mirror of https://github.com/torvalds/linux.git
344eb5539a
getuser() and putuser() (and there underscored variants) use two strb[t]/ldrb[t] instructions when they are asked to get/put 16-bits. This means that the read/write is not atomic even when performed to a 16-bit-aligned address. This leads to problems with vhost: vhost uses __getuser() to read the vring's 16-bit avail.index field, and if it happens to observe a partial update of the index, wrong descriptors will be used which will lead to a breakdown of the virtio communication. A similar problem exists for __putuser() which is used to write to the vring's used.index field. The reason these functions use strb[t]/ldrb[t] is because strht/ldrht instructions did not exist until ARMv6T2/ARMv7. So we should be easily able to fix this on ARMv7. Also, since all ARMv6 processors also don't actually use the unprivileged instructions anymore for uaccess (since CONFIG_CPU_USE_DOMAINS is not used) we can easily fix them too. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> |
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| .. | ||
| Makefile | ||
| ashldi3.S | ||
| ashrdi3.S | ||
| backtrace.S | ||
| bitops.h | ||
| bswapsdi2.S | ||
| call_with_stack.S | ||
| changebit.S | ||
| clear_user.S | ||
| clearbit.S | ||
| copy_from_user.S | ||
| copy_page.S | ||
| copy_template.S | ||
| copy_to_user.S | ||
| csumipv6.S | ||
| csumpartial.S | ||
| csumpartialcopy.S | ||
| csumpartialcopygeneric.S | ||
| csumpartialcopyuser.S | ||
| delay-loop.S | ||
| delay.c | ||
| div64.S | ||
| ecard.S | ||
| findbit.S | ||
| floppydma.S | ||
| getuser.S | ||
| io-acorn.S | ||
| io-readsb.S | ||
| io-readsl.S | ||
| io-readsw-armv3.S | ||
| io-readsw-armv4.S | ||
| io-writesb.S | ||
| io-writesl.S | ||
| io-writesw-armv3.S | ||
| io-writesw-armv4.S | ||
| lib1funcs.S | ||
| lshrdi3.S | ||
| memchr.S | ||
| memcpy.S | ||
| memmove.S | ||
| memset.S | ||
| muldi3.S | ||
| putuser.S | ||
| setbit.S | ||
| strchr.S | ||
| strrchr.S | ||
| testchangebit.S | ||
| testclearbit.S | ||
| testsetbit.S | ||
| uaccess_with_memcpy.c | ||
| ucmpdi2.S | ||
| xor-neon.c | ||