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2020-12-27Merge tag 'objtool-urgent-2020-12-27' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool fix from Ingo Molnar: "Fix a segfault that occurs when built with Clang" * tag 'objtool-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Fix seg fault with Clang non-section symbols
2020-12-16objtool: Fix seg fault with Clang non-section symbolsJosh Poimboeuf
The Clang assembler likes to strip section symbols, which means objtool can't reference some text code by its section. This confuses objtool greatly, causing it to seg fault. The fix is similar to what was done before, for ORC reloc generation: e81e07244325 ("objtool: Support Clang non-section symbols in ORC generation") Factor out that code into a common helper and use it for static call reloc generation as well. Reported-by: Arnd Bergmann <arnd@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://github.com/ClangBuiltLinux/linux/issues/1207 Link: https://lkml.kernel.org/r/ba6b6c0f0dd5acbba66e403955a967d9fdd1726a.1607983452.git.jpoimboe@redhat.com
2020-11-11tools: Factor HOSTCC, HOSTLD, HOSTAR definitionsJean-Philippe Brucker
Several Makefiles in tools/ need to define the host toolchain variables. Move their definition to tools/scripts/Makefile.include Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/bpf/20201110164310.2600671-2-jean-philippe@linaro.org
2020-10-14Merge tag 'objtool-core-2020-10-13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: "Most of the changes are cleanups and reorganization to make the objtool code more arch-agnostic. This is in preparation for non-x86 support. Other changes: - KASAN fixes - Handle unreachable trap after call to noreturn functions better - Ignore unreachable fake jumps - Misc smaller fixes & cleanups" * tag 'objtool-core-2020-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) perf build: Allow nested externs to enable BUILD_BUG() usage objtool: Allow nested externs to enable BUILD_BUG() objtool: Permit __kasan_check_{read,write} under UACCESS objtool: Ignore unreachable trap after call to noreturn functions objtool: Handle calling non-function symbols in other sections objtool: Ignore unreachable fake jumps objtool: Remove useless tests before save_reg() objtool: Decode unwind hint register depending on architecture objtool: Make unwind hint definitions available to other architectures objtool: Only include valid definitions depending on source file type objtool: Rename frame.h -> objtool.h objtool: Refactor jump table code to support other architectures objtool: Make relocation in alternative handling arch dependent objtool: Abstract alternative special case handling objtool: Move macros describing structures to arch-dependent code objtool: Make sync-check consider the target architecture objtool: Group headers to check in a single list objtool: Define 'struct orc_entry' only when needed objtool: Skip ORC entry creation for non-text sections objtool: Move ORC logic out of check() ...
2020-10-12Merge tag 'core-static_call-2020-10-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull static call support from Ingo Molnar: "This introduces static_call(), which is the idea of static_branch() applied to indirect function calls. Remove a data load (indirection) by modifying the text. They give the flexibility of function pointers, but with better performance. (This is especially important for cases where retpolines would otherwise be used, as retpolines can be pretty slow.) API overview: DECLARE_STATIC_CALL(name, func); DEFINE_STATIC_CALL(name, func); DEFINE_STATIC_CALL_NULL(name, typename); static_call(name)(args...); static_call_cond(name)(args...); static_call_update(name, func); x86 is supported via text patching, otherwise basic indirect calls are used, with function pointers. There's a second variant using inline code patching, inspired by jump-labels, implemented on x86 as well. The new APIs are utilized in the x86 perf code, a heavy user of function pointers, where static calls speed up the PMU handler by 4.2% (!). The generic implementation is not really excercised on other architectures, outside of the trivial test_static_call_init() self-test" * tag 'core-static_call-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) static_call: Fix return type of static_call_init tracepoint: Fix out of sync data passing by static caller tracepoint: Fix overly long tracepoint names x86/perf, static_call: Optimize x86_pmu methods tracepoint: Optimize using static_call() static_call: Allow early init static_call: Add some validation static_call: Handle tail-calls static_call: Add static_call_cond() x86/alternatives: Teach text_poke_bp() to emulate RET static_call: Add simple self-test for static calls x86/static_call: Add inline static call implementation for x86-64 x86/static_call: Add out-of-line static call implementation static_call: Avoid kprobes on inline static_call()s static_call: Add inline static call infrastructure static_call: Add basic static call infrastructure compiler.h: Make __ADDRESSABLE() symbol truly unique jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved() module: Properly propagate MODULE_STATE_COMING failure module: Fix up module_notifier return values ...
