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authorLinus Torvalds <torvalds@linux-foundation.org>2016-03-24 09:47:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-24 09:47:32 -0700
commitd88f48e12821ab4b2244124d50ac094568f48db5 (patch)
tree4eb16b46898190aac33ed6125a9a0e734d5be10e /arch/x86/kernel/process_64.c
parentbe53f58fa0fcd97c62a84f2eb98cff528f8b2443 (diff)
parent9da77666d6975219281fd400eb9608a047337414 (diff)
downloadlinux-d88f48e12821ab4b2244124d50ac094568f48db5.tar.bz2
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar: "Misc fixes: - fix hotplug bugs - fix irq live lock - fix various topology handling bugs - fix APIC ACK ordering - fix PV iopl handling - fix speling - fix/tweak memcpy_mcsafe() return value - fix fbcon bug - remove stray prototypes" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/msr: Remove unused native_read_tscp() x86/apic: Remove declaration of unused hw_nmi_is_cpu_stuck x86/oprofile/nmi: Add missing hotplug FROZEN handling x86/hpet: Use proper mask to modify hotplug action x86/apic/uv: Fix the hotplug notifier x86/apb/timer: Use proper mask to modify hotplug action x86/topology: Use total_cpus not nr_cpu_ids for logical packages x86/topology: Fix Intel HT disable x86/topology: Fix logical package mapping x86/irq: Cure live lock in fixup_irqs() x86/tsc: Prevent NULL pointer deref in calibrate_delay_is_known() x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt() x86/iopl: Fix iopl capability check on Xen PV x86/iopl/64: Properly context-switch IOPL on Xen PV selftests/x86: Add an iopl test x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe() x86/video: Don't assume all FB devices are PCI devices arch/x86/irq: Purge useless handler declarations from hw_irq.h x86: Fix misspellings in comments
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r--arch/x86/kernel/process_64.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index dfa2781610e8..6cbab31ac23a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -48,6 +48,7 @@
#include <asm/syscalls.h>
#include <asm/debugreg.h>
#include <asm/switch_to.h>
+#include <asm/xen/hypervisor.h>
asmlinkage extern void ret_from_fork(void);
@@ -413,6 +414,17 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
__switch_to_xtra(prev_p, next_p, tss);
+#ifdef CONFIG_XEN
+ /*
+ * On Xen PV, IOPL bits in pt_regs->flags have no effect, and
+ * current_pt_regs()->flags may not match the current task's
+ * intended IOPL. We need to switch it manually.
+ */
+ if (unlikely(static_cpu_has(X86_FEATURE_XENPV) &&
+ prev->iopl != next->iopl))
+ xen_set_iopl_mask(next->iopl);
+#endif
+
if (static_cpu_has_bug(X86_BUG_SYSRET_SS_ATTRS)) {
/*
* AMD CPUs have a misfeature: SYSRET sets the SS selector but