/*
- Asm versions of Xen pv-ops, suitable for either direct use or inlining.
- The inline versions are the same as the direct-use versions, with the
- pre- and post-amble chopped off.
-
- This code is encoded for size rather than absolute efficiency,
- with a view to being able to inline as much as possible.
-
- We only bother with direct forms (ie, vcpu in pda) of the operations
- here; the indirect forms are better handled in C, since they're
- generally too large to inline anyway.
+ * Asm versions of Xen pv-ops, suitable for either direct use or
+ * inlining. The inline versions are the same as the direct-use
+ * versions, with the pre- and post-amble chopped off.
+ *
+ * This code is encoded for size rather than absolute efficiency, with
+ * a view to being able to inline as much as possible.
+ *
+ * We only bother with direct forms (ie, vcpu in pda) of the
+ * operations here; the indirect forms are better handled in C, since
+ * they're generally too large to inline anyway.
*/
-#include <linux/linkage.h>
-
-#include <asm/asm-offsets.h>
-#include <asm/processor-flags.h>
#include <asm/errno.h>
+#include <asm/percpu.h>
+#include <asm/processor-flags.h>
#include <asm/segment.h>
#include <xen/interface/xen.h>
-#define RELOC(x, v) .globl x##_reloc; x##_reloc=v
-#define ENDPATCH(x) .globl x##_end; x##_end=.
-
-/* Pseudo-flag used for virtual NMI, which we don't implement yet */
-#define XEN_EFLAGS_NMI 0x80000000
-
-#if 1
-/*
- x86-64 does not yet support direct access to percpu variables
- via a segment override, so we just need to make sure this code
- never gets used
- */
-#define BUG ud2a
-#define PER_CPU_VAR(var, off) 0xdeadbeef
-#endif
-
-/*
- Enable events. This clears the event mask and tests the pending
- event status with one and operation. If there are pending
- events, then enter the hypervisor to get them handled.
- */
-ENTRY(xen_irq_enable_direct)
- BUG
-
- /* Unmask events */
- movb $0, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
-
- /* Preempt here doesn't matter because that will deal with
- any pending interrupts. The pending check may end up being
- run on the wrong CPU, but that doesn't hurt. */
-
- /* Test for pending */
- testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
- jz 1f
-
-2: call check_events
-1:
-ENDPATCH(xen_irq_enable_direct)
- ret
- ENDPROC(xen_irq_enable_direct)
- RELOC(xen_irq_enable_direct, 2b+1)
-
-/*
- Disabling events is simply a matter of making the event mask
- non-zero.
- */
-ENTRY(xen_irq_disable_direct)
- BUG
-
- movb $1, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
-ENDPATCH(xen_irq_disable_direct)
- ret
- ENDPROC(xen_irq_disable_direct)
- RELOC(xen_irq_disable_direct, 0)
-
-/*
- (xen_)save_fl is used to get the current interrupt enable status.
- Callers expect the status to be in X86_EFLAGS_IF, and other bits
- may be set in the return value. We take advantage of this by
- making sure that X86_EFLAGS_IF has the right value (and other bits
- in that byte are 0), but other bits in the return value are
- undefined. We need to toggle the state of the bit, because
- Xen and x86 use opposite senses (mask vs enable).
- */
-ENTRY(xen_save_fl_direct)
- BUG
-
- testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
- setz %ah
- addb %ah,%ah
-ENDPATCH(xen_save_fl_direct)
- ret
- ENDPROC(xen_save_fl_direct)
- RELOC(xen_save_fl_direct, 0)
-
-/*
- In principle the caller should be passing us a value return
- from xen_save_fl_direct, but for robustness sake we test only
- the X86_EFLAGS_IF flag rather than the whole byte. After
- setting the interrupt mask state, it checks for unmasked
- pending events and enters the hypervisor to get them delivered
- if so.
- */
-ENTRY(xen_restore_fl_direct)
- BUG
-
- testb $X86_EFLAGS_IF>>8, %ah
- setz PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
- /* Preempt here doesn't matter because that will deal with
- any pending interrupts. The pending check may end up being
- run on the wrong CPU, but that doesn't hurt. */
-
- /* check for unmasked and pending */
- cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
- jz 1f
-2: call check_events
-1:
-ENDPATCH(xen_restore_fl_direct)
- ret
- ENDPROC(xen_restore_fl_direct)
- RELOC(xen_restore_fl_direct, 2b+1)
-
-
-/*
- Force an event check by making a hypercall,
- but preserve regs before making the call.
