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556 lines
14 KiB
556 lines
14 KiB
/* |
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* arch/xtensa/kernel/traps.c |
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* |
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* Exception handling. |
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* |
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* Derived from code with the following copyrights: |
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* Copyright (C) 1994 - 1999 by Ralf Baechle |
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* Modified for R3000 by Paul M. Antoine, 1995, 1996 |
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* Complete output from die() by Ulf Carlsson, 1998 |
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* Copyright (C) 1999 Silicon Graphics, Inc. |
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* |
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* Essentially rewritten for the Xtensa architecture port. |
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* |
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* Copyright (C) 2001 - 2013 Tensilica Inc. |
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* |
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* Joe Taylor <[email protected], [email protected]> |
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* Chris Zankel <[email protected]> |
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* Marc Gauthier<[email protected], [email protected]> |
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* Kevin Chea |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file "COPYING" in the main directory of this archive |
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* for more details. |
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*/ |
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|
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#include <linux/kernel.h> |
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#include <linux/sched/signal.h> |
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#include <linux/sched/debug.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/stringify.h> |
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#include <linux/kallsyms.h> |
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#include <linux/delay.h> |
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#include <linux/hardirq.h> |
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#include <linux/ratelimit.h> |
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#include <linux/pgtable.h> |
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#include <asm/stacktrace.h> |
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#include <asm/ptrace.h> |
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#include <asm/timex.h> |
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#include <linux/uaccess.h> |
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#include <asm/processor.h> |
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#include <asm/traps.h> |
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#include <asm/hw_breakpoint.h> |
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|
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/* |
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* Machine specific interrupt handlers |
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*/ |
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extern void kernel_exception(void); |
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extern void user_exception(void); |
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extern void fast_illegal_instruction_user(void); |
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extern void fast_syscall_user(void); |
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extern void fast_alloca(void); |
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extern void fast_unaligned(void); |
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extern void fast_second_level_miss(void); |
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extern void fast_store_prohibited(void); |
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extern void fast_coprocessor(void); |
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extern void do_illegal_instruction (struct pt_regs*); |
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extern void do_interrupt (struct pt_regs*); |
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extern void do_nmi(struct pt_regs *); |
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extern void do_unaligned_user (struct pt_regs*); |
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extern void do_multihit (struct pt_regs*, unsigned long); |
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extern void do_page_fault (struct pt_regs*, unsigned long); |
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extern void do_debug (struct pt_regs*); |
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extern void system_call (struct pt_regs*); |
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/* |
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* The vector table must be preceded by a save area (which |
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* implies it must be in RAM, unless one places RAM immediately |
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* before a ROM and puts the vector at the start of the ROM (!)) |
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*/ |
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#define KRNL 0x01 |
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#define USER 0x02 |
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#define COPROCESSOR(x) \ |
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{ EXCCAUSE_COPROCESSOR ## x ## _DISABLED, USER, fast_coprocessor } |
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typedef struct { |
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int cause; |
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int fast; |
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void* handler; |
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} dispatch_init_table_t; |
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static dispatch_init_table_t __initdata dispatch_init_table[] = { |
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#ifdef CONFIG_USER_ABI_CALL0_PROBE |
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{ EXCCAUSE_ILLEGAL_INSTRUCTION, USER, fast_illegal_instruction_user }, |
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#endif |
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{ EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction}, |
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{ EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user }, |
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{ EXCCAUSE_SYSTEM_CALL, 0, system_call }, |
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/* EXCCAUSE_INSTRUCTION_FETCH unhandled */ |
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/* EXCCAUSE_LOAD_STORE_ERROR unhandled*/ |
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{ EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt }, |
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{ EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca }, |
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/* EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */ |
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/* EXCCAUSE_PRIVILEGED unhandled */ |
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#if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION |
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#ifdef CONFIG_XTENSA_UNALIGNED_USER |
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{ EXCCAUSE_UNALIGNED, USER, fast_unaligned }, |
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#endif |
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{ EXCCAUSE_UNALIGNED, 0, do_unaligned_user }, |
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{ EXCCAUSE_UNALIGNED, KRNL, fast_unaligned }, |
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#endif |
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#ifdef CONFIG_MMU |
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{ EXCCAUSE_ITLB_MISS, 0, do_page_fault }, |
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{ EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss}, |
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{ EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit }, |
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{ EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault }, |
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/* EXCCAUSE_SIZE_RESTRICTION unhandled */ |
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{ EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault }, |
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{ EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss}, |
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{ EXCCAUSE_DTLB_MISS, 0, do_page_fault }, |
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{ EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit }, |
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{ EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault }, |
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/* EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */ |
