Commit Graph

30 Commits

Author SHA1 Message Date
Ulrich Weigand a61674bdfc powerpc/module: Handle R_PPC64_ENTRY relocations
GCC 6 will include changes to generated code with -mcmodel=large,
which is used to build kernel modules on powerpc64le.  This was
necessary because the large model is supposed to allow arbitrary
sizes and locations of the code and data sections, but the ELFv2
global entry point prolog still made the unconditional assumption
that the TOC associated with any particular function can be found
within 2 GB of the function entry point:

func:
	addis r2,r12,(.TOC.-func)@ha
	addi  r2,r2,(.TOC.-func)@l
	.localentry func, .-func

To remove this assumption, GCC will now generate instead this global
entry point prolog sequence when using -mcmodel=large:

	.quad .TOC.-func
func:
	.reloc ., R_PPC64_ENTRY
	ld    r2, -8(r12)
	add   r2, r2, r12
	.localentry func, .-func

The new .reloc triggers an optimization in the linker that will
replace this new prolog with the original code (see above) if the
linker determines that the distance between .TOC. and func is in
range after all.

Since this new relocation is now present in module object files,
the kernel module loader is required to handle them too.  This
patch adds support for the new relocation and implements the
same optimization done by the GNU linker.

Cc: stable@vger.kernel.org
Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-01-13 12:37:05 +11:00
Anton Blanchard c7d1f6afe0 powerpc: Use pr_fmt in module loader code
Use pr_fmt to give some context to the error messages in the
module code, and convert open coded debug printk to pr_debug.

Use pr_err for error messages.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-02 17:33:54 +10:00
Laurent Dufour c2cbcf533a powerpc/module: Fix TOC symbol CRC
The commit 71ec7c55ed introduced the magic symbol ".TOC." for ELFv2 ABI.
This symbol is built manually and has no CRC value computed. A zero value
is put in the CRC section to avoid modpost complaining about a missing CRC.
Unfortunately, this breaks the kernel module loading when the kernel is
relocated (kdump case for instance) because of the relocation applied to
the kcrctab values.

This patch compute a CRC value for the TOC symbol which will match the one
compute by the kernel when it is relocated - aka '0 - relocate_start' done in
maybe_relocated called by check_version (module.c).

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-25 13:10:48 +10:00
Rusty Russell 872aa779bc powerpc/module: Fix stubs for BE
A simple patch which was supposed to swap r12 and r11 also
inexplicably changed the offset by two bytes.  This instruction
(to load r2) isn't used in LE, so it wasn't noticed.

Fixes: b1ce369e82 ("powerpc: modules: use r12 for stub jump address.)
Reported-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-20 10:56:01 +10:00
Anton Blanchard dd9fa16250 powerpc/modules: Create module_trampoline_target()
ftrace has way too much knowledge of our kernel module trampoline
layout hidden inside it. Create module_trampoline_target() that gives
the target address of a kernel module trampoline.

Signed-off-by: Anton Blanchard <anton@samba.org>
2014-04-23 10:05:34 +10:00
Anton Blanchard 83775b8566 powerpc/modules: Create is_module_trampoline()
ftrace has way too much knowledge of our kernel module trampoline
layout hidden inside it. Create is_module_trampoline() that can
abstract this away inside the module loader code.

