/*ARGSUSED*/
static faultcode_t
segkmem_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t size,
enum fault_type type, enum seg_rw rw)
{
pgcnt_t npages;
spgcnt_t pg;
page_t *pp;
struct vnode *vp = seg->s_data;
ASSERT(RW_READ_HELD(&seg->s_as->a_lock));
if (seg->s_as != &kas || size > seg->s_size ||
addr < seg->s_base || addr + size > seg->s_base + seg->s_size)
panic("segkmem_fault: bad args");
/*
* If it is one of segkp pages, call segkp_fault.
*/
if (segkp_bitmap && seg == &kvseg &&
BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
return (SEGOP_FAULT(hat, segkp, addr, size, type, rw));
if (rw != S_READ && rw != S_WRITE && rw != S_OTHER)
return (FC_NOSUPPORT);
npages = btopr(size);
switch (type) {
case F_SOFTLOCK: /* lock down already-loaded translations */
for (pg = 0; pg < npages; pg++) {
pp = page_lookup(vp, (u_offset_t)(uintptr_t)addr,
SE_SHARED);
if (pp == NULL) {
/*
* Hmm, no page. Does a kernel mapping
* exist for it?
*/
if (!hat_probe(kas.a_hat, addr)) {
addr -= PAGESIZE;
while (--pg >= 0) {
pp = page_find(vp, (u_offset_t)
(uintptr_t)addr);
if (pp)
page_unlock(pp);
addr -= PAGESIZE;
}
return (FC_NOMAP);
}
}
addr += PAGESIZE;
}
if (rw == S_OTHER)
hat_reserve(seg->s_as, addr, size);
return (0);
case F_SOFTUNLOCK:
while (npages--) {
pp = page_find(vp, (u_offset_t)(uintptr_t)addr);
if (pp)
page_unlock(pp);
addr += PAGESIZE;
}
return (0);
default:
return (FC_NOSUPPORT);
}
/*NOTREACHED*/
}
/*
* Perform I/O to a given process. This will return EIO if we dectect
* corrupt memory and ENXIO if there is no such mapped address in the
* user process's address space.
*/
static int
urw(proc_t *p, int writing, void *buf, size_t len, uintptr_t a)
{
caddr_t addr = (caddr_t)a;
caddr_t page;
caddr_t vaddr;
struct seg *seg;
int error = 0;
int err = 0;
uint_t prot;
uint_t prot_rw = writing ? PROT_WRITE : PROT_READ;
int protchanged;
on_trap_data_t otd;
int retrycnt;
struct as *as = p->p_as;
enum seg_rw rw;
/*
* Locate segment containing address of interest.
*/
page = (caddr_t)(uintptr_t)((uintptr_t)addr & PAGEMASK);
retrycnt = 0;
AS_LOCK_ENTER(as, &as->a_lock, RW_WRITER);
retry:
if ((seg = as_segat(as, page)) == NULL ||
!page_valid(seg, page)) {
AS_LOCK_EXIT(as, &as->a_lock);
return (ENXIO);
}
SEGOP_GETPROT(seg, page, 0, &prot);
protchanged = 0;
if ((prot & prot_rw) == 0) {
protchanged = 1;
err = SEGOP_SETPROT(seg, page, PAGESIZE, prot | prot_rw);
if (err == IE_RETRY) {
protchanged = 0;
ASSERT(retrycnt == 0);
retrycnt++;
goto retry;
}
if (err != 0) {
AS_LOCK_EXIT(as, &as->a_lock);
return (ENXIO);
}
}
/*
* segvn may do a copy-on-write for F_SOFTLOCK/S_READ case to break
* sharing to avoid a copy on write of a softlocked page by another
* thread. But since we locked the address space as a writer no other
* thread can cause a copy on write. S_READ_NOCOW is passed as the
* access type to tell segvn that it's ok not to do a copy-on-write
* for this SOFTLOCK fault.
*/
if (writing)
rw = S_WRITE;
else if (seg->s_ops == &segvn_ops)
rw = S_READ_NOCOW;
else
rw = S_READ;
if (SEGOP_FAULT(as->a_hat, seg, page, PAGESIZE, F_SOFTLOCK, rw)) {
if (protchanged)
(void) SEGOP_SETPROT(seg, page, PAGESIZE, prot);
AS_LOCK_EXIT(as, &as->a_lock);
return (ENXIO);
}
CPU_STATS_ADD_K(vm, softlock, 1);
/*
* Make sure we're not trying to read or write off the end of the page.
*/
ASSERT(len <= page + PAGESIZE - addr);
/*
* Map in the locked page, copy to our local buffer,
* then map the page out and unlock it.
*/
vaddr = mapin(as, addr, writing);
/*
* Since we are copying memory on behalf of the user process,
* protect against memory error correction faults.
*/
if (!on_trap(&otd, OT_DATA_EC)) {
if (seg->s_ops == &segdev_ops) {
/*
* Device memory can behave strangely; invoke
* a segdev-specific copy operation instead.
*/
if (writing) {
if (segdev_copyto(seg, addr, buf, vaddr, len))
error = ENXIO;
} else {
if (segdev_copyfrom(seg, addr, vaddr, buf, len))
error = ENXIO;
}
} else {
if (writing)
bcopy(buf, vaddr, len);
else
bcopy(vaddr, buf, len);
}
} else {
error = EIO;
}
no_trap();
/*
* If we're writing to an executable page, we may need to sychronize
* the I$ with the modifications we made through the D$.
*/
if (writing && (prot & PROT_EXEC))
sync_icache(vaddr, (uint_t)len);
mapout(as, addr, vaddr, writing);
if (rw == S_READ_NOCOW)
rw = S_READ;
(void) SEGOP_FAULT(as->a_hat, seg, page, PAGESIZE, F_SOFTUNLOCK, rw);
if (protchanged)
(void) SEGOP_SETPROT(seg, page, PAGESIZE, prot);
AS_LOCK_EXIT(as, &as->a_lock);
return (error);
}
