1 files changed, 71 insertions, 39 deletions

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 6c279c8f0a0e..ae2a2e2d6362 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -501,7 +501,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
 static inline bool desc_equal(const struct desc_struct *d1,
 			      const struct desc_struct *d2)
 {
-	return d1->a == d2->a && d1->b == d2->b;
+	return !memcmp(d1, d2, sizeof(*d1));
 }
 
 static void load_TLS_descriptor(struct thread_struct *t,
@@ -586,59 +586,91 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 	preempt_enable();
 }
 
+#ifdef CONFIG_X86_64
+struct trap_array_entry {
+	void (*orig)(void);
+	void (*xen)(void);
+	bool ist_okay;
+};
+
+static struct trap_array_entry trap_array[] = {
+	{ debug,                       xen_xendebug,                    true },
+	{ int3,                        xen_xenint3,                     true },
+	{ double_fault,                xen_double_fault,                true },
+#ifdef CONFIG_X86_MCE
+	{ machine_check,               xen_machine_check,               true },
+#endif
+	{ nmi,                         xen_nmi,                         true },
+	{ overflow,                    xen_overflow,                    false },
+#ifdef CONFIG_IA32_EMULATION
+	{ entry_INT80_compat,          xen_entry_INT80_compat,          false },
+#endif
+	{ page_fault,                  xen_page_fault,                  false },
+	{ divide_error,                xen_divide_error,                false },
+	{ bounds,                      xen_bounds,                      false },
+	{ invalid_op,                  xen_invalid_op,                  false },
+	{ device_not_available,        xen_device_not_available,        false },
+	{ coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
+	{ invalid_TSS,                 xen_invalid_TSS,                 false },
+	{ segment_not_present,         xen_segment_not_present,         false },
+	{ stack_segment,               xen_stack_segment,               false },
+	{ general_protection,          xen_general_protection,          false },
+	{ spurious_interrupt_bug,      xen_spurious_interrupt_bug,      false },
+	{ coprocessor_error,           xen_coprocessor_error,           false },
+	{ alignment_check,             xen_alignment_check,             false },
+	{ simd_coprocessor_error,      xen_simd_coprocessor_error,      false },
+};
+
+static bool get_trap_addr(void **addr, unsigned int ist)
+{
+	unsigned int nr;
+	bool ist_okay = false;
+
+	/*
+	 * Replace trap handler addresses by Xen specific ones.
+	 * Check for known traps using IST and whitelist them.
+	 * The debugger ones are the only ones we care about.
+	 * Xen will handle faults like double_fault, * so we should never see
+	 * them.  Warn if there's an unexpected IST-using fault handler.
+	 */
+	for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
+		struct trap_array_entry *entry = trap_array + nr;
+
+		if (*addr == entry->orig) {
+			*addr = entry->xen;
+			ist_okay = entry->ist_okay;
+			break;
+		}
+	}
+
+	if (WARN_ON(ist != 0 && !ist_okay))
+		return false;
+
+	return true;
+}
+#endif
+
 static int cvt_gate_to_trap(int vector, const gate_desc *val,
 			    struct trap_info *info)
 {
 	unsigned long addr;
 
-	if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
+	if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
 		return 0;
 
 	info->vector = vector;
 
-	addr = gate_offset(*val);
+	addr = gate_offset(val);
 #ifdef CONFIG_X86_64
-	/*
-	 * Look for known traps using IST, and substitute them
-	 * appropriately.  The debugger ones are the only ones we care
-	 * about.  Xen will handle faults like double_fault,
-	 * so we should never see them.  Warn if
-	 * there's an unexpected IST-using fault handler.
-	 */
-	if (addr == (unsigned long)debug)
-		addr = (unsigned long)xen_debug;
-	else if (addr == (unsigned long)int3)
-		addr = (unsigned long)xen_int3;
-	else if (addr == (unsigned long)stack_segment)
-		addr = (unsigned long)xen_stack_segment;
-	else if (addr == (unsigned long)double_fault) {
-		/* Don't need to handle these */
+	if (!get_trap_addr((void **)&addr, val->bits.ist))
 		return 0;
-#ifdef CONFIG_X86_MCE
-	} else if (addr == (unsigned long)machine_check) {
-		/*
-		 * when xen hypervisor inject vMCE to guest,
-		 * use native mce handler to handle it
-		 */
-		;
-#endif
-	} else if (addr == (unsigned long)nmi)
-		/*
-		 * Use the native version as well.
-		 */
-		;
-	else {
-		/* Some other trap using IST? */
-		if (WARN_ON(val->ist != 0))
-			return 0;
-	}
 #endif	/* CONFIG_X86_64 */
 	info->address = addr;
 
-	info->cs = gate_segment(*val);
-	info->flags = val->dpl;
+	info->cs = gate_segment(val);
+	info->flags = val->bits.dpl;
 	/* interrupt gates clear IF */
-	if (val->type == GATE_INTERRUPT)
+	if (val->bits.type == GATE_INTERRUPT)
 		info->flags |= 1 << 2;
 
 	return 1;