143 lines
4.0 KiB
C
143 lines
4.0 KiB
C
#define _XOPEN_SOURCE 700
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#include <fcntl.h> /* open */
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#include <stdint.h> /* uint64_t */
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#include <stdio.h> /* printf */
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#include <stdlib.h> /* size_t */
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#include <unistd.h> /* pread, sysconf */
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#include <sys/mman.h>
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#include <string.h>
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typedef struct {
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uint64_t pfn : 55;
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unsigned int soft_dirty : 1;
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unsigned int file_page : 1;
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unsigned int swapped : 1;
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unsigned int present : 1;
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} PagemapEntry;
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/* Parse the pagemap entry for the given virtual address.
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*
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* @param[out] entry the parsed entry
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* @param[in] pagemap_fd file descriptor to an open /proc/pid/pagemap file
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* @param[in] vaddr virtual address to get entry for
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* @return 0 for success, 1 for failure
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*/
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int pagemap_get_entry(PagemapEntry *entry, int pagemap_fd, uintptr_t vaddr)
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{
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size_t nread;
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ssize_t ret;
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uint64_t data;
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uintptr_t vpn;
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vpn = vaddr / sysconf(_SC_PAGE_SIZE);
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nread = 0;
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while (nread < sizeof(data)) {
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ret = pread(pagemap_fd, ((uint8_t*)&data) + nread, sizeof(data) - nread,
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vpn * sizeof(data) + nread);
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nread += ret;
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if (ret <= 0) {
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return 1;
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}
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}
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entry->pfn = data & (((uint64_t)1 << 55) - 1);
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entry->soft_dirty = (data >> 55) & 1;
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entry->file_page = (data >> 61) & 1;
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entry->swapped = (data >> 62) & 1;
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entry->present = (data >> 63) & 1;
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return 0;
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}
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/* Convert the given virtual address to physical using /proc/PID/pagemap.
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*
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* @param[out] paddr physical address
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* @param[in] pid process to convert for
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* @param[in] vaddr virtual address to get entry for
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* @return 0 for success, 1 for failure
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*/
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int virt_to_phys_user(uintptr_t *paddr, uintptr_t vaddr)
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{
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char pagemap_file[BUFSIZ];
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int pagemap_fd;
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snprintf(pagemap_file, sizeof(pagemap_file), "/proc/self/pagemap");
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pagemap_fd = open(pagemap_file, O_RDONLY);
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if (pagemap_fd < 0) {
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return 1;
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}
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PagemapEntry entry;
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if (pagemap_get_entry(&entry, pagemap_fd, vaddr)) {
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return 1;
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}
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close(pagemap_fd);
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*paddr = (entry.pfn * sysconf(_SC_PAGE_SIZE)) + (vaddr % sysconf(_SC_PAGE_SIZE));
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return 0;
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}
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int main(void)
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{
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/* Instead of allocating source, just use the constant string */
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//printf("Allocating 1024 bytes as source\n");
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//uintptr_t src = (uintptr_t)malloc(1024);
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char* src = "Hello, world! This is some data that is stored in system memory!";
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printf("Virtual address: %lx\n", src);
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uintptr_t src_phys;
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virt_to_phys_user(&src_phys, (uintptr_t)src);
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printf("Physical address: %lx\n", src_phys);
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printf("\n\n");
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printf("Allocating 1024 bytes as destination\n");
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char* dst = (char*)malloc(1024);
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printf("Virtual address: %p\n", dst);
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uintptr_t dst_phys;
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virt_to_phys_user(&dst_phys, (uintptr_t)dst);
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printf("Physical address: %lx\n", dst_phys);
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printf("\n\n");
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memset((void*)dst, 0, 1024);
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printf("mmaping PCIe space\n");
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// this is hardcoded, seems to be deterministic.
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uint32_t pcie_physical_base_offset = 0xfe800000;
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int fd = open("/dev/mem", O_RDWR|O_SYNC);
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uint32_t* pcie_base = (uint32_t*)mmap(0, 64, PROT_READ|PROT_WRITE, MAP_SHARED, fd, pcie_physical_base_offset);
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printf("Virtual PCIe Base: %p\n", pcie_base);
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printf("Sending read DMA\n");
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pcie_base[0] = (uint32_t)src_phys;
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pcie_base[1] = (uint32_t)(src_phys >> 32);
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pcie_base[2] = 0;
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pcie_base[3] = strlen(src);
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for (int i = 0; i < 4; i++) {
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printf("pcie_base[%d] = %x\n", i, pcie_base[i]);
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}
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pcie_base[4] = 1;
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printf("%d\n", pcie_base[4]);
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printf("\n\n");
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printf("Sending write DMA\n");
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printf("Sending read DMA\n");
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pcie_base[8] = (uint32_t)dst_phys;
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pcie_base[9] = (uint32_t)(dst_phys >> 32);
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pcie_base[10] = 0;
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pcie_base[11] = strlen(src);
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for (int i = 8; i < 12; i++) {
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printf("pcie_base[%d] = %x\n", i, pcie_base[i]);
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}
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pcie_base[12] = 1;
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printf("%d\n", pcie_base[12]);
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printf("\n\n");
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printf("strlen(dst)=%d\n", strlen(dst));
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printf("%s\n", dst);
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}
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