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Diffstat (limited to 'arch/x86/include/asm/segment.h')
-rw-r--r--arch/x86/include/asm/segment.h289
1 files changed, 157 insertions, 132 deletions
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index db257a58571f..5a9856eb12ba 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -3,8 +3,10 @@
#include <linux/const.h>
-/* Constructor for a conventional segment GDT (or LDT) entry */
-/* This is a macro so it can be used in initializers */
+/*
+ * Constructor for a conventional segment GDT (or LDT) entry.
+ * This is a macro so it can be used in initializers.
+ */
#define GDT_ENTRY(flags, base, limit) \
((((base) & _AC(0xff000000,ULL)) << (56-24)) | \
(((flags) & _AC(0x0000f0ff,ULL)) << 40) | \
@@ -12,198 +14,228 @@
(((base) & _AC(0x00ffffff,ULL)) << 16) | \
(((limit) & _AC(0x0000ffff,ULL))))
-/* Simple and small GDT entries for booting only */
+/* 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 3
+#define GDT_ENTRY_BOOT_TSS 4
+#define __BOOT_CS (GDT_ENTRY_BOOT_CS*8)
+#define __BOOT_DS (GDT_ENTRY_BOOT_DS*8)
+#define __BOOT_TSS (GDT_ENTRY_BOOT_TSS*8)
+
+/*
+ * Bottom two bits of selector give the ring
+ * privilege level
+ */
+#define SEGMENT_RPL_MASK 0x3
-#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1)
-#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8)
+/* User mode is privilege level 3: */
+#define USER_RPL 0x3
-#define GDT_ENTRY_BOOT_TSS (GDT_ENTRY_BOOT_CS + 2)
-#define __BOOT_TSS (GDT_ENTRY_BOOT_TSS * 8)
+/* Bit 2 is Table Indicator (TI): selects between LDT or GDT */
+#define SEGMENT_TI_MASK 0x4
+/* LDT segment has TI set ... */
+#define SEGMENT_LDT 0x4
+/* ... GDT has it cleared */
+#define SEGMENT_GDT 0x0
-#define SEGMENT_RPL_MASK 0x3 /*
- * Bottom two bits of selector give the ring
- * privilege level
- */
-#define SEGMENT_TI_MASK 0x4 /* Bit 2 is table indicator (LDT/GDT) */
-#define USER_RPL 0x3 /* User mode is privilege level 3 */
-#define SEGMENT_LDT 0x4 /* LDT segment has TI set... */
-#define SEGMENT_GDT 0x0 /* ... GDT has it cleared */
+#define GDT_ENTRY_INVALID_SEG 0
#ifdef CONFIG_X86_32
/*
* The layout of the per-CPU GDT under Linux:
*
- * 0 - null
+ * 0 - null <=== cacheline #1
* 1 - reserved
* 2 - reserved
* 3 - reserved
*
- * 4 - unused <==== new cacheline
+ * 4 - unused <=== cacheline #2
* 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
+ * 8 - TLS segment #3 <=== cacheline #3
* 9 - reserved
* 10 - reserved
* 11 - reserved
*
* ------- start of kernel segments:
*
- * 12 - kernel code segment <==== new cacheline
+ * 12 - kernel code segment <=== cacheline #4
* 13 - kernel data segment
* 14 - default user CS
* 15 - default user DS
- * 16 - TSS
+ * 16 - TSS <=== cacheline #5
* 17 - LDT
* 18 - PNPBIOS support (16->32 gate)
* 19 - PNPBIOS support
- * 20 - PNPBIOS support
+ * 20 - PNPBIOS support <=== cacheline #6
* 21 - PNPBIOS support
* 22 - PNPBIOS support
* 23 - APM BIOS support
- * 24 - APM BIOS support
+ * 24 - APM BIOS support <=== cacheline #7
* 25 - APM BIOS support
*
* 26 - ESPFIX small SS
* 27 - per-cpu [ offset to per-cpu data area ]
- * 28 - stack_canary-20 [ for stack protector ]
+ * 28 - stack_canary-20 [ for stack protector ] <=== cacheline #8
* 29 - unused
* 30 - unused
* 31 - TSS for double fault handler
*/
-#define GDT_ENTRY_TLS_MIN 6
-#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
+#define GDT_ENTRY_TLS_MIN 6
+#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
+#define GDT_ENTRY_KERNEL_CS 12
+#define GDT_ENTRY_KERNEL_DS 13
#define GDT_ENTRY_DEFAULT_USER_CS 14
-
#define GDT_ENTRY_DEFAULT_USER_DS 15
+#define GDT_ENTRY_TSS 16
+#define GDT_ENTRY_LDT 17
+#define GDT_ENTRY_PNPBIOS_CS32 18
+#define GDT_ENTRY_PNPBIOS_CS16 19
+#define GDT_ENTRY_PNPBIOS_DS 20
+#define GDT_ENTRY_PNPBIOS_TS1 21
+#define GDT_ENTRY_PNPBIOS_TS2 22
+#define GDT_ENTRY_APMBIOS_BASE 23
+
+#define GDT_ENTRY_ESPFIX_SS 26
+#define GDT_ENTRY_PERCPU 27
+#define GDT_ENTRY_STACK_CANARY 28
+
+#define GDT_ENTRY_DOUBLEFAULT_TSS 31
-#define GDT_ENTRY_KERNEL_BASE (12)
+/*
+ * Number of entries in the GDT table:
+ */
+#define GDT_ENTRIES 32
-#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE+0)
