The patch titled
x86: remove default_ldt, and simplify ldt-setting.
has been removed from the -mm tree. Its filename is
x86-remove-default_ldt-and-simplify-ldt-setting.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: x86: remove default_ldt, and simplify ldt-setting.
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
This patch removes the default_ldt[] array, as it has been unused since
iBCS stopped being supported. This means it is now possible to actually
set an empty LDT segment.
In order to deal with this, the set_ldt_desc/load_LDT pair has been
replaced with a single set_ldt() operation which is responsible for both
setting up the LDT descriptor in the GDT, and reloading the LDT register.
If there are no LDT entries, the LDT register is loaded with a NULL
descriptor.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Acked-by: Zachary Amsden <zach@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/ldt.c | 4 --
arch/i386/kernel/traps.c | 3 -
include/asm-i386/desc.h | 50 +++++++++++--------------------
include/asm-i386/mmu_context.h | 4 +-
4 files changed, 22 insertions(+), 39 deletions(-)
diff -puN arch/i386/kernel/ldt.c~x86-remove-default_ldt-and-simplify-ldt-setting arch/i386/kernel/ldt.c
--- a/arch/i386/kernel/ldt.c~x86-remove-default_ldt-and-simplify-ldt-setting
+++ a/arch/i386/kernel/ldt.c
@@ -160,16 +160,14 @@ static int read_default_ldt(void __user
{
int err;
unsigned long size;
- void *address;
err = 0;
- address = &default_ldt[0];
size = 5*sizeof(struct desc_struct);
if (size > bytecount)
size = bytecount;
err = size;
- if (copy_to_user(ptr, address, size))
+ if (clear_user(ptr, size))
err = -EFAULT;
return err;
diff -puN arch/i386/kernel/traps.c~x86-remove-default_ldt-and-simplify-ldt-setting arch/i386/kernel/traps.c
--- a/arch/i386/kernel/traps.c~x86-remove-default_ldt-and-simplify-ldt-setting
+++ a/arch/i386/kernel/traps.c
@@ -61,9 +61,6 @@ int panic_on_unrecovered_nmi;
asmlinkage int system_call(void);
-struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
- { 0, 0 }, { 0, 0 } };
-
/* Do we ignore FPU interrupts ? */
char ignore_fpu_irq = 0;
diff -puN include/asm-i386/desc.h~x86-remove-default_ldt-and-simplify-ldt-setting include/asm-i386/desc.h
--- a/include/asm-i386/desc.h~x86-remove-default_ldt-and-simplify-ldt-setting
+++ a/include/asm-i386/desc.h
@@ -33,11 +33,6 @@ static inline struct desc_struct *get_cp
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);
@@ -65,7 +60,6 @@ static inline void pack_gate(__u32 *a, _
#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))
@@ -115,13 +109,20 @@ static inline void __set_tss_desc(unsign
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)
+static inline void set_ldt(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);
+ if (likely(entries == 0))
+ __asm__ __volatile__("lldt %w0"::"q" (0));
+ else {
+ unsigned cpu = smp_processor_id();
+ __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);
+ __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
+ }
}
#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
@@ -153,35 +154,22 @@ static inline void set_ldt_desc(unsigned
static inline void clear_LDT(void)
{
- int cpu = get_cpu();
-
- set_ldt_desc(cpu, &default_ldt[0], 5);
- load_LDT_desc();
- put_cpu();
+ 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)
{
- 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();
+ 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();
}
static inline unsigned long get_desc_base(unsigned long *desc)
diff -puN include/asm-i386/mmu_context.h~x86-remove-default_ldt-and-simplify-ldt-setting include/asm-i386/mmu_context.h
--- a/include/asm-i386/mmu_context.h~x86-remove-default_ldt-and-simplify-ldt-setting
+++ a/include/asm-i386/mmu_context.h
@@ -44,7 +44,7 @@ static inline void switch_mm(struct mm_s
* load the LDT, if the LDT is different:
*/
if (unlikely(prev->context.ldt != next->context.ldt))
- load_LDT_nolock(&next->context, cpu);
+ load_LDT_nolock(&next->context);
}
#ifdef CONFIG_SMP
else {
@@ -56,7 +56,7 @@ static inline void switch_mm(struct mm_s
* tlb flush IPI delivery. We must reload %cr3.
*/
load_cr3(next->pgd);
- load_LDT_nolock(&next->context, cpu);
+ load_LDT_nolock(&next->context);
}
}
#endif
_
Patches currently in -mm which might be from jeremy@xxxxxxxx are
i386-use-asm-offsets-for-the-offsets-of-registers-into-the-pt_regs-struct-rather-than-having-hard-coded-constants.patch
i386-pda-basic-definitions-for-i386-pda.patch
i386-pda-initialize-the-per-cpu-data-area.patch
i386-pda-initialize-the-per-cpu-data-area-voyager-fix.patch
i386-pda-use-%gs-as-the-pda-base-segment-in-the-kernel.patch
i386-pda-fix-places-where-using-%gs-changes-the-usermode-abi.patch
i386-pda-update-sys_vm86-to-cope-with-changed-pt_regs-and-%gs-usage.patch
i386-pda-implement-smp_processor_id-with-the-pda.patch
i386-pda-implement-current-with-the-pda.patch
i386-pda-store-the-interrupt-regs-pointer-in-the-pda.patch
generic-bug-implementation.patch
generic-bug-for-i386.patch
generic-bug-for-x86-64.patch
uml-add-generic-bug-support.patch
use-generic-bug-for-ppc.patch
bug-test-1.patch
time-uninline-jiffiesh-fix.patch
-
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