linux_dsm_epyc7002/drivers/gpu
Linus Torvalds 594cc251fd make 'user_access_begin()' do 'access_ok()'
Originally, the rule used to be that you'd have to do access_ok()
separately, and then user_access_begin() before actually doing the
direct (optimized) user access.

But experience has shown that people then decide not to do access_ok()
at all, and instead rely on it being implied by other operations or
similar.  Which makes it very hard to verify that the access has
actually been range-checked.

If you use the unsafe direct user accesses, hardware features (either
SMAP - Supervisor Mode Access Protection - on x86, or PAN - Privileged
Access Never - on ARM) do force you to use user_access_begin().  But
nothing really forces the range check.

By putting the range check into user_access_begin(), we actually force
people to do the right thing (tm), and the range check vill be visible
near the actual accesses.  We have way too long a history of people
trying to avoid them.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 12:56:09 -08:00
..
drm make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
host1x gpu: host1x: Add Tegra194 support 2018-11-29 17:11:49 +01:00
ipu-v3 gpu: ipu-v3: image-convert: allow three rows or columns 2018-11-05 14:40:08 +01:00
vga drm-misc-next for v4.21, part 1: 2018-11-19 10:40:33 +10:00
Makefile