[RFC PATCH 19/33] Support gdt/idt/ldt handling on Xen.

[Chris Wright <chrisw@sous-sol.org>]

[-- Attachment #1: i386-desc --]
[-- Type: text/plain, Size: 8820 bytes --]

Move the macros which handle gdt/idt/ldt's into a subarch include
file and add implementations for running on Xen.

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
 arch/i386/mach-xen/memory.c               |   17 +++++++
 include/asm-i386/desc.h                   |   65 ++---------------------------
 include/asm-i386/mach-default/mach_desc.h |   67 ++++++++++++++++++++++++++++++
 include/asm-i386/mach-xen/mach_desc.h     |   62 +++++++++++++++++++++++++++
 4 files changed, 151 insertions(+), 60 deletions(-)

diff -r 3e5209fcdb56 arch/i386/mach-xen/memory.c
--- a/arch/i386/mach-xen/memory.c	Tue May  9 18:51:32 2006 +0100
+++ b/arch/i386/mach-xen/memory.c	Tue May  9 21:47:37 2006 +0100
@@ -29,3 +29,20 @@ void make_lowmem_page_readonly(unsigned 
 	rc = HYPERVISOR_update_va_mapping(address, pte_wrprotect(*pte), 0);
 	BUG_ON(rc);
 }
+
+void load_gdt(struct Xgt_desc_struct *gdt_descr)
+{
+	unsigned long frames[16];
+	unsigned long va;
+	int f;
+
+	for (va = gdt_descr->address, f = 0;
+	     va < gdt_descr->address + gdt_descr->size;
+	     va += PAGE_SIZE, f++) {
+		frames[f] = virt_to_mfn(va);
+		make_lowmem_page_readonly(va,
+					  XENFEAT_writable_descriptor_tables);
+	}
+	if (HYPERVISOR_set_gdt(frames, gdt_descr->size / 8))
+		BUG();
+}
diff -r 3e5209fcdb56 include/asm-i386/desc.h
--- a/include/asm-i386/desc.h	Tue May  9 18:51:32 2006 +0100
+++ b/include/asm-i386/desc.h	Tue May  9 21:47:37 2006 +0100
@@ -33,18 +33,7 @@ static inline struct desc_struct *get_cp
 	return (struct desc_struct *)per_cpu(cpu_gdt_descr, cpu).address;
 }
 
-#define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8))
-#define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8))
-
-#define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr))
-#define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr))
-#define load_tr(tr) __asm__ __volatile("ltr %0"::"mr" (tr))
-#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"mr" (ldt))
-
-#define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
-#define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
-#define store_tr(tr) __asm__ ("str %0":"=mr" (tr))
-#define store_ldt(ldt) __asm__ ("sldt %0":"=mr" (ldt))
+#include <mach_desc.h>
 
 /*
  * This is the ldt that every process will get unless we need
@@ -52,30 +41,6 @@ static inline struct desc_struct *get_cp
  */
 extern struct desc_struct default_ldt[];
 extern void set_intr_gate(unsigned int irq, void * addr);
-
-#define _set_tssldt_desc(n,addr,limit,type) \
-__asm__ __volatile__ ("movw %w3,0(%2)\n\t" \
-	"movw %w1,2(%2)\n\t" \
-	"rorl $16,%1\n\t" \
-	"movb %b1,4(%2)\n\t" \
-	"movb %4,5(%2)\n\t" \
-	"movb $0,6(%2)\n\t" \
-	"movb %h1,7(%2)\n\t" \
-	"rorl $16,%1" \
-	: "=m"(*(n)) : "q" (addr), "r"(n), "ir"(limit), "i"(type))
-
-static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
-{
-	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[entry], (int)addr,
-		offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
-}
-
-#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
-
-static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
-{
-	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
-}
 
 #define LDT_entry_a(info) \
 	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
@@ -102,30 +67,22 @@ static inline void set_ldt_desc(unsigned
 	(info)->seg_not_present	== 1	&& \
 	(info)->useable		== 0	)
 
-static inline void write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32 entry_b)
-{
-	__u32 *lp = (__u32 *)((char *)ldt + entry*8);
-	*lp = entry_a;
-	*(lp+1) = entry_b;
-}
-
 #if TLS_SIZE != 24
 # error update this code.
 #endif
 
 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 {
-#define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
-	C(0); C(1); C(2);
-#undef C
+	load_TLS_descriptor(t, cpu, 0);
+	load_TLS_descriptor(t, cpu, 1);
+	load_TLS_descriptor(t, cpu, 2);
 }
 
 static inline void clear_LDT(void)
 {
 	int cpu = get_cpu();
 
-	set_ldt_desc(cpu, &default_ldt[0], 5);
-	load_LDT_desc();
+	__set_ldt(cpu, DEFAULT_LDT, DEFAULT_LDT_SIZE);
 	put_cpu();
 }
 
