30f4728954
Move __KERNEL32_CS up into the unused gdt entry. __KERNEL32_CS is used when entering the kernel so putting it first is useful when trying to keep boot gdt sizes to a minimum. Set the accessed bit on all gdt entries. We don't care so there is no need for the cpu to burn the extra cycles, and it potentially allows the pages to be immutable. Plus it is confusing when debugging and your gdt entries mysteriously change. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
45 lines
1.2 KiB
C
45 lines
1.2 KiB
C
#ifndef _ASM_SEGMENT_H
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#define _ASM_SEGMENT_H
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#include <asm/cache.h>
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#define __KERNEL_CS 0x10
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#define __KERNEL_DS 0x18
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#define __KERNEL32_CS 0x08
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/*
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* we cannot use the same code segment descriptor for user and kernel
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* -- not even in the long flat mode, because of different DPL /kkeil
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* The segment offset needs to contain a RPL. Grr. -AK
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* GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
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*/
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#define __USER32_CS 0x23 /* 4*8+3 */
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#define __USER_DS 0x2b /* 5*8+3 */
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#define __USER_CS 0x33 /* 6*8+3 */
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#define __USER32_DS __USER_DS
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#define GDT_ENTRY_TSS 8 /* needs two entries */
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#define GDT_ENTRY_LDT 10 /* needs two entries */
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#define GDT_ENTRY_TLS_MIN 12
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#define GDT_ENTRY_TLS_MAX 14
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#define GDT_ENTRY_TLS_ENTRIES 3
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#define GDT_ENTRY_PER_CPU 15 /* Abused to load per CPU data from limit */
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#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU * 8 + 3)
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/* TLS indexes for 64bit - hardcoded in arch_prctl */
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#define FS_TLS 0
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#define GS_TLS 1
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#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
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#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
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#define IDT_ENTRIES 256
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#define GDT_ENTRIES 16
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#define GDT_SIZE (GDT_ENTRIES * 8)
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#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
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#endif
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