From: Ian.Campbell@xensource.com <Ian.Campbell@xensource.com>
Date: Wed, 11 Jan 2006 15:52:54 +0000 (+0000)
Subject: Pass NMIs to DOM0 via a dedicated callback, Xen/Linux i386 support.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~16541^2~61^2~10
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=716d68d4c2979938d4d4c36b0fe3fa34cc676621;p=xen.git

Pass NMIs to DOM0 via a dedicated callback, Xen/Linux i386 support.

Register our NMI handler with Xen. Use a pseudo-flag in EFLAGS in
indicate that we should return from the NMI via a hypervisor iret.

Signed-off-by: Ian Campbell <Ian.Campbell@XenSource.com>
---

diff --git a/linux-2.6-xen-sparse/arch/xen/i386/kernel/entry.S b/linux-2.6-xen-sparse/arch/xen/i386/kernel/entry.S
index 6522f7a249..9c50c32426 100644
--- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/entry.S
+++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/entry.S
@@ -76,7 +76,9 @@ IF_MASK		= 0x00000200
 DF_MASK		= 0x00000400 
 NT_MASK		= 0x00004000
 VM_MASK		= 0x00020000
-
+/* pseudo-eflags */
+NMI_MASK	= 0x80000000
+	
 /* Offsets into shared_info_t. */
 #define evtchn_upcall_pending		/* 0 */
 #define evtchn_upcall_mask		1
@@ -305,8 +307,8 @@ restore_all:
 	je ldt_ss			# returning to user-space with LDT SS
 #endif /* XEN */
 restore_nocheck:
-	testl $VM_MASK, EFLAGS(%esp)
-	jnz resume_vm86
+	testl $(VM_MASK|NMI_MASK), EFLAGS(%esp)
+	jnz hypervisor_iret
 	movb EVENT_MASK(%esp), %al
 	notb %al			# %al == ~saved_mask
 	XEN_GET_VCPU_INFO(%esi)
@@ -328,11 +330,11 @@ iret_exc:
 	.long 1b,iret_exc
 .previous
 
-resume_vm86:
-	XEN_UNBLOCK_EVENTS(%esi)
+hypervisor_iret:
+	andl $~NMI_MASK, EFLAGS(%esp)
 	RESTORE_REGS
 	movl %eax,(%esp)
-	movl $__HYPERVISOR_switch_vm86,%eax
+	movl $__HYPERVISOR_iret,%eax
 	int $0x82
 	ud2
 
@@ -691,6 +693,15 @@ debug_stack_correct:
 	call do_debug
 	jmp ret_from_exception
 
+ENTRY(nmi)
+	pushl %eax
+	SAVE_ALL
+	xorl %edx,%edx		# zero error code
+	movl %esp,%eax		# pt_regs pointer
+	call do_nmi
+	orl  $NMI_MASK, EFLAGS(%esp)
+	jmp restore_all
+
 #if 0 /* XEN */
 /*
  * NMI is doubly nasty. It can happen _while_ we're handling
diff --git a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/hypercall.h b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/hypercall.h
index 6fc4203116..04edbd3741 100644
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/hypercall.h
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/hypercall.h
@@ -32,6 +32,7 @@
 
 #include <asm-xen/xen-public/xen.h>
 #include <asm-xen/xen-public/sched.h>
+#include <asm-xen/xen-public/nmi.h>
 
 #define _hypercall0(type, name)			\
 ({						\
@@ -300,6 +301,14 @@ HYPERVISOR_suspend(
 			   SHUTDOWN_suspend, srec);
 }
 
+static inline int
+HYPERVISOR_nmi_op(
+	unsigned long op,
+	unsigned long arg)
+{
+	return _hypercall2(int, nmi_op, op, arg);
+}
+
 #endif /* __HYPERCALL_H__ */
 
 /*
diff --git a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/mach_traps.h b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/mach_traps.h
new file mode 100644
index 0000000000..14c607962b
--- /dev/null
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/mach_traps.h
@@ -0,0 +1,33 @@
+/*
+ *  include/asm-xen/asm-i386/mach-xen/mach_traps.h
+ *
+ *  Machine specific NMI handling for Xen
+ */
+#ifndef _MACH_TRAPS_H
+#define _MACH_TRAPS_H
+
+#include <linux/bitops.h>
+#include <asm-xen/xen-public/nmi.h>
+
+static inline void clear_mem_error(unsigned char reason) {}
+static inline void clear_io_check_error(unsigned char reason) {}
+
+static inline unsigned char get_nmi_reason(void)
+{
+	shared_info_t *s = HYPERVISOR_shared_info;
+	unsigned char reason = 0;
+
+	/* construct a value which looks like it came from
+	 * port 0x61.
+	 */
+	if (test_bit(_XEN_NMIREASON_io_error, &s->arch.nmi_reason))
+		reason |= 0x40;
+	if (test_bit(_XEN_NMIREASON_parity_error, &s->arch.nmi_reason))
+		reason |= 0x80;
+
+        return reason;
+}
+
+static inline void reassert_nmi(void) {}
+
+#endif /* !_MACH_TRAPS_H */
diff --git a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/setup_arch_post.h b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/setup_arch_post.h
index b30853d2cf..fa7d6191b1 100644
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/setup_arch_post.h
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/mach-xen/setup_arch_post.h
@@ -29,6 +29,7 @@ void __init machine_specific_modify_cpu_capabilities(struct cpuinfo_x86 *c)
 
 extern void hypervisor_callback(void);
 extern void failsafe_callback(void);
+extern void nmi(void);
 
 static void __init machine_specific_arch_setup(void)
 {
@@ -36,5 +37,7 @@ static void __init machine_specific_arch_setup(void)
 	    __KERNEL_CS, (unsigned long)hypervisor_callback,
 	    __KERNEL_CS, (unsigned long)failsafe_callback);
 
+	HYPERVISOR_nmi_op(XENNMI_register_callback, (unsigned long)&nmi);
+
 	machine_specific_modify_cpu_capabilities(&boot_cpu_data);
 }