linux-stable.git/arch/sparc/kernel/entry.h, branch linux-4.4.y

sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE

2015-06-01T05:15:01+00:00

sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE

Bit 9 of TTE is CV (Cacheable in V-cache) on sparc v9 processor while
the same bit 9 is MCDE (Memory Corruption Detection Enable) on M7
processor. This creates a conflicting usage of the same bit. Kernel
sets TTE.cv bit on all pages for sun4v architecture which works well
for sparc v9 but enables memory corruption detection on M7 processor
which is not the intent. This patch adds code to determine if kernel
is running on M7 processor and takes steps to not enable memory
corruption detection in TTE erroneously.

Signed-off-by: Khalid Aziz 
Signed-off-by: David S. Miller

arch: sparc: kernel: traps_64.c: Remove some unused functions

2015-03-02T05:33:58+00:00

Removes some functions that are not used anywhere:
do_fpdis_tl1() do_iae_tl1() do_dae_tl1() do_cee_tl1()

This was partially found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist 
Signed-off-by: David S. Miller

sparc64: Fix register corruption in top-most kernel stack frame during boot.

2014-10-24T16:52:49+00:00

Meelis Roos reported that kernels built with gcc-4.9 do not boot, we
eventually narrowed this down to only impacting machines using
UltraSPARC-III and derivitive cpus.

The crash happens right when the first user process is spawned:

[   54.451346] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
[   54.451346]
[   54.571516] CPU: 1 PID: 1 Comm: init Not tainted 3.16.0-rc2-00211-gd7933ab #96
[   54.666431] Call Trace:
[   54.698453]  [0000000000762f8c] panic+0xb0/0x224
[   54.759071]  [000000000045cf68] do_exit+0x948/0x960
[   54.823123]  [000000000042cbc0] fault_in_user_windows+0xe0/0x100
[   54.902036]  [0000000000404ad0] __handle_user_windows+0x0/0x10
[   54.978662] Press Stop-A (L1-A) to return to the boot prom
[   55.050713] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004

Further investigation showed that compiling only per_cpu_patch() with
an older compiler fixes the boot.

Detailed analysis showed that the function is not being miscompiled by
gcc-4.9, but it is using a different register allocation ordering.

With the gcc-4.9 compiled function, something during the code patching
causes some of the %i* input registers to get corrupted.  Perhaps
we have a TLB miss path into the firmware that is deep enough to
cause a register window spill and subsequent restore when we get
back from the TLB miss trap.

Let's plug this up by doing two things:

1) Stop using the firmware stack for client interface calls into
   the firmware.  Just use the kernel's stack.

2) As soon as we can, call into a new function "start_early_boot()"
   to put a one-register-window buffer between the firmware's
   deepest stack frame and the top-most initial kernel one.

Reported-by: Meelis Roos 
Tested-by: Meelis Roos 
Signed-off-by: David S. Miller

sparc: drop use of extern for prototypes in arch/sparc/*

2014-05-19T02:01:29+00:00

Drop the remaining uses of extern for prototypes in .h files
in the sparc specific part of the kernel tree.

Signed-off-by: Sam Ravnborg 
Signed-off-by: David S. Miller

sparc64: Implement HAVE_CONTEXT_TRACKING

2013-11-14T22:57:21+00:00

Mark the places when the system are in user or are in kernel.
This is used to make full dynticks system (tickless) --
CONFIG_NO_HZ_FULL dependence.

Signed-off-by: Kirill Tkhai 
CC: David Miller 
Signed-off-by: David S. Miller

sparc: delete cpuinit/CPUINIT usage from all users

2013-07-14T23:36:52+00:00

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/sparc uses of the __cpuinit macros from
C files and removes __CPUINIT from assembly files.  Note that even
though arch/sparc/kernel/trampoline_64.S has instances of ".previous"
in it, they are all paired off against explicit ".section" directives,
and not implicitly paired with __CPUINIT (unlike mips and arm were).

[1] https://lkml.org/lkml/2013/5/20/589

Cc: "David S. Miller" 
Cc: sparclinux@vger.kernel.org
Signed-off-by: Paul Gortmaker

sparc64: Improvde documentation and readability of atomic backoff code.

2012-10-28T20:04:47+00:00

Document what's going on in asm/backoff.h with a large and descriptive
comment.  Refer to it above the cpu_relax() definition in
asm/processor_64.h

Rename the pause patching section to have "3insn" in it's name like
the other patching sections do.

Based upon feedback from Sam Ravnborg.

Signed-off-by: David S. Miller

sparc64: Use pause instruction when available.

2012-10-28T06:00:41+00:00

In atomic backoff and cpu_relax(), use the pause instruction
found on SPARC-T4 and later.

It makes the cpu strand unselectable for the given number of
cycles, unless an intervening disrupting trap occurs.

Signed-off-by: David S. Miller

sparc64: Patch sun4v code sequences properly on module load.

2011-11-18T06:44:58+00:00

Some of the sun4v code patching occurs in inline functions visible
to, and usable by, modules.

Therefore we have to patch them up during module load.

Signed-off-by: David S. Miller

sparc: Use popc when possible for ffs/__ffs/ffz.

2011-08-03T04:28:53+00:00

Signed-off-by: David S. Miller