This is the first patch which add support for
user application debugging through brki rX, 0x18 vector.

This patch has side effect which also remove security issue
to use brki rX, 0x18 to freeze kernel.

Support for old gdb support via priviledged exception
(brk r0, r0) is still there. It will be remove in future.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We need to save instruction and the latest Microblaze shouldn't
have any problem with it.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Syscall can be called only from userspace that's why
we don't need to check which space kernel come from.

Kernel syscall calling is not check and shouldn't come
throught this part of code.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We can save one more instruction if PT_MODE is saved in delay slot
Signed-off-by: Michal Simek <monstr@monstr.eu>

Save instructions by using delay slot and
clear UMS only if kernel comes from user space.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Saving some instructions. Clear VMS bit if kernel comes
from kernel space.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Saving instructions by adding 2/3 addik instructions to one.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Saving instruction with delay slot usage.
Signed-off-by: Michal Simek <monstr@monstr.eu>

This change save one instruction if kernel comes from kernel
space.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Separate reg saving and mode setting.
Signed-off-by: Michal Simek <monstr@monstr.eu>

SAVE_STATE macro could be used by other rutines too.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We are not working with values from MSR that's why
we can discard it and use r11 for different purpose without
saving/restoring.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Remove set_vms because UMS is cleared and VMS is already setup.
Optimize function calling which save one additional instruction.
Signed-off-by: Michal Simek <monstr@monstr.eu>

VMS is always setup because VM mode was before
exception/syscall/interrupt. Kernel continues in kernel mode
that's why we have to clear UMS bit if kernel comes from
user space.
Signed-off-by: Michal Simek <monstr@monstr.eu>

PT_MODE stores information if kernel comes from user
or kernel space. If come from user space, PT_MODE
contains 0. If come from kernel store, PT_MODE contains
non zero value. We don't need to save value 1. I am using
r1 register which contains non zero value.
This change save one additional instruction.
Signed-off-by: Michal Simek <monstr@monstr.eu>

SAVE_STATE macro could be used for user_exception
or interrupt functions.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We don't need to save r0 to PT_R0. It could be additional
operation.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We don't need to save R11 register. There is easy way
to use only R1 which is saved and restore later.
Signed-off-by: Michal Simek <monstr@monstr.eu>

BIP is already setup.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Keep together all arguments for send_sig function.
Move returning address to delay slot which is executed.
Remove additional send_sig loading. I am using IMM part of
rtbd instruction with r0.

old solution:
addik r11, r0, send_sig
rtbd r11, 0
nop

new solution:
rtbd r0, send_sig
nop

There is one instruction saving.
Signed-off-by: Michal Simek <monstr@monstr.eu>

It is necessary to setup BIP and EE and clear EIP
only for unaligned exception handler. The rest of
hw exception handlers don't require it.
HW exception occured and we are not in virtual mode.
That's why we can do operations protected by EIP.
Interrupt, next hw exception or syscall can't occur.

EIP is cleared by rted.

This change speedup page_fault hw exception handler
which is critical path.

There is also necessary to save R11 content before
flag setup for unaligned exception.
Signed-off-by: Michal Simek <monstr@monstr.eu>

la is translated to addik by toolchain.
Signed-off-by: Michal Simek <monstr@monstr.eu>

SAVE_STATE macro is used in hw exceptions high level handling
functions. Hw exception doesn't disable IRQ that's why we don't
need to reenable it.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Remove code duplicity and move it to SAVE_STATE macro.
There is no impact on performance.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We don't need to protect by BIP whole ret_from_trap/ret_from_exc code.
Only restoring from user/hw exception should be covered.
If BIP is setup, IRQ can't occur.
Signed-off-by: Michal Simek <monstr@monstr.eu>

There is a way howto remove Kernel Mode variable. It is easier
to parse UMS bit in MSR to find out if I come from kernel or user
space. Loading MSR content should be in one cycle and loading
PER_CPU variable depends on memory state.
Signed-off-by: Michal Simek <monstr@monstr.eu>

We can save two instruction when MSR_VMS and MSR_UMS
are setup in one instruction.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Save and restore R3/R4 registers in macros. This change
help to cleanup entry.S.

In ret_from_trap function we are saving returning value from
syscall to pt_regs on stack that's why we don't need to save and
restore these values before kernel functions (schedule, do_signal).
Signed-off-by: Michal Simek <monstr@monstr.eu>

Jump behind macro. We don't want to execute nop instruction again.
Signed-off-by: Michal Simek <monstr@monstr.eu>

_start symbol stores physical address where kernel is.
Gdb uses this symbol for their purpose that's why
we have to rename it.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Remove spaces and use tabs instead.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Microblaze has only 11 pvr regs according manual.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Lower shifting values ensure that shifted 32bit counter
value doesn't exceed 64bit cycle variable too fast.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Microblaze has support for early printk. The second serial
driver (uart16550/8250) has no microblaze support for early
printk.
Signed-off-by: Michal Simek <monstr@monstr.eu>

HAVE_ARCH_PCI_SET_DMA_MASK was removed in 2.6.34 (no architecture has
the own implementation of pci_set_dma_mask).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Michal Simek <monstr@monstr.eu>

IRQsoff tracer requires to protect cpu_idle function
to get correct timing report.
Signed-off-by: Michal Simek <monstr@monstr.eu>

I had to comment sched_clock generic function because of broken toolchain.
It is fine grain timing.
Signed-off-by: Michal Simek <monstr@monstr.eu>

Implement intelligent backtracing by searching for stack frame creation,
and emitting only return addresses. Use print_hex_dump() to display the
entire binary kernel stack.

Limitation: MMU kernels are not currently able to trace beyond a system trap
(interrupt, syscall, etc.). It is the intent of this patch to provide
infrastructure that can be extended to add this capability later.

Changes from V1:
* Removed checks in find_frame_creation() that prevented location of the frame
  creation instruction in heavily optimized code
* Various formatting/commenting/file location tweaks per review comments
* Dropped Kconfig option to enable STACKTRACE as something logically separate
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>

Allow developer to configure memory page size at compile time.
Larger pages can improve performance on some workloads.

Based on PowerPC code.
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

Add trace_hardirqs_off and trace_hardirqs_on to do_IRQ function.
Signed-off-by: Michal Simek <monstr@monstr.eu>