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GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to
emit nops after the local entry point, rather than before it. This
allows us to use this in the kernel for ftrace purposes. A new script is
added under arch/powerpc/tools/ to help detect if nops are emitted after
the function local entry point, or before the global entry point.
With -fpatchable-function-entry, we no longer have the profiling
instructions generated at function entry, so we only need to validate
the presence of two nops at the ftrace location in ftrace_init_nop(). We
patch the preceding instruction with 'mflr r0' to match the
-mprofile-kernel ABI for subsequent ftrace use.
This changes the profiling instructions used on ppc32. The default -pg
option emits an additional 'stw' instruction after 'mflr r0' and before
the branch to _mcount 'bl _mcount'. This is very similar to the original
-mprofile-kernel implementation on ppc64le, where an additional 'std'
instruction was used to save LR to its save location in the caller's
stackframe. Subsequently, this additional store was removed in later
compiler versions for performance reasons. The same reasons apply for
ppc32 so we only patch in a 'mflr r0'.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org
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Build modules using PCREL addressing when CONFIG_PPC_KERNEL_PCREL=y.
- The module loader must handle several new relocation types:
* R_PPC64_REL24_NOTOC is a function call handled like R_PPC_REL24, but
does not restore r2 upon return. The external function call stub is
changed to use pcrel addressing to load the function pointer rather
than based on the module TOC.
* R_PPC64_GOT_PCREL34 is a reference to external data. A GOT table
must be built by hand, because the linker adds this during the final
link (which is not done for kernel modules). The GOT table is built
similarly to the way the external function call stub table is. This
section is called .mygot because .got has a special meaning for the
linker and can become upset.
* R_PPC64_PCREL34 is used for local data addressing, but there is a
special case where the percpu section is moved at load-time to the
percpu area which is out of range of this relocation. This requires
the PCREL34 relocations are converted to use GOT_PCREL34 addressing.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Some coding style & formatting fixups]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230408021752.862660-7-npiggin@gmail.com
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PC-Relative or PCREL addressing is an extension to the ELF ABI which
uses Power ISA v3.1 PC-relative instructions to calculate addresses,
rather than the traditional TOC scheme.
Add an option to build vmlinux using pcrel addressing. Modules continue
to use TOC addressing.
- TOC address helpers and r2 are poisoned with -1 when running vmlinux.
r2 could be used for something useful once things are ironed out.
- Assembly must call C functions with @notoc annotation, or the linker
complains aobut a missing nop after the call. This is done with the
CFUNC macro introduced earlier.
- Boot: with the exception of prom_init, the execution branches to the
kernel virtual address early in boot, before any addresses are
generated, which ensures 34-bit pcrel addressing does not miss the
high PAGE_OFFSET bits. TOC relative addressing has a similar
requirement. prom_init does not go to the virtual address and its
addresses should not carry over to the post-prom kernel.
- Ftrace trampolines are converted from TOC addressing to pcrel
addressing, including module ftrace trampolines that currently use the
kernel TOC to find ftrace target functions.
- BPF function prologue and function calling generation are converted
from TOC to pcrel.
- copypage_64.S has an interesting problem, prefixed instructions have
alignment restrictions so the linker can add padding, which makes the
assembler treat the difference between two local labels as
non-constant even if alignment is arranged so padding is not required.
This may need toolchain help to solve nicely, for now move the prefix
instruction out of the alternate patch section to work around it.
This reduces kernel text size by about 6%.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230408021752.862660-6-npiggin@gmail.com
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When a module with a livepatched function is unloaded and then reloaded,
klp attempts to dynamically re-patch it. On ppc64, that fails with the
following error:
module_64: livepatch_nfsd: Expected nop after call, got e8410018 at e_show+0x60/0x548 [livepatch_nfsd]
livepatch: failed to initialize patch 'livepatch_nfsd' for module 'nfsd' (-8)
livepatch: patch 'livepatch_nfsd' failed for module 'nfsd', refusing to load module 'nfsd'
The error happens because the restore r2 instruction had already
previously been written into the klp module's replacement function when
the original function was patched the first time. So the instruction
wasn't a nop as expected.
