Imbus/xv6-riscv-kernel
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Clean up memlayout.h

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Get rid of last instances of linear address and "la"
Get ready for detecting physical memory dynamically
This commit is contained in:
Frans Kaashoek 2011-08-16 15:47:22 -04:00
parent 427958cb71
commit c3dcf47966
6 changed files with 42 additions and 28 deletions
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14
mmu.h
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@ -100,32 +100,34 @@ struct segdesc {
#define STS_IG32 0xE // 32-bit Interrupt Gate
#define STS_TG32 0xF // 32-bit Trap Gate
// A linear address 'la' has a three-part structure as follows:
// A virtual 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) --/
// \--- PDX(va) --/ \--- PTX(va) --/
// page directory index
#define PDX(la) (((uint)(la) >> PDXSHIFT) & 0x3FF)
#define PDX(va) (((uint)(va) >> PDXSHIFT) & 0x3FF)
// page table index
#define PTX(la) (((uint)(la) >> PTXSHIFT) & 0x3FF)
#define PTX(va) (((uint)(va) >> PTXSHIFT) & 0x3FF)
// construct linear address from indexes and offset
// construct virtual address from indexes and offset
#define PGADDR(d, t, o) ((uint)((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 PTXSHIFT 12 // offset of PTX in a linear address
#define PDXSHIFT 22 // offset of PDX in a linear address
#define PGROUNDUP(sz) (((sz)+PGSIZE-1) & ~(PGSIZE-1))
#define PGROUNDDOWN(a) ((char*)((((unsigned int)(a)) & ~(PGSIZE-1))))
#define PGROUNDDOWN(a) (((a)) & ~(PGSIZE-1))
// Page table/directory entry flags.
#define PTE_P 0x001 // Present