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Commit 8866cd9d authored by Roland McGrath's avatar Roland McGrath Committed by Ingo Molnar
Browse files

x86: early_idt_handler improvements, 64-bit 



It's not too pretty, but I found this made the "PANIC: early exception"
messages become much more reliably useful: 1. print the vector number,
2. print the %cs value, 3. handle error-code-pushing vs non-pushing vectors.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent d504e39e

arch/x86/kernel/head64.c

+1 −1
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ void __init x86_64_start_kernel(char * real_mode_data) 
	zap_identity_mappings();



	for (i = 0; i < IDT_ENTRIES; i++)

		set_intr_gate(i, early_idt_handler);

		set_intr_gate(i, &early_idt_handlers[i]);

	load_idt((const struct desc_ptr *)&idt_descr);



	early_printk("Kernel alive\n");

arch/x86/kernel/head_64.S

+30 −4
Original line number Diff line number Diff line
@@ -267,14 +267,40 @@ init_rsp: 
bad_address:

	jmp bad_address



.macro early_idt_tramp first, last

	.ifgt \last-\first

	early_idt_tramp \first, \last-1

	.endif

	movl $\last,%esi

	jmp early_idt_handler

.endm



	.globl early_idt_handlers

early_idt_handlers:

	early_idt_tramp 0, 63

	early_idt_tramp 64, 127

	early_idt_tramp 128, 191

	early_idt_tramp 192, 255



ENTRY(early_idt_handler)

	cmpl $2,early_recursion_flag(%rip)

	jz  1f

	incl early_recursion_flag(%rip)

	xorl %eax,%eax

	movq 8(%rsp),%rsi	# get rip

	movq (%rsp),%rdx

	GET_CR2_INTO_RCX

	movq %rcx,%r9

	xorl %r8d,%r8d		# zero for error code

	movl %esi,%ecx		# get vector number

	# Test %ecx against mask of vectors that push error code.

	cmpl $31,%ecx

	ja 0f

	movl $1,%eax

	salq %cl,%rax

	testl $0x27d00,%eax

	je 0f

	popq %r8		# get error code

0:	movq 0(%rsp),%rcx	# get ip

	movq 8(%rsp),%rdx	# get cs

	xorl %eax,%eax

	leaq early_idt_msg(%rip),%rdi

	call early_printk

	cmpl $2,early_recursion_flag(%rip)
@@ -291,7 +317,7 @@ early_recursion_flag: 
	.long 0



early_idt_msg:

	.asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n"

	.asciz "PANIC: early exception %02lx rip %lx:%lx error %lx cr2 %lx\n"

early_idt_ripmsg:

	.asciz "RIP %s\n"

include/asm-x86/segment.h

+6 −0
Original line number Diff line number Diff line
@@ -195,4 +195,10 @@ 
#define GDT_ENTRY_TLS_ENTRIES 3

#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)



#ifdef __KERNEL__

#ifndef __ASSEMBLY__

extern const char early_idt_handlers[IDT_ENTRIES][10];

#endif

#endif



#endif