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x86/iopl: Remove legacy IOPL option

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The IOPL emulation via the I/O bitmap is sufficient. Remove the legacy
cruft dealing with the (e)flags based IOPL mechanism.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com> (Paravirt and Xen parts)
Acked-by: Andy Lutomirski <luto@kernel.org>
This commit is contained in:
Thomas Gleixner
2019-11-11 23:03:29 +01:00
parent c8137ace56
commit a24ca99768
10 changed files with 17 additions and 119 deletions
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11
arch/x86/kernel/process_64.c
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@@ -497,17 +497,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
switch_to_extra(prev_p, next_p);
#ifdef CONFIG_XEN_PV
/*
* 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