linux.git/arch/arc/kernel/entry.S, branch v3.9-rc2

ARC: Fix pt_orig_r8 access

2013-02-15T17:46:21+00:00

Syscall restarting fixes made pt_regs->orig_r8 a short word, which was
not reflected in the assembler code - thus could potentially break gdb
debugging.

Signed-off-by: Vineet Gupta

ARC: Support for single cycle Close Coupled Mem (CCM)

2013-02-15T17:46:10+00:00

* Includes mapping of CCMs in address space
* Annotations to move arbitrary code/data into CCM
* Moving some of the critical code/data into CCM
* Runtime detection/reporting

Signed-off-by: Vineet Gupta

ARC: Unaligned access emulation

2013-02-15T17:46:06+00:00

ARC700 doesn't natively support unaligned access, but can be emulated
-Unaligned Access Exception
-Disassembly at the Fault address to find the exact insn (long/short)

Also per Arnd's comment, we runtime control it using 2 sysctl knobs:
* SYSCTL_ARCH_UNALIGN_ALLOW: Runtime enable/disble
* SYSCTL_ARCH_UNALIGN_NO_WARN: Warn on each emulation attempt

Originally contributed by Tim Yao 

Signed-off-by: Vineet Gupta 
Cc: Tim Yao 
Acked-by: Arnd Bergmann

ARC: DWARF2 .debug_frame based stack unwinder

2013-02-15T17:46:03+00:00

-Originally written by Rajeshwar Ranga
-Derived off of generic unwinder in 2.6.19 and adapted to ARC

Signed-off-by: Vineet Gupta 
Cc: Rajeshwar Ranga

ARC: SMP support

2013-02-15T17:46:02+00:00

ARC common code to enable a SMP system + ISS provided SMP extensions.

ARC700 natively lacks SMP support, hence some of the core features are
are only enabled if SoCs have the necessary h/w pixie-dust. This
includes:
-Inter Processor Interrupts (IPI)
-Cache coherency
-load-locked/store-conditional
...

The low level exception handling would be completely broken in SMP
because we don't have hardware assisted stack switching. Thus a fair bit
of this code is repurposing the MMU_SCRATCH reg for event handler
prologues to keep them re-entrant.

Many thanks to Rajeshwar Ranga for his initial "major" contributions to
SMP Port (back in 2008), and to Noam Camus and Gilad Ben-Yossef for help
with resurrecting that in 3.2 kernel (2012).

Note that this platform code is again singleton design pattern - so
multiple SMP platforms won't build at the moment - this deficiency is
addressed in subsequent patches within this series.

Signed-off-by: Vineet Gupta 
Cc: Arnd Bergmann 
Cc: Thomas Gleixner 
Cc: Rajeshwar Ranga 
Cc: Noam Camus 
Cc: Gilad Ben-Yossef

ARC: Support for high priority interrupts in the in-core intc

2013-02-15T17:46:01+00:00

There is a bit of hack/kludge right now where we disable preemption if a
L2 (High prio) IRQ is taken while L1 (Low prio) is active.

Need to revisit this

Signed-off-by: Vineet Gupta

ARC: ptrace support

2013-02-15T17:45:59+00:00

Signed-off-by: Vineet Gupta 
Acked-by: Arnd Bergmann

ARC: [optim] Cache "current" in Register r25

2013-02-15T17:45:58+00:00

Signed-off-by: Vineet Gupta

ARC: [Review] Preparing to fix incorrect syscall restarts due to signals

2013-02-15T17:45:49+00:00

To avoid multiple syscall restarts (multiple signals) or no restart at
all (sigreturn), we need just an extra bit of state "literally 1 bit" in
struct pt_regs. orig_r8 is the best place to do this, however given the
way it is encoded currently, we can't add anything simplistically.

Current orig_r8:
* syscalls   -> 1 to NR_SYSCALLS
* Exceptions -> NR_SYSCALLS + 1
* Break-point-> NR_SYSCALLS + 2

In new scheme it is a bit-field
* lower short word contains the  exact event type (and a new bit to represent
   restart semantics : if syscall was already / can't be restarted)
* upper short word optionally containing the syscall num - needed by
  likes of tracehooks etc

This patch only changes how orig_r8 is organised and nothing should
change behaviourily.

Signed-off-by: Vineet Gupta 
Cc: Al Viro

ARC: Signal handling

2013-02-15T17:33:30+00:00

Includes following fixes courtesy review by Al-Viro

* Tracer poke to Callee-regs were lost

  Before going off into do_signal( ) we save the user-mode callee regs
  (as they are not saved by default as part of pt_regs). This is to make
  sure that that a Tracer (if tracing related signal) is able to do likes
  of PEEKUSR(callee-reg).

  However in return path we were simply discarding the user-mode callee
  regs, which would break a POKEUSR(callee-reg) from a tracer.

* Issue related to multiple syscall restarts are addressed in next patch

Signed-off-by: Vineet Gupta 
Cc: Al Viro 
Acked-by: Jonas Bonn