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Names of text are better.

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This commit is contained in:
Frans Kaashoek 2018-10-03 20:14:36 -04:00
parent eb72653bd7
commit 7ccc5f5f4f
4 changed files with 34 additions and 34 deletions
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52
mmu.h
View file

@ -15,12 +15,12 @@
// Segment selectors (indexes) in our GDTs.
// Defined by our convention, not the architecture.
#define KCSEG32 (1<<3) /* kernel 32-bit code segment */
#define KCSEG (2<<3) /* kernel code segment */
#define KDSEG (3<<3) /* kernel data segment */
#define TSSSEG (4<<3) /* tss segment - takes two slots */
#define UDSEG (6<<3) /* user data segment */
#define UCSEG (7<<3) /* user code segment */
#define SEG_KCODE32 (1<<3) // kernel 32-bit code segment
#define SEG_KCODE (2<<3) // kernel code segment
#define SEG_KDATA (3<<3) // kernel data segment
#define SEG_TSS (4<<3) // tss segment - takes two slots
#define SEG_UDATA (6<<3) // user data segment
#define SEG_UCODE (7<<3) // user code segment
#define NSEGS 8
@ -54,21 +54,21 @@ struct segdesc {
#define DPL_USER 0x3 // User DPL
#define SEG_A (1<<0) /* segment accessed bit */
#define SEG_R (1<<1) /* readable (code) */
#define SEG_W (1<<1) /* writable (data) */
#define SEG_C (1<<2) /* conforming segment (code) */
#define SEG_E (1<<2) /* expand-down bit (data) */
#define SEG_CODE (1<<3) /* code segment (instead of data) */
#define SEG_A (1<<0) // segment accessed bit
#define SEG_R (1<<1) // readable (code)
#define SEG_W (1<<1) // writable (data)
#define SEG_C (1<<2) // conforming segment (code)
#define SEG_E (1<<2) // expand-down bit (data)
#define SEG_CODE (1<<3) // code segment (instead of data)
// User and system segment bits.
#define SEG_S (1<<4) /* if 0, system descriptor */
#define SEG_DPL(x) ((x)<<5) /* descriptor privilege level (2 bits) */
#define SEG_P (1<<7) /* segment present */
#define SEG_AVL (1<<8) /* available for operating system use */
#define SEG_L (1<<9) /* long mode */
#define SEG_D (1<<10) /* default operation size 32-bit */
#define SEG_G (1<<11) /* granularity */
#define SEG_S (1<<4) // if 0, system descriptor
#define SEG_DPL(x) ((x)<<5) // descriptor privilege level (2 bits)
#define SEG_P (1<<7) // segment present
#define SEG_AVL (1<<8) // available for operating system use
#define SEG_L (1<<9) // long mode
#define SEG_D (1<<10) // default operation size 32-bit
#define SEG_G (1<<11) // granularity
// Application segment type bits
#define STA_X 0x8 // Executable segment
@ -76,12 +76,12 @@ struct segdesc {
#define STA_R 0x2 // Readable (executable segments)
// System segment type bits
#define SEG_LDT (2<<0) /* local descriptor table */
#define SEG_TSS64A (9<<0) /* available 64-bit TSS */
#define SEG_TSS64B (11<<0) /* busy 64-bit TSS */
#define SEG_CALL64 (12<<0) /* 64-bit call gate */
#define SEG_INTR64 (14<<0) /* 64-bit interrupt gate */
#define SEG_TRAP64 (15<<0) /* 64-bit trap gate */
#define SEG_LDT (2<<0) // local descriptor table
#define SEG_TSS64A (9<<0) // available 64-bit TSS
#define SEG_TSS64B (11<<0) // busy 64-bit TSS
#define SEG_CALL64 (12<<0) // 64-bit call gate
#define SEG_INTR64 (14<<0) // 64-bit interrupt gate
#define SEG_TRAP64 (15<<0) // 64-bit trap gate
// A virtual address 'la' has a six-part structure as follows:
//
@ -129,7 +129,7 @@ struct taskstate {
uint8 iopb[0];
} __attribute__ ((packed));
#define INT_P (1<<7) /* interrupt descriptor present */
#define INT_P (1<<7) // interrupt descriptor present
struct intgate
{

4
proc.c
View file

@ -139,8 +139,8 @@ userinit(void)
inituvm(p->pgdir, _binary_initcode_start, (uint64)_binary_initcode_size);
p->sz = PGSIZE;
memset(p->tf, 0, sizeof(*p->tf));
p->tf->cs = UCSEG | 0x3;
p->tf->ss = UDSEG | 0x3;
p->tf->cs = SEG_UCODE | DPL_USER;
p->tf->ss = SEG_UDATA | DPL_USER;
p->tf->r11 = FL_IF;
p->tf->rsp = PGSIZE;
p->tf->rcx = 0; // beginning of initcode.S

2
trap.c
View file

@ -20,7 +20,7 @@ tvinit(void)
int i;
for(i=0; i<256; i++) {
idt[i] = INTDESC(KCSEG, vectors[i], INT_P | SEG_INTR64);
idt[i] = INTDESC(SEG_KCODE, vectors[i], INT_P | SEG_INTR64);
}
idtinit();

10
vm.c
View file

@ -49,13 +49,13 @@ seginit(void)
// to (star >> 32) + 8 and the CS selector to (star >> 32).
// When executing a sysret instruction the CPU sets the SS selector
// to (star >> 48) + 8 and the CS selector to (star >> 48) + 16.
uint64 star = ((((uint64)UCSEG|0x3)- 16)<<48)|((uint64)(KCSEG)<<32);
uint64 star = ((((uint64)SEG_UCODE|0x3)- 16)<<48)|((uint64)(SEG_KCODE)<<32);
writemsr(MSR_STAR, star);
writemsr(MSR_LSTAR, (uint64)&sysentry);
writemsr(MSR_SFMASK, FL_TF | FL_IF);
// Initialize cpu-local storage.
writegs(KDSEG);
writegs(SEG_KDATA);
writemsr(MSR_GS_BASE, (uint64)c);
writemsr(MSR_GS_KERNBASE, (uint64)c);
}
@ -202,8 +202,8 @@ switchuvm(struct proc *p)
c = mycpu();
uint64 base = (uint64) &(c->ts);
c->gdt[TSSSEG>>3] = SEGDESC(base, (sizeof(c->ts)-1), SEG_P|SEG_TSS64A);
c->gdt[(TSSSEG>>3)+1] = SEGDESCHI(base);
c->gdt[SEG_TSS>>3] = SEGDESC(base, (sizeof(c->ts)-1), SEG_P|SEG_TSS64A);
c->gdt[(SEG_TSS>>3)+1] = SEGDESCHI(base);
c->ts.rsp[0] = (uint64) p->kstack + KSTACKSIZE;
c->ts.iomba = (ushort) 0xFFFF;
@ -211,7 +211,7 @@ switchuvm(struct proc *p)
dtr.base = (uint64)c->gdt;
lgdt((void *)&dtr.limit);
ltr(TSSSEG);
ltr(SEG_TSS);
lcr3(V2P(p->pgdir)); // switch to process's address space