the AC flag in eflags/rflags, pushed in the iframe by the CPU, is kept intact after handling the exception, since the fault handler is run with the faulted iframe and does a simple jump. The AC flag would otherwise be set until the syscall returns to userland.
Change-Id: I24f763032ab98029dd162fb411e1541586451606
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4040
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
SMAP will generated page faults when the kernel tries to access user pages unless overriden.
If SMAP is enabled, the override instructions are written where needed in memory with
binary "altcodepatches".
Support is enabled by default, might be disabled per safemode setting.
Change-Id: Ife26cd765056aeaf65b2ffa3cadd0dcf4e273a96
This patch adds user_access() which can be used to gracefully handle
page faults that may happen when accessing user memory. It is used
by arch_cpu_user{memcpy, memset, strlcpy}() to allow using optimized
functions from the standard library.
Currently only x64 uses this, but nothing really is arch specific here.
Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
