5a0015d626
The attached patches provides part 3 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
498 lines
12 KiB
C
498 lines
12 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 - 2005 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.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 <asm/ptrace.h>
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#include <asm/timex.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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#ifdef CONFIG_KGDB
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extern int gdb_enter;
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extern int return_from_debug_flag;
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#endif
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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_kernel(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_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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{ XCHAL_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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dispatch_init_table_t __init dispatch_init_table[] = {
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{ XCHAL_EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction},
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{ XCHAL_EXCCAUSE_SYSTEM_CALL, KRNL, fast_syscall_kernel },
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{ XCHAL_EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user },
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{ XCHAL_EXCCAUSE_SYSTEM_CALL, 0, system_call },
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/* XCHAL_EXCCAUSE_INSTRUCTION_FETCH unhandled */
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/* XCHAL_EXCCAUSE_LOAD_STORE_ERROR unhandled*/
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{ XCHAL_EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt },
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{ XCHAL_EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca },
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/* XCHAL_EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */
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/* XCHAL_EXCCAUSE_PRIVILEGED unhandled */
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#if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
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#ifdef CONFIG_UNALIGNED_USER
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{ XCHAL_EXCCAUSE_UNALIGNED, USER, fast_unaligned },
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#else
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{ XCHAL_EXCCAUSE_UNALIGNED, 0, do_unaligned_user },
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#endif
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{ XCHAL_EXCCAUSE_UNALIGNED, KRNL, fast_unaligned },
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#endif
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{ XCHAL_EXCCAUSE_ITLB_MISS, 0, do_page_fault },
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{ XCHAL_EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss},
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{ XCHAL_EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit },
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{ XCHAL_EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault },
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/* XCHAL_EXCCAUSE_SIZE_RESTRICTION unhandled */
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{ XCHAL_EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault },
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{ XCHAL_EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss},
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{ XCHAL_EXCCAUSE_DTLB_MISS, 0, do_page_fault },
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{ XCHAL_EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit },
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{ XCHAL_EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault },
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/* XCHAL_EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */
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{ XCHAL_EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited },
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{ XCHAL_EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault },
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{ XCHAL_EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault },
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/* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */
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#if (XCHAL_CP_MASK & 1)
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COPROCESSOR(0),
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#endif
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#if (XCHAL_CP_MASK & 2)
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COPROCESSOR(1),
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#endif
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#if (XCHAL_CP_MASK & 4)
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COPROCESSOR(2),
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#endif
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#if (XCHAL_CP_MASK & 8)
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COPROCESSOR(3),
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#endif
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#if (XCHAL_CP_MASK & 16)
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COPROCESSOR(4),
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#endif
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#if (XCHAL_CP_MASK & 32)
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COPROCESSOR(5),
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#endif
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#if (XCHAL_CP_MASK & 64)
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COPROCESSOR(6),
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#endif
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#if (XCHAL_CP_MASK & 128)
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COPROCESSOR(7),
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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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unsigned long exc_table[EXC_TABLE_SIZE/4];
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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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printk("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, current->pid, regs->pc, exccause);
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force_sig(SIGILL, current);
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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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* Level-1 interrupt.
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* We currently have no priority encoding.
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*/
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unsigned long ignored_level1_interrupts;
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extern void do_IRQ(int, struct pt_regs *);
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void do_interrupt (struct pt_regs *regs)
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{
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unsigned long intread = get_sr (INTREAD);
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unsigned long intenable = get_sr (INTENABLE);
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int i, mask;
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/* Handle all interrupts (no priorities).
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* (Clear the interrupt before processing, in case it's
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* edge-triggered or software-generated)
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*/
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for (i=0, mask = 1; i < XCHAL_NUM_INTERRUPTS; i++, mask <<= 1) {
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if (mask & (intread & intenable)) {
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set_sr (mask, INTCLEAR);
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do_IRQ (i,regs);
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}
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}
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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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printk("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n",
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current->comm, current->pid, regs->pc);
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force_sig(SIGILL, current);
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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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#ifndef CONFIG_UNALIGNED_USER
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void
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do_unaligned_user (struct pt_regs *regs)
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{
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siginfo_t info;
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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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printk("Unaligned memory access to %08lx in '%s' "
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"(pid = %d, pc = %#010lx)\n",
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regs->excvaddr, current->comm, current->pid, regs->pc);
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info.si_signo = SIGBUS;
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info.si_errno = 0;
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info.si_code = BUS_ADRALN;
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info.si_addr = (void *) regs->excvaddr;
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force_sig_info(SIGSEGV, &info, current);
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}
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#endif
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#endif
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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_KGDB
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/* If remote debugging is configured AND enabled, we give control to
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* kgdb. Otherwise, we fall through, perhaps giving control to the
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* native debugger.
