Add x86 debug register Xen support

* i386/xen/xen_boothdr.S: Add global visibility to __hyp_* symbols.
* i386/i386/locore.S [MACH_XEN] (dr6,dr0,dr1,dr2,dr3): Make get_debugreg and
set_debugreg hypercalls to manipulate debug registers.
(dr0,dr1,dr2,dr3): Fix dr7 field shift.
* i386/i386/xen.h (hyp_set_debugreg, hyp_get_debugreg): New prototypes.

3 files changed, 55 insertions, 2 deletions

diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index c640191..c1e6448 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -1419,7 +1419,14 @@ _inst_fetch_fault:
 
 
 ENTRY(dr6)
+#ifdef MACH_XEN
+	pushl	%ebx
+	movl	$6, %ebx
+	call	__hyp_get_debugreg
+	popl	%ebx
+#else /* MACH_XEN */
 	movl	%db6, %eax
+#endif /* MACH_XEN */
 	ret
 
 /*	dr<i>(address, type, len, persistence)
@@ -1427,33 +1434,67 @@ ENTRY(dr6)
 ENTRY(dr0)
 	movl	S_ARG0, %eax
 	movl	%eax,EXT(dr_addr)
+#ifdef MACH_XEN
+	pushl	%ebx
+	movl	$0,%ebx
+	movl	%eax,%ecx
+	call	__hyp_set_debugreg
+#else /* MACH_XEN */
 	movl	%eax, %db0
+#endif /* MACH_XEN */
 	movl	$0, %ecx
 	jmp	0f
 ENTRY(dr1)
 	movl	S_ARG0, %eax
 	movl	%eax,EXT(dr_addr)+1*4
+#ifdef MACH_XEN
+	pushl	%ebx
+	movl	$1,%ebx
+	movl	%eax,%ecx
+	call	__hyp_set_debugreg
+#else /* MACH_XEN */
 	movl	%eax, %db1
+#endif /* MACH_XEN */
 	movl	$2, %ecx
 	jmp	0f
 ENTRY(dr2)
 	movl	S_ARG0, %eax
 	movl	%eax,EXT(dr_addr)+2*4
+#ifdef MACH_XEN
+	pushl	%ebx
+	movl	$2,%ebx
+	movl	%eax,%ecx
+	call	__hyp_set_debugreg
+#else /* MACH_XEN */
 	movl	%eax, %db2
+#endif /* MACH_XEN */
 	movl	$4, %ecx
 	jmp	0f
 
 ENTRY(dr3)
 	movl	S_ARG0, %eax
 	movl	%eax,EXT(dr_addr)+3*4
+#ifdef MACH_XEN
+	pushl	%ebx
+	movl	$3,%ebx
+	movl	%eax,%ecx
+	call	__hyp_set_debugreg
+#else /* MACH_XEN */
 	movl	%eax, %db3
+#endif /* MACH_XEN */
 	movl	$6, %ecx
 
 0:
 	pushl	%ebp
 	movl	%esp, %ebp
 
+#ifdef MACH_XEN
+	movl	$7,%ebx
+	call	__hyp_get_debugreg
+	movl	%eax, %edx
+#else /* MACH_XEN */
 	movl	%db7, %edx
+#endif /* MACH_XEN */
 	movl	%edx,EXT(dr_addr)+4*4
 	andl	dr_msk(,%ecx,2),%edx	/* clear out new entry */
 	movl	%edx,EXT(dr_addr)+5*4
@@ -1464,6 +1505,7 @@ ENTRY(dr3)
 
 	movzbl	B_ARG1, %eax
 	andb	$3, %al
+	addb	%cl, %cl
 	addb	$0x10, %cl
 	shll	%cl, %eax
 	orl	%eax, %edx
@@ -1474,7 +1516,14 @@ ENTRY(dr3)
 	shll	%cl, %eax
 	orl	%eax, %edx
 
+#ifdef MACH_XEN
+	movl	$7,%ebx
+	movl	%edx, %ecx
+	call	__hyp_set_debugreg
+	popl	%ebx
+#else /* MACH_XEN */
 	movl	%edx, %db7
+#endif /* MACH_XEN */
 	movl	%edx,EXT(dr_addr)+7*4
 	movl	%edx, %eax
 	leave
diff --git a/i386/i386/xen.h b/i386/i386/xen.h
index 8094d34..731e5a2 100644
--- a/i386/i386/xen.h
+++ b/i386/i386/xen.h
@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org>
+ *  Copyright (C) 2006, 2009, 2010, 2011 Samuel Thibault <samuel.thibault@ens-lyon.org>
  *
  * This program is free software ; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -345,6 +345,9 @@ MACH_INLINE void __attribute__((noreturn)) hyp_reboot(void)
 	for(;;);
 }
 
+_hypcall2(int, set_debugreg, int, reg, unsigned long, value);
+_hypcall1(unsigned long, get_debugreg, int, reg);
+
 /* x86-specific */
 MACH_INLINE unsigned64_t hyp_cpu_clock(void) {
 	unsigned64_t tsc;
diff --git a/i386/xen/xen_boothdr.S b/i386/xen/xen_boothdr.S
index 6d595ab..1b32efb 100644
--- a/i386/xen/xen_boothdr.S
+++ b/i386/xen/xen_boothdr.S
@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org>
+ *  Copyright (C) 2006, 2009, 2010, 2011 Samuel Thibault <samuel.thibault@ens-lyon.org>
  *
  * This program is free software ; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -124,6 +124,7 @@ hyp_shared_info:
 /* Labels just for debuggers */
 #define hypcall(name, n) \
 	.org	hypcalls + n*32 ; \
+.globl __hyp_##name ; \
 __hyp_##name:
 
 hypcalls: