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-rw-r--r--arch/x86/xen/xen-asm_32.S185
1 files changed, 0 insertions, 185 deletions
diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S
deleted file mode 100644
index 4757cec33abe..000000000000
--- a/arch/x86/xen/xen-asm_32.S
+++ /dev/null
@@ -1,185 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Asm versions of Xen pv-ops, suitable for direct use.
- *
- * We only bother with direct forms (ie, vcpu in pda) of the
- * operations here; the indirect forms are better handled in C.
- */
-
-#include <asm/thread_info.h>
-#include <asm/processor-flags.h>
-#include <asm/segment.h>
-#include <asm/asm.h>
-
-#include <xen/interface/xen.h>
-
-#include <linux/linkage.h>
-
-/* Pseudo-flag used for virtual NMI, which we don't implement yet */
-#define XEN_EFLAGS_NMI 0x80000000
-
-/*
- * This is run where a normal iret would be run, with the same stack setup:
- * 8: eflags
- * 4: cs
- * esp-> 0: eip
- *
- * This attempts to make sure that any pending events are dealt with
- * on return to usermode, but there is a small window in which an
- * event can happen just before entering usermode. If the nested
- * interrupt ends up setting one of the TIF_WORK_MASK pending work
- * flags, they will not be tested again before returning to
- * usermode. This means that a process can end up with pending work,
- * which will be unprocessed until the process enters and leaves the
- * kernel again, which could be an unbounded amount of time. This
- * means that a pending signal or reschedule event could be
- * indefinitely delayed.
- *
- * The fix is to notice a nested interrupt in the critical window, and
- * if one occurs, then fold the nested interrupt into the current
- * interrupt stack frame, and re-process it iteratively rather than
- * recursively. This means that it will exit via the normal path, and
- * all pending work will be dealt with appropriately.
- *
- * Because the nested interrupt handler needs to deal with the current
- * stack state in whatever form its in, we keep things simple by only
- * using a single register which is pushed/popped on the stack.
- */
-
-.macro POP_FS
-1:
- popw %fs
-.pushsection .fixup, "ax"
-2: movw $0, (%esp)
- jmp 1b
-.popsection
- _ASM_EXTABLE(1b,2b)
-.endm
-
-SYM_CODE_START(xen_iret)
- /* test eflags for special cases */
- testl $(X86_EFLAGS_VM | XEN_EFLAGS_NMI), 8(%esp)
- jnz hyper_iret
-
- push %eax
- ESP_OFFSET=4 # bytes pushed onto stack
-
- /* Store vcpu_info pointer for easy access */
-#ifdef CONFIG_SMP
- pushw %fs
- movl $(__KERNEL_PERCPU), %eax
- movl %eax, %fs
- movl %fs:xen_vcpu, %eax
- POP_FS
-#else
- movl %ss:xen_vcpu, %eax
-#endif
-
- /* check IF state we're restoring */
- testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp)
-
- /*
- * Maybe enable events. Once this happens we could get a
- * recursive event, so the critical region starts immediately
- * afterwards. However, if that happens we don't end up
- * resuming the code, so we don't have to be worried about
- * being preempted to another CPU.
- */
- setz %ss:XEN_vcpu_info_mask(%eax)
-xen_iret_start_crit:
-
- /* check for unmasked and pending */
- cmpw $0x0001, %ss:XEN_vcpu_info_pending(%eax)
-
- /*
- * If there's something pending, mask events again so we can
- * jump back into exc_xen_hypervisor_callback. Otherwise do not
- * touch XEN_vcpu_info_mask.
- */
- jne 1f
- movb $1, %ss:XEN_vcpu_info_mask(%eax)
-
-1: popl %eax
-
- /*
- * From this point on the registers are restored and the stack
- * updated, so we don't need to worry about it if we're
- * preempted
- */
-iret_restore_end:
-
- /*
- * Jump to hypervisor_callback after fixing up the stack.
- * Events are masked, so jumping out of the critical region is
- * OK.
- */
- je xen_asm_exc_xen_hypervisor_callback
-
-1: iret
-xen_iret_end_crit:
- _ASM_EXTABLE(1b, asm_iret_error)
-
-hyper_iret:
- /* put this out of line since its very rarely used */
- jmp hypercall_page + __HYPERVISOR_iret * 32
-SYM_CODE_END(xen_iret)
-
- .globl xen_iret_start_crit, xen_iret_end_crit
-
-/*
- * This is called by xen_asm_exc_xen_hypervisor_callback in entry_32.S when it sees
- * that the EIP at the time of interrupt was between
- * xen_iret_start_crit and xen_iret_end_crit.
- *
- * The stack format at this point is:
- * ----------------
- * ss : (ss/esp may be present if we came from usermode)
- * esp :
- * eflags } outer exception info
- * cs }
- * eip }
- * ----------------
- * eax : outer eax if it hasn't been restored
- * ----------------
- * eflags }
- * cs } nested exception info
- * eip }
- * return address : (into xen_asm_exc_xen_hypervisor_callback)
- *
- * In order to deliver the nested exception properly, we need to discard the
- * nested exception frame such that when we handle the exception, we do it
- * in the context of the outer exception rather than starting a new one.
- *
- * The only caveat is that if the outer eax hasn't been restored yet (i.e.
- * it's still on stack), we need to restore its value here.
-*/
-.pushsection .noinstr.text, "ax"
-SYM_CODE_START(xen_iret_crit_fixup)
- /*
- * Paranoia: Make sure we're really coming from kernel space.
- * One could imagine a case where userspace jumps into the
- * critical range address, but just before the CPU delivers a
- * PF, it decides to deliver an interrupt instead. Unlikely?
- * Definitely. Easy to avoid? Yes.
- */
- testb $2, 2*4(%esp) /* nested CS */
- jnz 2f
-
- /*
- * If eip is before iret_restore_end then stack
- * hasn't been restored yet.
- */
- cmpl $iret_restore_end, 1*4(%esp)
- jae 1f
-
- movl 4*4(%esp), %eax /* load outer EAX */
- ret $4*4 /* discard nested EIP, CS, and EFLAGS as
- * well as the just restored EAX */
-
-1:
- ret $3*4 /* discard nested EIP, CS, and EFLAGS */
-
-2:
- ret
-SYM_CODE_END(xen_iret_crit_fixup)
-.popsection