x86/head: Move early exception panic code into early_fixup_exception() (0e861fbb) · Commits · 戴 / test

arch/x86/include/asm/uaccess.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -110,7 +110,7 @@ struct exception_table_entry {

		extern int fixup_exception(struct pt_regs *regs, int trapnr);
		extern bool ex_has_fault_handler(unsigned long ip);
		extern int early_fixup_exception(struct pt_regs *regs, int trapnr);
		extern void early_fixup_exception(struct pt_regs *regs, int trapnr);

		/*
		* These are the main single-value transfer routines. They automatically

arch/x86/kernel/head_32.S

+5 −44

Original line number	Diff line number	Diff line
		@@ -561,8 +561,6 @@ early_idt_handler_common:
		*/
		cld

		cmpl $2,%ss:early_recursion_flag
		je hlt_loop
		incl %ss:early_recursion_flag

		/* The vector number is in pt_regs->gs */
		@@ -594,13 +592,8 @@ early_idt_handler_common:
		movw %gs, PT_GS(%esp)
		movw $0, PT_GS+2(%esp)

		cmpl $(__KERNEL_CS),PT_CS(%esp)
		jne 10f

		movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */
		call early_fixup_exception
		andl %eax,%eax
		jz 10f /* Exception wasn't fixed up */

		popl %ebx /* pt_regs->bx */
		popl %ecx /* pt_regs->cx */
		@@ -616,29 +609,6 @@ early_idt_handler_common:
		decl %ss:early_recursion_flag
		addl $4, %esp /* pop pt_regs->orig_ax */
		iret

		10:
		#ifdef CONFIG_PRINTK
		xorl %eax,%eax
		movw %ax,PT_FS+2(%esp) /* clean up the segment values on some cpus */
		movw %ax,PT_DS+2(%esp)
		movw %ax,PT_ES+2(%esp)
		leal 40(%esp),%eax
		pushl %eax /* %esp before the exception */
		pushl %ebx
		pushl %ebp
		pushl %esi
		pushl %edi
		movl %cr2,%eax
		pushl %eax
		pushl (20+64)(%esp) / trapno */
		pushl $fault_msg
		call printk
		#endif
		call dump_stack
		hlt_loop:
		hlt
		jmp hlt_loop
		ENDPROC(early_idt_handler_common)

		/* This is the default interrupt "handler" :-) */
		@@ -674,10 +644,14 @@ ignore_int:
		popl %eax
		#endif
		iret

		hlt_loop:
		hlt
		jmp hlt_loop
		ENDPROC(ignore_int)
		__INITDATA
		.align 4
		early_recursion_flag:
		GLOBAL(early_recursion_flag)
		.long 0

		__REFDATA
		@@ -742,19 +716,6 @@ __INITRODATA
		int_msg:
		.asciz "Unknown interrupt or fault at: %p %p %p\n"

		fault_msg:
		/* fault info: */
		.ascii "BUG: Int %d: CR2 %p\n"
		/* regs pushed in early_idt_handler: */
		.ascii " EDI %p ESI %p EBP %p EBX %p\n"
		.ascii " ESP %p ES %p DS %p\n"
		.ascii " EDX %p ECX %p EAX %p\n"
		/* fault frame: */
		.ascii " vec %p err %p EIP %p CS %p flg %p\n"
		.ascii "Stack: %p %p %p %p %p %p %p %p\n"
		.ascii " %p %p %p %p %p %p %p %p\n"
		.asciz " %p %p %p %p %p %p %p %p\n"

		#include "../../x86/xen/xen-head.S"

		/*

arch/x86/kernel/head_64.S

+2 −43

Original line number	Diff line number	Diff line
		@@ -351,8 +351,6 @@ early_idt_handler_common:
		*/
		cld

		cmpl $2,early_recursion_flag(%rip)
		jz 1f
		incl early_recursion_flag(%rip)