When the restore r2 instruction has already been patched in, detect that
and skip the warning and the instruction write.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2f6329ffd9674df6ff57e03edeb2ca54414770ab.1674617130.git.jpoimboe@kernel.org
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restore_r2() returns 1 on success, which is surprising for a non-boolean
function. Change it to return 0 on success and -errno on error to match
kernel coding convention.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/15baf76c271a0ae09f7b8556e50f2b4251e7049d.1674617130.git.jpoimboe@kernel.org
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Override the generic module ELF check to provide a check for the ELF ABI
version. This becomes important if we allow big-endian ELF ABI V2 builds
but it doesn't hurt to check now.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221128041539.1742489-3-npiggin@gmail.com
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Use PPC_LI_MASK and PPC_LI() instead of opencoding.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3d56d7bc3200403773d54e62659d0e01292a055d.1652074503.git.christophe.leroy@csgroup.eu
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Replace all uses of PPC64_ELF_ABI_v1 and PPC64_ELF_ABI_v2 by
resp CONFIG_PPC64_ELF_ABI_V1 and CONFIG_PPC64_ELF_ABI_V2.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ba13d59e8c50bc9aa6328f1c7f0c0d0278e0a3a7.1652074503.git.christophe.leroy@csgroup.eu
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Various spelling mistakes in comments.
Detected with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220430185654.5855-1-Julia.Lawall@inria.fr
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Merge a topic branch we are maintaining with some cross-architecture
changes to function descriptor handling and their use in LKDTM.
From Christophe's cover letter:
Fix LKDTM for PPC64/IA64/PARISC
PPC64/IA64/PARISC have function descriptors. LKDTM doesn't work on those
three architectures because LKDTM messes up function descriptors with
functions.
This series does some cleanup in the three architectures and refactors
function descriptors so that it can then easily use it in a generic way
in LKDTM.
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Fix following coccicheck warning:
./arch/powerpc/kernel/module_64.c:432:40-41: WARNING: Use ARRAY_SIZE.
ARRAY_SIZE(arr) is a macro provided by the kernel. It makes sure that arr
is an array, so it's safer than sizeof(arr) / sizeof(arr[0]) and more
standard.
Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Reviewed-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220223075426.20939-1-guozhengkui@vivo.com
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We have three architectures using function descriptors, each with its
own type and name.
Add a common typedef that can be used in generic code.
Also add a stub typedef for architecture without function descriptors,
to avoid a forest of #ifdefs.
It replaces the similar 'func_desc_t' previously defined in
arch/powerpc/kernel/module_64.c
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f1f91b142b3c1082bdc1586ce71c9bac1e75213c.1644928018.git.christophe.leroy@csgroup.eu
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In preparation of making func_desc_t generic, change the ELFv2
version to a struct containing 'addr' element.
This allows using single helpers common to ELFv1 and ELFv2 and
reduces the amount of #ifdef's
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5c36105e08b27b98450535bff48d71b690c19739.1644928018.git.christophe.leroy@csgroup.eu
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'struct ppc64_opd_entry' is somehow redundant with 'struct func_desc',
the later is more correct/complete as it includes the third
field which is unused.
So use 'struct func_desc' instead of 'struct ppc64_opd_entry'
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/34e76bac6cbe95a63ecd37df69fb7feb93b0ea7c.1644928018.git.christophe.leroy@csgroup.eu
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Without this patch, module init sections are disabled by patching their
names in arch-specific code when they're loaded (which prevents code in
layout_sections from finding init sections). This patch uses the new
arch-specific module_init_section instead.
This allows modules that have .init_array sections to have the
initialisers properly called (on load, before init). Without this patch,
the initialisers are not called because .init_array is renamed to
_init_array, and thus isn't found by code in find_module_sections().
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220202055123.2144842-1-wedsonaf@google.com
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Livepatching a loaded module involves applying relocations through
apply_relocate_add(), which attempts to write to read-only memory when
CONFIG_STRICT_MODULE_RWX=y. Work around this by performing these
writes through the text poke area by using patch_instruction().
R_PPC_REL24 is the only relocation type generated by the kpatch-build
userspace tool or klp-convert kernel tree that I observed applying a
relocation to a post-init module.
A more comprehensive solution is planned, but using patch_instruction()
for R_PPC_REL24 on should serve as a sufficient fix.
This does have a performance impact, I observed ~15% overhead in
module_load() on POWER8 bare metal with checksum verification off.
