sanchayanmaity/xv6-cs450
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Eliminate annoying Pseudodesc structure.

Browse source 
Eliminate unnecessary parts of mmu.h.
This commit is contained in:
rsc 2006-07-16 16:55:52 +00:00
parent 6e6a1dd7d7
commit 564f787e91
6 changed files with 32 additions and 107 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

100
mmu.h
View file

@ -5,95 +5,10 @@
*/
/*
*
* Part 1. Paging data structures and constants.
*
* Register flags and fundamental constants.
*/
// A linear address 'la' has a three-part structure as follows:
//
// +--------10------+-------10-------+---------12----------+
// | Page Directory | Page Table | Offset within Page |
// | Index | Index | |
// +----------------+----------------+---------------------+
// \--- PDX(la) --/ \--- PTX(la) --/ \---- PGOFF(la) ----/
// \----------- PPN(la) -----------/
//
// The PDX, PTX, PGOFF, and PPN macros decompose linear addresses as shown.
// To construct a linear address la from PDX(la), PTX(la), and PGOFF(la),
// use PGADDR(PDX(la), PTX(la), PGOFF(la)).
// page number field of address
#define PPN(la) (((uintptr_t) (la)) >> PTXSHIFT)
#define VPN(la) PPN(la) // used to index into vpt[]
// page directory index
#define PDX(la) ((((uintptr_t) (la)) >> PDXSHIFT) & 0x3FF)
#define VPD(la) PDX(la) // used to index into vpd[]
// page table index
#define PTX(la) ((((uintptr_t) (la)) >> PTXSHIFT) & 0x3FF)
// offset in page
#define PGOFF(la) (((uintptr_t) (la)) & 0xFFF)
// construct linear address from indexes and offset
#define PGADDR(d, t, o) ((void*) ((d) << PDXSHIFT | (t) << PTXSHIFT | (o)))
// Page directory and page table constants.
#define NPDENTRIES 1024 // page directory entries per page directory
#define NPTENTRIES 1024 // page table entries per page table
#define PGSIZE 4096 // bytes mapped by a page
#define PGSHIFT 12 // log2(PGSIZE)
#define PTSIZE (PGSIZE*NPTENTRIES) // bytes mapped by a page directory entry
#define PTSHIFT 22 // log2(PTSIZE)
#define PTXSHIFT 12 // offset of PTX in a linear address
#define PDXSHIFT 22 // offset of PDX in a linear address
// Page table/directory entry flags.
#define PTE_P 0x001 // Present
#define PTE_W 0x002 // Writeable
#define PTE_U 0x004 // User
#define PTE_PWT 0x008 // Write-Through
#define PTE_PCD 0x010 // Cache-Disable
#define PTE_A 0x020 // Accessed
#define PTE_D 0x040 // Dirty
#define PTE_PS 0x080 // Page Size
#define PTE_MBZ 0x180 // Bits must be zero
// The PTE_AVAIL bits aren't used by the kernel or interpreted by the
// hardware, so user processes are allowed to set them arbitrarily.
#define PTE_AVAIL 0xE00 // Available for software use
// Only flags in PTE_USER may be used in system calls.
#define PTE_USER (PTE_AVAIL | PTE_P | PTE_W | PTE_U)
// address in page table entry
#define PTE_ADDR(pte) ((physaddr_t) (pte) & ~0xFFF)
// Control Register flags
#define CR0_PE 0x00000001 // Protection Enable
#define CR0_MP 0x00000002 // Monitor coProcessor
#define CR0_EM 0x00000004 // Emulation
#define CR0_TS 0x00000008 // Task Switched
#define CR0_ET 0x00000010 // Extension Type
#define CR0_NE 0x00000020 // Numeric Errror
#define CR0_WP 0x00010000 // Write Protect
#define CR0_AM 0x00040000 // Alignment Mask
#define CR0_NW 0x20000000 // Not Writethrough
#define CR0_CD 0x40000000 // Cache Disable
#define CR0_PG 0x80000000 // Paging
#define CR4_PCE 0x00000100 // Performance counter enable
#define CR4_MCE 0x00000040 // Machine Check Enable
#define CR4_PSE 0x00000010 // Page Size Extensions
#define CR4_DE 0x00000008 // Debugging Extensions
#define CR4_TSD 0x00000004 // Time Stamp Disable
#define CR4_PVI 0x00000002 // Protected-Mode Virtual Interrupts
#define CR4_VME 0x00000001 // V86 Mode Extensions
// Eflags register
#define FL_CF 0x00000001 // Carry Flag
@ -123,10 +38,9 @@
#define FEC_WR 0x2 // Page fault caused by a write
#define FEC_U 0x4 // Page fault occured while in user mode
/*
*
* Part 2. Segmentation data structures and constants.
* Segmentation data structures and constants.
*
*/
@ -202,7 +116,7 @@ struct Segdesc {
/*
*
* Part 3. Traps.
* Traps.
*
*/
@ -296,13 +210,5 @@ struct Gatedesc {
(gate).off_31_16 = (uint32_t) (off) >> 16; \
}
// Pseudo-descriptors used for LGDT, LLDT and LIDT instructions.
struct Pseudodesc {
uint16_t _garbage; // LGDT supposed to be from address 4N+2
uint16_t lim; // Limit
uint32_t base __attribute__ ((packed)); // Base address
};
#define PD_ADDR(desc) (&(desc).pd_lim)
#endif /* !__ASSEMBLER__ */

