![Eric W. Biederman](/assets/img/avatar_default.png)
As synchronous exceptions really only make sense against the current task (otherwise how are you synchronous) remove the task parameter from from force_sig_fault to make it explicit that is what is going on. The two known exceptions that deliver a synchronous exception to a stopped ptraced task have already been changed to force_sig_fault_to_task. The callers have been changed with the following emacs regular expression (with obvious variations on the architectures that take more arguments) to avoid typos: force_sig_fault[(]\([^,]+\)[,]\([^,]+\)[,]\([^,]+\)[,]\W+current[)] -> force_sig_fault(\1,\2,\3) Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
544 lines
14 KiB
C
544 lines
14 KiB
C
/*
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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 <joe@tensilica.com, joetylr@yahoo.com>
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* Chris Zankel <chris@zankel.net>
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* Marc Gauthier<marc@tensilica.com, marc@alumni.uwaterloo.ca>
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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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#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 <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/pgtable.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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* 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_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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{ 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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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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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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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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if (kernel_text_address(frame->pc))
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pr_cont(" [<%08lx>] %pB\n", frame->pc, (void *)frame->pc);
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return 0;
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}
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void show_trace(struct task_struct *task, unsigned long *sp)
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{
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if (!sp)
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sp = stack_pointer(task);
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pr_info("Call Trace:\n");
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walk_stackframe(sp, show_trace_cb, NULL);
|
|
#ifndef CONFIG_KALLSYMS
|
|
pr_cont("\n");
|
|
#endif
|
|
}
|
|
|
|
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;
|
|
|
|
pr_info("Stack:\n");
|
|
|
|
for (i = 0; i < kstack_depth_to_print; i++) {
|
|
if (kstack_end(sp))
|
|
break;
|
|
pr_cont(" %08lx", *sp++);
|
|
if (i % 8 == 7)
|
|
pr_cont("\n");
|
|
}
|
|
show_trace(task, stack);
|
|
}
|
|
|
|
DEFINE_SPINLOCK(die_lock);
|
|
|
|
void die(const char * str, struct pt_regs * regs, long err)
|
|
{
|
|
static int die_counter;
|
|
|
|
console_verbose();
|
|
spin_lock_irq(&die_lock);
|
|
|
|
pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter,
|
|
IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "");
|
|
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);
|
|
}
|