Fixes: c35717c71e98 ("powerpc: Set ARCH_HAS_STRICT_MODULE_RWX")
Cc: stable@vger.kernel.org # v5.14+
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
[mpe: Check return codes from patch_instruction()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211214121248.777249-1-mpe@ellerman.id.au
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To improve readability, use PPC_RAW_xx() macros instead of
open coding. Those macros are self-explanatory so the comments
can go as well.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/99d9ee8849d3992beeadb310a665aae01c3abfb1.1621506159.git.christophe.leroy@csgroup.eu
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Better describe what these functions do.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since commit c55d7b5e64265f ("powerpc: Remove STRICT_KERNEL_RWX
incompatibility with RELOCATABLE"), powerpc kernels with
-mprofile-kernel can crash in certain scenarios with a trace like below:
BUG: Unable to handle kernel instruction fetch (NULL pointer?)
Faulting instruction address: 0x00000000
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 DEBUG_PAGEALLOC NUMA PowerNV
<snip>
NIP [0000000000000000] 0x0
LR [c0080000102c0048] ext4_iomap_end+0x8/0x30 [ext4]
Call Trace:
iomap_apply+0x20c/0x920 (unreliable)
iomap_bmap+0xfc/0x160
ext4_bmap+0xa4/0x180 [ext4]
bmap+0x4c/0x80
jbd2_journal_init_inode+0x44/0x1a0 [jbd2]
ext4_load_journal+0x440/0x860 [ext4]
ext4_fill_super+0x342c/0x3ab0 [ext4]
mount_bdev+0x25c/0x290
ext4_mount+0x28/0x50 [ext4]
legacy_get_tree+0x4c/0xb0
vfs_get_tree+0x4c/0x130
do_mount+0xa18/0xc50
sys_mount+0x158/0x180
system_call+0x5c/0x68
The NIP points to NULL, or a random location (data even), while the LR
always points to the LEP of a function (with an offset of 8), indicating
that something went wrong with ftrace. However, ftrace is not
necessarily active when such crashes occur.
The kernel OOPS sometimes follows a warning from ftrace indicating that
some module functions could not be patched with a nop. Other times, if a
module is loaded early during boot, instruction patching can fail due to
a separate bug, but the error is not reported due to missing error
reporting.
In all the above cases when instruction patching fails, ftrace will be
disabled but certain kernel module functions will be left with default
calls to _mcount(). This is not a problem with ELFv1. However, with
-mprofile-kernel, the default stub is problematic since it depends on a
valid module TOC in r2. If the kernel (or a different module) calls into
a function that does not use the TOC, the function won't have a prologue
to setup the module TOC. When that function calls into _mcount(), we
will end up in the relocation stub that will use the previous TOC, and
end up trying to jump into a random location. From the above trace:
iomap_apply+0x20c/0x920 [kernel TOC]
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ext4_iomap_end+0x8/0x30 [no GEP == kernel TOC]
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_mcount() stub
[uses kernel TOC -> random entry]
To address this, let's change over to using the special stub that is
used for ftrace_[regs_]caller() for _mcount(). This ensures that we are
not dependent on a valid module TOC in r2 for default _mcount()
handling.
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Qian Cai <cai@lca.pw>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8affd4298d22099bbd82544fab8185700a6222b1.1587488954.git.naveen.n.rao@linux.vnet.ibm.com
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For -mprofile-kernel, we need special handling when generating stubs for
ftrace calls such as _mcount(). To faciliate this, we check if a
R_PPC64_REL24 relocation is for a symbol named "_mcount()" along with
also checking the instruction sequence. The latter is not really
required since "_mcount()" is an exported symbol and kernel modules
cannot use it. As such, drop the additional checking and simplify the
code. This helps unify stub creation for ftrace stubs with
-mprofile-kernel and aids in code reuse.
Also rename is_mprofile_mcount_callsite() to is_mprofile_ftrace_call()
to reflect the checking being done.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7d9c316adfa1fb787ad268bb4691e7e4059ff2d5.1587488954.git.naveen.n.rao@linux.vnet.ibm.com
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module_trampoline_target() is only used by ftrace. Move the prototype
within the appropriate #ifdef in the header. Also, move the function
body to the end of module_64.c so as to consolidate all ftrace code in
one place.