+/*
+ * Segment selector values corresponding to the above entries:
+ */
-#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE+1)
+#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
+#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
+#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
+#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
+#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8)
-#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE+4)
-#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE+5)
+/* segment for calling fn: */
+#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32*8)
+/* code segment for BIOS: */
+#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16*8)
-#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE+6)
-#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE+11)
+/* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */
+#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == PNP_CS32)
-#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE+14)
-#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8)
+/* data segment for BIOS: */
+#define PNP_DS (GDT_ENTRY_PNPBIOS_DS*8)
+/* transfer data segment: */
+#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1*8)
+/* another data segment: */
+#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2*8)
-#define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE+15)
#ifdef CONFIG_SMP
-#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
+# define __KERNEL_PERCPU (GDT_ENTRY_PERCPU*8)
#else
-#define __KERNEL_PERCPU 0
+# define __KERNEL_PERCPU 0
#endif
-#define GDT_ENTRY_STACK_CANARY (GDT_ENTRY_KERNEL_BASE+16)
#ifdef CONFIG_CC_STACKPROTECTOR
-#define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8)
+# define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8)
#else
-#define __KERNEL_STACK_CANARY 0
+# define __KERNEL_STACK_CANARY 0
#endif
-#define GDT_ENTRY_DOUBLEFAULT_TSS 31
-
-/*
- * The GDT has 32 entries
- */
-#define GDT_ENTRIES 32
+#else /* 64-bit: */
-/* 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 */
+#include <asm/cache.h>
+#define GDT_ENTRY_KERNEL32_CS 1
+#define GDT_ENTRY_KERNEL_CS 2
+#define GDT_ENTRY_KERNEL_DS 3
/*
- * Matching rules for certain types of segments.
+ * We cannot use the same code segment descriptor for user and kernel mode,
+ * not even in long flat mode, because of different DPL.
+ *
+ * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes
+ * selectors:
+ *
+ * if returning to 32-bit userspace: cs = STAR.SYSRET_CS,
+ * if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16,
+ *
+ * ss = STAR.SYSRET_CS+8 (in either case)
+ *
+ * thus USER_DS should be between 32-bit and 64-bit code selectors:
*/
+#define GDT_ENTRY_DEFAULT_USER32_CS 4
+#define GDT_ENTRY_DEFAULT_USER_DS 5
+#define GDT_ENTRY_DEFAULT_USER_CS 6
-/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
-#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
-
+/* Needs two entries */
+#define GDT_ENTRY_TSS 8
+/* Needs two entries */
+#define GDT_ENTRY_LDT 10
-#else
-#include <asm/cache.h>
-
-#define GDT_ENTRY_KERNEL32_CS 1
-#define GDT_ENTRY_KERNEL_CS 2
-#define GDT_ENTRY_KERNEL_DS 3
+#define GDT_ENTRY_TLS_MIN 12
+#define GDT_ENTRY_TLS_MAX 14
-#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS * 8)
+/* Abused to load per CPU data from limit */
+#define GDT_ENTRY_PER_CPU 15
/*
- * we cannot use the same code segment descriptor for user and kernel
- * -- not even in the long flat mode, because of different DPL /kkeil
- * The segment offset needs to contain a RPL. Grr. -AK
- * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
+ * Number of entries in the GDT table:
*/
-#define GDT_ENTRY_DEFAULT_USER32_CS 4
-#define GDT_ENTRY_DEFAULT_USER_DS 5
-#define GDT_ENTRY_DEFAULT_USER_CS 6
-#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8+3)
-#define __USER32_DS __USER_DS
-
-#define GDT_ENTRY_TSS 8 /* needs two entries */
-#define GDT_ENTRY_LDT 10 /* needs two entries */
-#define GDT_ENTRY_TLS_MIN 12
-#define GDT_ENTRY_TLS_MAX 14
-
-#define GDT_ENTRY_PER_CPU 15 /* Abused to load per CPU data from limit */
