[PATCH 09/19] introduce fill_ldt

Glauber de Oliveira Costa
2007-12-12T15:41:38Z

This patch introduces fill_ldt(), which populates a ldt descriptor
from a user_desc in once, instead of relying in the LDT_entry_a and
LDT_entry_b macros

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
---
arch/x86/kernel/ldt.c | 3 +--
arch/x86/kernel/process_64.c | 3 +--
arch/x86/kernel/tls.c | 7 +++----
include/asm-x86/desc_32.h | 15 ---------------
include/asm-x86/desc_64.h | 17 -----------------
include/asm-x86/ldt.h | 19 +++++++++++++++++++
6 files changed, 24 insertions(+), 40 deletions(-)

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 7eb0c8a..3e872b4 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -223,8 +223,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
}
}

- ldt.a = LDT_entry_a(&ldt_info);
- ldt.b = LDT_entry_b(&ldt_info);
+ fill_ldt(&ldt, &ldt_info);
if (oldmode)
ldt.avl = 0;

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e09d9f1..abf32e3 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -446,8 +446,7 @@ static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
};
struct desc_struct *desc = (void *)t->thread.tls_array;
desc += tls;
- desc->a = LDT_entry_a(&ud);
- desc->b = LDT_entry_b(&ud);
+ fill_ldt(desc, &ud);
}

static inline u32 read_32bit_tls(struct task_struct *t, int tls)
diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c
index 67a3776..74d2b65 100644
--- a/arch/x86/kernel/tls.c
+++ b/arch/x86/kernel/tls.c
@@ -67,10 +67,9 @@ int do_set_thread_area(struct task_struct *p, int idx,
if (LDT_empty(&info)) {
desc[0] = 0;
desc[1] = 0;
- } else {
- desc[0] = LDT_entry_a(&info);
- desc[1] = LDT_entry_b(&info);
- }
+ } else
+ fill_ldt((struct desc_struct *)desc, &info);
+
if (t == &current->thread)
load_TLS(t, cpu);

diff --git a/include/asm-x86/desc_32.h b/include/asm-x86/desc_32.h
index 54b2314..0370099 100644
--- a/include/asm-x86/desc_32.h
+++ b/include/asm-x86/desc_32.h
@@ -163,21 +163,6 @@ static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const vo

#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 && \
diff --git a/include/asm-x86/desc_64.h b/include/asm-x86/desc_64.h
index 8fe1b4c..e0aa4bc 100644
--- a/include/asm-x86/desc_64.h
+++ b/include/asm-x86/desc_64.h
@@ -147,23 +147,6 @@ static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
(unsigned long)addr, DESC_LDT, size * 8 - 1);
}

-#define LDT_entry_a(info) \
- ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
-/* Don't allow setting of the lm bit. It is useless anyways because
- 64bit system calls require __USER_CS. */
-#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) | \
- /* ((info)->lm << 21) | */ \
- 0x7000)
-
#define LDT_empty(info) (\
(info)->base_addr == 0 && \
(info)->limit == 0 && \
diff --git a/include/asm-x86/ldt.h b/include/asm-x86/ldt.h
index 20c5972..49013fd 100644
--- a/include/asm-x86/ldt.h
+++ b/include/asm-x86/ldt.h
@@ -5,6 +5,7 @@
*/
#ifndef _ASM_X86_LDT_H
#define _ASM_X86_LDT_H
+#include <asm/desc_defs.h>

/* Maximum number of LDT entries supported. */
#define LDT_ENTRIES 8192
@@ -32,6 +33,24 @@ struct user_desc {
#endif
};

+static inline void fill_ldt(struct desc_struct *desc, 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;
+ desc->s = 1;
+ desc->dpl = 0x3;
+ desc->p = info->seg_not_present ^ 1;
+ desc->limit = (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;
+}
+
#define MODIFY_LDT_CONTENTS_DATA 0
#define MODIFY_LDT_CONTENTS_STACK 1
#define MODIFY_LDT_CONTENTS_CODE 2
--
1.5.0.6