Use asm-offsets for offsets into struct pt_regs

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.

---
arch/i386/kernel/asm-offsets.c | 17 +++++
arch/i386/kernel/entry.S | 118 +++++++++++++++++-----------------------

2 files changed, 68 insertions(+), 67 deletions(-)

diff -r c7c67fa1698d arch/i386/kernel/asm-offsets.c
@@ -58,6 +58,23 @@ void foo(void)

	OFFSET(TI_sysenter_return, thread_info, sysenter_return);
	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();

diff -r c7c67fa1698d arch/i386/kernel/entry.S
@@ -53,22 +53,6 @@
 

#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
@@ -92,7 +76,7 @@ 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:
@@ -195,18 +179,18 @@ 4: movl $0,(%esp); \

#define RING0_PTREGS_FRAME \
	CFI_STARTPROC simple;\

- 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
@@ -234,8 +218,8 @@ ret_from_intr:
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
@@ -258,7 +242,7 @@ 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
@@ -323,15 +307,15 @@ 1: movl (%ebp),%ebp

	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
@@ -345,7 +329,7 @@ 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:
@@ -357,7 +341,7 @@ 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
@@ -368,12 +352,12 @@ 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
@@ -400,7 +384,7 @@ 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

@@ -450,7 +434,7 @@ 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
@@ -475,14 +459,14 @@ 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
@@ -507,11 +491,11 @@ 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

@@ -634,10 +618,10 @@ 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 %eax, 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 %eax, PT_ORIG_EAX(%esp)
+ movl %ecx, PT_ES(%esp)

	/*CFI_REL_OFFSET es, ES*/
	movl $(__USER_DS), %ecx
	movl %ecx, %ds
@@ -928,26 +912,26 @@ 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)