-#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU * 8 + 3)
+#define GDT_ENTRIES 16
-/* TLS indexes for 64bit - hardcoded in arch_prctl */
-#define FS_TLS 0
-#define GS_TLS 1
-
-#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
-#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
-
-#define GDT_ENTRIES 16
+/*
+ * Segment selector values corresponding to the above entries:
+ *
+ * Note, selectors also need to have a correct RPL,
+ * expressed with the +3 value for user-space selectors:
+ */
+#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS*8)
+#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
+#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
+#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
+#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
+#define __USER32_DS __USER_DS
+#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
+#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU*8 + 3)
+
+/* TLS indexes for 64-bit - hardcoded in arch_prctl(): */
+#define FS_TLS 0
+#define GS_TLS 1
+
+#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
+#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
#endif
-#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
-#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
-#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8+3)
-#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8+3)
#ifndef CONFIG_PARAVIRT
-#define get_kernel_rpl() 0
+# define get_kernel_rpl() 0
#endif
-#define IDT_ENTRIES 256
-#define NUM_EXCEPTION_VECTORS 32
-/* Bitmask of exception vectors which push an error code on the stack */
-#define EXCEPTION_ERRCODE_MASK 0x00027d00
-#define GDT_SIZE (GDT_ENTRIES * 8)
-#define GDT_ENTRY_TLS_ENTRIES 3
-#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
+#define IDT_ENTRIES 256
+#define NUM_EXCEPTION_VECTORS 32
+
+/* Bitmask of exception vectors which push an error code on the stack: */
+#define EXCEPTION_ERRCODE_MASK 0x00027d00
+
+#define GDT_SIZE (GDT_ENTRIES*8)
+#define GDT_ENTRY_TLS_ENTRIES 3
+#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8)
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
+
extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5];
#ifdef CONFIG_TRACING
-#define trace_early_idt_handlers early_idt_handlers
+# define trace_early_idt_handlers early_idt_handlers
#endif
/*
@@ -228,37 +260,30 @@ do { \
} while (0)
/*
- * Save a segment register away
+ * Save a segment register away:
*/
#define savesegment(seg, value) \
asm("mov %%" #seg ",%0":"=r" (value) : : "memory")
/*
- * x86_32 user gs accessors.
+ * x86-32 user GS accessors:
*/
#ifdef CONFIG_X86_32
-#ifdef CONFIG_X86_32_LAZY_GS
-#define get_user_gs(regs) (u16)({unsigned long v; savesegment(gs, v); v;})
-#define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
-#define task_user_gs(tsk) ((tsk)->thread.gs)
-#define lazy_save_gs(v) savesegment(gs, (v))
-#define lazy_load_gs(v) loadsegment(gs, (v))
-#else /* X86_32_LAZY_GS */
-#define get_user_gs(regs) (u16)((regs)->gs)
-#define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0)
-#define task_user_gs(tsk) (task_pt_regs(tsk)->gs)
-#define lazy_save_gs(v) do { } while (0)
-#define lazy_load_gs(v) do { } while (0)
-#endif /* X86_32_LAZY_GS */
+# ifdef CONFIG_X86_32_LAZY_GS
+# define get_user_gs(regs) (u16)({ unsigned long v; savesegment(gs, v); v; })
+# define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
+# define task_user_gs(tsk) ((tsk)->thread.gs)
+# define lazy_save_gs(v) savesegment(gs, (v))
+# define lazy_load_gs(v) loadsegment(gs, (v))
+# else /* X86_32_LAZY_GS */
+# define get_user_gs(regs) (u16)((regs)->gs)
+# define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0)
+# define task_user_gs(tsk) (task_pt_regs(tsk)->gs)
+# define lazy_save_gs(v) do { } while (0)
+# define lazy_load_gs(v) do { } while (0)
+# endif /* X86_32_LAZY_GS */
#endif /* X86_32 */
-static inline unsigned long get_limit(unsigned long segment)
-{
- unsigned long __limit;
- asm("lsll %1,%0" : "=r" (__limit) : "r" (segment));
- return __limit + 1;
-}
-
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-22 09:58:34 +0000