linux.git/arch/powerpc/include/asm/module.h, branch v5.6

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

powerpc/kbuild: move -mprofile-kernel check to Kconfig

2018-06-11T00:16:29+00:00

This eliminates the workaround that requires disabling
-mprofile-kernel by default in Kconfig.

Signed-off-by: Nicholas Piggin 
Acked-by: Michael Ellerman 
Signed-off-by: Masahiro Yamada

powerpc/modules: remove unused mod_arch_specific.toc field

2018-05-28T08:46:34+00:00

The toc field in the mod_arch_specific struct isn't actually used
anywhere, so remove it.

Also the ftrace-specific fields are now common between 32-bit and
64-bit, so simplify the struct definition a bit by moving them out of
the __powerpc64__ #ifdef.

Signed-off-by: Josh Poimboeuf 
Reviewed-by: Kamalesh Babulal 
Signed-off-by: Michael Ellerman

powerpc64/ftrace: Implement support for ftrace_regs_caller()

2018-05-03T12:32:29+00:00

With -mprofile-kernel, we always save the full register state in
ftrace_caller(). While this works, this is inefficient if we're not
interested in the register state, such as when we're using the function
tracer.

Rename the existing ftrace_caller() as ftrace_regs_caller() and provide
a simpler implementation for ftrace_caller() that is used when registers
are not required to be saved.

Signed-off-by: Naveen N. Rao 
Signed-off-by: Michael Ellerman

powerpc/modules: Fix crashes by adding CONFIG_RELOCATABLE to vermagic

2018-04-09T03:21:02+00:00

If you build the kernel with CONFIG_RELOCATABLE=n, then install the
modules, rebuild the kernel with CONFIG_RELOCATABLE=y and leave the
old modules installed, we crash something like:

  Unable to handle kernel paging request for data at address 0xd000000018d66cef
  Faulting instruction address: 0xc0000000021ddd08
  Oops: Kernel access of bad area, sig: 11 [#1]
  Modules linked in: x_tables autofs4
  CPU: 2 PID: 1 Comm: systemd Not tainted 4.16.0-rc6-gcc_ubuntu_le-g99fec39 #1
  ...
  NIP check_version.isra.22+0x118/0x170
  Call Trace:
    __ksymtab_xt_unregister_table+0x58/0xfffffffffffffcb8 [x_tables] (unreliable)
    resolve_symbol+0xb4/0x150
    load_module+0x10e8/0x29a0
    SyS_finit_module+0x110/0x140
    system_call+0x58/0x6c

This happens because since commit 71810db27c1c ("modversions: treat
symbol CRCs as 32 bit quantities"), a relocatable kernel encodes and
handles symbol CRCs differently from a non-relocatable kernel.

Although it's possible we could try and detect this situation and
handle it, it's much more robust to simply make the state of
CONFIG_RELOCATABLE part of the module vermagic.

Fixes: 71810db27c1c ("modversions: treat symbol CRCs as 32 bit quantities")
Signed-off-by: Michael Ellerman

powerpc64: Add .opd based function descriptor dereference

2018-01-09T09:45:37+00:00

We are moving towards separate kernel and module function descriptor
dereference callbacks. This patch enables it for powerpc64.

For pointers that belong to the kernel
-  Added __start_opd and __end_opd pointers, to track the kernel
   .opd section address range;

-  Added dereference_kernel_function_descriptor(). Now we
   will dereference only function pointers that are within
   [__start_opd, __end_opd);

For pointers that belong to a module
-  Added dereference_module_function_descriptor() to handle module
   function descriptor dereference. Now we will dereference only
   pointers that are within [module->opd.start, module->opd.end).

Link: http://lkml.kernel.org/r/20171109234830.5067-4-sergey.senozhatsky@gmail.com
To: Tony Luck 
To: Fenghua Yu 
To: Helge Deller 
To: Benjamin Herrenschmidt 
To: Paul Mackerras 
To: Michael Ellerman 
To: James Bottomley 
Cc: Andrew Morton 
Cc: Jessica Yu 
Cc: Petr Mladek 
Cc: Steven Rostedt 
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: Sergey Senozhatsky 
Cc: Sergey Senozhatsky 
Signed-off-by: Sergey Senozhatsky 
Tested-by: Santosh Sivaraj  #powerpc
Signed-off-by: Petr Mladek

powerpc/modules: If mprofile-kernel is enabled add it to vermagic

2017-05-15T09:31:38+00:00

On powerpc we can build the kernel with two different ABIs for mcount(), which
is used by ftrace. Kernels built with one ABI do not know how to load modules
built with the other ABI. The new style ABI is called "mprofile-kernel", for
want of a better name.

