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| author | kib <kib@FreeBSD.org> | 2015-01-26 10:11:55 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2015-01-26 10:11:55 +0000 |
| commit | 927059a62bc66b6c51c0752a41ff5f277629b10e (patch) | |
| tree | 9bcc005292870b60c1bac3c35f984c0168ef2266 /sys/arm | |
| parent | e0eed6b400483871c1ea8bce34af9d6f9643b54b (diff) | |
| download | FreeBSD-src-927059a62bc66b6c51c0752a41ff5f277629b10e.zip FreeBSD-src-927059a62bc66b6c51c0752a41ff5f277629b10e.tar.gz | |
Ensure that _tmppt KVA is used exclusively by providing exclusive sx
lock around the mapping and uiomove(). Before r277643, it was
partially protected by Giant (but potential sleeping in fault from
uiomove() would still allow other thread to reuse the mapping).
Noted by: ian
Reviewed by: alc, ian
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Diffstat (limited to 'sys/arm')
| -rw-r--r-- | sys/arm/arm/mem.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sys/arm/arm/mem.c b/sys/arm/arm/mem.c index 30d4b1d..58b0d25 100644 --- a/sys/arm/arm/mem.c +++ b/sys/arm/arm/mem.c @@ -55,6 +55,7 @@ __FBSDID("$FreeBSD$"); #include <sys/mutex.h> #include <sys/proc.h> #include <sys/signalvar.h> +#include <sys/sx.h> #include <sys/systm.h> #include <sys/uio.h> @@ -72,6 +73,9 @@ MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); struct mem_range_softc mem_range_softc; +static struct sx tmppt_lock; +SX_SYSINIT(tmppt, &tmppt_lock, "mem4map"); + /* ARGSUSED */ int memrw(struct cdev *dev, struct uio *uio, int flags) @@ -107,6 +111,7 @@ memrw(struct cdev *dev, struct uio *uio, int flags) } if (!address_valid) return (EINVAL); + sx_xlock(&tmppt_lock); pmap_kenter((vm_offset_t)_tmppt, v); o = (int)uio->uio_offset & PAGE_MASK; c = (u_int)(PAGE_SIZE - ((int)iov->iov_base & PAGE_MASK)); @@ -114,6 +119,7 @@ memrw(struct cdev *dev, struct uio *uio, int flags) c = min(c, (u_int)iov->iov_len); error = uiomove((caddr_t)&_tmppt[o], (int)c, uio); pmap_qremove((vm_offset_t)_tmppt, 1); + sx_xunlock(&tmppt_lock); continue; } else if (dev2unit(dev) == CDEV_MINOR_KMEM) { |
