Commit Graph

9 Commits

Author SHA1 Message Date
Nicolas Pitre 5c16595353 ARM: signal handling support for FDPIC_FUNCPTRS functions
Signal handlers are not direct function pointers but pointers to function
descriptor in that case. Therefore we must retrieve the actual function
address and load the GOT value into r9 from the descriptor before branching
to the actual handler.

If a restorer is provided, we also have to load its address and GOT from
its descriptor. That descriptor address and the code to load it is pushed
onto the stack to be executed as soon as the signal handler returns.

However, to be compatible with NX stacks, the FDPIC bounce code is also
copied to the signal page along with the other code stubs. Therefore this
code must get at the descriptor address whether it executes from the stack
or the signal page. To do so we use the stack pointer which points at the
signal stack frame where the descriptor address was stored. Because the
rt signal frame is different from the simpler frame, two versions of the
bounce code are needed, and two variants (ARM and Thumb) as well. The
asm-offsets facility is used to determine the actual offset in the signal
frame for each version, meaning that struct sigframe and rt_sigframe had
to be moved to a separate file.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Mickael GUENE <mickael.guene@st.com>
Tested-by: Vincent Abriou <vincent.abriou@st.com>
Tested-by: Andras Szemzo <szemzo.andras@gmail.com>
2017-09-10 19:31:46 -04:00
Russell King 48be69a026 ARM: move signal handlers into a vdso-like page
Move the signal handlers into a VDSO page rather than keeping them in
the vectors page.  This allows us to place them randomly within this
page, and also map the page at a random location within userspace
further protecting these code fragments from ROP attacks.  The new
VDSO page is also poisoned in the same way as the vector page.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-08-01 14:31:56 +01:00
Will Deacon 8d4150ccbb ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline""
This reverts commit 3b0c062267.

We no longer require the restart trampoline for syscall restarting.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-28 11:11:51 +01:00
Will Deacon 3b0c062267 ARM: 7442/1: Revert "remove unused restart trampoline"
This reverts commit fa18484d09.

We need the restart trampoline back so that we can revert a related
problematic patch 6b5c8045ec ("arm: new
way of handling ERESTART_RESTARTBLOCK").

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-05 09:50:56 +01:00
Al Viro fa18484d09 arm: remove unused restart trampoline
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-21 14:39:44 -04:00
Russell King ab72b00734 ARM: Fix signal restart issues with NX and OABI compat
The signal restarting code was placed on the user stack when OABI
compatibility is enabled.  Unfortunately, with an EABI NX executable,
this results in an attempt to run code from the non-executable stack,
which segfaults the application.

Fix this by placing the code in the vectors page, along side the
signal return code, and directing the application to that code.

Reported-by: saeed bishara <saeed.bishara@gmail.com>
Tested-by: saeed bishara <saeed.bishara@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-10-25 15:39:37 +00:00
Hyok S. Choi c760fc1997 [ARM] nommu: fixups for the exception vectors
The high page vector (0xFFFF0000) does not supported in nommu mode.
This patch allows the vectors to be 0x00000000 or the begining of DRAM
in nommu mode.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-27 15:18:50 +01:00
Nicolas Pitre fcca538b83 [ARM] 3270/1: ARM EABI: fix sigreturn and rt_sigreturn
Patch from Nicolas Pitre

The signal return path consists of user code provided by the kernel.
Since a syscall is used, it has to be updated to work with EABI.

Noticed by Daniel Jacobowitz.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-01-18 22:38:47 +00:00
Russell King e00d349e77 [PATCH] ARM: Move signal return code into vector page
Move the signal return code into the vector page instead of placing
it on the user mode stack, which will allow us to avoid flushing
the instruction cache on signals, as well as eventually allowing
non-exec stack.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-22 20:26:05 +01:00