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x86/entry/32: Migrate to C exit path 

This removes the hybrid asm-and-C implementation of exit work.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2baa438619ea6c027b40ec9fceacca52f09c74d09.1438378274.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-07-31 14:41:09 -07:00 committed by Ingo Molnar
parent c5f69fde26
commit 5d73fc7099
1 changed files with 11 additions and 51 deletions
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62
arch/x86/entry/entry_32.S
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@ -256,14 +256,10 @@ ret_from_intr:
ENTRY(resume_userspace) ENTRY(resume_userspace)
LOCKDEP_SYS_EXIT LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt DISABLE_INTERRUPTS(CLBR_ANY)
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx movl %esp, %eax
andl $_TIF_WORK_MASK, %ecx # is there any work to be done on call prepare_exit_to_usermode
# int/exception return?
jne work_pending
jmp restore_all jmp restore_all
END(ret_from_exception) END(ret_from_exception)
@ -341,7 +337,7 @@ sysenter_after_call:
TRACE_IRQS_OFF TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx movl TI_flags(%ebp), %ecx
testl $_TIF_ALLWORK_MASK, %ecx testl $_TIF_ALLWORK_MASK, %ecx
jnz syscall_exit_work jnz syscall_exit_work_irqs_off
sysenter_exit: sysenter_exit:
/* if something modifies registers it must also disable sysexit */ /* if something modifies registers it must also disable sysexit */
movl PT_EIP(%esp), %edx movl PT_EIP(%esp), %edx
@ -377,13 +373,7 @@ syscall_after_call:
movl %eax, PT_EAX(%esp) # store the return value movl %eax, PT_EAX(%esp) # store the return value
syscall_exit: syscall_exit:
LOCKDEP_SYS_EXIT LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt jmp syscall_exit_work
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testl $_TIF_ALLWORK_MASK, %ecx # current->work
jnz syscall_exit_work
restore_all: restore_all:
TRACE_IRQS_IRET TRACE_IRQS_IRET
@ -460,35 +450,6 @@ ldt_ss:
#endif #endif
ENDPROC(entry_INT80_32) ENDPROC(entry_INT80_32)
# perform work that needs to be done immediately before resumption
ALIGN
work_pending:
testb $_TIF_NEED_RESCHED, %cl
jz work_notifysig
work_resched:
call schedule
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
# than syscall tracing?
jz restore_all
testb $_TIF_NEED_RESCHED, %cl
jnz work_resched
work_notifysig: # deal with pending signals and
# notify-resume requests
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
movl %esp, %eax
xorl %edx, %edx
call do_notify_resume
jmp resume_userspace
END(work_pending)
# perform syscall exit tracing # perform syscall exit tracing
ALIGN ALIGN
syscall_trace_entry: syscall_trace_entry:
@ -503,15 +464,14 @@ END(syscall_trace_entry)
# perform syscall exit tracing # perform syscall exit tracing
ALIGN ALIGN
syscall_exit_work: syscall_exit_work_irqs_off:
testl $_TIF_WORK_SYSCALL_EXIT, %ecx
jz work_pending
TRACE_IRQS_ON TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call ENABLE_INTERRUPTS(CLBR_ANY)
# schedule() instead
syscall_exit_work:
movl %esp, %eax movl %esp, %eax
call syscall_trace_leave call syscall_return_slowpath
jmp resume_userspace jmp restore_all
END(syscall_exit_work) END(syscall_exit_work)
syscall_fault: syscall_fault: