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* powerpc/ftrace: Add support for -fpatchable-function-entryNaveen N Rao2023-08-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* powerpc/64: modules support building with PCREL addresingNicholas Piggin2023-04-201-28/+291
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* powerpc/64: vmlinux support building with PCREL addresingNicholas Piggin2023-04-201-15/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* powerpc/module_64: Fix "expected nop" error on module re-patchingJosh Poimboeuf2023-01-261-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | 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
* powerpc/module_64: Improve restore_r2() return semanticsJosh Poimboeuf2023-01-261-9/+6
| | | | | | | | | | | | | 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
* powerpc/64: Add module check for ELF ABI versionNicholas Piggin2022-12-021-0/+10
| | | | | | | | | | | | 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
* powerpc/modules: Use PPC_LI macros instead of opencodingChristophe Leroy2022-05-221-2/+1
| | | | | | | | | 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
* powerpc: Replace PPC64_ELF_ABI_v{1/2} by CONFIG_PPC64_ELF_ABI_V{1/2}Christophe Leroy2022-05-191-2/+2
| | | | | | | | | | 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
* powerpc: fix typos in commentsJulia Lawall2022-05-051-2/+2
| | | | | | | | | | | 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
* Merge branch 'topic/func-desc-lkdtm' into nextMichael Ellerman2022-03-071-25/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
| * asm-generic: Define 'func_desc_t' to commonly describe function descriptorsChristophe Leroy2022-02-161-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * powerpc: Prepare func_desc_t for refactorisationChristophe Leroy2022-02-161-18/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * powerpc: Use 'struct func_desc' instead of 'struct ppc64_opd_entry'Christophe Leroy2022-02-161-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | '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
* | powerpc/module_64: fix array_size.cocci warningGuo Zhengkui2022-02-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* | powerpc/module_64: use module_init_section instead of patching namesWedson Almeida Filho2022-02-031-5/+6
|/ | | | | | | | | | | | | | | | | 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
* powerpc/module_64: Fix livepatching for RO modulesRussell Currey2021-12-141-8/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | 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
* powerpc/modules: Use PPC_RAW_xx() macrosChristophe Leroy2021-06-151-38/+17
| | | | | | | | | | | 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
* maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofaultChristoph Hellwig2020-06-171-2/+4
| | | | | | | | 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>
* powerpc/module_64: Use special stub for _mcount() with -mprofile-kernelNaveen N. Rao2020-06-021-118/+104
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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] | V ext4_iomap_end+0x8/0x30 [no GEP == kernel TOC] | V _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
* powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocationsNaveen N. Rao2020-06-021-14/+4
| | | | | | | | | | | | | | | | | | 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
* powerpc/module_64: Consolidate ftrace codeNaveen N. Rao2020-06-021-36/+33
| | | | | | | | | | | | | 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
* powerpc: Use a macro for creating instructions from u32sJordan Niethe2020-05-181-1/+2
| | | | | | | | | | | | | | 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
* powerpc: module_[32|64].c: replace swap function with built-in oneAndrey Abramov2020-05-111-16/+1
| | | | | | | | | | | | | | | 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
* Merge tag 'powerpc-5.3-1' of ↵Linus Torvalds2019-07-141-26/+36
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * powerpc/module64: Use symbolic instructions names.Christophe Leroy2019-07-051-18/+35
| | | | | | | | | | | | | | | | | | 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>
| * powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.hChristophe Leroy2019-07-051-7/+0
| | | | | | | | | | | | | | | | | | 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>
| * powerpc/module64: Fix comment in R_PPC64_ENTRY handlingMichael Ellerman2019-07-051-1/+1
| | | | | | | | | | | | | | | | 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>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner2019-05-301-13/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* powerpc/64/module: REL32 relocation range checkNicholas Piggin2018-10-201-1/+8
| | | | | | | | | | | | | | | | 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>
* powerpc64/module elfv1: Set opd addresses after module relocationNaveen N. Rao2018-10-201-5/+0
| | | | | | | | | | | | 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>
* powerpc/kbuild: move -mprofile-kernel check to KconfigNicholas Piggin2018-06-111-2/+2
| | | | | | | | | 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>
* powerpc/modules: remove unused mod_arch_specific.toc fieldJosh Poimboeuf2018-05-281-1/+0
| | | | | | | | | | | | | 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>
* powerpc64/ftrace: Implement support for ftrace_regs_caller()Naveen N. Rao2018-05-031-7/+21
| | | | | | | | | | | | | | 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>
* powerpc64/module: Tighten detection of mcount call sites with -mprofile-kernelNaveen N. Rao2018-05-031-6/+9
| | | | | | | | | | | | | | | | | | | | | | | 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>
* Merge tag 'powerpc-4.16-1' of ↵Linus Torvalds2018-02-021-9/+26
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * powerpc/modules: Fix alignment of .toc section in kernel modulesAlan Modra2017-12-111-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * powerpc/modules: Improve restore_r2() error messageJosh Poimboeuf2017-12-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * powerpc/modules: Don't try to restore r2 after a sibling callJosh Poimboeuf2017-12-111-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * powerpc/modules: Add REL24 relocation support of livepatch symbolsKamalesh Babulal2017-12-111-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | powerpc64: Add .opd based function descriptor dereferenceSergey Senozhatsky2018-01-091-0/+14
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* powerpc/modules: Use WARN_ON() in stub_for_addr()Kamalesh Babulal2017-10-131-1/+2
| | | | | | | | 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>
* modversions: treat symbol CRCs as 32 bit quantitiesArd Biesheuvel2017-02-031-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* powerpc/module: Add support for R_PPC64_REL32 relocationsMichael Ellerman2016-11-141-0/+5
| | | | | | | 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>
* powerpc/modules: Never restore r2 for a mprofile-kernel style mcount() callMichael Ellerman2016-07-211-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* powerpc: Define and use PPC64_ELF_ABI_v2/v1Michael Ellerman2016-06-141-2/+2
| | | | | | | | | | | | | | | | 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>
* Merge branch 'topic/mprofile-kernel' into nextMichael Ellerman2016-03-111-62/+152
|\ | | | | | | | | | | 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.
| * powerpc/ftrace: Add support for -mprofile-kernel ftrace ABITorsten Duwe2016-03-071-3/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * powerpc/module: Create a special stub for ftrace_caller()Michael Ellerman2016-03-071-1/+68
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * powerpc/module: Mark module stubs with a magic valueMichael Ellerman2016-03-071-52/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * powerpc/module: Only try to generate the ftrace_caller() stub onceMichael Ellerman2016-03-071-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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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