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![Jim Wilson](/assets/img/avatar_default.png)
Adding 4 to sepc is pointless, and is wrong if we executed a 2-byte compressed breakpoint. This plus a corresponding gdb patch allows compressed breakpoints to work in gdb. Gdb maintainers have already agreed that this is the right approach. Signed-off-by: Jim Wilson <jimw@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
167 lines
4.4 KiB
C
167 lines
4.4 KiB
C
/*
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* Copyright (C) 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/sched/signal.h>
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#include <linux/signal.h>
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#include <linux/kdebug.h>
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#include <linux/uaccess.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/irq.h>
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#include <asm/processor.h>
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#include <asm/ptrace.h>
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#include <asm/csr.h>
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int show_unhandled_signals = 1;
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extern asmlinkage void handle_exception(void);
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static DEFINE_SPINLOCK(die_lock);
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void die(struct pt_regs *regs, const char *str)
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{
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static int die_counter;
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int ret;
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oops_enter();
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spin_lock_irq(&die_lock);
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console_verbose();
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bust_spinlocks(1);
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pr_emerg("%s [#%d]\n", str, ++die_counter);
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print_modules();
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show_regs(regs);
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ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, SIGSEGV);
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bust_spinlocks(0);
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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spin_unlock_irq(&die_lock);
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oops_exit();
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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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if (ret != NOTIFY_STOP)
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do_exit(SIGSEGV);
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}
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void do_trap(struct pt_regs *regs, int signo, int code,
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unsigned long addr, struct task_struct *tsk)
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{
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if (show_unhandled_signals && unhandled_signal(tsk, signo)
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&& printk_ratelimit()) {
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pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
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tsk->comm, task_pid_nr(tsk), signo, code, addr);
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print_vma_addr(KERN_CONT " in ", GET_IP(regs));
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pr_cont("\n");
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show_regs(regs);
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}
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force_sig_fault(signo, code, (void __user *)addr, tsk);
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}
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static void do_trap_error(struct pt_regs *regs, int signo, int code,
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unsigned long addr, const char *str)
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{
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if (user_mode(regs)) {
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do_trap(regs, signo, code, addr, current);
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} else {
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if (!fixup_exception(regs))
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die(regs, str);
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}
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}
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#define DO_ERROR_INFO(name, signo, code, str) \
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asmlinkage void name(struct pt_regs *regs) \
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{ \
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do_trap_error(regs, signo, code, regs->sepc, "Oops - " str); \
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}
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DO_ERROR_INFO(do_trap_unknown,
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SIGILL, ILL_ILLTRP, "unknown exception");
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DO_ERROR_INFO(do_trap_insn_misaligned,
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SIGBUS, BUS_ADRALN, "instruction address misaligned");
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DO_ERROR_INFO(do_trap_insn_fault,
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SIGSEGV, SEGV_ACCERR, "instruction access fault");
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DO_ERROR_INFO(do_trap_insn_illegal,
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SIGILL, ILL_ILLOPC, "illegal instruction");
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DO_ERROR_INFO(do_trap_load_misaligned,
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SIGBUS, BUS_ADRALN, "load address misaligned");
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DO_ERROR_INFO(do_trap_load_fault,
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SIGSEGV, SEGV_ACCERR, "load access fault");
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DO_ERROR_INFO(do_trap_store_misaligned,
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SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
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DO_ERROR_INFO(do_trap_store_fault,
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SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
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DO_ERROR_INFO(do_trap_ecall_u,
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SIGILL, ILL_ILLTRP, "environment call from U-mode");
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DO_ERROR_INFO(do_trap_ecall_s,
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SIGILL, ILL_ILLTRP, "environment call from S-mode");
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DO_ERROR_INFO(do_trap_ecall_m,
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SIGILL, ILL_ILLTRP, "environment call from M-mode");
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asmlinkage void do_trap_break(struct pt_regs *regs)
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{
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#ifdef CONFIG_GENERIC_BUG
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if (!user_mode(regs)) {
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enum bug_trap_type type;
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type = report_bug(regs->sepc, regs);
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switch (type) {
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case BUG_TRAP_TYPE_NONE:
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break;
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case BUG_TRAP_TYPE_WARN:
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regs->sepc += sizeof(bug_insn_t);
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return;
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case BUG_TRAP_TYPE_BUG:
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die(regs, "Kernel BUG");
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}
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}
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#endif /* CONFIG_GENERIC_BUG */
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force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current);
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}
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#ifdef CONFIG_GENERIC_BUG
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int is_valid_bugaddr(unsigned long pc)
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{
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bug_insn_t insn;
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if (pc < PAGE_OFFSET)
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return 0;
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if (probe_kernel_address((bug_insn_t *)pc, insn))
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return 0;
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return (insn == __BUG_INSN);
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}
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#endif /* CONFIG_GENERIC_BUG */
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void __init trap_init(void)
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{
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/*
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* Set sup0 scratch register to 0, indicating to exception vector
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* that we are presently executing in the kernel
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*/
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csr_write(sscratch, 0);
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/* Set the exception vector address */
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csr_write(stvec, &handle_exception);
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/* Enable all interrupts */
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csr_write(sie, -1);
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}
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