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Commit ec5c0926 authored by Chuck Ebbert's avatar Chuck Ebbert Committed by Andi Kleen
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[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: default avatarChuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent 78be3706

arch/i386/kernel/head.S

+67 −0
Original line number Diff line number Diff line
@@ -371,8 +371,65 @@ rp_sidt: 
	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 @@ ignore_int: 
	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 @@ ENTRY(stack_start) 


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