[PATCH 8/16] add native functions for descriptors handling

Glauber de Oliveira Costa
2007-10-31T23:01:26Z

This patch turns the basic descriptor handling into native_
functions. It is basically write_idt, load_idt, write_gdt,
load_gdt, set_ldt, store_tr, load_tls, and the ones
for updating a single entry.

In the process of doing that, we change the definition of
load_LDT_nolock, and caller sites have to be patched. We
also patch call sites that now needs a typecast.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
---
arch/x86/kernel/ldt_64.c | 7 +-
include/asm-x86/desc_64.h | 172 +++++++++++++++++++++++++-------------
include/asm-x86/mmu_context_64.h | 23 ++++--
3 files changed, 132 insertions(+), 70 deletions(-)

diff --git a/arch/x86/kernel/ldt_64.c b/arch/x86/kernel/ldt_64.c
index 60e57ab..ab1ff6e 100644
--- a/arch/x86/kernel/ldt_64.c
+++ b/arch/x86/kernel/ldt_64.c
@@ -171,7 +171,7 @@ static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode)
{
struct task_struct *me = current;
struct mm_struct * mm = me->mm;
- __u32 entry_1, entry_2, *lp;
+ __u32 entry_1, entry_2;
int error;
struct user_desc ldt_info;

@@ -200,7 +200,6 @@ static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode)
goto out_unlock;
}

- lp = (__u32 *) ((ldt_info.entry_number << 3) + (char *) mm->context.ldt);

/* Allow LDTs to be cleared by the user. */
if (ldt_info.base_addr == 0 && ldt_info.limit == 0) {
@@ -218,8 +217,8 @@ static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode)

/* Install the new entry ... */
install:
- *lp = entry_1;
- *(lp+1) = entry_2;
+ write_ldt_entry(mm->context.ldt, ldt_info.entry_number,
+ entry_1, entry_2);
error = 0;

out_unlock:
diff --git a/include/asm-x86/desc_64.h b/include/asm-x86/desc_64.h
index 7d9c938..f7008bb 100644
--- a/include/asm-x86/desc_64.h
+++ b/include/asm-x86/desc_64.h
@@ -16,20 +16,18 @@

extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];

-#define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
-#define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
-#define clear_LDT() asm volatile("lldt %w0"::"r" (0))
+static inline void native_load_tr_desc(void)
+{
+ asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8));
+}

-static inline unsigned long __store_tr(void)
+static inline unsigned long native_store_tr(void)
{
unsigned long tr;
-
asm volatile ("str %w0":"=r" (tr));
return tr;
}

-#define store_tr(tr) (tr) = __store_tr()
-
/*
* This is the ldt that every process will get unless we need
* something other than this.
@@ -41,62 +39,51 @@ extern struct desc_ptr cpu_gdt_descr[];
/* the cpu gdt accessor */
#define cpu_gdt(_cpu) ((struct desc_struct *)cpu_gdt_descr[_cpu].address)

-static inline void load_gdt(const struct desc_ptr *ptr)
+static inline void native_load_gdt(const struct desc_ptr *ptr)
{
asm volatile("lgdt %w0"::"m" (*ptr));
}

-static inline void store_gdt(struct desc_ptr *ptr)
+static inline void native_store_gdt(struct desc_ptr *ptr)
{
- asm("sgdt %w0":"=m" (*ptr));
+ asm volatile ("sgdt %w0":"=m" (*ptr));
}

-static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
+static inline void native_write_idt_entry(void *adr, struct gate_struct *s)
{
- struct gate_struct s;
- s.offset_low = PTR_LOW(func);
- s.segment = __KERNEL_CS;
- s.ist = ist;
- s.p = 1;
- s.dpl = dpl;
- s.zero0 = 0;
- s.zero1 = 0;
- s.type = type;
- s.offset_middle = PTR_MIDDLE(func);
- s.offset_high = PTR_HIGH(func);
- /* does not need to be atomic because it is only done once at setup time */
- memcpy(adr, &s, 16);
-}
-
-static inline void set_intr_gate(int nr, void *func)
-{
- BUG_ON((unsigned)nr > 0xFF);
- _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
-}
+ /* does not need to be atomic because
+ * it is only done once at setup time */
+ memcpy(adr, s, 16);
+}

-static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
-{
- BUG_ON((unsigned)nr > 0xFF);
- _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
-}
+static inline void native_write_gdt_entry(void *ptr, void *entry,
+ unsigned type, unsigned size)
+{
+ memcpy(ptr, entry, size);
+}

-static inline void set_system_gate(int nr, void *func)
-{
- BUG_ON((unsigned)nr > 0xFF);
- _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
-}
+/*
+ * This one unfortunately can't go with the others, in below, because it has
+ * an user anxious for its definition: set_tssldt_descriptor
+ */
+#ifndef CONFIG_PARAVIRT
+#define write_gdt_entry(_ptr, _e, _type, _size) \
+ native_write_gdt_entry((_ptr), (_e), (_type), (_size))
+#endif

-static inline void set_system_gate_ist(int nr, void *func, unsigned ist)
+static inline void write_dt_entry(struct desc_struct *dt,
+ int entry, u32 entry_low, u32 entry_high)
{
- _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, ist);
+ ((struct n_desc_struct *)dt)[entry].a = entry_low;
+ ((struct n_desc_struct *)dt)[entry].b = entry_high;
}

-static inline void load_idt(const struct desc_ptr *ptr)
+static inline void native_load_idt(const struct desc_ptr *ptr)
{
asm volatile("lidt %w0"::"m" (*ptr));
}