Currently if we build a module using the old style ABI, and the kernel with
mprofile-kernel, when we load the module we'll oops something like:

  # insmod autofs4-no-mprofile-kernel.ko
  ftrace-powerpc: Unexpected instruction f8810028 around bl _mcount
  ------------[ cut here ]------------
  WARNING: CPU: 6 PID: 3759 at ../kernel/trace/ftrace.c:2024 ftrace_bug+0x2b8/0x3c0
  CPU: 6 PID: 3759 Comm: insmod Not tainted 4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269 #11
  ...
  NIP [c0000000001eaa48] ftrace_bug+0x2b8/0x3c0
  LR [c0000000001eaff8] ftrace_process_locs+0x4a8/0x590
  Call Trace:
    alloc_pages_current+0xc4/0x1d0 (unreliable)
    ftrace_process_locs+0x4a8/0x590
    load_module+0x1c8c/0x28f0
    SyS_finit_module+0x110/0x140
    system_call+0x38/0xfc
  ...
  ftrace failed to modify
  [] 0xd000000002a31024
   actual:   35:65:00:48

We can avoid this by including in the vermagic whether the kernel/module was
built with mprofile-kernel. Which results in:

  # insmod autofs4-pg.ko
  autofs4: version magic
  '4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269 SMP mod_unload modversions '
  should be
  '4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269-dirty SMP mod_unload modversions mprofile-kernel'
  insmod: ERROR: could not insert module autofs4-pg.ko: Invalid module format

Fixes: 8c50b72a3b4f ("powerpc/ftrace: Add Kconfig & Make glue for mprofile-kernel")
Signed-off-by: Michael Ellerman 
Acked-by: Balbir Singh 
Acked-by: Jessica Yu 
Signed-off-by: Michael Ellerman

modversions: treat symbol CRCs as 32 bit quantities

2017-02-03T16:28:25+00:00

The modversion symbol CRCs are emitted as ELF symbols, which allows us
to easily populate the kcrctab sections by relying on the linker to
associate each kcrctab slot with the correct value.

This has a couple of downsides:

 - Given that the CRCs are treated as memory addresses, we waste 4 bytes
   for each CRC on 64 bit architectures,

 - On architectures that support runtime relocation, a R__RELATIVE
   relocation entry is emitted for each CRC value, which identifies it
   as a quantity that requires fixing up based on the actual runtime
   load offset of the kernel. This results in corrupted CRCs unless we
   explicitly undo the fixup (and this is currently being handled in the
   core module code)

 - Such runtime relocation entries take up 24 bytes of __init space
   each, resulting in a x8 overhead in [uncompressed] kernel size for
   CRCs.

Switching to explicit 32 bit values on 64 bit architectures fixes most
of these issues, given that 32 bit values are not treated as quantities
that require fixing up based on the actual runtime load offset.  Note
that on some ELF64 architectures [such as PPC64], these 32-bit values
are still emitted as [absolute] runtime relocatable quantities, even if
the value resolves to a build time constant.  Since relative relocations
are always resolved at build time, this patch enables MODULE_REL_CRCS on
powerpc when CONFIG_RELOCATABLE=y, which turns the absolute CRC
references into relative references into .rodata where the actual CRC
value is stored.

So redefine all CRC fields and variables as u32, and redefine the
__CRC_SYMBOL() macro for 64 bit builds to emit the CRC reference using
inline assembler (which is necessary since 64-bit C code cannot use
32-bit types to hold memory addresses, even if they are ultimately
resolved using values that do not exceed 0xffffffff).  To avoid
potential problems with legacy 32-bit architectures using legacy
toolchains, the equivalent C definition of the kcrctab entry is retained
for 32-bit architectures.

Note that this mostly reverts commit d4703aefdbc8 ("module: handle ppc64
relocating kcrctabs when CONFIG_RELOCATABLE=y")

Acked-by: Rusty Russell 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Linus Torvalds

powerpc: Build-time sort the exception table

2016-11-14T00:11:51+00:00

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman

Merge branch 'topic/mprofile-kernel' into next

2016-03-11T00:20:15+00:00

Merge the ftrace changes to support -mprofile-kernel on ppc64le. This is
a prerequisite for live patching, the support for which will be merged
via the livepatch tree based on this topic branch.