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authorThomas Gleixner <tglx@linutronix.de>2020-05-21 23:05:26 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-06-11 16:15:08 +0300
commit2f6474e4636bcc68af6c44abb2703f12d7f083da (patch)
tree317a6b92fc169077e1eb9c3d7a10e3c62869109d /drivers/xen
parent1de16e0c17155d138282f3a9f65914a9a5da757e (diff)
downloadlinux-2f6474e4636bcc68af6c44abb2703f12d7f083da.tar.xz
x86/entry: Switch XEN/PV hypercall entry to IDTENTRY
Convert the XEN/PV hypercall to IDTENTRY: - Emit the ASM stub with DECLARE_IDTENTRY - Remove the ASM idtentry in 64-bit - Remove the open coded ASM entry code in 32-bit - Remove the old prototypes The handler stubs need to stay in ASM code as they need corner case handling and adjustment of the stack pointer. Provide a new C function which invokes the entry/exit handling and calls into the XEN handler on the interrupt stack if required. The exit code is slightly different from the regular idtentry_exit() on non-preemptible kernels. If the hypercall is preemptible and need_resched() is set then XEN provides a preempt hypercall scheduling function. Move this functionality into the entry code so it can use the existing idtentry functionality. [ mingo: Build fixes. ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Acked-by: Juergen Gross <jgross@suse.com> Tested-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20200521202118.055270078@linutronix.de
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/Makefile2
-rw-r--r--drivers/xen/preempt.c42
2 files changed, 1 insertions, 43 deletions
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 0c4efa6fe450..0d322f3d90cd 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
-obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o
+obj-y += grant-table.o features.o balloon.o manage.o time.o
obj-y += mem-reservation.o
obj-y += events/
obj-y += xenbus/
diff --git a/drivers/xen/preempt.c b/drivers/xen/preempt.c
deleted file mode 100644
index 17240c5325a3..000000000000
--- a/drivers/xen/preempt.c
+++ /dev/null
@@ -1,42 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Preemptible hypercalls
- *
- * Copyright (C) 2014 Citrix Systems R&D ltd.
- */
-
-#include <linux/sched.h>
-#include <xen/xen-ops.h>
-
-#ifndef CONFIG_PREEMPTION
-
-/*
- * Some hypercalls issued by the toolstack can take many 10s of
- * seconds. Allow tasks running hypercalls via the privcmd driver to
- * be voluntarily preempted even if full kernel preemption is
- * disabled.
- *
- * Such preemptible hypercalls are bracketed by
- * xen_preemptible_hcall_begin() and xen_preemptible_hcall_end()
- * calls.
- */
-
-DEFINE_PER_CPU(bool, xen_in_preemptible_hcall);
-EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall);
-
-asmlinkage __visible void xen_maybe_preempt_hcall(void)
-{
- if (unlikely(__this_cpu_read(xen_in_preemptible_hcall)
- && need_resched())) {
- /*
- * Clear flag as we may be rescheduled on a different
- * cpu.
- */
- __this_cpu_write(xen_in_preemptible_hcall, false);
- local_irq_enable();
- cond_resched();
- local_irq_disable();
- __this_cpu_write(xen_in_preemptible_hcall, true);
- }
-}
-#endif /* CONFIG_PREEMPTION */