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[PATCH] i386: Use asm-offsets for the offsets of registers into the p…
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…t_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>
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Jeremy Fitzhardinge authored and Andi Kleen committed Dec 7, 2006
1 parent bcddc01 commit eb5b7b9
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Showing 2 changed files with 69 additions and 68 deletions.
17 changes: 17 additions & 0 deletions arch/i386/kernel/asm-offsets.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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();
Expand Down
120 changes: 52 additions & 68 deletions arch/i386/kernel/entry.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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:
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand All @@ -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
Expand Down Expand Up @@ -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
Expand All @@ -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:
Expand All @@ -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
Expand All @@ -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
Expand All @@ -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
Expand All @@ -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
Expand Down Expand Up @@ -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
Expand All @@ -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
Expand All @@ -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

Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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)
Expand Down

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