7
proc.c
View file

@ -38,9 +38,6 @@ setupsegs(struct proc *p)
p->gdt[SEG_TSS].s = 0;
p->gdt[SEG_UCODE] = SEG(STA_X|STA_R, (unsigned)p->mem, p->sz, 3);
p->gdt[SEG_UDATA] = SEG(STA_W, (unsigned)p->mem, p->sz, 3);
p->gdt_pd._garbage = 0;
p->gdt_pd.lim = sizeof(p->gdt) - 1;
p->gdt_pd.base = (unsigned) p->gdt;
}
// Look in the process table for an UNUSED proc.
@ -159,7 +156,9 @@ scheduler(void)
// to confine all the inline assembly.
// XXX probably ought to lgdt on trap return too, in case
// a system call has moved a program or changed its size.
asm volatile("lgdt %0" : : "g" (p->gdt_pd.lim));
lgdt(p->gdt, sizeof p->gdt);
// asm volatile("lgdt %0" : : "g" (p->gdt_pd.lim));
ltr(SEG_TSS << 3);
// Switch to chosen process. It is the process's job

1
proc.h
View file

@ -50,7 +50,6 @@ struct proc{
struct Taskstate ts; // only to give cpu address of kernel stack
struct Segdesc gdt[NSEGS];
struct Pseudodesc gdt_pd;
unsigned esp; // kernel stack pointer
unsigned ebp; // kernel frame pointer

3
trap.c
View file

@ -8,7 +8,6 @@
#include "syscall.h"
struct Gatedesc idt[256];
struct Pseudodesc idt_pd = { 0, sizeof(idt) - 1, (unsigned) &idt };
extern unsigned vectors[]; /* vectors.S, array of 256 entry point addresses */
extern void trapenter();
@ -28,7 +27,7 @@ tvinit()
void
idtinit()
{
asm volatile("lidt %0" : : "g" (idt_pd.lim));
lidt(idt, sizeof idt);
}
void

1
types.h
View file

@ -4,3 +4,4 @@ typedef unsigned short uint16_t;
typedef unsigned char uint8_t;
typedef uint32_t uintptr_t;
typedef uint32_t physaddr_t;
typedef unsigned int uint;

27
x86.h
View file

@ -12,7 +12,10 @@ static __inline void outsw(int port, const void *addr, int cnt) __attribute__((a
static __inline void outsl(int port, const void *addr, int cnt) __attribute__((always_inline));
static __inline void outl(int port, uint32_t data) __attribute__((always_inline));
static __inline void invlpg(void *addr) __attribute__((always_inline));
static __inline void lidt(void *p) __attribute__((always_inline));
struct Segdesc;
static __inline void lgdt(struct Segdesc *p, int) __attribute__((always_inline));
struct Gatedesc;
static __inline void lidt(struct Gatedesc *p, int) __attribute__((always_inline));
static __inline void lldt(uint16_t sel) __attribute__((always_inline));
static __inline void ltr(uint16_t sel) __attribute__((always_inline));
static __inline void lcr0(uint32_t val) __attribute__((always_inline));
@ -141,9 +144,27 @@ invlpg(void *addr)
}
static __inline void
lidt(void *p)
lgdt(struct Segdesc *p, int size)
{
__asm __volatile("lidt (%0)" : : "r" (p));
volatile uint16_t pd[3];
pd[0] = size-1;
pd[1] = (uint)p;
pd[2] = (uint)p >> 16;
asm volatile("lgdt (%0)" : : "g" (pd));
}
static __inline void
lidt(struct Gatedesc *p, int size)
{
volatile uint16_t pd[3];
pd[0] = size-1;
pd[1] = (uint)p;
pd[2] = (uint)p >> 16;
asm volatile("lidt (%0)" : : "g" (pd));
}
static __inline void