diff options
Diffstat (limited to 'src/mmuhack.c')
| -rw-r--r-- | src/mmuhack.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/src/mmuhack.c b/src/mmuhack.c new file mode 100644 index 0000000..00bc8e1 --- /dev/null +++ b/src/mmuhack.c @@ -0,0 +1,344 @@ +#include <stdio.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <linux/fb.h>
+#include <unistd.h>
+#include <stropts.h>
+#include <string.h>
+
+extern int errno;
+
+int memfd;
+
+void *trymmap (void *start, size_t length, int prot, int flags, int fd, off_t offset)
+{
+ char *p;
+ int aa;
+
+ //printf ("mmap(%X, %X, %X, %X, %X, %X) ... ", (unsigned int)start, length, prot, flags, fd, (unsigned int)offset);
+ p = mmap (start, length, prot, flags, fd, offset);
+ if (p == (char *)0xFFFFFFFF)
+ {
+ aa = errno;
+ printf ("failed mmap(%X, %X, %X, %X, %X, %X) errno = %d\n", (unsigned int)start, length, prot, flags, fd, (unsigned int)offset, aa);
+ }
+ else
+ {
+ //printf ("OK! (%X)\n", (unsigned int)p);
+ }
+
+ return p;
+}
+
+unsigned char initphys (void)
+{
+ memfd = open("/dev/mem", O_RDWR);
+ if (memfd == -1)
+ {
+ printf ("Open failed\n");
+ return 0;
+ }
+
+ printf ("/dev/mem opened successfully - fd = %d\n", memfd);
+
+ return 1;
+}
+
+void closephys (void)
+{
+ close (memfd);
+}
+
+int myuname(char *buffer)
+{
+ asm volatile ("swi #0x90007a");
+}
+
+void DecodeCoarse (unsigned int indx, unsigned int sa)
+{
+ unsigned int cpt[256];
+ unsigned int dom = (sa >> 5) & 15;
+ unsigned int temp;
+ unsigned int i = 0;
+ unsigned int wb = 0;
+
+ sa &= 0xfffffc00;
+ indx *= 1048576;
+
+ //printf (" > %08X\n", sa);
+ //printf ("%d\n",
+ lseek (memfd, sa, SEEK_SET);
+ memset (cpt, 0, 256*4);
+ temp = read (memfd, cpt, 256*4);
+ //printf ("%d\n", temp);
+ if (temp != 256*4)
+ {
+ printf (" # Bad read\n");
+ return;
+ }
+
+ //printf ("%08X %08X %08X %08X\n", cpt[0], cpt[4], cpt[8], cpt[12]);
+
+ for (i = 0; i < 256; i ++)
+ {
+ if (cpt[i])
+ {
+ switch (cpt[i] & 3)
+ {
+ case 0:
+ //printf (" -- [%08X] Invalid --\n", cpt[i]);
+ break;
+ case 1:
+ printf (" VA: %08X PA: %08X - %08X A: %d %d %d %d D: %d C: %d B: %d\n", indx,
+ cpt[i] & 0xFFFF0000, (cpt[i] & 0xFFFF0000) | 0xFFFF,
+ (cpt[i] >> 10) & 3, (cpt[i] >> 8) & 3, (cpt[i] >> 6) & 3,
+ (cpt[i] >> 4) & 3, dom, (cpt[i] >> 3) & 1, (cpt[i] >> 2) & 1);
+ break;
+ case 2:
+ printf (" VA: %08X PA: %08X - %08X A: %d %d %d %d D: %d C: %d B: %d\n", indx,
+ cpt[i] & 0xfffff000, (cpt[i] & 0xfffff000) | 0xFFF,
+ (cpt[i] >> 10) & 3, (cpt[i] >> 8) & 3, (cpt[i] >> 6) & 3,
+ (cpt[i] >> 4) & 3, dom, (cpt[i] >> 3) & 1, (cpt[i] >> 2) & 1);
+ // This is where we look for any virtual addresses that map to physical address 0x03000000 and
+ // alter the cachable and bufferable bits...