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{ EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited }, |
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{ EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault }, |
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{ EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault }, |
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#endif /* CONFIG_MMU */ |
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/* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */ |
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#if XTENSA_HAVE_COPROCESSOR(0) |
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COPROCESSOR(0), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(1) |
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COPROCESSOR(1), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(2) |
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COPROCESSOR(2), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(3) |
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COPROCESSOR(3), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(4) |
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COPROCESSOR(4), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(5) |
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COPROCESSOR(5), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(6) |
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COPROCESSOR(6), |
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#endif |
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#if XTENSA_HAVE_COPROCESSOR(7) |
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COPROCESSOR(7), |
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#endif |
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#if XTENSA_FAKE_NMI |
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{ EXCCAUSE_MAPPED_NMI, 0, do_nmi }, |
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#endif |
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{ EXCCAUSE_MAPPED_DEBUG, 0, do_debug }, |
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{ -1, -1, 0 } |
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}; |
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/* The exception table <exc_table> serves two functions: |
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* 1. it contains three dispatch tables (fast_user, fast_kernel, default-c) |
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* 2. it is a temporary memory buffer for the exception handlers. |
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*/ |
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DEFINE_PER_CPU(struct exc_table, exc_table); |
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DEFINE_PER_CPU(struct debug_table, debug_table); |
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void die(const char*, struct pt_regs*, long); |
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static inline void |
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__die_if_kernel(const char *str, struct pt_regs *regs, long err) |
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{ |
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if (!user_mode(regs)) |
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die(str, regs, err); |
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} |
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/* |
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* Unhandled Exceptions. Kill user task or panic if in kernel space. |
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*/ |
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void do_unhandled(struct pt_regs *regs, unsigned long exccause) |
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{ |
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__die_if_kernel("Caught unhandled exception - should not happen", |
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regs, SIGKILL); |
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/* If in user mode, send SIGILL signal to current process */ |
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pr_info_ratelimited("Caught unhandled exception in '%s' " |
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"(pid = %d, pc = %#010lx) - should not happen\n" |
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"\tEXCCAUSE is %ld\n", |
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current->comm, task_pid_nr(current), regs->pc, |
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exccause); |
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force_sig(SIGILL); |
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} |
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/* |
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* Multi-hit exception. This if fatal! |
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*/ |
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void do_multihit(struct pt_regs *regs, unsigned long exccause) |
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{ |
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die("Caught multihit exception", regs, SIGKILL); |
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} |
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/* |
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* IRQ handler. |
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*/ |
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extern void do_IRQ(int, struct pt_regs *); |
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#if XTENSA_FAKE_NMI |
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#define IS_POW2(v) (((v) & ((v) - 1)) == 0) |
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#if !(PROFILING_INTLEVEL == XCHAL_EXCM_LEVEL && \ |
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IS_POW2(XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL))) |
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#warning "Fake NMI is requested for PMM, but there are other IRQs at or above its level." |
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#warning "Fake NMI will be used, but there will be a bugcheck if one of those IRQs fire." |
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static inline void check_valid_nmi(void) |
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{ |
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unsigned intread = xtensa_get_sr(interrupt); |
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unsigned intenable = xtensa_get_sr(intenable); |
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BUG_ON(intread & intenable & |
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~(XTENSA_INTLEVEL_ANDBELOW_MASK(PROFILING_INTLEVEL) ^ |
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XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL) ^ |
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BIT(XCHAL_PROFILING_INTERRUPT))); |
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} |
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#else |
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static inline void check_valid_nmi(void) |
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{ |
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} |
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#endif |
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irqreturn_t xtensa_pmu_irq_handler(int irq, void *dev_id); |
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DEFINE_PER_CPU(unsigned long, nmi_count); |
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void do_nmi(struct pt_regs *regs) |
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{ |
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struct pt_regs *old_regs; |
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if ((regs->ps & PS_INTLEVEL_MASK) < LOCKLEVEL) |
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trace_hardirqs_off(); |
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old_regs = set_irq_regs(regs); |
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nmi_enter(); |
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++*this_cpu_ptr(&nmi_count); |
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check_valid_nmi(); |
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xtensa_pmu_irq_handler(0, NULL); |
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nmi_exit(); |
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set_irq_regs(old_regs); |
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} |
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#endif |
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void do_interrupt(struct pt_regs *regs) |
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{ |
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static const unsigned int_level_mask[] = { |
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0, |
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XCHAL_INTLEVEL1_MASK, |
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XCHAL_INTLEVEL2_MASK, |
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XCHAL_INTLEVEL3_MASK, |
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XCHAL_INTLEVEL4_MASK, |
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XCHAL_INTLEVEL5_MASK, |
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XCHAL_INTLEVEL6_MASK, |
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XCHAL_INTLEVEL7_MASK, |
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}; |
