[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: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Keith Owens <kaos@ocs.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>

2 files changed, 69 insertions, 68 deletions

diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c
index e94d910a28bd..70b19807acf9 100644
--- a/arch/i386/kernel/asm-offsets.c
+++ b/arch/i386/kernel/asm-offsets.c
@@ -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();
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index c38d801ba0bb..0069bf01603e 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -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)