- */
-check_events:
- push %rax
- push %rcx
- push %rdx
- push %rsi
- push %rdi
- push %r8
- push %r9
- push %r10
- push %r11
- call xen_force_evtchn_callback
- pop %r11
- pop %r10
- pop %r9
- pop %r8
- pop %rdi
- pop %rsi
- pop %rdx
- pop %rcx
- pop %rax
- ret
+#include "xen-asm.h"
ENTRY(xen_adjust_exception_frame)
- mov 8+0(%rsp),%rcx
- mov 8+8(%rsp),%r11
+ mov 8+0(%rsp), %rcx
+ mov 8+8(%rsp), %r11
ret $16
hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
/*
- Xen64 iret frame:
-
- ss
- rsp
- rflags
- cs
- rip <-- standard iret frame
-
- flags
-
- rcx }
- r11 }<-- pushed by hypercall page
-rsp -> rax }
+ * Xen64 iret frame:
+ *
+ * ss
+ * rsp
+ * rflags
+ * cs
+ * rip <-- standard iret frame
+ *
+ * flags
+ *
+ * rcx }
+ * r11 }<-- pushed by hypercall page
+ * rsp->rax }
*/
ENTRY(xen_iret)
pushq $0
RELOC(xen_iret, 1b+1)
/*
- sysexit is not used for 64-bit processes, so it's
- only ever used to return to 32-bit compat userspace.
+ * sysexit is not used for 64-bit processes, so it's only ever used to
+ * return to 32-bit compat userspace.
*/
ENTRY(xen_sysexit)
pushq $__USER32_DS
RELOC(xen_sysexit, 1b+1)
ENTRY(xen_sysret64)
- /* We're already on the usermode stack at this point, but still
- with the kernel gs, so we can easily switch back */
- movq %rsp, %gs:pda_oldrsp
- movq %gs:pda_kernelstack,%rsp
+ /*
+ * We're already on the usermode stack at this point, but
+ * still with the kernel gs, so we can easily switch back
+ */
+ movq %rsp, PER_CPU_VAR(old_rsp)
+ movq PER_CPU_VAR(kernel_stack), %rsp
pushq $__USER_DS
- pushq %gs:pda_oldrsp
+ pushq PER_CPU_VAR(old_rsp)
pushq %r11
pushq $__USER_CS
pushq %rcx
RELOC(xen_sysret64, 1b+1)
ENTRY(xen_sysret32)
- /* We're already on the usermode stack at this point, but still
- with the kernel gs, so we can easily switch back */
- movq %rsp, %gs:pda_oldrsp
- movq %gs:pda_kernelstack, %rsp
+ /*
+ * We're already on the usermode stack at this point, but
+ * still with the kernel gs, so we can easily switch back
+ */
+ movq %rsp, PER_CPU_VAR(old_rsp)
+ movq PER_CPU_VAR(kernel_stack), %rsp
pushq $__USER32_DS
- pushq %gs:pda_oldrsp
+ pushq PER_CPU_VAR(old_rsp)
pushq %r11
pushq $__USER32_CS
pushq %rcx
RELOC(xen_sysret32, 1b+1)
/*
- Xen handles syscall callbacks much like ordinary exceptions,
- which means we have:
- - kernel gs
- - kernel rsp
- - an iret-like stack frame on the stack (including rcx and r11):
- ss
- rsp
- rflags
- cs
- rip
- r11
- rsp-> rcx
-
- In all the entrypoints, we undo all that to make it look
- like a CPU-generated syscall/sysenter and jump to the normal
- entrypoint.
+ * Xen handles syscall callbacks much like ordinary exceptions, which
+ * means we have:
+ * - kernel gs
+ * - kernel rsp
+ * - an iret-like stack frame on the stack (including rcx and r11):
+ * ss
+ * rsp
+ * rflags
+ * cs
+ * rip
+ * r11
+ * rsp->rcx
+ *
+ * In all the entrypoints, we undo all that to make it look like a
+ * CPU-generated syscall/sysenter and jump to the normal entrypoint.
*/
.macro undo_xen_syscall
- mov 0*8(%rsp),%rcx
- mov 1*8(%rsp),%r11
- mov 5*8(%rsp),%rsp
+ mov 0*8(%rsp), %rcx
+ mov 1*8(%rsp), %r11
+ mov 5*8(%rsp), %rsp
.endm
/* Normal 64-bit system call target */
ENTRY(xen_syscall32_target)
ENTRY(xen_sysenter_target)
- lea 16(%rsp), %rsp /* strip %rcx,%r11 */
+ lea 16(%rsp), %rsp /* strip %rcx, %r11 */
mov $-ENOSYS, %rax
pushq $VGCF_in_syscall
jmp hypercall_iret
git.samba.org / sfrench / cifs-2.6.git / blobdiff