		/* The vector number is currently in the pt_regs->di slot. */
		@@ -373,9 +371,6 @@ early_idt_handler_common:
		pushq %r14 /* pt_regs->r14 */
		pushq %r15 /* pt_regs->r15 */

		cmpl $__KERNEL_CS,CS(%rsp)
		jne 11f

		cmpq $14,%rsi /* Page fault? */
		jnz 10f
		GET_CR2_INTO(%rdi) /* Can clobber any volatile register if pv */
		@@ -386,37 +381,8 @@ early_idt_handler_common:
		10:
		movq %rsp,%rdi /* RDI = pt_regs; RSI is already trapnr */
		call early_fixup_exception
		andl %eax,%eax
		jnz 20f # Found an exception entry

		11:
		#ifdef CONFIG_EARLY_PRINTK
		/*
		* On paravirt kernels, GET_CR2_INTO clobbers callee-clobbered regs.
		* We only care about RSI, so we need to save it.
		*/
		movq %rsi,%rbx /* Save vector number */
		GET_CR2_INTO(%r9)
		movq ORIG_RAX(%rsp),%r8 /* error code */
		movq %rbx,%rsi /* vector number */
		movq CS(%rsp),%rdx
		movq RIP(%rsp),%rcx
		xorl %eax,%eax
		leaq early_idt_msg(%rip),%rdi
		call early_printk
		cmpl $2,early_recursion_flag(%rip)
		jz 1f
		call dump_stack
		#ifdef CONFIG_KALLSYMS
		leaq early_idt_ripmsg(%rip),%rdi
		movq RIP(%rsp),%rsi # %rip again
		call __print_symbol
		#endif
		#endif /* EARLY_PRINTK */
		1: hlt
		jmp 1b

		20: /* Exception table entry found or page table generated */
		20:
		decl early_recursion_flag(%rip)
		jmp restore_regs_and_iret
		ENDPROC(early_idt_handler_common)
		@@ -424,16 +390,9 @@ ENDPROC(early_idt_handler_common)
		__INITDATA

		.balign 4
		early_recursion_flag:
		GLOBAL(early_recursion_flag)
		.long 0

		#ifdef CONFIG_EARLY_PRINTK
		early_idt_msg:
		.asciz "PANIC: early exception %02lx rip %lx:%lx error %lx cr2 %lx\n"
		early_idt_ripmsg:
		.asciz "RIP %s\n"
		#endif /* CONFIG_EARLY_PRINTK */

		#define NEXT_PAGE(name) \
		.balign PAGE_SIZE; \
		GLOBAL(name)

arch/x86/mm/extable.c

+24 −5

Original line number	Diff line number	Diff line
		@@ -83,8 +83,10 @@ int fixup_exception(struct pt_regs *regs, int trapnr)
		return handler(e, regs, trapnr);
		}

		extern unsigned int early_recursion_flag;

		/* Restricted version used during very early boot */
		int __init early_fixup_exception(struct pt_regs *regs, int trapnr)
		void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
		{
		const struct exception_table_entry *e;
		unsigned long new_ip;
		@@ -92,19 +94,36 @@ int __init early_fixup_exception(struct pt_regs *regs, int trapnr)

		/* Ignore early NMIs. */
		if (trapnr == X86_TRAP_NMI)
		return 1;
		return;

		if (early_recursion_flag > 2)
		goto halt_loop;

		if (regs->cs != __KERNEL_CS)
		goto fail;

		e = search_exception_tables(regs->ip);
		if (!e)
		return 0;
		goto fail;

		new_ip = ex_fixup_addr(e);
		handler = ex_fixup_handler(e);

		/* special handling not supported during early boot */
		if (handler != ex_handler_default)
		return 0;
		goto fail;

		regs->ip = new_ip;
		return 1;
		return;

		fail:
		early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n",
		(unsigned)trapnr, (unsigned long)regs->cs, regs->ip,
		regs->orig_ax, read_cr2());

		show_regs(regs);

		halt_loop:
		while (true)
		halt();
		}

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