Viewing file:  desc.h (11.25 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_DESC_H
#define _ASM_X86_DESC_H
#include <asm/desc_defs.h>
#include <asm/ldt.h>
#include <asm/mmu.h>
#include <asm/fixmap.h>
#include <asm/irq_vectors.h>
#include <asm/cpu_entry_area.h>
#include <linux/debug_locks.h>
#include <linux/smp.h>
#include <linux/percpu.h>
static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *info)
{
desc->limit0 = info->limit & 0x0ffff;
desc->base0 = (info->base_addr & 0x0000ffff);
desc->base1 = (info->base_addr & 0x00ff0000) >> 16;
desc->type = (info->read_exec_only ^ 1) << 1;
desc->type |= info->contents << 2;
/* Set the ACCESS bit so it can be mapped RO */
desc->type |= 1;
desc->s = 1;
desc->dpl = 0x3;
desc->p = info->seg_not_present ^ 1;
desc->limit1 = (info->limit & 0xf0000) >> 16;
desc->avl = info->useable;
desc->d = info->seg_32bit;
desc->g = info->limit_in_pages;
desc->base2 = (info->base_addr & 0xff000000) >> 24;
/*
* Don't allow setting of the lm bit. It would confuse
* user_64bit_mode and would get overridden by sysret anyway.
*/
desc->l = 0;
}
struct gdt_page {
struct desc_struct gdt[GDT_ENTRIES];
} __attribute__((aligned(PAGE_SIZE)));
DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page);
/* Provide the original GDT */
static inline struct desc_struct *get_cpu_gdt_rw(unsigned int cpu)
{
return per_cpu(gdt_page, cpu).gdt;
}
/* Provide the current original GDT */
static inline struct desc_struct *get_current_gdt_rw(void)
{
return this_cpu_ptr(&gdt_page)->gdt;
}
/* Provide the fixmap address of the remapped GDT */
static inline struct desc_struct *get_cpu_gdt_ro(int cpu)
{
return (struct desc_struct *)&get_cpu_entry_area(cpu)->gdt;
}
/* Provide the current read-only GDT */
static inline struct desc_struct *get_current_gdt_ro(void)
{
return get_cpu_gdt_ro(smp_processor_id());
}
/* Provide the physical address of the GDT page. */
static inline phys_addr_t get_cpu_gdt_paddr(unsigned int cpu)
{
return per_cpu_ptr_to_phys(get_cpu_gdt_rw(cpu));
}
static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
unsigned dpl, unsigned ist, unsigned seg)
{
gate->offset_low = (u16) func;
gate->bits.p = 1;
gate->bits.dpl = dpl;
gate->bits.zero = 0;
gate->bits.type = type;
gate->offset_middle = (u16) (func >> 16);
#ifdef CONFIG_X86_64
gate->segment = __KERNEL_CS;
gate->bits.ist = ist;
gate->reserved = 0;
gate->offset_high = (u32) (func >> 32);
#else
gate->segment = seg;
gate->bits.ist = 0;
#endif
}
static inline int desc_empty(const void *ptr)
{
const u32 *desc = ptr;
return !(desc[0] | desc[1]);
}
#ifdef CONFIG_PARAVIRT_XXL
#include <asm/paravirt.h>
#else
#define load_TR_desc() native_load_tr_desc()
#define load_gdt(dtr) native_load_gdt(dtr)
#define load_idt(dtr) native_load_idt(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) native_store_gdt(dtr)
#define store_tr(tr) (tr = native_store_tr())
#define load_TLS(t, cpu) native_load_tls(t, cpu)
#define set_ldt native_set_ldt
#define write_ldt_entry(dt, entry, desc) native_write_ldt_entry(dt, entry, desc)
#define write_gdt_entry(dt, entry, desc, type) native_write_gdt_entry(dt, entry, desc, type)
#define write_idt_entry(dt, entry, g) native_write_idt_entry(dt, entry, g)
static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
{
}
static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
{
}
#endif /* CONFIG_PARAVIRT_XXL */
#define store_ldt(ldt) asm("sldt %0" : "=m"(ldt))
static inline void native_write_idt_entry(gate_desc *idt, int entry, const gate_desc *gate)
{
memcpy(&idt[entry], gate, sizeof(*gate));
}
static inline void native_write_ldt_entry(struct desc_struct *ldt, int entry, const void *desc)
{
memcpy(&ldt[entry], desc, 8);
}
