From 3c1140db93b633efd838f1580ef0ec6021f9ee27 Mon Sep 17 00:00:00 2001 From: kib Date: Fri, 9 Jan 2015 02:35:19 +0000 Subject: [PATCH] MFC r276523: Restore access to the page at zero through /dev/mem after r263475. git-svn-id: svn://svn.freebsd.org/base/stable/10@276871 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- sys/amd64/amd64/mem.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/sys/amd64/amd64/mem.c b/sys/amd64/amd64/mem.c index 170da3ffa..2b6b1129e 100644 --- a/sys/amd64/amd64/mem.c +++ b/sys/amd64/amd64/mem.c @@ -77,7 +77,7 @@ int memrw(struct cdev *dev, struct uio *uio, int flags) { struct iovec *iov; - u_long c, v; + u_long c, v, vd; int error, o, sflags; vm_offset_t addr, eaddr; @@ -98,15 +98,15 @@ memrw(struct cdev *dev, struct uio *uio, int flags) kmemphys: o = v & PAGE_MASK; c = min(uio->uio_resid, (u_int)(PAGE_SIZE - o)); - v = PHYS_TO_DMAP(v); - if (v < DMAP_MIN_ADDRESS || - (v > DMAP_MIN_ADDRESS + dmaplimit && - v <= DMAP_MAX_ADDRESS) || - pmap_kextract(v) == 0) { + vd = PHYS_TO_DMAP(v); + if (vd < DMAP_MIN_ADDRESS || + (vd > DMAP_MIN_ADDRESS + dmaplimit && + vd <= DMAP_MAX_ADDRESS) || + (pmap_kextract(vd) == 0 && (v & PG_FRAME) != 0)) { error = EFAULT; goto ret; } - error = uiomove((void *)v, (int)c, uio); + error = uiomove((void *)vd, (int)c, uio); continue; } else if (dev2unit(dev) == CDEV_MINOR_KMEM) { v = uio->uio_offset; -- 2.45.0