From 623b0355d5b1f9c6d05005b649a2f3a7b9fd7816 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 13 Mar 2007 17:59:11 +0100 Subject: [AVR32] Clean up exception handling code * Use generic BUG() handling * Remove some useless debug statements * Use a common function _exception() to send signals or oops when an exception can't be handled. This makes sure init doesn't enter an infinite exception loop as well. Borrowed from powerpc. * Add some basic exception tracing support to the page fault code. * Rework dump_stack(), show_regs() and friends and move everything into process.c * Print information about configuration options and chip type when oopsing Signed-off-by: Haavard Skinnemoen --- arch/avr32/mm/fault.c | 116 ++++++++++++++++++-------------------------------- 1 file changed, 41 insertions(+), 75 deletions(-) (limited to 'arch/avr32/mm') diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c index 678557260a3..146ebdbdc30 100644 --- a/arch/avr32/mm/fault.c +++ b/arch/avr32/mm/fault.c @@ -16,26 +16,8 @@ #include #include #include -#include #include - -#ifdef DEBUG -static void dump_code(unsigned long pc) -{ - char *p = (char *)pc; - char val; - int i; - - - printk(KERN_DEBUG "Code:"); - for (i = 0; i < 16; i++) { - if (__get_user(val, p + i)) - break; - printk(" %02x", val); - } - printk("\n"); -} -#endif +#include #ifdef CONFIG_KPROBES ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); @@ -68,17 +50,19 @@ static inline int notify_page_fault(enum die_val val, struct pt_regs *regs, } #endif +int exception_trace = 1; + /* * This routine handles page faults. It determines the address and the * problem, and then passes it off to one of the appropriate routines. * * ecr is the Exception Cause Register. Possible values are: - * 5: Page not found (instruction access) * 6: Protection fault (instruction access) - * 12: Page not found (read access) - * 13: Page not found (write access) - * 14: Protection fault (read access) - * 15: Protection fault (write access) + * 15: Protection fault (read access) + * 16: Protection fault (write access) + * 20: Page not found (instruction access) + * 24: Page not found (read access) + * 28: Page not found (write access) */ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) { @@ -88,7 +72,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) const struct exception_table_entry *fixup; unsigned long address; unsigned long page; - int writeaccess = 0; + int writeaccess; + long signr; + int code; if (notify_page_fault(DIE_PAGE_FAULT, regs, ecr, SIGSEGV) == NOTIFY_STOP) @@ -99,6 +85,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) tsk = current; mm = tsk->mm; + signr = SIGSEGV; + code = SEGV_MAPERR; + /* * If we're in an interrupt or have no user context, we must * not take the fault... @@ -125,7 +114,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) * can handle it... */ good_area: - //pr_debug("good area: vm_flags = 0x%lx\n", vma->vm_flags); + code = SEGV_ACCERR; + writeaccess = 0; + switch (ecr) { case ECR_PROTECTION_X: case ECR_TLB_MISS_X: @@ -176,46 +167,24 @@ survive: * map. Fix it, but check if it's kernel or user first... */ bad_area: - pr_debug("Bad area [%s:%u]: addr %08lx, ecr %lu\n", - tsk->comm, tsk->pid, address, ecr); - up_read(&mm->mmap_sem); if (user_mode(regs)) { - /* Hmm...we have to pass address and ecr somehow... */ - /* tsk->thread.address = address; - tsk->thread.error_code = ecr; */ -#ifdef DEBUG - show_regs(regs); - dump_code(regs->pc); - - page = sysreg_read(PTBR); - printk("ptbr = %08lx", page); - if (page) { - page = ((unsigned long *)page)[address >> 22]; - printk(" pgd = %08lx", page); - if (page & _PAGE_PRESENT) { - page &= PAGE_MASK; - address &= 0x003ff000; - page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT]; - printk(" pte = %08lx\n", page); - } - } -#endif - pr_debug("Sending SIGSEGV to PID %d...\n", - tsk->pid); - force_sig(SIGSEGV, tsk); + if (exception_trace) + printk("%s%s[%d]: segfault at %08lx pc %08lx " + "sp %08lx ecr %lu\n", + is_init(tsk) ? KERN_EMERG : KERN_INFO, + tsk->comm, tsk->pid, address, regs->pc, + regs->sp, ecr); + _exception(SIGSEGV, regs, code, address); return; } no_context: - pr_debug("No context\n"); - /* Are we prepared to handle this kernel fault? */ fixup = search_exception_tables(regs->pc); if (fixup) { regs->pc = fixup->fixup; - pr_debug("Found fixup at %08lx\n", fixup->fixup); return; } @@ -230,7 +199,6 @@ no_context: printk(KERN_ALERT "Unable to handle kernel paging request"); printk(" at virtual address %08lx\n", address); - printk(KERN_ALERT "pc = %08lx\n", regs->pc); page = sysreg_read(PTBR); printk(KERN_ALERT "ptbr = %08lx", page); @@ -241,20 +209,20 @@ no_context: page &= PAGE_MASK; address &= 0x003ff000; page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT]; - printk(" pte = %08lx\n", page); + printk(" pte = %08lx", page); } } - die("\nOops", regs, ecr); - do_exit(SIGKILL); + printk("\n"); + die("Kernel access of bad area", regs, signr); + return; /* * We ran out of memory, or some other thing happened to us * that made us unable to handle the page fault gracefully. */ out_of_memory: - printk("Out of memory\n"); up_read(&mm->mmap_sem); - if (current->pid == 1) { + if (is_init(current)) { yield(); down_read(&mm->mmap_sem); goto survive; @@ -267,21 +235,20 @@ out_of_memory: do_sigbus: up_read(&mm->mmap_sem); - /* - * Send a sigbus, regardless of whether we were in kernel or - * user mode. - */ - /* address, error_code, trap_no, ... */ -#ifdef DEBUG - show_regs(regs); - dump_code(regs->pc); -#endif - pr_debug("Sending SIGBUS to PID %d...\n", tsk->pid); - force_sig(SIGBUS, tsk); - /* Kernel mode? Handle exceptions or die */ + signr = SIGBUS; + code = BUS_ADRERR; if (!user_mode(regs)) goto no_context; + + if (exception_trace) + printk("%s%s[%d]: bus error at %08lx pc %08lx " + "sp %08lx ecr %lu\n", + is_init(tsk) ? KERN_EMERG : KERN_INFO, + tsk->comm, tsk->pid, address, regs->pc, + regs->sp, ecr); + + _exception(SIGBUS, regs, BUS_ADRERR, address); } asmlinkage void do_bus_error(unsigned long addr, int write_access, @@ -292,8 +259,7 @@ asmlinkage void do_bus_error(unsigned long addr, int write_access, addr, write_access ? "write" : "read"); printk(KERN_INFO "DTLB dump:\n"); dump_dtlb(); - die("Bus Error", regs, write_access); - do_exit(SIGKILL); + die("Bus Error", regs, SIGKILL); } /* -- cgit v1.2.3-70-g09d2