/* * 'traps.c' handles hardware traps and faults after we have saved some * state in 'entry.S'. * * SuperH version: Copyright (C) 1999 Niibe Yutaka * Copyright (C) 2000 Philipp Rumpf * Copyright (C) 2000 David Howells * Copyright (C) 2002 - 2007 Paul Mundt * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. */ #include <linux/kernel.h> #include <linux/ptrace.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/module.h> #include <linux/kallsyms.h> #include <linux/io.h> #include <linux/bug.h> #include <linux/debug_locks.h> #include <linux/kdebug.h> #include <linux/kexec.h> #include <linux/limits.h> #include <asm/system.h> #include <asm/uaccess.h> #ifdef CONFIG_SH_KGDB #include <asm/kgdb.h> #define CHK_REMOTE_DEBUG(regs) \ { \ if (kgdb_debug_hook && !user_mode(regs))\ (*kgdb_debug_hook)(regs); \ } #else #define CHK_REMOTE_DEBUG(regs) #endif #ifdef CONFIG_CPU_SH2 # define TRAP_RESERVED_INST 4 # define TRAP_ILLEGAL_SLOT_INST 6 # define TRAP_ADDRESS_ERROR 9 # ifdef CONFIG_CPU_SH2A # define TRAP_DIVZERO_ERROR 17 # define TRAP_DIVOVF_ERROR 18 # endif #else #define TRAP_RESERVED_INST 12 #define TRAP_ILLEGAL_SLOT_INST 13 #endif static void dump_mem(const char *str, unsigned long bottom, unsigned long top) { unsigned long p; int i; printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top); for (p = bottom & ~31; p < top; ) { printk("%04lx: ", p & 0xffff); for (i = 0; i < 8; i++, p += 4) { unsigned int val; if (p < bottom || p >= top) printk(" "); else { if (__get_user(val, (unsigned int __user *)p)) { printk("\n"); return; } printk("%08x ", val); } } printk("\n"); } } static DEFINE_SPINLOCK(die_lock); void die(const char * str, struct pt_regs * regs, long err) { static int die_counter; oops_enter(); console_verbose(); spin_lock_irq(&die_lock); bust_spinlocks(1); printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter); CHK_REMOTE_DEBUG(regs); print_modules(); show_regs(regs); printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm, current->pid, task_stack_page(current) + 1); if (!user_mode(regs) || in_interrupt()) dump_mem("Stack: ", regs->regs[15], THREAD_SIZE + (unsigned long)task_stack_page(current)); bust_spinlocks(0); add_taint(TAINT_DIE); spin_unlock_irq(&die_lock); if (kexec_should_crash(current)) crash_kexec(regs); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); oops_exit(); 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); } /* * 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) /* * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit * opcodes.. */ #ifndef CONFIG_CPU_SH2A static int handle_unaligned_notify_count = 10; 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(KERN_NOTICE "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 += instruction_size(instruction); return ret; } #endif /* CONFIG_CPU_SH2A */ #ifdef CONFIG_CPU_HAS_SR_RB #define lookup_exception_vector(x) \ __asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x))) #else #define lookup_exception_vector(x) \ __asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x))) #endif /* * Handle various address error exceptions: * - instruction address error: * misaligned PC * PC >= 0x80000000 in user mode * - data address error (read and write) * misaligned data access * access to >= 0x80000000 is user mode * Unfortuntaly we can't distinguish between instruction address error * and data address errors caused by read accesses. */ asmlinkage void do_address_error(struct pt_regs *regs, unsigned long writeaccess, unsigned long address) { unsigned long error_code = 0; mm_segment_t oldfs; siginfo_t info; #ifndef CONFIG_CPU_SH2A u16 instruction; int tmp; #endif /* Intentional ifdef */ #ifdef CONFIG_CPU_HAS_SR_RB lookup_exception_vector(error_code); #endif oldfs = get_fs(); if (user_mode(regs)) { int si_code = BUS_ADRERR; local_irq_enable(); /* bad PC is not something we can fix */ if (regs->pc & 1) { si_code = BUS_ADRALN; goto uspace_segv; } #ifndef CONFIG_CPU_SH2A 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 */ #endif uspace_segv: printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned " "access (PC %lx PR %lx)\n", current->comm, regs->pc, regs->pr); info.si_signo = SIGBUS; info.si_errno = 0; info.si_code = si_code; info.si_addr = (void __user *)address; force_sig_info(SIGBUS, &info, current); } else { if (regs->pc & 1) die("unaligned program counter", regs, error_code); #ifndef CONFIG_CPU_SH2A 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); #else printk(KERN_NOTICE "Killing process \"%s\" due to unaligned " "access\n", current->comm); force_sig(SIGSEGV, current); #endif } } #ifdef CONFIG_SH_DSP /* * SH-DSP support gerg@snapgear.com. */ int is_dsp_inst(struct pt_regs *regs) { unsigned short inst = 0; /* * Safe guard if DSP mode is already enabled or we're lacking * the DSP altogether. */ if (!