Commit eb5b7b9d authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Andi Kleen
Browse files

[PATCH] i386: Use asm-offsets for the offsets of registers into the pt_regs struct 



Use asm-offsets for the offsets of registers into the pt_regs struct, rather
than having hard-coded constants

I left the constants in the comments of entry.S because they're useful for
reference; the code in entry.S is very dependent on the layout of pt_regs,
even when using asm-offsets.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Keith Owens <kaos@ocs.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent bcddc015

arch/i386/kernel/asm-offsets.c

+17 −0
Original line number Diff line number Diff line
@@ -63,6 +63,23 @@ void foo(void) 
	OFFSET(GDS_pad, Xgt_desc_struct, pad);

	BLANK();



	OFFSET(PT_EBX, pt_regs, ebx);

	OFFSET(PT_ECX, pt_regs, ecx);

	OFFSET(PT_EDX, pt_regs, edx);

	OFFSET(PT_ESI, pt_regs, esi);

	OFFSET(PT_EDI, pt_regs, edi);

	OFFSET(PT_EBP, pt_regs, ebp);

	OFFSET(PT_EAX, pt_regs, eax);

	OFFSET(PT_DS,  pt_regs, xds);

	OFFSET(PT_ES,  pt_regs, xes);

	OFFSET(PT_ORIG_EAX, pt_regs, orig_eax);

	OFFSET(PT_EIP, pt_regs, eip);

	OFFSET(PT_CS,  pt_regs, xcs);

	OFFSET(PT_EFLAGS, pt_regs, eflags);

	OFFSET(PT_OLDESP, pt_regs, esp);

	OFFSET(PT_OLDSS,  pt_regs, xss);

	BLANK();



	OFFSET(EXEC_DOMAIN_handler, exec_domain, handler);

	OFFSET(RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext);

	BLANK();

arch/i386/kernel/entry.S

+52 −68
Original line number Diff line number Diff line
@@ -54,22 +54,6 @@ 


#define nr_syscalls ((syscall_table_size)/4)



EBX		= 0x00

ECX		= 0x04

EDX		= 0x08

ESI		= 0x0C

EDI		= 0x10

EBP		= 0x14

EAX		= 0x18

DS		= 0x1C

ES		= 0x20

ORIG_EAX	= 0x24

EIP		= 0x28

CS		= 0x2C

EFLAGS		= 0x30

OLDESP		= 0x34

OLDSS		= 0x38



CF_MASK		= 0x00000001

TF_MASK		= 0x00000100

IF_MASK		= 0x00000200
@@ -93,7 +77,7 @@ VM_MASK = 0x00020000 


.macro TRACE_IRQS_IRET

#ifdef CONFIG_TRACE_IRQFLAGS

	testl $IF_MASK,EFLAGS(%esp)     # interrupts off?

	testl $IF_MASK,PT_EFLAGS(%esp)     # interrupts off?

	jz 1f

	TRACE_IRQS_ON

1:
@@ -199,18 +183,18 @@ VM_MASK = 0x00020000 
#define RING0_PTREGS_FRAME \

	CFI_STARTPROC simple;\

	CFI_SIGNAL_FRAME;\

	CFI_DEF_CFA esp, OLDESP-EBX;\

	/*CFI_OFFSET cs, CS-OLDESP;*/\

	CFI_OFFSET eip, EIP-OLDESP;\

	/*CFI_OFFSET es, ES-OLDESP;*/\

	/*CFI_OFFSET ds, DS-OLDESP;*/\

	CFI_OFFSET eax, EAX-OLDESP;\

	CFI_OFFSET ebp, EBP-OLDESP;\

	CFI_OFFSET edi, EDI-OLDESP;\

	CFI_OFFSET esi, ESI-OLDESP;\

	CFI_OFFSET edx, EDX-OLDESP;\

	CFI_OFFSET ecx, ECX-OLDESP;\

	CFI_OFFSET ebx, EBX-OLDESP

	CFI_DEF_CFA esp, PT_OLDESP-PT_EBX;\

	/*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/\

	CFI_OFFSET eip, PT_EIP-PT_OLDESP;\

	/*CFI_OFFSET es, PT_ES-PT_OLDESP;*/\

	/*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/\

	CFI_OFFSET eax, PT_EAX-PT_OLDESP;\

	CFI_OFFSET ebp, PT_EBP-PT_OLDESP;\

	CFI_OFFSET edi, PT_EDI-PT_OLDESP;\

	CFI_OFFSET esi, PT_ESI-PT_OLDESP;\

	CFI_OFFSET edx, PT_EDX-PT_OLDESP;\

	CFI_OFFSET ecx, PT_ECX-PT_OLDESP;\

	CFI_OFFSET ebx, PT_EBX-PT_OLDESP



ENTRY(ret_from_fork)