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struct pt_regs *old_regs; |
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unsigned unhandled = ~0u; |
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trace_hardirqs_off(); |
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old_regs = set_irq_regs(regs); |
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irq_enter(); |
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for (;;) { |
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unsigned intread = xtensa_get_sr(interrupt); |
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unsigned intenable = xtensa_get_sr(intenable); |
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unsigned int_at_level = intread & intenable; |
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unsigned level; |
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for (level = LOCKLEVEL; level > 0; --level) { |
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if (int_at_level & int_level_mask[level]) { |
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int_at_level &= int_level_mask[level]; |
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if (int_at_level & unhandled) |
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int_at_level &= unhandled; |
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else |
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unhandled |= int_level_mask[level]; |
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break; |
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} |
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} |
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if (level == 0) |
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break; |
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/* clear lowest pending irq in the unhandled mask */ |
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unhandled ^= (int_at_level & -int_at_level); |
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do_IRQ(__ffs(int_at_level), regs); |
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} |
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irq_exit(); |
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set_irq_regs(old_regs); |
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} |
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/* |
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* Illegal instruction. Fatal if in kernel space. |
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*/ |
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void |
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do_illegal_instruction(struct pt_regs *regs) |
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{ |
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__die_if_kernel("Illegal instruction in kernel", regs, SIGKILL); |
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/* If in user mode, send SIGILL signal to current process. */ |
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pr_info_ratelimited("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n", |
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current->comm, task_pid_nr(current), regs->pc); |
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force_sig(SIGILL); |
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} |
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/* |
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* Handle unaligned memory accesses from user space. Kill task. |
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* |
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* If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory |
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* accesses causes from user space. |
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*/ |
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#if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION |
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void |
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do_unaligned_user (struct pt_regs *regs) |
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{ |
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__die_if_kernel("Unhandled unaligned exception in kernel", |
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regs, SIGKILL); |
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current->thread.bad_vaddr = regs->excvaddr; |
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current->thread.error_code = -3; |
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pr_info_ratelimited("Unaligned memory access to %08lx in '%s' " |
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"(pid = %d, pc = %#010lx)\n", |
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regs->excvaddr, current->comm, |
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task_pid_nr(current), regs->pc); |
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force_sig_fault(SIGBUS, BUS_ADRALN, (void *) regs->excvaddr); |
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} |
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#endif |
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/* Handle debug events. |
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* When CONFIG_HAVE_HW_BREAKPOINT is on this handler is called with |
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* preemption disabled to avoid rescheduling and keep mapping of hardware |
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* breakpoint structures to debug registers intact, so that |
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* DEBUGCAUSE.DBNUM could be used in case of data breakpoint hit. |
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*/ |
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void |
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do_debug(struct pt_regs *regs) |
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{ |
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#ifdef CONFIG_HAVE_HW_BREAKPOINT |
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int ret = check_hw_breakpoint(regs); |
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preempt_enable(); |
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if (ret == 0) |
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return; |
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#endif |
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__die_if_kernel("Breakpoint in kernel", regs, SIGKILL); |
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/* If in user mode, send SIGTRAP signal to current process */ |
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force_sig(SIGTRAP); |
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} |
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#define set_handler(type, cause, handler) \ |
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do { \ |
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unsigned int cpu; \ |
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\ |
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for_each_possible_cpu(cpu) \ |
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per_cpu(exc_table, cpu).type[cause] = (handler);\ |
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} while (0) |
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/* Set exception C handler - for temporary use when probing exceptions */ |
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void * __init trap_set_handler(int cause, void *handler) |
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{ |
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void *previous = per_cpu(exc_table, 0).default_handler[cause]; |
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set_handler(default_handler, cause, handler); |
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return previous; |
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} |
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static void trap_init_excsave(void) |
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{ |
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unsigned long excsave1 = (unsigned long)this_cpu_ptr(&exc_table); |
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__asm__ __volatile__("wsr %0, excsave1\n" : : "a" (excsave1)); |
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} |
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static void trap_init_debug(void) |
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{ |
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unsigned long debugsave = (unsigned long)this_cpu_ptr(&debug_table); |
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this_cpu_ptr(&debug_table)->debug_exception = debug_exception; |
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__asm__ __volatile__("wsr %0, excsave" __stringify(XCHAL_DEBUGLEVEL) |
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:: "a"(debugsave)); |
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} |
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/* |
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* Initialize dispatch tables. |
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* |
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* The exception vectors are stored compressed the __init section in the |
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* dispatch_init_table. This function initializes the following three tables |
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* from that compressed table: |
