /* * 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) { console_verbose(); spin_lock_irq(&die_lock); printk("%s: %04lx\n", str, err & 0xffff); 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)) { unsigned long fixup; fixup = search_exception_table(regs->pc); if (fixup) { regs->pc = 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 * - if the branch would be taken PC points to the branch * - if the branch would not be taken, PC points to delay-slot * - return 0 if handled, -EFAULT if failed (may not return if in kernel) */ 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) regs->pc += (instruction&0x00FF)*2 + 4; break; case 0x0900: /* bt lab - no delayslot */ break; case 0x0D00: /* bt/s lab */ ret = handle_unaligned_delayslot(regs); if (ret==0) regs->pc += (instruction&0x00FF)*2 + 4; break; } break; case 0xA000: /* bra label */ ret = handle_unaligned_delayslot(regs); if (ret==0) regs->pc += (instruction&0x0FFF)*2 + 4; break; case 0xB000: /* bsr label */ ret = handle_unaligned_delayslot(regs); if (ret==0) { regs->pr = regs->pc + 4; regs->pc += (instruction&0x0FFF)*2 + 4; } 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)) { sti(); 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); } } DO_ERROR(12, SIGILL, "reserved instruction", reserved_inst, current) DO_ERROR(13, 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; #endif void __init trap_init(void) { extern void *vbr_base; extern void *exception_handling_table[14]; exception_handling_table[12] = (void *)do_reserved_inst; exception_handling_table[13] = (void *)do_illegal_slot_inst; #if defined(CONFIG_SH_STANDARD_BIOS) /* * 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. */ { register unsigned long vbr; 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 /* 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 dump_stack(void) { unsigned long *start; unsigned long *end; unsigned long *p; asm("mov r15, %0" : "=r" (start)); asm("stc r7_bank, %0" : "=r" (end)); end += 8192/4; printk("%08lx:%08lx\n", (unsigned long)start, (unsigned long)end); for (p=start; p < end; p++) { extern long _text, _etext; unsigned long v=*p; if ((v >= (unsigned long )&_text) && (v <= (unsigned long )&_etext)) { printk("%08lx\n", v); } } }