	CFI_STARTPROC
@@ -242,8 +226,8 @@ ret_from_exception: 
ret_from_intr:

	GET_THREAD_INFO(%ebp)

check_userspace:

	movl EFLAGS(%esp), %eax		# mix EFLAGS and CS

	movb CS(%esp), %al

	movl PT_EFLAGS(%esp), %eax	# mix EFLAGS and CS

	movb PT_CS(%esp), %al

	andl $(VM_MASK | SEGMENT_RPL_MASK), %eax

	cmpl $USER_RPL, %eax

	jb resume_kernel		# not returning to v8086 or userspace
@@ -266,7 +250,7 @@ need_resched: 
	movl TI_flags(%ebp), %ecx	# need_resched set ?

	testb $_TIF_NEED_RESCHED, %cl

	jz restore_all

	testl $IF_MASK,EFLAGS(%esp)     # interrupts off (exception path) ?

	testl $IF_MASK,PT_EFLAGS(%esp)	# interrupts off (exception path) ?

	jz restore_all

	call preempt_schedule_irq

	jmp need_resched
@@ -332,15 +316,15 @@ sysenter_past_esp: 
	cmpl $(nr_syscalls), %eax

	jae syscall_badsys

	call *sys_call_table(,%eax,4)

	movl %eax,EAX(%esp)

	movl %eax,PT_EAX(%esp)

	DISABLE_INTERRUPTS

	TRACE_IRQS_OFF

	movl TI_flags(%ebp), %ecx

	testw $_TIF_ALLWORK_MASK, %cx

	jne syscall_exit_work

/* if something modifies registers it must also disable sysexit */

	movl EIP(%esp), %edx

	movl OLDESP(%esp), %ecx

	movl PT_EIP(%esp), %edx

	movl PT_OLDESP(%esp), %ecx

	xorl %ebp,%ebp

	TRACE_IRQS_ON

	ENABLE_INTERRUPTS_SYSEXIT
@@ -354,7 +338,7 @@ ENTRY(system_call) 
	CFI_ADJUST_CFA_OFFSET 4

	SAVE_ALL

	GET_THREAD_INFO(%ebp)

	testl $TF_MASK,EFLAGS(%esp)

	testl $TF_MASK,PT_EFLAGS(%esp)

	jz no_singlestep

	orl $_TIF_SINGLESTEP,TI_flags(%ebp)

no_singlestep:
@@ -366,7 +350,7 @@ no_singlestep: 
	jae syscall_badsys

syscall_call:

	call *sys_call_table(,%eax,4)

	movl %eax,EAX(%esp)		# store the return value

	movl %eax,PT_EAX(%esp)		# store the return value

syscall_exit:

	DISABLE_INTERRUPTS		# make sure we don't miss an interrupt

					# setting need_resched or sigpending
@@ -377,12 +361,12 @@ syscall_exit: 
	jne syscall_exit_work



restore_all:

	movl EFLAGS(%esp), %eax		# mix EFLAGS, SS and CS

	# Warning: OLDSS(%esp) contains the wrong/random values if we

	movl PT_EFLAGS(%esp), %eax	# mix EFLAGS, SS and CS

	# Warning: PT_OLDSS(%esp) contains the wrong/random values if we

	# are returning to the kernel.

	# See comments in process.c:copy_thread() for details.

	movb OLDSS(%esp), %ah

	movb CS(%esp), %al

	movb PT_OLDSS(%esp), %ah

	movb PT_CS(%esp), %al

	andl $(VM_MASK | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax

	cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax

	CFI_REMEMBER_STATE
@@ -409,7 +393,7 @@ iret_exc: 


	CFI_RESTORE_STATE

ldt_ss:

	larl OLDSS(%esp), %eax

	larl PT_OLDSS(%esp), %eax

	jnz restore_nocheck

	testl $0x00400000, %eax		# returning to 32bit stack?

	jnz restore_nocheck		# allright, normal return
@@ -419,7 +403,7 @@ ldt_ss: 
	 * This is an "official" bug of all the x86-compatible

