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Diffstat (limited to 'arch/x86/include/asm/desc.h')
| -rw-r--r-- | arch/x86/include/asm/desc.h | 451 |
1 files changed, 451 insertions, 0 deletions
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h new file mode 100644 index 000000000..13c5ee878 --- /dev/null +++ b/arch/x86/include/asm/desc.h @@ -0,0 +1,451 @@ +/* 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/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; +} + +extern struct desc_ptr idt_descr; +extern gate_desc idt_table[]; +extern const struct desc_ptr debug_idt_descr; +extern gate_desc debug_idt_table[]; + +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 +#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 */ + +#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 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)); +} + +/* + * 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 update_intr_gate(unsigned int n, const void *addr); +void alloc_intr_gate(unsigned int n, const void *addr); + +extern unsigned long system_vectors[]; + +#ifdef CONFIG_X86_64 +DECLARE_PER_CPU(u32, debug_idt_ctr); +static inline bool is_debug_idt_enabled(void) +{ + if (this_cpu_read(debug_idt_ctr)) + return true; + + return false; +} + +static inline void load_debug_idt(void) +{ + load_idt((const struct desc_ptr *)&debug_idt_descr); +} +#else +static inline bool is_debug_idt_enabled(void) +{ + return false; +} + +static inline void load_debug_idt(void) +{ +} +#endif + +/* + * The load_current_idt() must be called with interrupts disabled + * to avoid races. That way the IDT will always be set back to the expected + * descriptor. It's also called when a CPU is being initialized, and + * that doesn't need to disable interrupts, as nothing should be + * bothering the CPU then. + */ +static inline void load_current_idt(void) +{ + if (is_debug_idt_enabled()) + load_debug_idt(); + else + load_idt((const struct desc_ptr *)&idt_descr); +} + +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); + +#ifdef CONFIG_X86_64 +extern void idt_setup_early_pf(void); +extern void idt_setup_ist_traps(void); +extern void idt_setup_debugidt_traps(void); +#else +static inline void idt_setup_early_pf(void) { } +static inline void idt_setup_ist_traps(void) { } +static inline void idt_setup_debugidt_traps(void) { } +#endif + +extern void idt_invalidate(void *addr); + +#endif /* _ASM_X86_DESC_H */ |