No functional changes.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2527351f65c53c5866068ae130dc34c5d4ee8ad9.1587488954.git.naveen.n.rao@linux.vnet.ibm.com
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In preparation for instructions having a more complex data type start
using a macro, ppc_inst(), for making an instruction out of a u32. A
macro is used so that instructions can be used as initializer elements.
Currently this does nothing, but it will allow for creating a data type
that can represent prefixed instructions.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Change include guard to _ASM_POWERPC_INST_H]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-7-jniethe5@gmail.com
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Replace relaswap with built-in one, because relaswap
does a simple byte to byte swap.
Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.
Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed-by: George Spelvin <lkml@sdf.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/994931554238042@iva8-b333b7f98ab0.qloud-c.yandex.net
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Removal of the NPU DMA code, used by the out-of-tree Nvidia driver,
as well as some other functions only used by drivers that haven't
(yet?) made it upstream.
- A fix for a bug in our handling of hardware watchpoints (eg. perf
record -e mem: ...) which could lead to register corruption and
kernel crashes.
- Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for
vmalloc when using the Radix MMU.
- A large but incremental rewrite of our exception handling code to
use gas macros rather than multiple levels of nested CPP macros.
And the usual small fixes, cleanups and improvements.
Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab,
Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann,
Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe
Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis
Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert
Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz,
Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro
Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N.
Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi
Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher
Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj
Jitindar Singh, Thiago Jung Bauermann, YueHaibing"
* tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits)
powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state.
powerpc/eeh: Handle hugepages in ioremap space
ocxl: Update for AFU descriptor template version 1.1
powerpc/boot: pass CONFIG options in a simpler and more robust way
powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h
powerpc/irq: Don't WARN continuously in arch_local_irq_restore()
powerpc/module64: Use symbolic instructions names.
powerpc/module32: Use symbolic instructions names.
powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h
powerpc/module64: Fix comment in R_PPC64_ENTRY handling
powerpc/boot: Add lzo support for uImage
powerpc/boot: Add lzma support for uImage
powerpc/boot: don't force gzipped uImage
powerpc/8xx: Add microcode patch to move SMC parameter RAM.
powerpc/8xx: Use IO accessors in microcode programming.
powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c
powerpc/8xx: refactor programming of microcode CPM params.
powerpc/8xx: refactor printing of microcode patch name.
powerpc/8xx: Refactor microcode write
powerpc/8xx: refactor writing of CPM microcode arrays
...
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To increase readability/maintainability, replace hard coded
instructions values by symbolic names.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fix R_PPC64_ENTRY case, the addi reads from r2 not r12]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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PPC_HA() PPC_HI() and PPC_LO() macros are nice macros. Move them
from module64.c to ppc-opcode.h in order to use them in other places.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Clean up formatting in new code, drop duplicates in ftrace.c]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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The comment here is wrong, the addi reads from r2 not r12. The code is
correct, 0x38420000 = addi r2,r2,0.
Fixes: a61674bdfc7c ("powerpc/module: Handle R_PPC64_ENTRY relocations")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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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 this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1334 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The recent module relocation overflow crash demonstrated that we
have no range checking on REL32 relative relocations. This patch
implements a basic check, the same kernel that previously oopsed
and rebooted now continues with some of these errors when loading
the module:
module_64: x_tables: REL32 527703503449812 out of range!
Possibly other relocations (ADDR32, REL16, TOC16, etc.) should also have
overflow checks.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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module_frob_arch_sections() is called before the module is moved to its
final location. The function descriptor section addresses we are setting
here are thus invalid. Fix this by processing opd section during
module_finalize()
Fixes: 5633e85b2c313 ("powerpc64: Add .opd based function descriptor dereference")
Cc: stable@vger.kernel.org # v4.16
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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This eliminates the workaround that requires disabling
-mprofile-kernel by default in Kconfig.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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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 <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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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 <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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For R_PPC64_REL24 relocations, we suppress emitting instructions for TOC
load/restore in the relocation stub if the relocation is for _mcount()
call when using -mprofile-kernel ABI.
To detect this, we check if the preceding instructions are per the
standard set of instructions emitted by gcc: either the two instruction
sequence of 'mflr r0; std r0,16(r1)', or the more optimized variant of a
single 'mflr r0'. This is not sufficient since nothing prevents users
from hand coding sequences involving a 'mflr r0' followed by a 'bl'.
For removing the toc save instruction from the stub, we additionally
check if the symbol is "_mcount". Add the same check here as well.
Also rename is_early_mcount_callsite() to is_mprofile_mcount_callsite()
since that is what is being checked. The use of "early" is misleading
since there is nothing involving this function that qualifies as early.
Fixes: 153086644fd1f ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Highlights:
- Enable support for memory protection keys aka "pkeys" on Power7/8/9
when using the hash table MMU.
- Extend our interrupt soft masking to support masking PMU interrupts
as well as "normal" interrupts, and then use that to implement
local_t for a ~4x speedup vs the current atomics-based
implementation.
- A new driver "ocxl" for "Open Coherent Accelerator Processor
Interface (OpenCAPI)" devices.
- Support for new device tree properties on PowerVM to describe
hotpluggable memory and devices.
- Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE to the 64-bit
VDSO.
- Freescale updates from Scott: fixes for CPM GPIO and an FSL PCI
erratum workaround, plus a minor cleanup patch.
As well as quite a lot of other changes all over the place, and small
fixes and cleanups as always.
Thanks to: Alan Modra, Alastair D'Silva, Alexey Kardashevskiy,
Alistair Popple, Andreas Schwab, Andrew Donnellan, Aneesh Kumar K.V,
Anju T Sudhakar, Anshuman Khandual, Anton Blanchard, Arnd Bergmann,
Balbir Singh, Benjamin Herrenschmidt, Bhaktipriya Shridhar, Bryant G.
Ly, Cédric Le Goater, Christophe Leroy, Christophe Lombard, Cyril Bur,
David Gibson, Desnes A. Nunes do Rosario, Dmitry Torokhov, Frederic
Barrat, Geert Uytterhoeven, Guilherme G. Piccoli, Gustavo A. R. Silva,
Gustavo Romero, Ivan Mikhaylov, Joakim Tjernlund, Joe Perches, Josh
Poimboeuf, Juan J. Alvarez, Julia Cartwright, Kamalesh Babulal,
Madhavan Srinivasan, Mahesh Salgaonkar, Mathieu Malaterre, Michael
Bringmann, Michael Hanselmann, Michael Neuling, Nathan Fontenot,
Naveen N. Rao, Nicholas Piggin, Paul Mackerras, Philippe Bergheaud,
Ram Pai, Russell Currey, Santosh Sivaraj, Scott Wood, Seth Forshee,
Simon Guo, Stewart Smith, Sukadev Bhattiprolu, Thiago Jung Bauermann,
Vaibhav Jain, Vasyl Gomonovych"
* tag 'powerpc-4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (199 commits)
powerpc/mm/radix: Fix build error when RADIX_MMU=n
macintosh/ams-input: Use true and false for boolean values
macintosh: change some data types from int to bool
powerpc/watchdog: Print the NIP in soft_nmi_interrupt()
powerpc/watchdog: regs can't be null in soft_nmi_interrupt()
powerpc/watchdog: Tweak watchdog printks
powerpc/cell: Remove axonram driver
rtc-opal: Fix handling of firmware error codes, prevent busy loops
powerpc/mpc52xx_gpt: make use of raw_spinlock variants
macintosh/adb: Properly mark continued kernel messages
powerpc/pseries: Fix cpu hotplug crash with memoryless nodes
powerpc/numa: Ensure nodes initialized for hotplug
powerpc/numa: Use ibm,max-associativity-domains to discover possible nodes
powerpc/kernel: Block interrupts when updating TIDR
powerpc/powernv/idoa: Remove unnecessary pcidev from pci_dn
powerpc/mm/nohash: do not flush the entire mm when range is a single page
powerpc/pseries: Add Initialization of VF Bars
powerpc/pseries/pci: Associate PEs to VFs in configure SR-IOV
powerpc/eeh: Add EEH notify resume sysfs
powerpc/eeh: Add EEH operations to notify resume
...