	 * CPUs, which we can try to work around to make

	 * dosemu and wine happy. */

	movl OLDESP(%esp), %eax

	movl PT_OLDESP(%esp), %eax

	movl %esp, %edx

	call patch_espfix_desc

	pushl $__ESPFIX_SS
@@ -454,7 +438,7 @@ work_resched: 


work_notifysig:				# deal with pending signals and

					# notify-resume requests

	testl $VM_MASK, EFLAGS(%esp)

	testl $VM_MASK, PT_EFLAGS(%esp)

	movl %esp, %eax

	jne work_notifysig_v86		# returning to kernel-space or

					# vm86-space
@@ -479,14 +463,14 @@ work_notifysig_v86: 
	# perform syscall exit tracing

	ALIGN

syscall_trace_entry:

	movl $-ENOSYS,EAX(%esp)

	movl $-ENOSYS,PT_EAX(%esp)

	movl %esp, %eax

	xorl %edx,%edx

	call do_syscall_trace

	cmpl $0, %eax

	jne resume_userspace		# ret != 0 -> running under PTRACE_SYSEMU,

					# so must skip actual syscall

	movl ORIG_EAX(%esp), %eax

	movl PT_ORIG_EAX(%esp), %eax

	cmpl $(nr_syscalls), %eax

	jnae syscall_call

	jmp syscall_exit
@@ -511,11 +495,11 @@ syscall_fault: 
	CFI_ADJUST_CFA_OFFSET 4

	SAVE_ALL

	GET_THREAD_INFO(%ebp)

	movl $-EFAULT,EAX(%esp)

	movl $-EFAULT,PT_EAX(%esp)

	jmp resume_userspace



syscall_badsys:

	movl $-ENOSYS,EAX(%esp)

	movl $-ENOSYS,PT_EAX(%esp)

	jmp resume_userspace

	CFI_ENDPROC
@@ -636,10 +620,10 @@ error_code: 
	popl %ecx

	CFI_ADJUST_CFA_OFFSET -4

	/*CFI_REGISTER es, ecx*/

	movl ES(%esp), %edi		# get the function address

	movl ORIG_EAX(%esp), %edx	# get the error code

	movl $-1, ORIG_EAX(%esp)

	movl %ecx, ES(%esp)

	movl PT_ES(%esp), %edi		# get the function address

	movl PT_ORIG_EAX(%esp), %edx	# get the error code

	movl $-1, PT_ORIG_EAX(%esp)

	movl %ecx, PT_ES(%esp)

	/*CFI_REL_OFFSET es, ES*/

	movl $(__USER_DS), %ecx

	movl %ecx, %ds
@@ -942,26 +926,26 @@ ENTRY(arch_unwind_init_running) 
	movl	4(%esp), %edx

	movl	(%esp), %ecx

	leal	4(%esp), %eax

	movl	%ebx, EBX(%edx)

	movl	%ebx, PT_EBX(%edx)

	xorl	%ebx, %ebx

	movl	%ebx, ECX(%edx)

	movl	%ebx, EDX(%edx)

	movl	%esi, ESI(%edx)

	movl	%edi, EDI(%edx)

	movl	%ebp, EBP(%edx)

	movl	%ebx, EAX(%edx)

	movl	$__USER_DS, DS(%edx)

	movl	$__USER_DS, ES(%edx)

	movl	%ebx, ORIG_EAX(%edx)

	movl	%ecx, EIP(%edx)

	movl	%ebx, PT_ECX(%edx)

	movl	%ebx, PT_EDX(%edx)

	movl	%esi, PT_ESI(%edx)

	movl	%edi, PT_EDI(%edx)

	movl	%ebp, PT_EBP(%edx)

	movl	%ebx, PT_EAX(%edx)

	movl	$__USER_DS, PT_DS(%edx)

	movl	$__USER_DS, PT_ES(%edx)

	movl	%ebx, PT_ORIG_EAX(%edx)

	movl	%ecx, PT_EIP(%edx)

	movl	12(%esp), %ecx

	movl	$__KERNEL_CS, CS(%edx)

	movl	%ebx, EFLAGS(%edx)

	movl	%eax, OLDESP(%edx)

	movl	$__KERNEL_CS, PT_CS(%edx)

	movl	%ebx, PT_EFLAGS(%edx)

	movl	%eax, PT_OLDESP(%edx)

	movl	8(%esp), %eax

	movl	%ecx, 8(%esp)

	movl	EBX(%edx), %ebx

	movl	$__KERNEL_DS, OLDSS(%edx)

	movl	PT_EBX(%edx), %ebx

	movl	$__KERNEL_DS, PT_OLDSS(%edx)

	jmpl	*%eax

	CFI_ENDPROC

ENDPROC(arch_unwind_init_running)

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