Merge ../linux-2.6-watchdog-mm

[pandora-kernel.git] / arch / i386 / kernel / entry.S

diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index d274612..5e47683 100644 (file)
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -53,6 +53,19 @@
 #include <asm/dwarf2.h>
 #include "irq_vectors.h"
 
+/*
+ * We use macros for low-level operations which need to be overridden
+ * for paravirtualization.  The following will never clobber any registers:
+ *   INTERRUPT_RETURN (aka. "iret")
+ *   GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
+ *   ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
+ *
+ * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
+ * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
+ * Allowing a register to be clobbered can shrink the paravirt replacement
+ * enough to patch inline, increasing performance.
+ */
+
 #define nr_syscalls ((syscall_table_size)/4)
 
 CF_MASK                = 0x00000001
@@ -63,9 +76,9 @@ NT_MASK               = 0x00004000
 VM_MASK                = 0x00020000
 
 #ifdef CONFIG_PREEMPT
-#define preempt_stop           DISABLE_INTERRUPTS; TRACE_IRQS_OFF
+#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
 #else
-#define preempt_stop
+#define preempt_stop(clobbers)
 #define resume_kernel          restore_nocheck
 #endif
 
@@ -226,7 +239,7 @@ ENTRY(ret_from_fork)
        ALIGN
        RING0_PTREGS_FRAME
 ret_from_exception:
-       preempt_stop
+       preempt_stop(CLBR_ANY)
 ret_from_intr:
        GET_THREAD_INFO(%ebp)
 check_userspace:
@@ -237,7 +250,7 @@ check_userspace:
        jb resume_kernel                # not returning to v8086 or userspace
 
 ENTRY(resume_userspace)
-       DISABLE_INTERRUPTS              # make sure we don't miss an interrupt
+       DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
                                        # setting need_resched or sigpending
                                        # between sampling and the iret
        movl TI_flags(%ebp), %ecx
@@ -248,7 +261,7 @@ ENTRY(resume_userspace)
 
 #ifdef CONFIG_PREEMPT
 ENTRY(resume_kernel)
-       DISABLE_INTERRUPTS
+       DISABLE_INTERRUPTS(CLBR_ANY)
        cmpl $0,TI_preempt_count(%ebp)  # non-zero preempt_count ?
        jnz restore_nocheck
 need_resched:
@@ -277,7 +290,7 @@ sysenter_past_esp:
         * No need to follow this irqs on/off section: the syscall
         * disabled irqs and here we enable it straight after entry:
         */
-       ENABLE_INTERRUPTS
+       ENABLE_INTERRUPTS(CLBR_NONE)
        pushl $(__USER_DS)
        CFI_ADJUST_CFA_OFFSET 4
        /*CFI_REL_OFFSET ss, 0*/
@@ -289,12 +302,16 @@ sysenter_past_esp:
        pushl $(__USER_CS)
        CFI_ADJUST_CFA_OFFSET 4
        /*CFI_REL_OFFSET cs, 0*/
+#ifndef CONFIG_COMPAT_VDSO
        /*
         * Push current_thread_info()->sysenter_return to the stack.
         * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
         * pushed above; +8 corresponds to copy_thread's esp0 setting.
         */
        pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
+#else
+       pushl $SYSENTER_RETURN
+#endif
        CFI_ADJUST_CFA_OFFSET 4
        CFI_REL_OFFSET eip, 0
 
@@ -322,7 +339,7 @@ sysenter_past_esp:
        jae syscall_badsys
        call *sys_call_table(,%eax,4)
        movl %eax,PT_EAX(%esp)
-       DISABLE_INTERRUPTS
+       DISABLE_INTERRUPTS(CLBR_ECX|CLBR_EDX)
        TRACE_IRQS_OFF
        movl TI_flags(%ebp), %ecx
        testw $_TIF_ALLWORK_MASK, %cx
@@ -364,7 +381,7 @@ syscall_call:
        call *sys_call_table(,%eax,4)
        movl %eax,PT_EAX(%esp)          # store the return value
 syscall_exit:
-       DISABLE_INTERRUPTS              # make sure we don't miss an interrupt
+       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
@@ -393,7 +410,7 @@ restore_nocheck_notrace:
 .section .fixup,"ax"
 iret_exc:
        TRACE_IRQS_ON
-       ENABLE_INTERRUPTS
+       ENABLE_INTERRUPTS(CLBR_NONE)
        pushl $0                        # no error code
        pushl $do_iret_error
        jmp error_code
@@ -436,7 +453,7 @@ ldt_ss:
        CFI_ADJUST_CFA_OFFSET 4
        pushl %eax
        CFI_ADJUST_CFA_OFFSET 4
-       DISABLE_INTERRUPTS
+       DISABLE_INTERRUPTS(CLBR_EAX)
        TRACE_IRQS_OFF
        lss (%esp), %esp
        CFI_ADJUST_CFA_OFFSET -8
@@ -451,7 +468,7 @@ work_pending:
        jz work_notifysig
 work_resched:
        call schedule
-       DISABLE_INTERRUPTS              # make sure we don't miss an interrupt
+       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
@@ -509,7 +526,7 @@ syscall_exit_work:
        testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
        jz work_pending
        TRACE_IRQS_ON
-       ENABLE_INTERRUPTS               # could let do_syscall_trace() call
+       ENABLE_INTERRUPTS(CLBR_ANY)     # could let do_syscall_trace() call
                                        # schedule() instead
        movl %esp, %eax
        movl $1, %edx
@@ -693,7 +710,7 @@ ENTRY(device_not_available)
        GET_CR0_INTO_EAX
        testl $0x4, %eax                # EM (math emulation bit)
        jne device_not_available_emulate
-       preempt_stop
+       preempt_stop(CLBR_ANY)
        call math_state_restore
        jmp ret_from_exception
 device_not_available_emulate:
@@ -966,38 +983,6 @@ ENTRY(spurious_interrupt_bug)
        jmp error_code
        CFI_ENDPROC
 
-#ifdef CONFIG_STACK_UNWIND
-ENTRY(arch_unwind_init_running)
-       CFI_STARTPROC
-       movl    4(%esp), %edx
-       movl    (%esp), %ecx
-       leal    4(%esp), %eax
-       movl    %ebx, PT_EBX(%edx)
-       xorl    %ebx, %ebx
-       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    $0, PT_GS(%edx)
-       movl    %ebx, PT_ORIG_EAX(%edx)
-       movl    %ecx, PT_EIP(%edx)
-       movl    12(%esp), %ecx
-       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    PT_EBX(%edx), %ebx
-       movl    $__KERNEL_DS, PT_OLDSS(%edx)
-       jmpl    *%eax
-       CFI_ENDPROC
-ENDPROC(arch_unwind_init_running)
-#endif
-
 ENTRY(kernel_thread_helper)
        pushl $0                # fake return address for unwinder
        CFI_STARTPROC