mirror of
git://projects.qi-hardware.com/ben-blinkenlights.git
synced 2024-11-17 19:55:21 +02:00
0dbf29e599
- physmem.c (align_brk): don't waste memory if already aligned - physmem.c (ALIGN, calloc_phys_vec): align by DMA transfer size - physmem.c (calloc_phys_vec): make sure allocations don't straddle page boundaries - physmem.c (xlat_one): print "unsigned long" with %lx, not %x
131 lines
2.6 KiB
C
131 lines
2.6 KiB
C
/*
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* physmem.c - Physical memory allocator
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*
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* Written 2011 by Werner Almesberger
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* Copyright 2011 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#define PAGEMAP_FILE "/proc/self/pagemap"
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#define PAGE_SIZE 4096
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#define PM_PSHIFT 55 /* page size */
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#define PM_PSHIFT_MASK 63
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#define PM_SWAPPED 62
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#define PM_PRESENT 63
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#define ALIGN 32 /* DMA transfer size */
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static void align_brk(int alignment)
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{
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unsigned long addr, remainder;
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addr = (unsigned long) sbrk(0);
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remainder = addr % alignment;
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if (remainder)
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sbrk(alignment-remainder);
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}
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void **calloc_phys_vec(size_t n, size_t size)
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{
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void **vec;
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unsigned long pos;
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int i;
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vec = malloc(sizeof(void *)*n);
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if (!vec) {
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perror("malloc");
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exit(1);
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}
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for (i = 0; i != n; i++) {
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align_brk(ALIGN);
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pos = (unsigned long) sbrk(0);
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if ((pos & ~(PAGE_SIZE-1)) != ((pos+size) & ~(PAGE_SIZE-1)))
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sbrk(PAGE_SIZE-(pos & (PAGE_SIZE-1)));
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vec[i] = sbrk(size);
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memset(vec[i], 0, size);
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}
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return vec;
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}
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static unsigned long xlat_one(int fd, unsigned long vaddr)
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{
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unsigned long page, offset, paddr;
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ssize_t got;
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uint64_t map;
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int pshift;
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offset = vaddr & (PAGE_SIZE-1);
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page = vaddr/PAGE_SIZE;
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if (lseek(fd, page*8, SEEK_SET) < 0) {
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perror("lseek");
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exit(1);
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}
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got = read(fd, &map, 8);
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if (got < 0) {
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perror("read");
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exit(1);
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}
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if (got != 8) {
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fprintf(stderr, "bad read: got %d instead of 8\n", got);
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exit(1);
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}
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if (!((map >> PM_PRESENT) & 1)) {
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fprintf(stderr, "page %lu is not present\n", page);
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abort();
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}
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if ((map >> PM_SWAPPED) & 1) {
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fprintf(stderr, "page %lu is swapped\n", page);
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abort();
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}
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pshift = (map >> PM_PSHIFT) & PM_PSHIFT_MASK;
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if ((1 << pshift) != PAGE_SIZE) {
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fprintf(stderr, "page claims to have size %u\n", 1 << pshift);
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abort();
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}
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paddr = ((map & 0x7fffffffffffffULL) << pshift) | offset;
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// fprintf(stderr, "0x%lx -> 0x%lx\n", vaddr, paddr);
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return paddr;
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}
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unsigned long *xlat_virt(void *const *v, size_t n)
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{
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unsigned long *res;
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int fd;
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int i;
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res = malloc(n*sizeof(unsigned long));
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if (!res) {
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perror("malloc");
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exit(1);
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}
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fd = open(PAGEMAP_FILE, O_RDONLY);
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if (fd < 0) {
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perror(PAGEMAP_FILE);
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exit(1);
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}
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for (i = 0; i != n; i++)
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res[i] = xlat_one(fd, (unsigned long) v[i]);
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close(fd);
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return res;
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}
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