Provide hooks into the kernel entry and exit paths to permit control
of userspace visibility to the kernel. The intended use is:
- on entry to kernel from user, uaccess_disable will be called to
disable userspace visibility
- on exit from kernel to user, uaccess_enable will be called to
enable userspace visibility
- on entry from a kernel exception, uaccess_save_and_disable will be
called to save the current userspace visibility setting, and disable
access
- on exit from a kernel exception, uaccess_restore will be called to
restore the userspace visibility as it was before the exception
occurred.
These hooks allows us to keep userspace visibility disabled for the
vast majority of the kernel, except for localised regions where we
want to explicitly access userspace.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Improve the do_ldrd_abort macro code - firstly, it inefficiently checks
for the LDRD encoding by doing a multi-stage test of various bits. This
can be simplified by generating a mask, bitmasking the instruction and
then comparing the result.
Secondly, we want to be able to test the result rather than branching
to do_DataAbort, so remove the branch at the end and rename the macro
to 'teq_ldrd' to reflect it's new usage. teq_ldrd macro returns 'eq'
if the instruction was a LDRD.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit be020f8618, "ARM: entry: abort-macro: specify registers to be
used for macros", while replacing register numbers with macro parameter
names, mismatched the name used for r1. For me, this resulted in user
space built for EABI with -march=armv4t -mtune=arm920t -mthumb-interwork
-mthumb broken on my OMAP1510 based Amstrad Delta (old ABI and no thumb
still worked for me though).
Fix this by using correct parameter name fsr instead of mismatched psr,
used by callers for another purpose.
Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tail-call the main C data abort handler code from the per-CPU helper
code. Update the comments in the code wrt the new calling and return
register state.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We can test bits 27:25 and 20 of the instruction at the same time;
there's no need to separate out the check of bit 20.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Require all callers of abort macros to specify the registers to be
used. This improves the documentation at the callsites as to which
registers are being used by this assembly code.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Russell King
Janusz Krzysztofik
Linus Torvalds