(current_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 */ #ifdef CONFIG_CPU_SH2A asmlinkage void do_divide_error(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { siginfo_t info; switch (r4) { case TRAP_DIVZERO_ERROR: info.si_code = FPE_INTDIV; break; case TRAP_DIVOVF_ERROR: info.si_code = FPE_INTOVF; break; } force_sig_info(SIGFPE, &info, current); } #endif /* arch/sh/kernel/cpu/sh4/fpu.c */ extern int do_fpu_inst(unsigned short, struct pt_regs *); extern asmlinkage void do_fpu_state_restore(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs); asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { struct pt_regs *regs = RELOC_HIDE(&__regs, 0); unsigned long error_code; struct task_struct *tsk = current; #ifdef CONFIG_SH_FPU_EMU unsigned short inst = 0; int err; get_user(inst, (unsigned short*)regs->pc); err = do_fpu_inst(inst, regs); if (!err) { regs->pc += instruction_size(inst); return; } /* not a FPU inst. */ #endif #ifdef CONFIG_SH_DSP /* Check if it's a DSP instruction */ if (is_dsp_inst(regs)) { /* Enable DSP mode, and restart instruction. */ regs->sr |= SR_DSP; return; } #endif lookup_exception_vector(error_code); local_irq_enable(); CHK_REMOTE_DEBUG(regs); force_sig(SIGILL, tsk); die_if_no_fixup("reserved instruction", regs, error_code); } #ifdef CONFIG_SH_FPU_EMU static int emulate_branch(unsigned short inst, struct pt_regs* regs) { /* * bfs: 8fxx: PC+=d*2+4; * bts: 8dxx: PC+=d*2+4; * bra: axxx: PC+=D*2+4; * bsr: bxxx: PC+=D*2+4 after PR=PC+4; * braf:0x23: PC+=Rn*2+4; * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4; * jmp: 4x2b: PC=Rn; * jsr: 4x0b: PC=Rn after PR=PC+4; * rts: 000b: PC=PR; */ if ((inst & 0xfd00) == 0x8d00) { regs->pc += SH_PC_8BIT_OFFSET(inst); return 0; } if ((inst & 0xe000) == 0xa000) { regs->pc += SH_PC_12BIT_OFFSET(inst); return 0; } if ((inst & 0xf0df) == 0x0003) { regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4; return 0; } if ((inst & 0xf0df) == 0x400b) { regs->pc = regs->regs[(inst & 0x0f00) >> 8]; return 0; } if ((inst & 0xffff) == 0x000b) { regs->pc = regs->pr; return 0; } return 1; } #endif asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { struct pt_regs *regs = RELOC_HIDE(&__regs, 0); unsigned long error_code; struct task_struct *tsk = current; #ifdef CONFIG_SH_FPU_EMU unsigned short inst = 0; get_user(inst, (unsigned short *)regs->pc + 1); if (!do_fpu_inst(inst, regs)) { get_user(inst, (unsigned short *)regs->pc); if (!emulate_branch(inst, regs)) return; /* fault in branch.*/ } /* not a FPU inst. */ #endif lookup_exception_vector(error_code); local_irq_enable(); CHK_REMOTE_DEBUG(regs); force_sig(SIGILL, tsk); die_if_no_fixup("illegal slot instruction", regs, error_code); } asmlinkage void do_exception_error(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { struct pt_regs *regs = RELOC_HIDE(&__regs, 0); long ex; lookup_exception_vector(ex); die_if_kernel("exception", regs, 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 *set_exception_table_vec(unsigned int vec, void *handler) { extern void *exception_handling_table[]; void *old_handler; old_handler = exception_handling_table[vec]; exception_handling_table[vec] = handler; return old_handler; } extern asmlinkage void address_error_handler(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs); void __init trap_init(void) { set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst); set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst); #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \ defined(CONFIG_SH_FPU_EMU) /* * For SH-4 lacking an FPU, treat floating point instructions as * reserved. They'll be handled in the math-emu case, or faulted on * otherwise. */ set_exception_table_evt(0x800, do_reserved_inst); set_exception_table_evt(0x820, do_illegal_slot_inst); #elif defined(CONFIG_SH_FPU) #ifdef CONFIG_CPU_SUBTYPE_SHX3 set_exception_table_evt(0xd80, do_fpu_state_restore); set_exception_table_evt(0xda0, do_fpu_state_restore); #else set_exception_table_evt(0x800, do_fpu_state_restore); set_exception_table_evt(0x820, do_fpu_state_restore); #endif #endif #ifdef CONFIG_CPU_SH2 set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_handler); #endif #ifdef CONFIG_CPU_SH2A set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error); set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error); #endif /* Setup VBR for boot cpu */ per_cpu_trap_init(); } #ifdef CONFIG_BUG void handle_BUG(struct pt_regs *regs) { enum bug_trap_type tt; tt = report_bug(regs->pc, regs); if (tt == BUG_TRAP_TYPE_WARN) { regs->pc += 2; return; } die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff); } int is_valid_bugaddr(unsigned long addr) { return addr >= PAGE_OFFSET; } #endif void show_trace(struct task_struct *tsk, unsigned long *sp, struct pt_regs *regs) { unsigned long addr; if (regs && user_mode(regs)) return; printk("\nCall trace: "); #ifdef CONFIG_KALLSYMS printk("\n"); #endif while (!kstack_end(sp)) { addr = *sp++; if (kernel_text_address(addr)) print_ip_sym(addr); } printk("\n"); if (!tsk) tsk = current; debug_show_held_locks(tsk); } void show_stack(struct task_struct *tsk, unsigned long *sp) { unsigned long stack; if (!tsk) tsk = current; if (tsk == current) sp = (unsigned long *)current_stack_pointer; else sp = (unsigned long *)tsk->thread.sp; stack = (unsigned long)sp; dump_mem("Stack: ", stack, THREAD_SIZE + (unsigned long)task_stack_page(tsk)); show_trace(tsk, sp, NULL); } void dump_stack(void) { show_stack(NULL, NULL); } EXPORT_SYMBOL(dump_stack);