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Diffstat (limited to 'arch/xtensa/kernel/traps.c')
| -rw-r--r-- | arch/xtensa/kernel/traps.c | 517 |
1 files changed, 517 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c new file mode 100644 index 000000000..9d2f45f01 --- /dev/null +++ b/arch/xtensa/kernel/traps.c @@ -0,0 +1,517 @@ +/* + * 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 - 2013 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/stacktrace.h> +#include <asm/ptrace.h> +#include <asm/timex.h> +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/processor.h> +#include <asm/traps.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_XTENSA_UNALIGNED_USER +{ EXCCAUSE_UNALIGNED, USER, fast_unaligned }, +#endif +{ EXCCAUSE_UNALIGNED, 0, do_unaligned_user }, +{ 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. + */ + +DEFINE_PER_CPU(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); +} + +/* + * IRQ handler. + */ + +extern void do_IRQ(int, struct pt_regs *); + +void do_interrupt(struct pt_regs *regs) +{ + static const unsigned int_level_mask[] = { + 0, + XCHAL_INTLEVEL1_MASK, + XCHAL_INTLEVEL2_MASK, + XCHAL_INTLEVEL3_MASK, + XCHAL_INTLEVEL4_MASK, + XCHAL_INTLEVEL5_MASK, + XCHAL_INTLEVEL6_MASK, + XCHAL_INTLEVEL7_MASK, + }; + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + + for (;;) { + unsigned intread = get_sr(interrupt); + unsigned intenable = get_sr(intenable); + unsigned int_at_level = intread & intenable; + unsigned level; + + for (level = LOCKLEVEL; level > 0; --level) { + if (int_at_level & int_level_mask[level]) { + int_at_level &= int_level_mask[level]; + break; + } + } + + if (level == 0) + break; + + do_IRQ(__ffs(int_at_level), regs); + } + + irq_exit(); + set_irq_regs(old_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 +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 + +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); +} + + +static void set_handler(int idx, void *handler) +{ + unsigned int cpu; + + for_each_possible_cpu(cpu) + per_cpu(exc_table, cpu)[idx] = (unsigned long)handler; +} + +/* Set exception C handler - for temporary use when probing exceptions */ + +void * __init trap_set_handler(int cause, void *handler) +{ + void *previous = (void *)per_cpu(exc_table, 0)[ + EXC_TABLE_DEFAULT / 4 + cause]; + set_handler(EXC_TABLE_DEFAULT / 4 + cause, handler); + return previous; +} + + +static void trap_init_excsave(void) +{ + unsigned long excsave1 = (unsigned long)this_cpu_ptr(exc_table); + __asm__ __volatile__("wsr %0, excsave1\n" : : "a" (excsave1)); +} + +/* + * 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. + */ + +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. */ + trap_init_excsave(); +} + +#ifdef CONFIG_SMP +void secondary_trap_init(void) +{ + trap_init_excsave(); +} +#endif + +/* + * This function dumps the current valid window frame and other base registers. + */ + +void show_regs(struct pt_regs * regs) +{ + int i, wmask; + + show_regs_print_info(KERN_DEFAULT); + + wmask = regs->wmask & ~1; + + for (i = 0; i < 16; i++) { + if ((i % 8) == 0) + printk(KERN_INFO "a%02d:", i); + printk(KERN_CONT " %08lx", regs->areg[i]); + } + printk(KERN_CONT "\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); +} + +static int show_trace_cb(struct stackframe *frame, void *data) +{ + if (kernel_text_address(frame->pc)) { + printk(" [<%08lx>] ", frame->pc); + print_symbol("%s\n", frame->pc); + } + return 0; +} + +void show_trace(struct task_struct *task, unsigned long *sp) +{ + if (!sp) + sp = stack_pointer(task); + + printk("Call Trace:"); +#ifdef CONFIG_KALLSYMS + printk("\n"); +#endif + walk_stackframe(sp, show_trace_cb, NULL); + 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 = stack_pointer(task); + 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 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, LOCKDEP_NOW_UNRELIABLE); + spin_unlock_irq(&die_lock); + + if (in_interrupt()) + panic("Fatal exception in interrupt"); + + if (panic_on_oops) + panic("Fatal exception"); + + do_exit(err); +} |