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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 <tony.luck@intel.com>
To: Fenghua Yu <fenghua.yu@intel.com>
To: Helge Deller <deller@gmx.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Paul Mackerras <paulus@samba.org>
To: Michael Ellerman <mpe@ellerman.id.au>
To: James Bottomley <jejb@parisc-linux.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
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 <sergey.senozhatsky@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Santosh Sivaraj <santosh@fossix.org> #powerpc
Signed-off-by: Petr Mladek <pmladek@suse.com>
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powerpc64 gcc can generate code that offsets an address, to access
part of an object in memory. If the address is a -mcmodel=medium toc
pointer relative address then code like the following is possible.
addis r9,r2,var@toc@ha
ld r3,var@toc@l(r9)
ld r4,(var+8)@toc@l(r9)
This works fine so long as var is naturally aligned, *and* r2 is
sufficiently aligned. If not, there is a possibility that the offset
added to access var+8 wraps over a n*64k+32k boundary. Modules don't
have any guarantee that r2 is sufficiently aligned. Moreover, code
generated by older compilers generates a .toc section with 2**0
alignment, which can result in relocation failures at module load time
even without the wrap problem.
Thus, this patch links modules with an aligned .toc section (Makefile
and module.lds changes), and forces alignment for out of tree modules
or those without a .toc section (module_64.c changes).
Signed-off-by: Alan Modra <amodra@gmail.com>
[desnesn: updated patch to apply to powerpc-next kernel v4.15 ]
Signed-off-by: Desnes A. Nunes do Rosario <desnesn@linux.vnet.ibm.com>
[mpe: Fix out-of-tree build, swap -256 for ~0xff, reflow comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Print the function address associated with the restore_r2() error to
make it easier to debug the problem.
Also clarify the wording a bit.
Before:
module_64: patch_foo: Expect noop after relocate, got 3c820000
After:
module_64: patch_foo: Expected nop after call, got 7c630034 at netdev_has_upper_dev+0x54/0xb0 [patch_foo]
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
[mpe: Change noop to nop, as that's the name of the instruction]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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When attempting to load a livepatch module, I got the following error:
module_64: patch_module: Expect noop after relocate, got 3c820000
The error was triggered by the following code in
unregister_netdevice_queue():
14c: 00 00 00 48 b 14c <unregister_netdevice_queue+0x14c>
14c: R_PPC64_REL24 net_set_todo
150: 00 00 82 3c addis r4,r2,0
GCC didn't insert a nop after the branch to net_set_todo() because it's
a sibling call, so it never returns. The nop isn't needed after the
branch in that case.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-and-tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Livepatch re-uses module loader function apply_relocate_add() to write
relocations, instead of managing them by arch-dependent
klp_write_module_reloc() function.
apply_relocate_add() doesn't understand livepatch symbols (marked with
SHN_LIVEPATCH symbol section index) and assumes them to be local
symbols by default for R_PPC64_REL24 relocation type. It fails with an
error, when trying to calculate offset with local_entry_offset():
module_64: kpatch_meminfo: REL24 -1152921504897399800 out of range!
Whereas livepatch symbols are essentially SHN_UNDEF, should be called
via stub used for global calls. This issue can be fixed by teaching
apply_relocate_add() to handle both SHN_UNDEF/SHN_LIVEPATCH symbols
via the same stub. This patch extends SHN_UNDEF code to handle
livepatch symbols too.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Use WARN_ON(), while running out of stubs in stub_for_addr()
and abort loading of the module instead of BUG_ON().
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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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_<arch>_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 <rusty@rustcorp.com.au>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We haven't seen these before, but the soon to be merged relative
exception tables support causes them to be generated.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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In the module loader we process relocations, and for long jumps we
generate trampolines (aka stubs). At the call site for one of these
trampolines we usually need to generate a load instruction to restore
the TOC pointer into r2.
There is one exception however, which is calls to mcount() using the
mprofile-kernel ABI, they handle the TOC inside the stub, and so for
them we do not generate a TOC load.
The bug is in how the code in restore_r2() decides if it needs to
generate the TOC load. It does so by looking for a nop following the
branch, and if it sees a nop, it replaces it with the load. In general
the compiler has no reason to generate a nop following the mcount()
call and so that check works OK.
However if we combine a jump label at the start of a function, with an
early return, such that GCC applies the shrink-wrapping optimisation, we
can then end up with an mcount call followed immediately by a nop.
However the nop is not there for a TOC load, it is for the jump label.
