1991/0613/pc/mem.h (diff list | history)

pc/mem.h on 1991/0613
1991/0613		#define SELGDT (0<<3) /* selector is in gdt */ #define SELLDT (1<<3) /* selector is in ldt */ #define SELECTOR(i, t, p) (((i)<<4) | (t) | (p)) /* * segment descriptor/gate */ typedef struct Segdesc Segdesc; struct Segdesc { ulong d0; ulong d1; }; #define SEGDATA (0x10<<8) /* data/stack segment */ #define SEGEXEC (0x18<<8) /* executable segment */ #define SEGCG (0x0C<<8) /* call gate */ #define SEGIG (0x0E<<8) /* interrupt gate */ #define SEGTG (0x0F<<8) /* task gate */ #define SEGP (1<<15) /* segment present */ #define SEGPL(x) ((x)<<13) /* priority level */ #define SEGB (1<<22) /* granularity 1==4k (for expand-down) */ #define SEGG (1<<23) /* granularity 1==4k (for other) */ #define SEGE (1<<10) /* expand down */ #define SEGW (1<<9) /* writable (for data/stack) */ #define SEGR (1<<9) /* readable (for code) */ #define SEGD (1<<22) /* default 1==32bit (for code) */ /* * gate initializers */ #define TRAPGATE(s,o,p) { (o)&0xFFFF0000|SEGP|SEGPL(p)|SEGTG, (o)&0xFFFF|((s)<<16) } #define INTRGATE(s,o,p) { (o)&0xFFFF0000|SEGP|SEGPL(p)|SEGIG, (o)&0xFFFF|((s)<<16) } #define CALLGATE(s,o,p) { (o)&0xFFFF0000|SEGP|SEGPL(p)|SEGCG, (o)&0xFFFF|((s)<<16) } /* * segment descriptor initializers */ #define DATASEG(p) { SEGG|(0xF<<16)|SEGP|SEGPL(p)|SEGDATA|SEGW, 0xFFFF } #define EXECSEG(p) { SEGG|SEGD|(0xF<<16)|SEGP|SEGPL(p)|SEGEXEC|SEGR, 0xFFFF } /* * known segments (in GDT) and their selectors */ enum { NULLSEG=0, /* null segment */ KESEG= 1, /* kernel executable */ KDSEG= 2, /* kernel data/stack */ UESEG= 3, /* user executable */ UDSEG= 4, /* user data/stack */ SYSGATE=5, /* system call gate */ }; #define NULLSEL SELECTOR(NULLSEG, SELGDT, 0) #define KESEL SELECTOR(KESEG, SELGDT, 0) #define KDSEL SELECTOR(KDSEG, SELGDT, 0) #define KSSEL SELECTOR(KDSEG, SELGDT, 0) #define UESEL SELECTOR(UESEG, SELGDT, 3) #define UDSEL SELECTOR(UDSEG, SELGDT, 3) #define USSEL SELECTOR(UDSEG, SELGDT, 3) /* * task state segment. Plan 9 ignores all the task switching goo and just * uses the tss for esp0 and ss0 on gate's into the kernel, interrupts, * and exceptions. The rest is completely ignored. * * This means that we only need one tss in the whole system. */ typedef struct Tss Tss; struct Tss { ulong backlink; /* unused */ ulong esp0; /* pl0 stack pointer */ ulong ss0; /* pl0 stack selector */ ulong esp1; /* pl1 stack pointer */ ulong ss1; /* pl1 stack selector */ ulong esp2; /* pl2 stack pointer */ ulong ss2; /* pl2 stack selector */ ulong cr3; /* page table descriptor */ ulong eip; /* instruction pointer */ ulong eflags; /* processor flags */ ulong eax; /* general (hah?) registers */ ulong ecx; ulong edx; ulong ebx; ulong esp; ulong ebp; ulong esi; ulong edi; ulong es; /* segment selectors */ ulong cs; ulong ss; ulong ds; ulong fs; ulong gs; ulong ldt; /* local descriptor table */ ulong iomap; /* io map base */ };