mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 12:42:02 +00:00
78be3706b2
We allow for the fact that the guest kernel may not run in ring 0. This requires some abstraction in a few places when setting %cs or checking privilege level (user vs kernel). This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather than using #define USER_MODE_MASK which depends on a config option, we use Zach's more flexible approach of assuming ring 3 == userspace. I also used "get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in the code... 1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a get_kernel_rpl() macro, and don't assume it's zero. And: Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
133 lines
3.8 KiB
C
133 lines
3.8 KiB
C
#ifndef _ASM_SEGMENT_H
|
|
#define _ASM_SEGMENT_H
|
|
|
|
/*
|
|
* The layout of the per-CPU GDT under Linux:
|
|
*
|
|
* 0 - null
|
|
* 1 - reserved
|
|
* 2 - reserved
|
|
* 3 - reserved
|
|
*
|
|
* 4 - unused <==== new cacheline
|
|
* 5 - unused
|
|
*
|
|
* ------- start of TLS (Thread-Local Storage) segments:
|
|
*
|
|
* 6 - TLS segment #1 [ glibc's TLS segment ]
|
|
* 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
|
|
* 8 - TLS segment #3
|
|
* 9 - reserved
|
|
* 10 - reserved
|
|
* 11 - reserved
|
|
*
|
|
* ------- start of kernel segments:
|
|
*
|
|
* 12 - kernel code segment <==== new cacheline
|
|
* 13 - kernel data segment
|
|
* 14 - default user CS
|
|
* 15 - default user DS
|
|
* 16 - TSS
|
|
* 17 - LDT
|
|
* 18 - PNPBIOS support (16->32 gate)
|
|
* 19 - PNPBIOS support
|
|
* 20 - PNPBIOS support
|
|
* 21 - PNPBIOS support
|
|
* 22 - PNPBIOS support
|
|
* 23 - APM BIOS support
|
|
* 24 - APM BIOS support
|
|
* 25 - APM BIOS support
|
|
*
|
|
* 26 - ESPFIX small SS
|
|
* 27 - unused
|
|
* 28 - unused
|
|
* 29 - unused
|
|
* 30 - unused
|
|
* 31 - TSS for double fault handler
|
|
*/
|
|
#define GDT_ENTRY_TLS_ENTRIES 3
|
|
#define GDT_ENTRY_TLS_MIN 6
|
|
#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
|
|
|
|
#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
|
|
|
|
#define GDT_ENTRY_DEFAULT_USER_CS 14
|
|
#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS * 8 + 3)
|
|
|
|
#define GDT_ENTRY_DEFAULT_USER_DS 15
|
|
#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS * 8 + 3)
|
|
|
|
#define GDT_ENTRY_KERNEL_BASE 12
|
|
|
|
#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE + 0)
|
|
#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8)
|
|
|
|
#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE + 1)
|
|
#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8)
|
|
|
|
#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE + 4)
|
|
#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE + 5)
|
|
|
|
#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 6)
|
|
#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 11)
|
|
|
|
#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14)
|
|
#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
|
|
|
|
#define GDT_ENTRY_DOUBLEFAULT_TSS 31
|
|
|
|
/*
|
|
* The GDT has 32 entries
|
|
*/
|
|
#define GDT_ENTRIES 32
|
|
|
|
#define GDT_SIZE (GDT_ENTRIES * 8)
|
|
|
|
/* Matches __KERNEL_CS and __USER_CS (they must be 2 entries apart) */
|
|
#define SEGMENT_IS_FLAT_CODE(x) (((x) & 0xec) == GDT_ENTRY_KERNEL_CS * 8)
|
|
/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
|
|
#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
|
|
|
|
/* Simple and small GDT entries for booting only */
|
|
|
|
#define GDT_ENTRY_BOOT_CS 2
|
|
#define __BOOT_CS (GDT_ENTRY_BOOT_CS * 8)
|
|
|
|
#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1)
|
|
#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8)
|
|
|
|
/* The PnP BIOS entries in the GDT */
|
|
#define GDT_ENTRY_PNPBIOS_CS32 (GDT_ENTRY_PNPBIOS_BASE + 0)
|
|
#define GDT_ENTRY_PNPBIOS_CS16 (GDT_ENTRY_PNPBIOS_BASE + 1)
|
|
#define GDT_ENTRY_PNPBIOS_DS (GDT_ENTRY_PNPBIOS_BASE + 2)
|
|
#define GDT_ENTRY_PNPBIOS_TS1 (GDT_ENTRY_PNPBIOS_BASE + 3)
|
|
#define GDT_ENTRY_PNPBIOS_TS2 (GDT_ENTRY_PNPBIOS_BASE + 4)
|
|
|
|
/* The PnP BIOS selectors */
|
|
#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
|
|
#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
|
|
#define PNP_DS (GDT_ENTRY_PNPBIOS_DS * 8) /* data segment for BIOS */
|
|
#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1 * 8) /* transfer data segment */
|
|
#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2 * 8) /* another data segment */
|
|
|
|
/*
|
|
* The interrupt descriptor table has room for 256 idt's,
|
|
* the global descriptor table is dependent on the number
|
|
* of tasks we can have..
|
|
*/
|
|
#define IDT_ENTRIES 256
|
|
|
|
/* Bottom two bits of selector give the ring privilege level */
|
|
#define SEGMENT_RPL_MASK 0x3
|
|
/* Bit 2 is table indicator (LDT/GDT) */
|
|
#define SEGMENT_TI_MASK 0x4
|
|
|
|
/* User mode is privilege level 3 */
|
|
#define USER_RPL 0x3
|
|
/* LDT segment has TI set, GDT has it cleared */
|
|
#define SEGMENT_LDT 0x4
|
|
#define SEGMENT_GDT 0x0
|
|
|
|
#define get_kernel_rpl() 0
|
|
#endif
|