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*/
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if (gdb_enter) {
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extern void gdb_handle_exception(struct pt_regs *);
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gdb_handle_exception(regs);
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return_from_debug_flag = 1;
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return;
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}
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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, current);
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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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#define set_handler(idx,handler) (exc_table[idx] = (unsigned long) (handler))
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void 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 < 64; i++) {
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set_handler(EXC_TABLE_FAST_USER/4 + i, user_exception);
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set_handler(EXC_TABLE_FAST_KERNEL/4 + i, kernel_exception);
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set_handler(EXC_TABLE_DEFAULT/4 + 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 (EXC_TABLE_DEFAULT/4 + cause, handler);
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if (fast && fast & USER)
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set_handler (EXC_TABLE_FAST_USER/4 + cause, handler);
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if (fast && fast & KRNL)
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set_handler (EXC_TABLE_FAST_KERNEL/4 + 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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i = (unsigned long)exc_table;
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__asm__ __volatile__("wsr %0, "__stringify(EXCSAVE_1)"\n" : : "a" (i));
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}
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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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wmask = regs->wmask & ~1;
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for (i = 0; i < 32; i++) {
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if (wmask & (1 << (i / 4)))
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break;
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if ((i % 8) == 0)
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printk ("\n" KERN_INFO "a%02d: ", i);
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printk("%08lx ", regs->areg[i]);
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}
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printk("\n");
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printk("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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printk("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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printk("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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void show_trace(struct task_struct *task, unsigned long *sp)
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{
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unsigned long a0, a1, pc;
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unsigned long sp_start, sp_end;
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a1 = (unsigned long)sp;
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if (a1 == 0)
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__asm__ __volatile__ ("mov %0, a1\n" : "=a"(a1));
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sp_start = a1 & ~(THREAD_SIZE-1);
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sp_end = sp_start + THREAD_SIZE;
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printk("Call Trace:");
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#ifdef CONFIG_KALLSYMS
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printk("\n");
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#endif
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spill_registers();
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while (a1 > sp_start && a1 < sp_end) {
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sp = (unsigned long*)a1;
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a0 = *(sp - 4);
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a1 = *(sp - 3);
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if (a1 <= (unsigned long) sp)
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break;
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pc = MAKE_PC_FROM_RA(a0, a1);
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if (kernel_text_address(pc)) {
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printk(" [<%08lx>] ", pc);
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print_symbol("%s\n", pc);
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}
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}
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printk("\n");
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}
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/*
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* This routine abuses get_user()/put_user() to reference pointers
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* with at least a bit of error checking ...
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*/
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static int kstack_depth_to_print = 24;
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void show_stack(struct task_struct *task, unsigned long *sp)
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{
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int i = 0;
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unsigned long *stack;
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if (sp == 0)
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__asm__ __volatile__ ("mov %0, a1\n" : "=a"(sp));
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stack = sp;
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printk("\nStack: ");
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for (i = 0; i < kstack_depth_to_print; i++) {
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if (kstack_end(sp))
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break;
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if (i && ((i % 8) == 0))
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printk("\n ");
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printk("%08lx ", *sp++);
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}
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printk("\n");
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show_trace(task, stack);
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}
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void dump_stack(void)
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{
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show_stack(current, NULL);
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}
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EXPORT_SYMBOL(dump_stack);
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void show_code(unsigned int *pc)
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{
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long i;
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printk("\nCode:");
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for(i = -3 ; i < 6 ; i++) {
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unsigned long insn;
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if (__get_user(insn, pc + i)) {
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printk(" (Bad address in pc)\n");
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break;
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}
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printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>'));
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}
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}
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spinlock_t die_lock = SPIN_LOCK_UNLOCKED;
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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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int nl = 0;
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console_verbose();
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spin_lock_irq(&die_lock);
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printk("%s: sig: %ld [#%d]\n", str, err, ++die_counter);
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#ifdef CONFIG_PREEMPT
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printk("PREEMPT ");
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nl = 1;
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#endif
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if (nl)
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printk("\n");
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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]);
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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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printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(5 * HZ);
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panic("Fatal exception");
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}
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do_exit(err);
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}
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