-static inline void store_idt(struct desc_ptr *dtr)
+static inline void native_store_idt(struct desc_ptr *dtr)
{
asm("sidt %w0":"=m" (*dtr));
}
@@ -114,7 +101,7 @@ static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned
d.limit1 = (size >> 16) & 0xF;
d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
d.base3 = PTR_HIGH(tss);
- memcpy(ptr, &d, 16);
+ write_gdt_entry(ptr, &d, type, 16);
}

static inline void set_tss_desc(unsigned cpu, void *addr)
@@ -165,7 +152,7 @@ static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
(info)->useable == 0 && \
(info)->lm == 0)

-static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
+static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
{
unsigned int i;
u64 *gdt = (u64 *)(cpu_gdt(cpu) + GDT_ENTRY_TLS_MIN);
@@ -173,28 +160,93 @@ static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
gdt[i] = t->tls_array[i];
}
+static inline void native_set_ldt(const void *addr,
+ unsigned int entries)
+{
+ if (likely(entries == 0))
+ __asm__ __volatile__ ("lldt %w0" :: "r" (0));
+ else {
+ unsigned cpu = smp_processor_id();
+
+ set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_LDT],
+ (unsigned long)addr, DESC_LDT,
+ entries * 8 - 1);
+ __asm__ __volatile__ ("lldt %w0"::"r" (GDT_ENTRY_LDT*8));
+ }
+}
+
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
+#define load_TR_desc() native_load_tr_desc()
+#define load_gdt(ptr) native_load_gdt(ptr)
+#define load_idt(ptr) native_load_idt(ptr)
+#define load_TLS(t, cpu) native_load_tls(t, cpu)
+#define set_ldt(addr, entries) native_set_ldt(addr, entries)
+#define store_tr(tr) (tr) = native_store_tr()
+#define store_gdt(ptr) native_store_gdt(ptr)
+#define store_idt(ptr) native_store_idt(ptr)
+
+#define write_idt_entry(_adr, _s) native_write_idt_entry((_adr), (_s))
+#define write_ldt_entry(_ldt, _number, _entry1, _entry2) \
+ write_dt_entry((_ldt), (_number), (_entry1), (_entry2))
+#endif
+
+static inline void _set_gate(void *adr, unsigned type, unsigned long func,
+ unsigned dpl, unsigned ist)
+{
+ struct gate_struct s;
+ s.offset_low = PTR_LOW(func);
+ s.segment = __KERNEL_CS;
+ s.ist = ist;
+ s.p = 1;
+ s.dpl = dpl;
+ s.zero0 = 0;
+ s.zero1 = 0;
+ s.type = type;
+ s.offset_middle = PTR_MIDDLE(func);
+ s.offset_high = PTR_HIGH(func);
+ write_idt_entry(adr, &s);
+}
+
+static inline void set_intr_gate(int nr, void *func)
+{
+ BUG_ON((unsigned)nr > 0xFF);
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
+}
+
+static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
+{
+ BUG_ON((unsigned)nr > 0xFF);
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
+}
+
+static inline void set_system_gate(int nr, void *func)
+{
+ BUG_ON((unsigned)nr > 0xFF);
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
+}
+
+static inline void set_system_gate_ist(int nr, void *func, unsigned ist)
+{
+ _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, ist);
+}
+
+#define clear_LDT() set_ldt(NULL, 0)

/*
* load one particular LDT into the current CPU
*/
-static inline void load_LDT_nolock (mm_context_t *pc, int cpu)
+static inline void load_LDT_nolock(mm_context_t *pc)
{
- int count = pc->size;
-
- if (likely(!count)) {
- clear_LDT();
- return;
- }
-
- set_ldt_desc(cpu, pc->ldt, count);
- load_LDT_desc();
+ set_ldt(pc->ldt, pc->size);
}

static inline void load_LDT(mm_context_t *pc)
{
- int cpu = get_cpu();
- load_LDT_nolock(pc, cpu);
- put_cpu();
+ preempt_disable();
+ load_LDT_nolock(pc);
+ preempt_enable();
}

extern struct desc_ptr idt_descr;
diff --git a/include/asm-x86/mmu_context_64.h b/include/asm-x86/mmu_context_64.h
index 0cce83a..841ee33 100644
--- a/include/asm-x86/mmu_context_64.h
+++ b/include/asm-x86/mmu_context_64.h
@@ -7,7 +7,16 @@
#include <asm/pda.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
+
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
#include <asm-generic/mm_hooks.h>
+static inline void paravirt_activate_mm(struct mm_struct *prev,
+ struct mm_struct *next)
+{
+}
+#endif /* CONFIG_PARAVIRT */

/*
* possibly do the LDT unload here?
@@ -25,7 +34,7 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)

static inline void load_cr3(pgd_t *pgd)
{
- asm volatile("movq %0,%%cr3" :: "r" (__pa(pgd)) : "memory");
+ write_cr3(__pa(pgd));
}

static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
@@ -43,7 +52,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
load_cr3(next->pgd);

if (unlikely(next->context.ldt != prev->context.ldt))
- load_LDT_nolock(&next->context, cpu);
+ load_LDT_nolock(&next->context);
}
#ifdef CONFIG_SMP
else {
@@ -56,7 +65,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
* to make sure to use no freed page tables.
*/
load_cr3(next->pgd);
- load_LDT_nolock(&next->context, cpu);
+ load_LDT_nolock(&next->context);
}
}
#endif
@@ -67,8 +76,10 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
asm volatile("movl %0,%%fs"::"r"(0)); \
} while(0)

-#define activate_mm(prev, next) \
- switch_mm((prev),(next),NULL)
-
+#define activate_mm(prev, next) \
+do { \
+ paravirt_activate_mm(prev, next); \
+ switch_mm((prev), (next), NULL); \
+} while (0)

#endif
--
1.4.4.2