android_kernel_motorola_sm6225/include/asm-i386/desc.h
Rusty Russell 522e93e3fc [PATCH] i386: Descriptor and trap table cleanups.
The implementation comes from Zach's [RFC, PATCH 10/24] i386 Vmi
descriptor changes:

Descriptor and trap table cleanups.  Add cleanly written accessors for
IDT and GDT gates so the subarch may override them.  Note that this
allows the hypervisor to transparently tweak the DPL of the descriptors
as well as the RPL of segments in those descriptors, with no unnecessary
kernel code modification.  It also allows the hypervisor implementation
of the VMI to tweak the gates, allowing for custom exception frames or
extra layers of indirection above the guest fault / IRQ handlers.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
2006-09-26 10:52:35 +02:00

198 lines
5.4 KiB
C

#ifndef __ARCH_DESC_H
#define __ARCH_DESC_H
#include <asm/ldt.h>
#include <asm/segment.h>
#define CPU_16BIT_STACK_SIZE 1024
#ifndef __ASSEMBLY__
#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/percpu.h>
#include <asm/mmu.h>
extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
struct Xgt_desc_struct {
unsigned short size;
unsigned long address __attribute__((packed));
unsigned short pad;
} __attribute__ ((packed));
extern struct Xgt_desc_struct idt_descr;
DECLARE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr);
static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
{
return (struct desc_struct *)per_cpu(cpu_gdt_descr, cpu).address;
}
/*
* This is the ldt that every process will get unless we need
* something other than this.
*/
extern struct desc_struct default_ldt[];
extern struct desc_struct idt_table[];
extern void set_intr_gate(unsigned int irq, void * addr);
static inline void pack_descriptor(__u32 *a, __u32 *b,
unsigned long base, unsigned long limit, unsigned char type, unsigned char flags)
{
*a = ((base & 0xffff) << 16) | (limit & 0xffff);
*b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
((type & 0xff) << 8) | ((flags & 0xf) << 12);
}
static inline void pack_gate(__u32 *a, __u32 *b,
unsigned long base, unsigned short seg, unsigned char type, unsigned char flags)
{
*a = (seg << 16) | (base & 0xffff);
*b = (base & 0xffff0000) | ((type & 0xff) << 8) | (flags & 0xff);
}
#define DESCTYPE_LDT 0x82 /* present, system, DPL-0, LDT */
#define DESCTYPE_TSS 0x89 /* present, system, DPL-0, 32-bit TSS */
#define DESCTYPE_TASK 0x85 /* present, system, DPL-0, task gate */
#define DESCTYPE_INT 0x8e /* present, system, DPL-0, interrupt gate */
#define DESCTYPE_TRAP 0x8f /* present, system, DPL-0, trap gate */
#define DESCTYPE_DPL3 0x60 /* DPL-3 */
#define DESCTYPE_S 0x10 /* !system */
#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"::"m" (tr))
#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"m" (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":"=m" (tr))
#define store_ldt(ldt) __asm__ ("sldt %0":"=m" (ldt))
#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
}
static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
{
__u32 *lp = (__u32 *)((char *)dt + entry*8);
*lp = entry_a;
*(lp+1) = entry_b;
}
#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
#define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
{
__u32 a, b;
pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
write_idt_entry(idt_table, gate, a, b);
}
static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
{
__u32 a, b;
pack_descriptor(&a, &b, (unsigned long)addr,
offsetof(struct tss_struct, __cacheline_filler) - 1,
DESCTYPE_TSS, 0);
write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
}
static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int entries)
{
__u32 a, b;
pack_descriptor(&a, &b, (unsigned long)addr,
entries * sizeof(struct desc_struct) - 1,
DESCTYPE_LDT, 0);
write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, a, b);
}
#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
#define LDT_entry_a(info) \
((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
#define LDT_entry_b(info) \
(((info)->base_addr & 0xff000000) | \
(((info)->base_addr & 0x00ff0000) >> 16) | \
((info)->limit & 0xf0000) | \
(((info)->read_exec_only ^ 1) << 9) | \
((info)->contents << 10) | \
(((info)->seg_not_present ^ 1) << 15) | \
((info)->seg_32bit << 22) | \
((info)->limit_in_pages << 23) | \
((info)->useable << 20) | \
0x7000)
#define LDT_empty(info) (\
(info)->base_addr == 0 && \
(info)->limit == 0 && \
(info)->contents == 0 && \
(info)->read_exec_only == 1 && \
(info)->seg_32bit == 0 && \
(info)->limit_in_pages == 0 && \
(info)->seg_not_present == 1 && \
(info)->useable == 0 )
static inline void clear_LDT(void)
{
int cpu = get_cpu();
set_ldt_desc(cpu, &default_ldt[0], 5);
load_LDT_desc();
put_cpu();
}
/*
* load one particular LDT into the current CPU
*/
static inline void load_LDT_nolock(mm_context_t *pc, int cpu)
{
void *segments = pc->ldt;
int count = pc->size;
if (likely(!count)) {
segments = &default_ldt[0];
count = 5;
}
set_ldt_desc(cpu, segments, count);
load_LDT_desc();
}
static inline void load_LDT(mm_context_t *pc)
{
int cpu = get_cpu();
load_LDT_nolock(pc, cpu);
put_cpu();
}
static inline unsigned long get_desc_base(unsigned long *desc)
{
unsigned long base;
base = ((desc[0] >> 16) & 0x0000ffff) |
((desc[1] << 16) & 0x00ff0000) |
(desc[1] & 0xff000000);
return base;
}
#endif /* !__ASSEMBLY__ */
#endif