+ /*if (((cpt[i] & 0xffff0000) == 0x03000000) && ((cpt[i] & 12)==0))
+ {
+ //printf("c and b bits not set, overwriting\n");
+ cpt[i] |= 0xFFC;
+ wb = 1;
+ }*/
+ if (((cpt[i] & 0xff000000) == 0x02000000) )
+ {
+ //printf("SOUND c and b bits not set, overwriting\n");
+ if((cpt[i] & 12)==0) {
+ cpt[i] |= 0xFFC;
+ wb++;
+ }
+ }
+ //if ((a>=0x31 && a<=0x36) && ((cpt[i] & 12)==0))
+ if (((cpt[i] & 0xff000000) == 0x03000000) )
+ {
+ //printf("SDL c and b bits not set, overwriting\n");
+ if((cpt[i] & 12)==0) {
+ cpt[i] |= 0xFFC;
+ wb++;
+ }
+ }
+ break;
+ case 3:
+ //printf (" -- [%08X/%d] Unsupported --\n", cpt[i],cpt[i] & 3);
+ break;
+ default:
+ //printf (" -- [%08X/%d] Unknown --\n", cpt[i], cpt[i] & 3);
+ break;
+ }
+ }
+ indx += 4096;
+ }
+ //printf ("%08X %08X %08X %08X\n", cpt[0], cpt[4], cpt[8], cpt[12]);
+ if (wb)
+ {
+ //printf("Hacking cpt\n");
+ lseek (memfd, sa, SEEK_SET);
+ temp = write (memfd, cpt, 256*4);
+ printf("%d bytes written, %s\n", temp, temp == 1024 ? "yay!" : "oh fooble :(!");
+ }
+}
+
+void dumppgtable (unsigned int ttb)
+{
+ unsigned int pgtable[4096];
+ char *desctypes[] = {"Invalid", "Coarse", "Section", "Fine"};
+
+ memset (pgtable, 0, 4096*4);
+ lseek (memfd, ttb, SEEK_SET);
+ read (memfd, pgtable, 4096*4);
+
+ int i;
+ for (i = 0; i < 4096; i ++)
+ {
+ int temp;
+
+ if (pgtable[i])
+ {
+ printf ("Indx: %d VA: %08X Type: %d [%s] \n", i, i * 1048576, pgtable[i] & 3, desctypes[pgtable[i]&3]);
+ switch (pgtable[i]&3)
+ {
+ case 0:
+ //printf (" -- Invalid --\n");
+ break;
+ case 1:
+ DecodeCoarse(i, pgtable[i]);
+ break;
+ case 2:
+ temp = pgtable[i] & 0xFFF00000;
+ //printf (" PA: %08X - %08X A: %d D: %d C: %d B: %d\n", temp, temp | 0xFFFFF,
+ // (pgtable[i] >> 10) & 3, (pgtable[i] >> 5) & 15, (pgtable[i] >> 3) & 1,
+ // (pgtable[i] >> 2) & 1);
+
+ break;
+ case 3:
+ printf (" -- Unsupported! --\n");
+ break;
+ }
+ }
+ }
+}
+
+void benchmark (void *memptr)
+{
+ int starttime = time (NULL);
+ int a,b,c,d;
+ volatile unsigned int *pp = (unsigned int *) memptr;
+
+ while (starttime == time (NULL));
+
+ printf ("\n\nmemory benchmark of volatile VA: %08X\n\nread test\n", memptr);
+ for (d = 0; d < 3; d ++)
+ {
+ starttime = time (NULL);
+ b = 0;
+ c = 0;
+ while (starttime == time (NULL))
+ {
+ for (a = 0; a < 20000; a ++)
+ {
+ b += pp[a];
+ }
+ c ++;
+ }
+ printf ("Count is %d. %dMB/sec\n", c, (c * 20000)/1024/1024);
+ }
+
+ printf ("write test\n");
+ for (d = 0; d < 3; d ++)
+ {
+ starttime = time (NULL);
+ b = 0;
+ c = 0;
+ while (starttime == time (NULL))
+ {
+ for (a = 0; a < 20000; a ++)
+ {
+ pp[a] = 0x37014206;
+ }
+ c ++;
+ }
+ printf ("Count is %d. %dMB/sec\n", c, (c * 20000)/1024/1024);
+ }
+
+ printf ("combined test (read, write back)\n");
+ for (d = 0; d < 3; d ++)
+ {
+ starttime = time (NULL);
+ b = 0;
+ c = 0;
+ while (starttime == time (NULL))
+ {
+ for (a = 0; a < 20000; a ++)
+ {
+ pp[a] += 0x55017601;
+ }
+ c ++;
+ }
+ printf ("Count is %d. %dMB/sec\n", c, (c * 20000)/1024/1024);
+ }
+
+ printf ("test complete\n");
+}
+
+void hackpgtable (void)
+{
+ unsigned int oldc1, oldc2, oldc3, oldc4;
+ unsigned int newc1 = 0xee120f10, newc2 = 0xe12fff1e;
+ unsigned int ttb, ttx;
+ char name[256];
+
+ // We need to execute a "MRC p15, 0, r0, c2, c0, 0", to get the pointer to the translation table base, but we can't
+ // do this in user mode, so we have to patch the kernel to get it to run it for us in supervisor mode. We do this
+ // at the moment by overwriting the sys_newuname function and then calling it.