@@ -138,12 +95,11 @@ static inline void load_LDT_nolock(mm_co
 	int count = pc->size;
 
 	if (likely(!count)) {
-		segments = &default_ldt[0];
-		count = 5;
+		segments = DEFAULT_LDT;
+		count = DEFAULT_LDT_SIZE;
 	}
 		
-	set_ldt_desc(cpu, segments, count);
-	load_LDT_desc();
+	__set_ldt(cpu, segments, count);
 }
 
 static inline void load_LDT(mm_context_t *pc)
diff -r 3e5209fcdb56 include/asm-i386/mach-default/mach_desc.h
--- /dev/null	Thu Jan  1 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-default/mach_desc.h	Tue May  9 21:47:37 2006 +0100
@@ -0,0 +1,62 @@
+#ifndef __ASM_MACH_DESC_H
+#define __ASM_MACH_DESC_H
+
+#define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8))
+#define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8))
+
+#define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr))
+#define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr))
+#define load_tr(tr) __asm__ __volatile("ltr %0"::"mr" (tr))
+#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"mr" (ldt))
+
+#define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
+#define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
+#define store_tr(tr) __asm__ ("str %0":"=mr" (tr))
+#define store_ldt(ldt) __asm__ ("sldt %0":"=mr" (ldt))
+
+#define _set_tssldt_desc(n,addr,limit,type) \
+__asm__ __volatile__ ("movw %w3,0(%2)\n\t" \
+	"movw %w1,2(%2)\n\t" \
+	"rorl $16,%1\n\t" \
+	"movb %b1,4(%2)\n\t" \
+	"movb %4,5(%2)\n\t" \
+	"movb $0,6(%2)\n\t" \
+	"movb %h1,7(%2)\n\t" \
+	"rorl $16,%1" \
+	: "=m"(*(n)) : "q" (addr), "r"(n), "ir"(limit), "i"(type))
+
+static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
+{
+	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[entry], (int)addr,
+		offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
+}
+
+#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
+
+static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
+{
+	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
+}
+
+#define DEFAULT_LDT &default_ldt[0]
+#define DEFAULT_LDT_SIZE 5
+static inline void __set_ldt(unsigned int cpu, void *addr, unsigned int size)
+{
+	set_ldt_desc(cpu, addr, size);
+	load_LDT_desc();
+}
+
+static inline void write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32 entry_b)
+{
+	__u32 *lp = (__u32 *)((char *)ldt + entry*8);
+	*lp = entry_a;
+	*(lp+1) = entry_b;
+}
+
+static inline void load_TLS_descriptor(struct thread_struct *t,
+				       unsigned int cpu, unsigned int i)
+{
+	get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
+}
+
+#endif /* __ASM_MACH_DESC_H */
diff -r 3e5209fcdb56 include/asm-i386/mach-xen/mach_desc.h
--- /dev/null	Thu Jan  1 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-xen/mach_desc.h	Tue May  9 21:47:37 2006 +0100
@@ -0,0 +1,51 @@
+#ifndef __ASM_MACH_DESC_H
+#define __ASM_MACH_DESC_H
+
+extern struct trap_info xen_trap_table[];
+
+#define load_TR_desc()
+
+void load_gdt(struct Xgt_desc_struct *gdt_descr);
+
+#define load_idt(dtr) HYPERVISOR_set_trap_table(xen_trap_table)
+#define load_tr(tr) __asm__ __volatile("ltr %0"::"mr" (tr))
+#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"mr" (ldt))
+
+#define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
+#define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
+#define store_tr(tr) __asm__ ("str %0":"=mr" (tr))
+#define store_ldt(ldt) __asm__ ("sldt %0":"=mr" (ldt))
+
+#define set_tss_desc(cpu,addr)
+
+static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
+{
+}
+
+#define DEFAULT_LDT NULL
+#define DEFAULT_LDT_SIZE 0
+static inline void __set_ldt(unsigned int cpu, void *addr, unsigned int size)
+{
+	struct mmuext_op op;
+	op.cmd = MMUEXT_SET_LDT;
+	op.arg1.linear_addr = (unsigned long)addr;
+	op.arg2.nr_ents = size;
+	BUG_ON(HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF) < 0);
+}
+
+static inline void write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32 entry_b) {
+        unsigned long lp = (unsigned long)ldt + entry * 8;
+        maddr_t mach_lp = arbitrary_virt_to_machine(lp);
+        HYPERVISOR_update_descriptor(mach_lp, (u64)entry_a |
+				     ((u64)entry_b<<32));
+}
+
+static inline void load_TLS_descriptor(struct thread_struct *t,
+				       unsigned int cpu, unsigned int i)
+{
+	HYPERVISOR_update_descriptor(
+		virt_to_machine(&get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN+i]),
+		*(u64 *)&t->tls_array[i]);
+}
+
+#endif /* __ASM_MACH_DESC_H */

--