The pmem infrastructure uses memcpy_mcsafe in the pmem layer so as to
convert machine check exceptions into a return value on failure in case
a machine check exception is encountered during the memcpy. The return
value is the number of bytes remaining to be copied.

This patch largely borrows from the copyuser_power7 logic and does not add
the VMX optimizations, largely to keep the patch simple. If needed those
optimizations can be folded in.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[arbab@linux.ibm.com: Added symbol export]
Co-developed-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820081352.8641-7-santosh@fossix.org

PPC32 also have flush_dcache_range() so it can also support
ARCH_HAS_PMEM_API and ARCH_HAS_UACCESS_FLUSHCACHE without changes.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a682a2f9db308c5cfe77e45aa3352e41bc9f4e33.1564554634.git.christophe.leroy@c-s.fr

The entire code in ldstfp.o is enclosed into #ifdef CONFIG_PPC_FPU,
so there is no point in building it when this config is not selected.

Fixes: cd64d1697cf0 ("powerpc: mtmsrd not defined")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

quad.o is only for PPC64, and already included in obj64-y,
so it doesn't have to be in obj-y

Fixes: 31bfdb036f12 ("powerpc: Use instruction emulation infrastructure to handle alignment faults")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

All files containing functions run before kasan_early_init() is called
must have KASAN instrumentation disabled.

For those file, branch profiling also have to be disabled otherwise
each if () generates a call to ftrace_likely_update().

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

CONFIG_KASAN implements wrappers for memcpy() memmove() and memset()
Those wrappers are doing the verification then call respectively
__memcpy() __memmove() and __memset(). The arches are therefore
expected to rename their optimised functions that way.

For files on which KASAN is inhibited, #defines are used to allow
them to directly call optimised versions of the functions without
going through the KASAN wrappers.

See commit 393f203f5fd5 ("x86_64: kasan: add interceptors for
memset/memmove/memcpy functions") for details.

Other string / mem functions do not (yet) have kasan wrappers,
we therefore have to fallback to the generic versions when
KASAN is active, otherwise KASAN checks will be skipped.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fixups to keep selftests working]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This enhances the current selftest framework for validating
the in-kernel instruction emulation infrastructure by adding
support for compute type instructions i.e. integer ALU-based
instructions. Originally, this framework was limited to only
testing load and store instructions.

While most of the GPRs can be validated, support for SPRs is
limited to LR, CR and XER for now.

When writing the test cases, one must ensure that the Stack
Pointer (GPR1) or the Thread Pointer (GPR13) are not touched
by any means as these are vital non-volatile registers.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
[mpe: Use patch_site for the code patching]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We implement regs_set_return_value() and override_function_with_return()
for this purpose.

On powerpc, a return from a function (blr) just branches to the location
contained in the link register. So, we can just update pt_regs rather
than redirecting execution to a dummy function that returns.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Back when I added -Werror in commit ba55bd74360e ("powerpc: Add
configurable -Werror for arch/powerpc") I did it by adding it to most
of the arch Makefiles.

At the time we excluded math-emu, because apparently it didn't build
cleanly. But that seems to have been fixed somewhere in the interim.

So move the -Werror addition to the top-level of the arch, this saves
us from repeating it in every Makefile and means we won't forget to
add it to any new sub-dirs.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The generic implementation of strlen() reads strings byte per byte.

This patch implements strlen() in assembly based on a read of entire
words, in the same spirit as what some other arches and glibc do.

On a 8xx the time spent in strlen is reduced by 3/4 for long strings.

strlen() selftest on an 8xx provides the following values:

Before the patch (ie with the generic strlen() in lib/string.c):

  len 256 : time = 1.195055
  len 016 : time = 0.083745
  len 008 : time = 0.046828
  len 004 : time = 0.028390

After the patch:

  len 256 : time = 0.272185 ==> 78% improvment
  len 016 : time = 0.040632 ==> 51% improvment
  len 008 : time = 0.033060 ==> 29% improvment
  len 004 : time = 0.029149 ==> 2% degradation

On a 832x:

Before the patch:

  len 256 : time = 0.236125
  len 016 : time = 0.018136
  len 008 : time = 0.011000
  len 004 : time = 0.007229

After the patch:

  len 256 : time = 0.094950 ==> 60% improvment
  len 016 : time = 0.013357 ==> 26% improvment
  len 008 : time = 0.010586 ==> 4% improvment
  len 004 : time = 0.008784

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>