+
+ lseek (memfd, 0x6ec00, SEEK_SET); // fixme: We should ask the kernel for this address rather than assuming it...
+ read (memfd, &oldc1, 4);
+ read (memfd, &oldc2, 4);
+ read (memfd, &oldc3, 4);
+ read (memfd, &oldc4, 4);
+
+ printf ("0:%08X %08X\n", oldc1, oldc2);
+
+ lseek (memfd, 0x6ec00, SEEK_SET);
+ write (memfd, &newc1, 4);
+ write (memfd, &newc2, 4);
+
+ ttb = myuname(name);
+
+ lseek (memfd, 0x6ec00, SEEK_SET);
+ write (memfd, &oldc1, 4);
+ write (memfd, &oldc2, 4);
+
+ printf ("1:%08X\n", ttb);
+
+ //printf ("Restored contents\n");
+
+ // We now have the translation table base ! Walk the table looking for our allocation and hack it :)
+ dumppgtable(ttb);
+
+ // Now drain the write buffer and flush the tlb caches. Something else we can't do in user mode...
+ unsigned int tlbc1 = 0xe3a00000; // mov r0, #0
+ unsigned int tlbc2 = 0xee070f9a; // mcr 15, 0, r0, cr7, cr10, 4
+ unsigned int tlbc3 = 0xee080f17; // mcr 15, 0, r0, cr8, cr7, 0
+ unsigned int tlbc4 = 0xe1a0f00e; // mov pc, lr
+
+ lseek (memfd, 0x6ec00, SEEK_SET);
+ write (memfd, &tlbc1, 4);
+ write (memfd, &tlbc2, 4);
+ write (memfd, &tlbc3, 4);
+ write (memfd, &tlbc4, 4);
+
+ ttx = myuname(name);
+
+ //printf ("Return from uname: %08X\n", ttx);
+
+ lseek (memfd, 0x6ec00, SEEK_SET);
+ write (memfd, &oldc1, 4);
+ write (memfd, &oldc2, 4);
+ write (memfd, &oldc3, 4);
+ write (memfd, &oldc4, 4);
+
+ //printf ("Restored contents\n");
+
+ //printf ("Pagetable after modification!\n");
+ //printf ("-------------------------------\n");
+ //dumppgtable(ttb);
+}
+
+/*int
+main( int argc, char* argv[] )
+{
+ if (!initphys())
+ return 0;
+
+ volatile unsigned int *myBuf = trymmap((void *)0, 65536, PROT_READ | PROT_WRITE, MAP_SHARED, memfd, 0x03000000);
+ volatile unsigned int *secbuf = (unsigned int *)malloc (204800);
+
+ //memset ((void *)myBuf, 0x55, 65536);
+ //memset ((void *)secbuf, 0x55, 65536);
+
+ printf("mmaped 0x03000000 buffer @ VA: %08X malloc'd buffer @ VA: %08X\n", myBuf, secbuf);
+
+ hackpgtable();
+
+ //benchmark ((void*)myBuf);
+ //benchmark ((void*)secbuf);
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////////////
+ printf ("\n\nCleaning up...\n");
+ printf ("Closing files...\n");
+ close (memfd);
+ printf ("Exiting...\n");
+
+ return 0;
+} */
\ No newline at end of file |