Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7bbcdb1c authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/head: Pass a real pt_regs and trapnr to early_fixup_exception() 



early_fixup_exception() is limited by the fact that it doesn't have a
real struct pt_regs.  Change both the 32-bit and 64-bit asm and the
C code to pass and accept a real pt_regs.

Tested-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: KVM list <kvm@vger.kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel <Xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/e3fb680fcfd5e23e38237e8328b64a25cc121d37.1459605520.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6aa6dbfc

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(unsigned long *ip);

extern int 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

+51 −23
Original line number Diff line number Diff line
@@ -568,29 +568,64 @@ early_idt_handler_common: 
	je hlt_loop

	incl %ss:early_recursion_flag



	push %eax		# 16(%esp)

	push %ecx		# 12(%esp)

	push %edx		#  8(%esp)

	push %ds		#  4(%esp)

	push %es		#  0(%esp)

	movl $(__KERNEL_DS),%eax

	movl %eax,%ds

	movl %eax,%es

	/* The vector number is in pt_regs->gs */



	cmpl $(__KERNEL_CS),32(%esp)

	cld

	pushl	%fs		/* pt_regs->fs */

	movw	$0, 2(%esp)	/* clear high bits (some CPUs leave garbage) */

	pushl	%es		/* pt_regs->es */

	movw	$0, 2(%esp)	/* clear high bits (some CPUs leave garbage) */

	pushl	%ds		/* pt_regs->ds */

	movw	$0, 2(%esp)	/* clear high bits (some CPUs leave garbage) */

	pushl	%eax		/* pt_regs->ax */

	pushl	%ebp		/* pt_regs->bp */

	pushl	%edi		/* pt_regs->di */

	pushl	%esi		/* pt_regs->si */

	pushl	%edx		/* pt_regs->dx */

	pushl	%ecx		/* pt_regs->cx */

	pushl	%ebx		/* pt_regs->bx */



	/* Fix up DS and ES */

	movl	$(__KERNEL_DS), %ecx

	movl	%ecx, %ds

	movl	%ecx, %es



	/* Load the vector number into EDX */

	movl	PT_GS(%esp), %edx



	/* Load GS into pt_regs->gs and clear high bits */

	movw	%gs, PT_GS(%esp)

	movw	$0, PT_GS+2(%esp)



	cmpl $(__KERNEL_CS),PT_CS(%esp)

	jne 10f



	leal 28(%esp),%eax	# Pointer to %eip

	movl	%esp, %eax	/* args are pt_regs (EAX), trapnr (EDX) */

	call	early_fixup_exception

	andl	%eax,%eax

	jnz ex_entry		/* found an exception entry */

	jz	10f		/* Exception wasn't fixed up */



	popl	%ebx		/* pt_regs->bx */

	popl	%ecx		/* pt_regs->cx */

	popl	%edx		/* pt_regs->dx */

	popl	%esi		/* pt_regs->si */

	popl	%edi		/* pt_regs->di */

	popl	%ebp		/* pt_regs->bp */

	popl	%eax		/* pt_regs->ax */

	popl	%ds		/* pt_regs->ds */

	popl	%es		/* pt_regs->es */

	popl	%fs		/* pt_regs->fs */

	popl	%gs		/* pt_regs->gs */

	decl	%ss:early_recursion_flag

	addl	$4, %esp	/* pop pt_regs->orig_ax */

	iret



10:

#ifdef CONFIG_PRINTK

	xorl %eax,%eax

	movw %ax,2(%esp)	/* clean up the segment values on some cpus */

	movw %ax,6(%esp)

	movw %ax,34(%esp)

	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
@@ -608,13 +643,6 @@ hlt_loop: 
	hlt

	jmp hlt_loop



ex_entry:

	pop %es

	pop %ds

	pop %edx

	pop %ecx

	pop %eax

	decl %ss:early_recursion_flag

.Lis_nmi:

	addl $8,%esp		/* drop vector number and error code */

	iret

arch/x86/kernel/head_64.S

+37 −31
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <asm/processor-flags.h>

