/* * arch/xtensa/kernel/traps.c * * Exception handling. * * Derived from code with the following copyrights: * Copyright (C) 1994 - 1999 by Ralf Baechle * Modified for R3000 by Paul M. Antoine, 1995, 1996 * Complete output from die() by Ulf Carlsson, 1998 * Copyright (C) 1999 Silicon Graphics, Inc. * * Essentially rewritten for the Xtensa architecture port. * * Copyright (C) 2001 - 2005 Tensilica Inc. * * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> * Chris Zankel <chris@zankel.net> * Marc Gauthier<marc@tensilica.com, marc@alumni.uwaterloo.ca> * Kevin Chea * * 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/sched.h> #include <linux/init.h> #include <linux/module.h> #include <linux/stringify.h> #include <linux/kallsyms.h> #include <linux/delay.h> #include <linux/hardirq.h> #include <asm/ptrace.h> #include <asm/timex.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/processor.h> #ifdef CONFIG_KGDB extern int gdb_enter; extern int return_from_debug_flag; #endif /* * Machine specific interrupt handlers */ extern void kernel_exception(void); extern void user_exception(void); extern void fast_syscall_kernel(void); extern void fast_syscall_user(void); extern void fast_alloca(void); extern void fast_unaligned(void); extern void fast_second_level_miss(void); extern void fast_store_prohibited(void); extern void fast_coprocessor(void); extern void do_illegal_instruction (struct pt_regs*); extern void do_interrupt (struct pt_regs*); extern void do_unaligned_user (struct pt_regs*); extern void do_multihit (struct pt_regs*, unsigned long); extern void do_page_fault (struct pt_regs*, unsigned long); extern void do_debug (struct pt_regs*); extern void system_call (struct pt_regs*); /* * The vector table must be preceded by a save area (which * implies it must be in RAM, unless one places RAM immediately * before a ROM and puts the vector at the start of the ROM (!)) */ #define KRNL 0x01 #define USER 0x02 #define COPROCESSOR(x) \ { EXCCAUSE_COPROCESSOR ## x ## _DISABLED, USER, fast_coprocessor } typedef struct { int cause; int fast; void* handler; } dispatch_init_table_t; static dispatch_init_table_t __initdata dispatch_init_table[] = { { EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction}, { EXCCAUSE_SYSTEM_CALL, KRNL, fast_syscall_kernel }, { EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user }, { EXCCAUSE_SYSTEM_CALL, 0, system_call }, /* EXCCAUSE_INSTRUCTION_FETCH unhandled */ /* EXCCAUSE_LOAD_STORE_ERROR unhandled*/ { EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt }, { EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca }, /* EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */ /* EXCCAUSE_PRIVILEGED unhandled */ #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION #ifdef CONFIG_UNALIGNED_USER { EXCCAUSE_UNALIGNED, USER, fast_unaligned }, #else { EXCCAUSE_UNALIGNED, 0, do_unaligned_user }, #endif { EXCCAUSE_UNALIGNED, KRNL, fast_unaligned }, #endif #ifdef CONFIG_MMU { EXCCAUSE_ITLB_MISS, 0, do_page_fault }, { EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss}, { EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit }, { EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault }, /* EXCCAUSE_SIZE_RESTRICTION unhandled */ { EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault }, { EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss}, { EXCCAUSE_DTLB_MISS, 0, do_page_fault }, { EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit }, { EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault }, /* EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */ { EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited }, { EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault }, { EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault }, #endif /* CONFIG_MMU */ /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */ #if XTENSA_HAVE_COPROCESSOR(0) COPROCESSOR(0), #endif #if XTENSA_HAVE_COPROCESSOR(1) COPROCESSOR(1), #endif #if XTENSA_HAVE_COPROCESSOR(2) COPROCESSOR(2), #endif #if XTENSA_HAVE_COPROCESSOR(3) COPROCESSOR(3), #endif #if XTENSA_HAVE_COPROCESSOR(4) COPROCESSOR(4), #endif #if XTENSA_HAVE_COPROCESSOR(5) COPROCESSOR(5), #endif #if XTENSA_HAVE_COPROCESSOR(6) COPROCESSOR(6), #endif #if XTENSA_HAVE_COPROCESSOR(7) COPROCESSOR(7), #endif { EXCCAUSE_MAPPED_DEBUG, 0, do_debug }, { -1, -1, 0 } }; /* The exception table <exc_table> serves two functions: * 1. it contains three dispatch tables (fast_user, fast_kernel, default-c) * 2. it is a temporary memory buffer for the exception handlers. */ unsigned long exc_table[EXC_TABLE_SIZE/4]; void die(const char*, struct pt_regs*, long); static inline void __die_if_kernel(const char *str, struct pt_regs *regs, long err) { if (!user_mode(regs)) die(str, regs, err); } /* * Unhandled Exceptions. Kill user task or panic if in kernel space. */ void do_unhandled(struct pt_regs *regs, unsigned long exccause) { __die_if_kernel("Caught unhandled exception - should not happen", regs, SIGKILL); /* If in user mode, send SIGILL signal to current process */ printk("Caught unhandled exception in '%s' " "(pid = %d, pc = %#010lx) - should not happen\n" "\tEXCCAUSE is %ld\n", current->comm, task_pid_nr(current), regs->pc, exccause); force_sig(SIGILL, current); } /* * Multi-hit exception. This if fatal! */ void do_multihit(struct pt_regs *regs, unsigned long exccause) { die("Caught multihit exception", regs, SIGKILL); } /* * Level-1 interrupt. * We currently have no priority encoding. */ unsigned long ignored_level1_interrupts; extern void do_IRQ(int, struct pt_regs *); void do_interrupt (struct pt_regs *regs) { unsigned long intread = get_sr (INTREAD); unsigned long intenable = get_sr (INTENABLE); int i, mask; /* Handle all interrupts (no priorities). * (Clear the interrupt before processing, in case it's * edge-triggered or software-generated) */ for (i=0, mask = 1; i < XCHAL_NUM_INTERRUPTS; i++, mask <<= 1) { if (mask & (intread & intenable)) { set_sr (mask, INTCLEAR); do_IRQ (i,regs); } } } /* * Illegal instruction. Fatal if in kernel space. */ void do_illegal_instruction(struct pt_regs *regs) { __die_if_kernel("Illegal instruction in kernel", regs, SIGKILL); /* If in user mode, send SIGILL signal to current process. */ printk("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n", current->comm, task_pid_nr(current), regs->pc); force_sig(SIGILL, current); } /* * Handle unaligned memory accesses from user space. Kill task. * * If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory * accesses causes from user space. */ #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION #ifndef CONFIG_UNALIGNED_USER void do_unaligned_user (struct pt_regs *regs) { siginfo_t info; __die_if_kernel("Unhandled unaligned exception in kernel", regs, SIGKILL); current->thread.bad_vaddr = regs->excvaddr; current->thread.error_code = -3; printk("Unaligned memory access to %08lx in '%s' " "(pid = %d, pc = %#010lx)\n", regs->excvaddr, current->comm, task_pid_nr(current), regs->pc); info.si_signo = SIGBUS; info.si_errno = 0; info.si_code = BUS_ADRALN; info.si_addr = (void *) regs->excvaddr; force_sig_info(SIGSEGV, &info, current); } #endif #endif void do_debug(struct pt_regs *regs) { #ifdef CONFIG_KGDB /* If remote debugging is configured AND enabled, we give control to * kgdb. Otherwise, we fall through, perhaps giving control to the * native debugger. */ if (gdb_enter) { extern void gdb_handle_exception(struct pt_regs *); gdb_handle_exception(regs); return_from_debug_flag = 1; return; } #endif __die_if_kernel("Breakpoint in kernel", regs, SIGKILL); /* If in user mode, send SIGTRAP signal to current process */ force_sig(SIGTRAP, current); } /* * Initialize dispatch tables. * * The exception vectors are stored compressed the __init section in the * dispatch_init_table. This