linux-toradex.git/arch/sparc/kernel/head_64.S, branch v4.10

sparc64: Delete now unused user copy assembler helpers.

2016-10-25T04:22:27+00:00

All of __ret{,l}_mone{_asi,_fp,_asi_fpu} are now unused.

Signed-off-by: David S. Miller

sparc64: Prepare to move to more saner user copy exception handling.

2016-10-24T18:31:58+00:00

The fixup helper function mechanism for handling user copy fault
handling is not %100 accurrate, and can never be made so.

We are going to transition the code to return the running return
return length, which is always kept track in one or more registers
of each of these routines.

In order to convert them one by one, we have to allow the existing
behavior to continue functioning.

Therefore make all the copy code that wants the fixup helper to be
used return negative one.

After all of the user copy routines have been converted, this logic
and the fixup helpers themselves can be removed completely.

Signed-off-by: David S. Miller

sparc64: Delete __ret_efault.

2016-10-24T18:29:25+00:00

It is completely unused.

Signed-off-by: David S. Miller

sparc: move exports to definitions

2016-08-08T03:55:43+00:00

Acked-by: David S. Miller 
Signed-off-by: Al Viro

sparc64: Fix bootup regressions on some Kconfig combinations.

2016-04-27T21:27:37+00:00

The system call tracing bug fix mentioned in the Fixes tag
below increased the amount of assembler code in the sequence
of assembler files included by head_64.S

This caused to total set of code to exceed 0x4000 bytes in
size, which overflows the expression in head_64.S that works
to place swapper_tsb at address 0x408000.

When this is violated, the TSB is not properly aligned, and
also the trap table is not aligned properly either.  All of
this together results in failed boots.

So, do two things:

1) Simplify some code by using ba,a instead of ba/nop to get
   those bytes back.

2) Add a linker script assertion to make sure that if this
   happens again the build will fail.

Fixes: 1a40b95374f6 ("sparc: Fix system call tracing register handling.")
Reported-by: Meelis Roos 
Reported-by: Joerg Abraham 
Signed-off-by: David S. Miller

sparc64: recognize and support Sonoma CPU type

2016-04-21T20:43:47+00:00

Add code to recognize SPARC-Sonoma cpu correctly and update cpu hardware
caps and cpu distribution map. SPARC-Sonoma is based upon SPARC-M7 core
along with additional PCI functions added on and is reported by firmware
as "SPARC-SN".

Signed-off-by: Khalid Aziz 
Acked-by: Allen Pais 
Signed-off-by: David S. Miller

locking/lockdep: Eliminate lockdep_init()

2016-02-09T11:03:25+00:00

Lockdep is initialized at compile time now.  Get rid of lockdep_init().

Signed-off-by: Andrey Ryabinin 
Signed-off-by: Andrew Morton 
Cc: Linus Torvalds 
Cc: Mike Krinkin 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Cc: mm-commits@vger.kernel.org
Signed-off-by: Ingo Molnar

sparc64: fix FP corruption in user copy functions

2015-12-24T17:13:18+00:00

Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.

Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.

The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.

The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.

This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.

n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address.  This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.

Signed-off-by: Rob Gardner 
Signed-off-by: Dave Aldridge 
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

sparc64: correctly recognise M6 and M7 cpu type

2014-09-09T22:24:10+00:00

The following patch adds support for correctly
recognising M6 and M7 cpu type.

Signed-off-by: Allen Pais 
Signed-off-by: David S. Miller