/*
* Write bytes somewhere in the kernel text. Make the text
* pages writable temporarily.
*/
static void
db_write_text(vaddr_t addr, size_t size, char *data)
{
vaddr_t pgva;
size_t limit;
uint32_t bits;
char *dst;
if (size == 0)
return;
dst = (char *)addr;
do {
/*
* Get the PTE for the page.
*/
bits = pmap_pte_bits(addr);
if ((bits & PG_V) == 0) {
printf(" address %p not a valid page\n", dst);
return;
}
/*
* Get the VA for the page.
*/
if (bits & PG_PS) {
if (cpu_pae)
pgva = (vaddr_t)dst & PG_LGFRAME_PAE;
else
pgva = (vaddr_t)dst & PG_LGFRAME;
} else
pgva = trunc_page((vaddr_t)dst);
/*
* Compute number of bytes that can be written
* with this mapping and subtract it from the
* total size.
*/
#ifdef NBPD_L2
if (bits & PG_PS)
limit = NBPD_L2 - ((vaddr_t)dst & (NBPD_L2 - 1));
else
#endif
limit = PAGE_SIZE - ((vaddr_t)dst & PGOFSET);
if (limit > size)
limit = size;
size -= limit;
pmap_update_pg(pgva);
pmap_pte_setbits(addr, PG_RW, 0);
/*
* Page is now writable. Do as much access as we
* can in this page.
*/
for (; limit > 0; limit--)
*dst++ = *data++;
/*
* Restore the old PTE.
*/
pmap_update_pg(pgva);
pmap_pte_setbits(addr, 0, bits);
} while (size != 0);
}
/*
* Write bytes somewhere in the kernel text. Make the text
* pages writable temporarily.
*/
static void
db_write_text(vaddr_t addr, size_t size, const char *data)
{
pt_entry_t *ppte, pte;
size_t limit;
char *dst;
if (size == 0)
return;
dst = (char *)addr;
do {
addr = (vaddr_t)dst;
/*
* Get the PTE for the page.
*/
ppte = kvtopte(addr);
pte = *ppte;
if ((pte & PG_V) == 0) {
printf(" address %p not a valid page\n", dst);
return;
}
/*
* Compute number of bytes that can be written
* with this mapping and subtract it from the
* total size.
*/
if (pte & PG_PS)
limit = NBPD_L2 - (addr & (NBPD_L2 - 1));
else
limit = PAGE_SIZE - (addr & PGOFSET);
if (limit > size)
limit = size;
size -= limit;
/*
* Make the kernel text page writable.
*/
pmap_pte_clearbits(ppte, PG_KR);
pmap_pte_setbits(ppte, PG_KW);
pmap_update_pg(addr);
/*
* MULTIPROCESSOR: no shootdown required as the PTE continues to
* map the same page and other CPUs do not need write access.
*/
/*
* Page is now writable. Do as much access as we
* can in this page.
*/
for (; limit > 0; limit--)
*dst++ = *data++;
/*
* Turn the page back to read-only.
*/
pmap_pte_clearbits(ppte, PG_KW);
pmap_pte_setbits(ppte, PG_KR);
pmap_update_pg(addr);
/*
* MULTIPROCESSOR: no shootdown required as all other CPUs
* should be in CPUF_PAUSE state and will not cache the PTE
* with the write access set.
*/
} while (size != 0);
}