That confuses restore_r2() into replacing the jump label nop with a TOC
load, which in turn confuses ftrace into replacing the mcount call with
a b +8 (fixed in the previous commit). The end result is we jump over
the jump label, which if it was supposed to return means we incorrectly
run the body of the function.
We have seen this in practice with some yet-to-be-merged patches that
use jump labels more extensively.
The fix is relatively simple, in restore_r2() we check for an
mprofile-kernel style mcount() call first, before looking for the
presence of a nop.
Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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We're approaching 20 locations where we need to check for ELF ABI v2.
That's fine, except the logic is a bit awkward, because we have to check
that _CALL_ELF is defined and then what its value is.
So check it once in asm/types.h and define PPC64_ELF_ABI_v2 when ELF ABI
v2 is detected.
We also have a few places where what we're really trying to check is
that we are using the 64-bit v1 ABI, ie. function descriptors. So also
add a #define for that, which simplifies several checks.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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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.
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The gcc switch -mprofile-kernel defines a new ABI for calling _mcount()
very early in the function with minimal overhead.
Although mprofile-kernel has been available since GCC 3.4, there were
bugs which were only fixed recently. Currently it is known to work in
GCC 4.9, 5 and 6.
Additionally there are two possible code sequences generated by the
flag, the first uses mflr/std/bl and the second is optimised to omit the
std. Currently only gcc 6 has the optimised sequence. This patch
supports both sequences.
Initial work started by Vojtech Pavlik, used with permission.
Key changes:
- rework _mcount() to work for both the old and new ABIs.
- implement new versions of ftrace_caller() and ftrace_graph_caller()
which deal with the new ABI.
- updates to __ftrace_make_nop() to recognise the new mcount calling
sequence.
- updates to __ftrace_make_call() to recognise the nop'ed sequence.
- implement ftrace_modify_call().
- updates to the module loader to surpress the toc save in the module
stub when calling mcount with the new ABI.
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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In order to support the new -mprofile-kernel ABI, we need to be able to
call from the module back to ftrace_caller() (in the kernel) without
using the module's r2. That is because the function in this module which
is calling ftrace_caller() may not have setup r2, if it doesn't
otherwise need it (ie. it accesses no globals).
To make that work we add a new stub which is used for calling
ftrace_caller(), which uses the kernel toc instead of the module toc.
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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When a module is loaded, calls out to the kernel go via a stub which is
generated at runtime. One of these stubs is used to call _mcount(),
which is the default target of tracing calls generated by the compiler
with -pg.
If dynamic ftrace is enabled (which it typically is), another stub is
used to call ftrace_caller(), which is the target of tracing calls when
ftrace is actually active.
ftrace then wants to disable the calls to _mcount() at module startup,
and enable/disable the calls to ftrace_caller() when enabling/disabling
tracing - all of these it does by patching the code.
As part of that code patching, the ftrace code wants to confirm that the
branch it is about to modify, is in fact a call to a module stub which
calls _mcount() or ftrace_caller().
Currently it does that by inspecting the instructions and confirming
they are what it expects. Although that works, the code to do it is
pretty intricate because it requires lots of knowledge about the exact
format of the stub.
We can make that process easier by marking the generated stubs with a
magic value, and then looking for that magic value. Altough this is not
as rigorous as the current method, I believe it is sufficient in
practice.
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Currently we generate the module stub for ftrace_caller() at the bottom
of apply_relocate_add(). However apply_relocate_add() is potentially
called more than once per module, which means we will try to generate
the ftrace_caller() stub multiple times.
Although the current code deals with that correctly, ie. it only
generates a stub the first time, it would be clearer to only try to
generate the stub once.
Note also on first reading it may appear that we generate a different
stub for each section that requires relocation, but that is not the
case. The code in stub_for_addr() that searches for an existing stub
uses sechdrs[me->arch.stubs_section], ie. the single stub section for
this module.
A cleaner approach is to only generate the ftrace_caller() stub once,
from module_finalize(). Although the original code didn't check to see
if the stub was actually generated correctly, it seems prudent to add a
check, so do that. And an additional benefit is we can clean the ifdefs
up a little.
Finally we must propagate the const'ness of some of the pointers passed
to module_finalize(), but that is also an improvement.
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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