#include <asm/percpu.h>

#include <asm/nops.h>

#include "../entry/calling.h"



#ifdef CONFIG_PARAVIRT

#include <asm/asm-offsets.h>
@@ -357,39 +358,52 @@ early_idt_handler_common: 
	jz  1f

	incl early_recursion_flag(%rip)



	pushq %rax		# 64(%rsp)

	pushq %rcx		# 56(%rsp)

	pushq %rdx		# 48(%rsp)

	pushq %rsi		# 40(%rsp)

	pushq %rdi		# 32(%rsp)

	pushq %r8		# 24(%rsp)

	pushq %r9		# 16(%rsp)

	pushq %r10		#  8(%rsp)

	pushq %r11		#  0(%rsp)



	cmpl $__KERNEL_CS,96(%rsp)

	/* The vector number is currently in the pt_regs->di slot. */

	pushq %rsi				/* pt_regs->si */

	movq 8(%rsp), %rsi			/* RSI = vector number */

	movq %rdi, 8(%rsp)			/* pt_regs->di = RDI */

	pushq %rdx				/* pt_regs->dx */

	pushq %rcx				/* pt_regs->cx */

	pushq %rax				/* pt_regs->ax */

	pushq %r8				/* pt_regs->r8 */

	pushq %r9				/* pt_regs->r9 */

	pushq %r10				/* pt_regs->r10 */

	pushq %r11				/* pt_regs->r11 */

	pushq %rbx				/* pt_regs->bx */

	pushq %rbp				/* pt_regs->bp */

	pushq %r12				/* pt_regs->r12 */

	pushq %r13				/* pt_regs->r13 */

	pushq %r14				/* pt_regs->r14 */

	pushq %r15				/* pt_regs->r15 */



	cmpl $__KERNEL_CS,CS(%rsp)

	jne 11f



	cmpl $14,72(%rsp)	# Page fault?

	cmpq $14,%rsi		/* Page fault? */

	jnz 10f

	GET_CR2_INTO(%rdi)	# can clobber any volatile register if pv

	GET_CR2_INTO(%rdi)	/* Can clobber any volatile register if pv */

	call early_make_pgtable

	andl %eax,%eax

	jz 20f			# All good

	jz 20f			/* All good */



10:

	leaq 88(%rsp),%rdi	# Pointer to %rip

	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

	GET_CR2_INTO(%r9)	# can clobber any volatile register if pv

	movl 80(%rsp),%r8d	# error code

	movl 72(%rsp),%esi	# vector number

	movl 96(%rsp),%edx	# %cs

	movq 88(%rsp),%rcx	# %rip

	/*

	 * 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
@@ -398,24 +412,16 @@ early_idt_handler_common: 
	call dump_stack

#ifdef CONFIG_KALLSYMS	

	leaq early_idt_ripmsg(%rip),%rdi

	movq 40(%rsp),%rsi	# %rip again

	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

	popq %r11

	popq %r10

	popq %r9

	popq %r8

	popq %rdi

	popq %rsi

	popq %rdx

	popq %rcx

	popq %rax

20:	/* Exception table entry found or page table generated */

	decl early_recursion_flag(%rip)

	jmp restore_regs_and_iret

.Lis_nmi:

	addq $16,%rsp		# drop vector number and error code

	INTERRUPT_RETURN

arch/x86/mm/extable.c

+3 −3
Original line number Diff line number Diff line
@@ -83,13 +83,13 @@ int fixup_exception(struct pt_regs *regs, int trapnr) 
}



/* Restricted version used during very early boot */

int __init early_fixup_exception(unsigned long *ip)

int __init early_fixup_exception(struct pt_regs *regs, int trapnr)

{

	const struct exception_table_entry *e;

	unsigned long new_ip;

	ex_handler_t handler;



	e = search_exception_tables(*ip);

	e = search_exception_tables(regs->ip);

	if (!e)

		return 0;
@@ -100,6 +100,6 @@ int __init early_fixup_exception(unsigned long *ip) 
	if (handler != ex_handler_default)

		return 0;



	*ip = new_ip;

	regs->ip = new_ip;

	return 1;

}