[PATCH] i386: Do better early exception handlers
Add early i386 fault handlers with debug information for common faults.
Handles:
divide error
invalid opcode
protection fault
page fault
Also adds code to detect early recursive/multiple faults and halt the
system when they happen (taken from x86_64.)
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index a6b8bd8..be9d883 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -371,8 +371,65 @@
addl $8,%edi
dec %ecx
jne rp_sidt
+
+.macro set_early_handler handler,trapno
+ lea \handler,%edx
+ movl $(__KERNEL_CS << 16),%eax
+ movw %dx,%ax
+ movw $0x8E00,%dx /* interrupt gate - dpl=0, present */
+ lea idt_table,%edi
+ movl %eax,8*\trapno(%edi)
+ movl %edx,8*\trapno+4(%edi)
+.endm
+
+ set_early_handler handler=early_divide_err,trapno=0
+ set_early_handler handler=early_illegal_opcode,trapno=6
+ set_early_handler handler=early_protection_fault,trapno=13
+ set_early_handler handler=early_page_fault,trapno=14
+
ret
+early_divide_err:
+ xor %edx,%edx
+ pushl $0 /* fake errcode */
+ jmp early_fault
+
+early_illegal_opcode:
+ movl $6,%edx
+ pushl $0 /* fake errcode */
+ jmp early_fault
+
+early_protection_fault:
+ movl $13,%edx
+ jmp early_fault
+
+early_page_fault:
+ movl $14,%edx
+ jmp early_fault
+
+early_fault:
+ cld
+#ifdef CONFIG_PRINTK
+ movl $(__KERNEL_DS),%eax
+ movl %eax,%ds
+ movl %eax,%es
+ cmpl $2,early_recursion_flag
+ je hlt_loop
+ incl early_recursion_flag
+ movl %cr2,%eax
+ pushl %eax
+ pushl %edx /* trapno */
+ pushl $fault_msg
+#ifdef CONFIG_EARLY_PRINTK
+ call early_printk
+#else
+ call printk
+#endif
+#endif
+hlt_loop:
+ hlt
+ jmp hlt_loop
+
/* This is the default interrupt "handler" :-) */
ALIGN
ignore_int:
@@ -386,6 +443,9 @@
movl $(__KERNEL_DS),%eax
movl %eax,%ds
movl %eax,%es
+ cmpl $2,early_recursion_flag
+ je hlt_loop
+ incl early_recursion_flag
pushl 16(%esp)
pushl 24(%esp)
pushl 32(%esp)
@@ -431,9 +491,16 @@
ready: .byte 0
+early_recursion_flag:
+ .long 0
+
int_msg:
.asciz "Unknown interrupt or fault at EIP %p %p %p\n"
+fault_msg:
+ .ascii "Int %d: CR2 %p err %p EIP %p CS %p flags %p\n"
+ .asciz "Stack: %p %p %p %p %p %p %p %p\n"
+
/*
* The IDT and GDT 'descriptors' are a strange 48-bit object
* only used by the lidt and lgdt instructions. They are not