Signed-off-by: Anton Blanchard <anton@samba.org>
2014-04-23 10:05:34 +10:00
Rusty Russell 008d7a914e powerpc: modules: implement stubs for ELFv2 ABI.
ELFv2 doesn't use function descriptors, because it doesn't need to
load a new r2 when calling into a function.  On the other hand, you're
supposed to use a local entry point for R_PPC_REL24 branches.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:32 +10:00
Rusty Russell 5c729a115e powerpc: modules: skip r2 setup for ELFv2
ELFv2 doesn't need to set up r2 when calling a function.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:31 +10:00
Rusty Russell b1ce369e82 powerpc: modules: use r12 for stub jump address.
In ELFv2, r12 is supposed to equal to PC on entry to a function.
Our stubs use r11, so change swap that with r12.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:31 +10:00
Rusty Russell d2fae54803 powerpc: modules: change r2 save/restore offset for ELFv2 ABI.
ELFv2 uses a different stack offset (24 vs 40) to save r2.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:30 +10:00
Rusty Russell 5b12c5c694 powerpc: modules: comment about de-dotifying symbols when using the ELFv2 ABI.
ELFv2 doesn't use function descriptors, so we don't expect symbols to
start with ".".  But because depmod and modpost strip ".", and we have
the special symbol ".TOC.", we still need to do it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:30 +10:00
Rusty Russell 0906584a0a powerpc: Handle new ELFv2 module relocations
The new ELF ABI tends to use R_PPC64_REL16_LO and R_PPC64_REL16_HA
relocations (PC-relative), so implement them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:29 +10:00
Rusty Russell 4edebbeae3 powerpc: Fix up TOC. for modules.
The kernel resolved the '.TOC.' to a fake symbol, so we need to fix it up
to point to our .toc section plus 0x8000.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:29 +10:00
Rusty Russell d247da0a8e powerpc: modules implement R_PPC64_TOCSAVE relocation.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:28 +10:00
Rusty Russell 0e60e46e2a powerpc: make module stub code endian independent
By representing them as words, rather than chars, we can avoid
endian ifdefs.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-23 10:05:27 +10:00
Robert Jennings b88c4767d9 powerpc: Move local setup.h declarations to arch includes
Move the few declarations from arch/powerpc/kernel/setup.h
into arch/powerpc/include/asm/setup.h.  This resolves a
sparse warning for arch/powerpc/mm/numa.c which defines
do_init_bootmem() but can't include the setup.h header
in the prior path.

Resolves:
arch/powerpc/mm/numa.c:998:13:
        warning: symbol 'do_init_bootmem' was not declared.
                 Should it be static?

Signed-off-by: Robert C Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-30 16:00:31 +11:00
Eugene Surovegin fed8393ef9 powerpc: Make kernel module helper endian-safe.
Signed-off-by: Eugene Surovegin <surovegin@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 16:53:22 +11:00
Anton Blanchard 1fbe9cf259 powerpc: Build kernel with -mcmodel=medium
Finally remove the two level TOC and build with -mcmodel=medium.

Unfortunately we can't build modules with -mcmodel=medium due to
the tricks the kernel module loader plays with percpu data:

# -mcmodel=medium breaks modules because it uses 32bit offsets from
# the TOC pointer to create pointers where possible. Pointers into the
# percpu data area are created by this method.
#
# The kernel module loader relocates the percpu data section from the
# original location (starting with 0xd...) to somewhere in the base
# kernel percpu data space (starting with 0xc...). We need a full
# 64bit relocation for this to work, hence -mcmodel=large.

On older kernels we fall back to the two level TOC (-mminimal-toc)

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-01-10 17:00:31 +11:00
Jonas Bonn 66574cc054 modules: make arch's use default loader hooks
This patch removes all the module loader hook implementations in the
architecture specific code where the functionality is the same as that
now provided by the recently added default hooks.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-07-24 22:06:04 +09:30
Kumar Gala 16c57b3620 powerpc: Unify opcode definitions and support
Create a new header that becomes a single location for defining PowerPC
opcodes used by code that is either generationg instructions
at runtime (fixups, debug, etc.), emulating instructions, or just
compiling instructions old assemblers don't know about.

We currently don't handle the floating point emulation or alignment decode
as both are better handled by the specific decode support they already
have.

Added support for the new dcbzl, dcbal, msgsnd, tlbilx, & wait instructions
since older assemblers don't know about them.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-02-23 10:48:56 +11:00
Steven Rostedt f48cb8b48b powerpc/ppc64: ftrace, handle module trampolines for dyn ftrace
Impact: Allow 64 bit PowerPC to trace modules with dynamic ftrace

This adds code to handle the PPC64 module trampolines, and allows for
PPC64 to use dynamic ftrace.

Thanks to Paul Mackerras for these updates:

  - fix the mod and rec->arch.mod NULL checks.
  - fix to is_bl_op compare.