static inline void
native_write_gdt_entry(struct desc_struct *gdt, int entry, const void *desc, int type)
{
unsigned int size;
switch (type) {
case DESC_TSS: size = sizeof(tss_desc); break;
case DESC_LDT: size = sizeof(ldt_desc); break;
default: size = sizeof(*gdt); break;
}
memcpy(&gdt[entry], desc, size);
}
static inline void set_tssldt_descriptor(void *d, unsigned long addr,
unsigned type, unsigned size)
{
struct ldttss_desc *desc = d;
memset(desc, 0, sizeof(*desc));
desc->limit0 = (u16) size;
desc->base0 = (u16) addr;
desc->base1 = (addr >> 16) & 0xFF;
desc->type = type;
desc->p = 1;
desc->limit1 = (size >> 16) & 0xF;
desc->base2 = (addr >> 24) & 0xFF;
#ifdef CONFIG_X86_64
desc->base3 = (u32) (addr >> 32);
#endif
}
static inline void __set_tss_desc(unsigned cpu, unsigned int entry, struct x86_hw_tss *addr)
{
struct desc_struct *d = get_cpu_gdt_rw(cpu);
tss_desc tss;
set_tssldt_descriptor(&tss, (unsigned long)addr, DESC_TSS,
__KERNEL_TSS_LIMIT);
write_gdt_entry(d, entry, &tss, DESC_TSS);
}
#define set_tss_desc(cpu, addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
static inline void native_set_ldt(const void *addr, unsigned int entries)
{
if (likely(entries == 0))
asm volatile("lldt %w0"::"q" (0));
else {
unsigned cpu = smp_processor_id();
ldt_desc ldt;
set_tssldt_descriptor(&ldt, (unsigned long)addr, DESC_LDT,
entries * LDT_ENTRY_SIZE - 1);
write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_LDT,
&ldt, DESC_LDT);
asm volatile("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
}
}
static inline void native_load_gdt(const struct desc_ptr *dtr)
{
asm volatile("lgdt %0"::"m" (*dtr));
}
static __always_inline void native_load_idt(const struct desc_ptr *dtr)
{
asm volatile("lidt %0"::"m" (*dtr));
}
static inline void native_store_gdt(struct desc_ptr *dtr)
{
asm volatile("sgdt %0":"=m" (*dtr));
}
static inline void store_idt(struct desc_ptr *dtr)
{
asm volatile("sidt %0":"=m" (*dtr));
}
static inline void native_gdt_invalidate(void)
{
const struct desc_ptr invalid_gdt = {
.address = 0,
.size = 0
};
native_load_gdt(&invalid_gdt);
}
static inline void native_idt_invalidate(void)
{
const struct desc_ptr invalid_idt = {
.address = 0,
.size = 0
};
native_load_idt(&invalid_idt);
}
/*
* The LTR instruction marks the TSS GDT entry as busy. On 64-bit, the GDT is
* a read-only remapping. To prevent a page fault, the GDT is switched to the
* original writeable version when needed.
*/
#ifdef CONFIG_X86_64
static inline void native_load_tr_desc(void)
{
struct desc_ptr gdt;
int cpu = raw_smp_processor_id();
bool restore = 0;
struct desc_struct *fixmap_gdt;
native_store_gdt(&gdt);
fixmap_gdt = get_cpu_gdt_ro(cpu);
/*
* If the current GDT is the read-only fixmap, swap to the original
* writeable version. Swap back at the end.
*/
if (gdt.address == (unsigned long)fixmap_gdt) {
load_direct_gdt(cpu);
restore = 1;
}
asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
if (restore)
load_fixmap_gdt(cpu);
}
#else
static inline void native_load_tr_desc(void)
{
asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
}
#endif
static inline unsigned long native_store_tr(void)
{
unsigned long tr;
asm volatile("str %0":"=r" (tr));
return tr;
}
static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
{
struct desc_struct *gdt = get_cpu_gdt_rw(cpu);
unsigned int i;
for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
}
DECLARE_PER_CPU(bool, __tss_limit_invalid);
static inline void force_reload_TR(void)
{
struct desc_struct *d = get_current_gdt_rw();
tss_desc tss;
memcpy(&tss, &d[GDT_ENTRY_TSS], sizeof(tss_desc));
/*
* LTR requires an available TSS, and the TSS is currently
* busy. Make it be available so that LTR will work.