function initializes the following three tables * from that compressed table: * - fast user first dispatch table for user exceptions * - fast kernel first dispatch table for kernel exceptions * - default C-handler C-handler called by the default fast handler. * * See vectors.S for more details. */ #define set_handler(idx,handler) (exc_table[idx] = (unsigned long) (handler)) void __init trap_init(void) { int i; /* Setup default vectors. */ for(i = 0; i < 64; i++) { set_handler(EXC_TABLE_FAST_USER/4 + i, user_exception); set_handler(EXC_TABLE_FAST_KERNEL/4 + i, kernel_exception); set_handler(EXC_TABLE_DEFAULT/4 + i, do_unhandled); } /* Setup specific handlers. */ for(i = 0; dispatch_init_table[i].cause >= 0; i++) { int fast = dispatch_init_table[i].fast; int cause = dispatch_init_table[i].cause; void *handler = dispatch_init_table[i].handler; if (fast == 0) set_handler (EXC_TABLE_DEFAULT/4 + cause, handler); if (fast && fast & USER) set_handler (EXC_TABLE_FAST_USER/4 + cause, handler); if (fast && fast & KRNL) set_handler (EXC_TABLE_FAST_KERNEL/4 + cause, handler); } /* Initialize EXCSAVE_1 to hold the address of the exception table. */ i = (unsigned long)exc_table; __asm__ __volatile__("wsr %0, "__stringify(EXCSAVE_1)"\n" : : "a" (i)); } /* * This function dumps the current valid window frame and other base registers. */ void show_regs(struct pt_regs * regs) { int i, wmask; wmask = regs->wmask & ~1; for (i = 0; i < 16; i++) { if ((i % 8) == 0) printk ("\n" KERN_INFO "a%02d: ", i); printk("%08lx ", regs->areg[i]); } printk("\n"); printk("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n", regs->pc, regs->ps, regs->depc, regs->excvaddr); printk("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n", regs->lbeg, regs->lend, regs->lcount, regs->sar); if (user_mode(regs)) printk("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n", regs->windowbase, regs->windowstart, regs->wmask, regs->syscall); } void show_trace(struct task_struct *task, unsigned long *sp) { unsigned long a0, a1, pc; unsigned long sp_start, sp_end; if (sp) a1 = (unsigned long)sp; else a1 = task->thread.sp; sp_start = a1 & ~(THREAD_SIZE-1); sp_end = sp_start + THREAD_SIZE; printk("Call Trace:"); #ifdef CONFIG_KALLSYMS printk("\n"); #endif spill_registers(); while (a1 > sp_start && a1 < sp_end) { sp = (unsigned long*)a1; a0 = *(sp - 4); a1 = *(sp - 3); if (a1 <= (unsigned long) sp) break; pc = MAKE_PC_FROM_RA(a0, a1); if (kernel_text_address(pc)) { printk(" [<%08lx>] ", pc); print_symbol("%s\n", pc); } } printk("\n"); } /* * This routine abuses get_user()/put_user() to reference pointers * with at least a bit of error checking ... */ static int kstack_depth_to_print = 24; void show_stack(struct task_struct *task, unsigned long *sp) { int i = 0; unsigned long *stack; if (!sp) sp = (unsigned long *)task->thread.sp; stack = sp; printk("\nStack: "); for (i = 0; i < kstack_depth_to_print; i++) { if (kstack_end(sp)) break; if (i && ((i % 8) == 0)) printk("\n "); printk("%08lx ", *sp++); } printk("\n"); show_trace(task, stack); } void dump_stack(void) { show_stack(current, NULL); } EXPORT_SYMBOL(dump_stack); void show_code(unsigned int *pc) { long i; printk("\nCode:"); for(i = -3 ; i < 6 ; i++) { unsigned long insn; if (__get_user(insn, pc + i)) { printk(" (Bad address in pc)\n"); break; } printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>')); } } DEFINE_SPINLOCK(die_lock); void die(const char * str, struct pt_regs * regs, long err) { static int die_counter; int nl = 0; console_verbose(); spin_lock_irq(&die_lock); printk("%s: sig: %ld [#%d]\n", str, err, ++die_counter); #ifdef CONFIG_PREEMPT printk("PREEMPT "); nl = 1; #endif if (nl) printk("\n"); show_regs(regs); if (!user_mode(regs)) show_stack(NULL, (unsigned long*)regs->areg[1]); add_taint(TAINT_DIE); spin_unlock_irq(&die_lock); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); do_exit(err); }