[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 <hskinnemoen@atmel.com>
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index 6785572..146ebdb 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -16,26 +16,8 @@
#include <asm/kdebug.h>
#include <asm/mmu_context.h>
#include <asm/sysreg.h>
-#include <asm/uaccess.h>
#include <asm/tlb.h>
-
-#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 <asm/uaccess.h>
#ifdef CONFIG_KPROBES
ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
@@ -68,17 +50,19 @@
}
#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 @@
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 @@
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 @@
* 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 @@
* 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 @@
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 @@
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 @@
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 @@
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);
}
/*