Thanks to Milton Miller for:

  - finding the nasty race with using two nops, and recommending
    instead that I use a branch 8 forward.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2008-11-20 10:52:28 -08:00
James Bottomley 2d291e9027 Fix compile failure with non modular builds
Commit deac93df26 ("lib: Correct printk
%pF to work on all architectures") broke the non modular builds by
moving an essential function into modules.c.  Fix this by moving it
out again and into asm/sections.h as an inline.  To do this, the
definition of struct ppc64_opd_entry has been lifted out of modules.c
and put in asm/elf.h where it belongs.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-09-17 09:14:42 -07:00
James Bottomley deac93df26 lib: Correct printk %pF to work on all architectures
It was introduced by "vsprintf: add support for '%pS' and '%pF' pointer
formats" in commit 0fe1ef24f7.  However,
the current way its coded doesn't work on parisc64.  For two reasons: 1)
parisc isn't in the #ifdef and 2) parisc has a different format for
function descriptors

Make dereference_function_descriptor() more accommodating by allowing
architecture overrides.  I put the three overrides (for parisc64, ppc64
and ia64) in arch/kernel/module.c because that's where the kernel
internal linker which knows how to deal with function descriptors sits.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-09 11:51:15 -07:00
Michael Ellerman b7bcda631e powerpc: Add PPC_NOP_INSTR, a hash define for the preferred nop instruction
A bunch of code has hard-coded the value for a "nop" instruction, it
would be nice to have a #define for it.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01 11:28:23 +10:00
Kumar Gala f0c426bc35 powerpc: Move common module code into its own file
Refactor common code between ppc32 and ppc64 module handling into a
shared filed.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01 11:28:05 +10:00
Emil Medve eda09fbdcd [POWERPC] Optimize counting distinct entries in the relocation sections
When a module has relocation sections with tens of thousands of
entries, counting the distinct/unique entries only (i.e. no
duplicates) at load time can take tens of seconds and up to minutes.
The sore point is the count_relocs() function which is called as part
of the architecture specific module loading processing path:

	-> load_module()			generic
	   -> module_frob_arch_sections()	arch specific
	      -> get_plt_size()		32-bit
	      -> get_stubs_size()	64-bit
		 -> count_relocs()

Here count_relocs is being called to find out how many distinct
targets of R_PPC_REL24 relocations there are, since each distinct
target needs a PLT entry or a stub created for it.

The previous counting algorithm has O(n^2) complexity.  Basically two
solutions were proposed on the e-mail list: a hash based approach and
a sort based approach.

The hash based approach is the fastest (O(n)) but the has it needs
additional memory and for certain corner cases it could take lots of
memory due to the degeneration of the hash.  One such proposal was
submitted here:

http://ozlabs.org/pipermail/linuxppc-dev/2007-June/037641.html

The sort based approach is slower (O(n * log n + n)) but if the
sorting is done "in place" it doesn't need additional memory.
This has O(n + n * log n) complexity with no additional memory
requirements.

This commit implements the in-place sort option.

Signed-off-by: Emil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-12-21 15:05:58 +11:00
Jeremy Fitzhardinge 73c9ceab40 [POWERPC] Generic BUG for powerpc
This makes powerpc use the generic BUG machinery.  The biggest reports the
function name, since it is redundant with kallsyms, and not needed in general.

There is an overall reduction of code, since module_32/64 duplicated several
functions.

Unfortunately there's no way to tell gcc that BUG won't return, so the BUG
macro includes a goto loop.  This will generate a real jmp instruction, which
is never used.

[akpm@osdl.org: build fix]
[paulus@samba.org: remove infinite loop in BUG_ON]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-12-11 16:35:07 +11:00
Benjamin Herrenschmidt 21c4ff80cb [POWERPC] Support feature fixups in modules
This patch adds support for feature fixups in modules. This involves
adding support for R_PPC64_REL64 relocs to the 64 bits module loader.
It also modifies modpost.c to ignore the powerpc fixup sections (or it
would warn when used in .init.text).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-25 11:54:13 +10:00
Alan Modra f749edae5e [PATCH] powerpc64: Fix loading of modules without a .toc section
Normally, ppc64 module .ko files contain a table-of-contents (.toc)
section, but if the module doesn't reference any static or external
data or external procedures, it is possible for gcc/binutils to
generate a .ko that doesn't have a .toc.  Currently the module
loader refuses to load such a module, since it needs the address
of the .toc section to use in relocations.

This patch fixes the problem by using the address of the .stubs
section instead, which is an acceptable substitute in this situation.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-28 21:04:49 +10:00
Paul Mackerras 7568cb4ef6 powerpc: Move most remaining ppc64 files over to arch/powerpc
Also deletes files in arch/ppc64 that are no longer used now that
we don't compile with ARCH=ppc64 any more.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-14 17:30:17 +11:00