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* - fast user first dispatch table for user exceptions |
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* - fast kernel first dispatch table for kernel exceptions |
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* - default C-handler C-handler called by the default fast handler. |
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* |
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* See vectors.S for more details. |
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*/ |
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void __init trap_init(void) |
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{ |
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int i; |
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/* Setup default vectors. */ |
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for (i = 0; i < EXCCAUSE_N; i++) { |
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set_handler(fast_user_handler, i, user_exception); |
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set_handler(fast_kernel_handler, i, kernel_exception); |
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set_handler(default_handler, i, do_unhandled); |
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} |
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/* Setup specific handlers. */ |
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for(i = 0; dispatch_init_table[i].cause >= 0; i++) { |
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int fast = dispatch_init_table[i].fast; |
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int cause = dispatch_init_table[i].cause; |
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void *handler = dispatch_init_table[i].handler; |
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if (fast == 0) |
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set_handler(default_handler, cause, handler); |
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if ((fast & USER) != 0) |
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set_handler(fast_user_handler, cause, handler); |
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if ((fast & KRNL) != 0) |
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set_handler(fast_kernel_handler, cause, handler); |
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} |
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/* Initialize EXCSAVE_1 to hold the address of the exception table. */ |
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trap_init_excsave(); |
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trap_init_debug(); |
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} |
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#ifdef CONFIG_SMP |
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void secondary_trap_init(void) |
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{ |
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trap_init_excsave(); |
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trap_init_debug(); |
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} |
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#endif |
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/* |
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* This function dumps the current valid window frame and other base registers. |
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*/ |
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void show_regs(struct pt_regs * regs) |
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{ |
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int i, wmask; |
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show_regs_print_info(KERN_DEFAULT); |
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wmask = regs->wmask & ~1; |
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for (i = 0; i < 16; i++) { |
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if ((i % 8) == 0) |
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pr_info("a%02d:", i); |
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pr_cont(" %08lx", regs->areg[i]); |
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} |
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pr_cont("\n"); |
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pr_info("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n", |
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regs->pc, regs->ps, regs->depc, regs->excvaddr); |
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pr_info("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n", |
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regs->lbeg, regs->lend, regs->lcount, regs->sar); |
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if (user_mode(regs)) |
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pr_cont("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n", |
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regs->windowbase, regs->windowstart, regs->wmask, |
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regs->syscall); |
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} |
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static int show_trace_cb(struct stackframe *frame, void *data) |
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{ |
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const char *loglvl = data; |
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if (kernel_text_address(frame->pc)) |
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printk("%s [<%08lx>] %pB\n", |
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loglvl, frame->pc, (void *)frame->pc); |
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return 0; |
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} |
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static void show_trace(struct task_struct *task, unsigned long *sp, |
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const char *loglvl) |
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{ |
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if (!sp) |
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sp = stack_pointer(task); |
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printk("%sCall Trace:\n", loglvl); |
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walk_stackframe(sp, show_trace_cb, (void *)loglvl); |
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} |
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#define STACK_DUMP_ENTRY_SIZE 4 |
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#define STACK_DUMP_LINE_SIZE 32 |
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static size_t kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; |
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void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) |
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{ |
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size_t len; |
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if (!sp) |
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sp = stack_pointer(task); |
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len = min((-(size_t)sp) & (THREAD_SIZE - STACK_DUMP_ENTRY_SIZE), |
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kstack_depth_to_print * STACK_DUMP_ENTRY_SIZE); |
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printk("%sStack:\n", loglvl); |
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print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE, |
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STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE, |
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sp, len, false); |
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show_trace(task, sp, loglvl); |
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} |
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DEFINE_SPINLOCK(die_lock); |
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void die(const char * str, struct pt_regs * regs, long err) |
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{ |
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static int die_counter; |
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const char *pr = ""; |
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if (IS_ENABLED(CONFIG_PREEMPTION)) |
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pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT"; |
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console_verbose(); |
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spin_lock_irq(&die_lock); |
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pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter, pr); |
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show_regs(regs); |
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if (!user_mode(regs)) |
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show_stack(NULL, (unsigned long *)regs->areg[1], KERN_INFO); |
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); |
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spin_unlock_irq(&die_lock); |
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if (in_interrupt()) |
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panic("Fatal exception in interrupt"); |
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if (panic_on_oops) |
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panic("Fatal exception"); |
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do_exit(err); |
|
}
|
|
|