3rd-party/linux-kernel-module-cheat
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Code Issues Releases Wiki Activity

virt_to_phys_user

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Ciro Santilli
2017-07-30 23:31:22 +01:00
parent 7d6449d47b
commit 25f9913e0c
5 changed files with 155 additions and 67 deletions
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11
kernel_module/user/mmap.c
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@@ -2,10 +2,13 @@
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h> /* uintmax_t */
#include <string.h>
#include <sys/mman.h>
#include <unistd.h> /* sysconf */
#include "common.h" /* virt_to_phys_user */
enum { BUFFER_SIZE = 4 };
int main(int argc, char **argv)
@@ -14,6 +17,7 @@ int main(int argc, char **argv)
long page_size;
char *address1, *address2;
char buf[BUFFER_SIZE];
uintptr_t paddr;
if (argc < 2) {
printf("Usage: %s <mmap_file>\n", argv[0]);
@@ -54,6 +58,13 @@ int main(int argc, char **argv)
/* Also modified. So both virtual addresses point to the same physical address. */
assert(!strcmp(address2, "qwer"));
/* Check that the physical addresses are the same.
* They are, but TODO why virt_to_phys on kernel gives a different value? */
assert(!virt_to_phys_user(&paddr, getpid(), (uintptr_t)address1));
printf("paddr1 = 0x%jx\n", (uintmax_t)paddr);
assert(!virt_to_phys_user(&paddr, getpid(), (uintptr_t)address2));
printf("paddr2 = 0x%jx\n", (uintmax_t)paddr);
/* Check that modifications made from userland are also visible from the kernel. */
read(fd, buf, BUFFER_SIZE);
assert(!memcmp(buf, "qwer", BUFFER_SIZE));