selftests/powerpc: Add automatically allocating read_file

A couple of tests roll their own auto-allocating file read logic.

Add a generic implementation and convert them to use it.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203003947.38033-6-bgray@linux.ibm.com

selftests/powerpc: Add generic read/write file util

File read/write is reimplemented in about 5 different ways in the
various PowerPC selftests. This indicates it should be a common util.

Add a common read_file / write_file implementation and convert users
to it where (easily) possible.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203003947.38033-2-bgray@linux.ibm.com

selftests/powerpc: Use req_max_processed_len from sysfs NX capabilities

On PowerVM, the hypervisor defines the maximum buffer length for
each NX request and the kernel exported this value via sysfs.

This patch reads this value if the sysfs entry is available and
is used to limit the request length.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ed908341b1eb7ca0183c028a4ed4a0cf48bfe0f6.camel@linux.ibm.com

selftests/powerpc: remove unneeded semicolon

Eliminate the following coccicheck warning:
./tools/testing/selftests/powerpc/nx-gzip/gzfht_test.c:327:4-5: Unneeded
semicolon

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1612780870-95890-1-git-send-email-yang.lee@linux.alibaba.com

selftests/powerpc: Use proper error code to check fault address

ERR_NX_TRANSLATION(CSB.CC=5) is for internal to VAS for fault handling
and should not used by OS. ERR_NX_AT_FAULT(CSB.CC=250) is the proper
error code should be reported by OS when NX encounters address
translation failure.

This patch uses CC=250 to determine the fault address when the request
is not successful.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0315251705baff94f678c33178491b5008723511.camel@linux.ibm.com

selftests/powerpc: Add NX-GZIP engine compress testcase

Add a compression testcase for the powerpc NX-GZIP engine.

Signed-off-by: Bulent Abali <abali@us.ibm.com>
Signed-off-by: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200420205538.25181-4-rzinsly@linux.ibm.com