Ravi Bangoria 83afab4ce0 powerpc/sstep: Fix kernel crash if VSX is not present
emulate_step() is not checking runtime VSX feature flag before
emulating an instruction. This is causing kernel crash when kernel
is compiled with CONFIG_VSX=y but running on a machine where VSX
is not supported or disabled. Ex, while running emulate_step tests
on P6 machine:

  Oops: Exception in kernel mode, sig: 4 [#1]
  NIP [c000000000095c24] .load_vsrn+0x28/0x54
  LR [c000000000094bdc] .emulate_loadstore+0x167c/0x17b0
  Call Trace:
    0x40fe240c7ae147ae (unreliable)
    .emulate_loadstore+0x167c/0x17b0
    .emulate_step+0x25c/0x5bc
    .test_lxvd2x_stxvd2x+0x64/0x154
    .test_emulate_step+0x38/0x4c
    .do_one_initcall+0x5c/0x2c0
    .kernel_init_freeable+0x314/0x4cc
    .kernel_init+0x24/0x160
    .ret_from_kernel_thread+0x58/0xb4

With fix:
  emulate_step_test: lxvd2x         : FAIL
  emulate_step_test: stxvd2x        : FAIL

Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-06-04 00:39:08 +10:00
2018-01-06 10:59:44 -07:00
2018-04-29 14:17:42 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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