x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/lguest_hcall.h

@@ -0,0 +1,71 @@
+/* Architecture specific portion of the lguest hypercalls */
+#ifndef ASM_X86__LGUEST_HCALL_H
+#define ASM_X86__LGUEST_HCALL_H
+
+#define LHCALL_FLUSH_ASYNC	0
+#define LHCALL_LGUEST_INIT	1
+#define LHCALL_SHUTDOWN		2
+#define LHCALL_LOAD_GDT		3
+#define LHCALL_NEW_PGTABLE	4
+#define LHCALL_FLUSH_TLB	5
+#define LHCALL_LOAD_IDT_ENTRY	6
+#define LHCALL_SET_STACK	7
+#define LHCALL_TS		8
+#define LHCALL_SET_CLOCKEVENT	9
+#define LHCALL_HALT		10
+#define LHCALL_SET_PTE		14
+#define LHCALL_SET_PMD		15
+#define LHCALL_LOAD_TLS		16
+#define LHCALL_NOTIFY		17
+
+#define LGUEST_TRAP_ENTRY 0x1F
+
+/* Argument number 3 to LHCALL_LGUEST_SHUTDOWN */
+#define LGUEST_SHUTDOWN_POWEROFF	1
+#define LGUEST_SHUTDOWN_RESTART		2
+
+#ifndef __ASSEMBLY__
+#include <asm/hw_irq.h>
+
+/*G:031 But first, how does our Guest contact the Host to ask for privileged
+ * operations?  There are two ways: the direct way is to make a "hypercall",
+ * to make requests of the Host Itself.
+ *
+ * Our hypercall mechanism uses the highest unused trap code (traps 32 and
+ * above are used by real hardware interrupts).  Fifteen hypercalls are
+ * available: the hypercall number is put in the %eax register, and the
+ * arguments (when required) are placed in %edx, %ebx and %ecx.  If a return
+ * value makes sense, it's returned in %eax.
+ *
+ * Grossly invalid calls result in Sudden Death at the hands of the vengeful
+ * Host, rather than returning failure.  This reflects Winston Churchill's
+ * definition of a gentleman: "someone who is only rude intentionally". */
+static inline unsigned long
+hcall(unsigned long call,
+      unsigned long arg1, unsigned long arg2, unsigned long arg3)
+{
+	/* "int" is the Intel instruction to trigger a trap. */
+	asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
+		     /* The call in %eax (aka "a") might be overwritten */
+		     : "=a"(call)
+		       /* The arguments are in %eax, %edx, %ebx & %ecx */
+		     : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3)
+		       /* "memory" means this might write somewhere in memory.
+			* This isn't true for all calls, but it's safe to tell
+			* gcc that it might happen so it doesn't get clever. */
+		     : "memory");
+	return call;
+}
+/*:*/
+
+/* Can't use our min() macro here: needs to be a constant */
+#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32)
+
+#define LHCALL_RING_SIZE 64
+struct hcall_args {
+	/* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */
+	unsigned long arg0, arg2, arg3, arg1;
+};
+
+#endif /* !__ASSEMBLY__ */
+#endif /* ASM_X86__LGUEST_HCALL_H */