The 32-bit wide variant of "mov pc, reg" in Thumb-2 is unpredictable
causing improper handling of the undefined instructions not caught by
the kernel. This patch adds a movw_pc macro for such situations
(currently only used in call_fpe).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit 200b812d00 "Clear the exclusive monitor when returning from an
exception" broke the vast majority of ARM systems in the wild which are
still pre ARMv6. The kernel is crashing on the first occurrence of an
exception due to the removal of the actual return instruction for them.
Let's add it back.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch adds a CLREX or dummy STREX to the exception return path. This
is needed because several atomic/locking operations use a pair of
LDREX/STREXEQ and the EQ condition may not always be satisfied. This
would leave the exclusive monitor status set and may cause problems with
atomic/locking operations in the interrupted code.
With this patch, the atomic_set() operation can be a simple STR
instruction (on SMP systems, the global exclusive monitor is cleared by
STR anyway). Clearing the exclusive monitor during context switch is no
longer needed as this is handled by the exception return path anyway.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jamie Lokier <jamie@shareable.org>
5d25ac038a broke VFP builds due to
enable_irq not being defined as an assembly macro. Move it to
assembler.h so everyone can use it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Nicolas Pitre
The ARM EABI says that the stack pointer has to be 64-bit aligned for
reasons already mentioned in patch #3101 when calling C functions.
We therefore must verify and adjust sp accordingly when taking an
exception from kernel mode since sp might not necessarily be 64-bit
aligned if the exception occurs in the middle of a kernel function.
If the exception occurs while in user mode then no sp fixup is needed as
long as sizeof(struct pt_regs) as well as any additional syscall data
stack space remain multiples of 8.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current vector entry system does not allow for SMP. In
order to work around this, we need to eliminate our reliance
on the fixed save areas, which breaks the way we enable
alignment traps. This patch makes the alignment trap enable
code independent of the way we handle the save areas.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>
SVC_MODE reflects the MODE_SVC definition in asm/ptrace.h. Use
the asm/ptrace.h definition instead, and remove SVC_MODE.
Signed-off-by: Russell King <rmk@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!
Catalin Marinas