*/
tss.type = DESC_TSS;
write_gdt_entry(d, GDT_ENTRY_TSS, &tss, DESC_TSS);
load_TR_desc();
this_cpu_write(__tss_limit_invalid, false);
}
/*
* Call this if you need the TSS limit to be correct, which should be the case
* if and only if you have TIF_IO_BITMAP set or you're switching to a task
* with TIF_IO_BITMAP set.
*/
static inline void refresh_tss_limit(void)
{
DEBUG_LOCKS_WARN_ON(preemptible());
if (unlikely(this_cpu_read(__tss_limit_invalid)))
force_reload_TR();
}
/*
* If you do something evil that corrupts the cached TSS limit (I'm looking
* at you, VMX exits), call this function.
*
* The optimization here is that the TSS limit only matters for Linux if the
* IO bitmap is in use. If the TSS limit gets forced to its minimum value,
* everything works except that IO bitmap will be ignored and all CPL 3 IO
* instructions will #GP, which is exactly what we want for normal tasks.
*/
static inline void invalidate_tss_limit(void)
{
DEBUG_LOCKS_WARN_ON(preemptible());
if (unlikely(test_thread_flag(TIF_IO_BITMAP)))
force_reload_TR();
else
this_cpu_write(__tss_limit_invalid, true);
}
/* This intentionally ignores lm, since 32-bit apps don't have that field. */
#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)
/* Lots of programs expect an all-zero user_desc to mean "no segment at all". */
static inline bool LDT_zero(const struct user_desc *info)
{
return (info->base_addr == 0 &&
info->limit == 0 &&
info->contents == 0 &&
info->read_exec_only == 0 &&
info->seg_32bit == 0 &&
info->limit_in_pages == 0 &&
info->seg_not_present == 0 &&
info->useable == 0);
}
static inline void clear_LDT(void)
{
set_ldt(NULL, 0);
}
static inline unsigned long get_desc_base(const struct desc_struct *desc)
{
return (unsigned)(desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24));
}
static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
{
desc->base0 = base & 0xffff;
desc->base1 = (base >> 16) & 0xff;
desc->base2 = (base >> 24) & 0xff;
}
static inline unsigned long get_desc_limit(const struct desc_struct *desc)
{
return desc->limit0 | (desc->limit1 << 16);
}
static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
{
desc->limit0 = limit & 0xffff;
desc->limit1 = (limit >> 16) & 0xf;
}
void alloc_intr_gate(unsigned int n, const void *addr);
static inline void init_idt_data(struct idt_data *data, unsigned int n,
const void *addr)
{
BUG_ON(n > 0xFF);
memset(data, 0, sizeof(*data));
data->vector = n;
data->addr = addr;
data->segment = __KERNEL_CS;
data->bits.type = GATE_INTERRUPT;
data->bits.p = 1;
}
static inline void idt_init_desc(gate_desc *gate, const struct idt_data *d)
{
unsigned long addr = (unsigned long) d->addr;
gate->offset_low = (u16) addr;
gate->segment = (u16) d->segment;
gate->bits = d->bits;
gate->offset_middle = (u16) (addr >> 16);
#ifdef CONFIG_X86_64
gate->offset_high = (u32) (addr >> 32);
gate->reserved = 0;
#endif
}
extern unsigned long system_vectors[];
extern void load_current_idt(void);
extern void idt_setup_early_handler(void);
extern void idt_setup_early_traps(void);
extern void idt_setup_traps(void);
extern void idt_setup_apic_and_irq_gates(void);
extern bool idt_is_f00f_address(unsigned long address);
#ifdef CONFIG_X86_64
extern void idt_setup_early_pf(void);
#else
static inline void idt_setup_early_pf(void) { }
#endif
extern void idt_invalidate(void);
#endif /* _ASM_X86_DESC_H */
|