linux-toradex.git/arch/arc/kernel/entry.S, branch v3.10.67

ARC: !PREEMPT: Ensure Return to kernel mode is IRQ safe

2014-05-13T11:59:46+00:00

commit 8aa9e85adac609588eeec356e5a85059b3b819ba upstream.

There was a very small race window where resume to kernel mode from a
Exception Path (or pure kernel mode which is true for most of ARC
exceptions anyways), was not disabling interrupts in restore_regs,
clobbering the exception regs

Anton found the culprit call flow (after many sleepless nights)

| 1. we got a Trap from user land
| 2. started to service it.
| 3. While doing some stuff on user-land memory (I think it is padzero()),
|     we got a DataTlbMiss
| 4. On return from it we are taking "resume_kernel_mode" path
| 5. NEED_RESHED is not set, so we go to "return from exception" path in
|     restore regs.
| 6. there seems to be IRQ happening

Signed-off-by: Vineet Gupta 
Cc: Anton Kolesov 
Cc: Francois Bedard 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ARC: Entry Handler tweaks: Optimize away redundant IRQ_DISABLE_SAVE

2014-05-13T11:59:42+00:00

commit fce16bc35ae4a45634f3dc348d8d297a25c277cf upstream.

In the exception return path, for both U/K cases, intr are already
disabled (for various existing reasons). So when we drop down to
@restore_regs, we need not redo that.

There was subtle issue - when intr were NOT being disabled for
ret-to-kernel-but-no-preemption case - now fixed by moving the
IRQ_DISABLE further up in @resume_kernel_mode.

So what do we gain:

* Shaves off a few insn in return path.

* Eliminates the need for IRQ_DISABLE_SAVE assembler macro for ARCv2
  hence allows for entry code sharing.

Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: Entry Handler tweaks: Simplify branch for in-kernel preemption

2014-05-13T11:59:42+00:00

commit 147aece29b15051173eb1e767018135361cdba89 upstream.

Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: gdbserver breakage in Big-Endian configuration #1

2013-08-29T16:47:29+00:00

[Based on mainline commit 502a0c775c7f0a: "ARC: pt_regs update #5"]

gdbserver needs @stop_pc, served by ptrace, but fetched from pt_regs
differently, based on in_brkpt_traps(), which in turn relies on
additional machine state in pt_regs->event bitfield.

        unsigned long orig_r8:16, event:16;

For big endian config, this macro was returning false, despite being in
breakpoint Trap exception, causing wrong @stop_pc to be returned to gdb.

Issue #1: In BE, @event above is at offset 2 in word, while a STW insn
          at offset 0 was used to update it. Resort to using ST insn
	  which updates the half-word at right location.

Issue #2: The union involving bitfields causes all the members to be
	  laid out at offset 0. So with fix #1 above, ASM was now
	  updating at offset 2, "C" code was still referencing at
	  offset 0. Fixed by wrapping bitfield in a struct.

Reported-by: Noam Camus 
Tested-by: Anton Kolesov 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: unaligned access emulation broken if callee-reg dest of LD/ST

2013-05-07T08:13:55+00:00

The fixup code correctly updates the callee-regs on stack, but
fails to unwind it into actual register file. Thus userspace won't see
the update.

Reported-by: Noam Camus 
Signed-off-by: Vineet Gupta

ARC: unaligned access emulation error handling consolidation

2013-05-07T08:13:55+00:00

If CONFIG_ARC_MISALIGN_ACCESS is not enabled, or if the fixup fails,
call the same error handler: same signal/si_code to user (SIGBUS)

Signed-off-by: Vineet Gupta

ARC: Fix the typo in event identifier flags used by ptrace

2013-03-20T13:15:45+00:00

orig_r8_IS_EXCPN and orig_r8_IS_BRKPT were same values due to a
copy/paste error. Although it looks bad and is wrong, it really doesn't
affect gdb working.

orig_r8_IS_BRKPT is the one relevant to debugging (breakpoints), since
it is used to provide EFA vs. ERET to a ptrace "stop_pc" request.

So when gdb has inserted a breakpoint, orig_r8_IS_BRKPT is already set,
and anything else (i.e. orig_r8_IS_EXCPN) becoming same as it, really
doesn't hurt gdb. The corollary case, could be nasty but nobody uses the
ptrace "stop_pc" request in that case

Signed-off-by: Vineet Gupta

ARC: ABIv3: fork/vfork wrappers not needed in "no-legacy-syscall" ABI

2013-03-11T13:31:10+00:00

When switching to clone() only ABI - I missed out pruning the low level
asm syscall wrappers

Signed-off-by: Vineet Gupta

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