linux-toradex.git/arch/powerpc/kernel/ppc_ksyms.c, branch v4.3

powerpc: Rename __get_SP() to current_stack_pointer()

2014-10-15T00:23:20+00:00

Michael points out that __get_SP() is a pretty horrible
function name. Let's give it a better name.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Reimplement __get_SP() as a function not a define

2014-10-15T00:23:19+00:00

Li Zhong points out an issue with our current __get_SP()
implementation. If ftrace function tracing is enabled (ie -pg
profiling using _mcount) we spill a stack frame on 64bit all the
time.

If a function calls __get_SP() and later calls a function that is
tail call optimised, we will pop the stack frame and the value
returned by __get_SP() is no longer valid. An example from Li can
be found in save_stack_trace -> save_context_stack:

c0000000000432c0 <.save_stack_trace>:
c0000000000432c0:       mflr    r0
c0000000000432c4:       std     r0,16(r1)
c0000000000432c8:       stdu    r1,-128(r1) <-- stack frame for _mcount
c0000000000432cc:       std     r3,112(r1)
c0000000000432d0:       bl      <._mcount>
c0000000000432d4:       nop

c0000000000432d8:       mr      r4,r1 <-- __get_SP()

c0000000000432dc:       ld      r5,632(r13)
c0000000000432e0:       ld      r3,112(r1)
c0000000000432e4:       li      r6,1

c0000000000432e8:       addi    r1,r1,128 <-- pop stack frame

c0000000000432ec:       ld      r0,16(r1)
c0000000000432f0:       mtlr    r0
c0000000000432f4:       b       <.save_context_stack> <-- tail call optimized

save_context_stack ends up with a stack pointer below the current
one, and it is likely to be scribbled over.

Fix this by making __get_SP() a function which returns the
callers stack frame. Also replace inline assembly which grabs
the stack pointer in save_stack_trace and show_stack with
__get_SP().

This also fixes an issue with perf_arch_fetch_caller_regs().
It currently unwinds the stack once, which will skip a
valid stack frame on a leaf function. With the __get_SP() fixes
in this patch, we never need to unwind the stack frame to get
to the first interesting frame.

We have to export __get_SP() because perf_arch_fetch_caller_regs()
(which is used in modules) calls it from a header file.

Reported-by: Li Zhong 
Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Separate ppc32 symbol exports into ppc_ksyms_32.c

2014-09-25T13:14:40+00:00

Simplify things considerably by moving all the ppc32 specific
symbol exports into its own file.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Move lib symbol exports into arch/powerpc/lib/ppc_ksyms.c

2014-09-25T13:14:39+00:00

Move the lib symbol exports closer to their function definitions

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Remove unused 32bit symbol exports

2014-09-25T13:14:38+00:00

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Move more symbol exports next to function definitions

2014-09-25T13:14:38+00:00

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Move via-cuda symbol exports next to function definitions

2014-09-25T13:14:37+00:00

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Move adb symbol exports next to function definitions

2014-09-25T13:14:37+00:00

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: memcpy optimization for 64bit LE

2014-04-30T05:26:18+00:00

Unaligned stores take alignment exceptions on POWER7 running in little-endian.
This is a dumb little-endian base memcpy that prevents unaligned stores.
Once booted the feature fixup code switches over to the VMX copy loops
(which are already endian safe).

The question is what we do before that switch over. The base 64bit
memcpy takes alignment exceptions on POWER7 so we can't use it as is.
Fixing the causes of alignment exception would slow it down, because
we'd need to ensure all loads and stores are aligned either through
rotate tricks or bytewise loads and stores. Either would be bad for
all other 64bit platforms.

[ I simplified the loop a bit - Anton ]

Signed-off-by: Philippe Bergheaud 
Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Export flush_icache_range

2014-04-28T03:08:46+00:00

Commit aac416fc38c (lkdtm: flush icache and report actions) calls
flush_icache_range from a module. It's exported on most architectures
that implement it, but not on powerpc. This patch exports it to fix
the module link failure.

Signed-off-by: Jeff Mahoney 
Signed-off-by: Benjamin Herrenschmidt