2020-10-12Merge tag 'locking-core-2020-10-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "These are the locking updates for v5.10: - Add deadlock detection for recursive read-locks. The rationale is outlined in commit 224ec489d3cd ("lockdep/ Documention: Recursive read lock detection reasoning") The main deadlock pattern we want to detect is: TASK A: TASK B: read_lock(X); write_lock(X); read_lock_2(X); - Add "latch sequence counters" (seqcount_latch_t): A sequence counter variant where the counter even/odd value is used to switch between two copies of protected data. This allows the read path, typically NMIs, to safely interrupt the write side critical section. We utilize this new variant for sched-clock, and to make x86 TSC handling safer. - Other seqlock cleanups, fixes and enhancements - KCSAN updates - LKMM updates - Misc updates, cleanups and fixes" * tag 'locking-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits) lockdep: Revert "lockdep: Use raw_cpu_*() for per-cpu variables" lockdep: Fix lockdep recursion lockdep: Fix usage_traceoverflow locking/atomics: Check atomic-arch-fallback.h too locking/seqlock: Tweak DEFINE_SEQLOCK() kernel doc lockdep: Optimize the memory usage of circular queue seqlock: Unbreak lockdep seqlock: PREEMPT_RT: Do not starve seqlock_t writers seqlock: seqcount_LOCKNAME_t: Introduce PREEMPT_RT support seqlock: seqcount_t: Implement all read APIs as statement expressions seqlock: Use unique prefix for seqcount_t property accessors seqlock: seqcount_LOCKNAME_t: Standardize naming convention seqlock: seqcount latch APIs: Only allow seqcount_latch_t rbtree_latch: Use seqcount_latch_t x86/tsc: Use seqcount_latch_t timekeeping: Use seqcount_latch_t time/sched_clock: Use seqcount_latch_t seqlock: Introduce seqcount_latch_t mm/swap: Do not abuse the seqcount_t latching API time/sched_clock: Use raw_read_seqcount_latch() during suspend ...
2020-10-12Merge tag 'ras_updates_for_v5.10' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RAS updates from Borislav Petkov: - Extend the recovery from MCE in kernel space also to processes which encounter an MCE in kernel space but while copying from user memory by sending them a SIGBUS on return to user space and umapping the faulty memory, by Tony Luck and Youquan Song. - memcpy_mcsafe() rework by splitting the functionality into copy_mc_to_user() and copy_mc_to_kernel(). This, as a result, enables support for new hardware which can recover from a machine check encountered during a fast string copy and makes that the default and lets the older hardware which does not support that advance recovery, opt in to use the old, fragile, slow variant, by Dan Williams. - New AMD hw enablement, by Yazen Ghannam and Akshay Gupta. - Do not use MSR-tracing accessors in #MC context and flag any fault while accessing MCA architectural MSRs as an architectural violation with the hope that such hw/fw misdesigns are caught early during the hw eval phase and they don't make it into production. - Misc fixes, improvements and cleanups, as always. * tag 'ras_updates_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce: Allow for copy_mc_fragile symbol checksum to be generated x86/mce: Decode a kernel instruction to determine if it is copying from user x86/mce: Recover from poison found while copying from user space x86/mce: Avoid tail copy when machine check terminated a copy from user x86/mce: Add _ASM_EXTABLE_CPY for copy user access x86/mce: Provide method to find out the type of an exception handler x86/mce: Pass pointer to saved pt_regs to severity calculation routines x86/copy_mc: Introduce copy_mc_enhanced_fast_string() x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}() x86/mce: Drop AMD-specific "DEFERRED" case from Intel severity rule list x86/mce: Add Skylake quirk for patrol scrub reported errors RAS/CEC: Convert to DEFINE_SHOW_ATTRIBUTE() x86/mce: Annotate mce_rd/wrmsrl() with noinstr x86/mce/dev-mcelog: Do not update kflags on AMD systems x86/mce: Stop mce_reign() from re-computing severity for every CPU x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR x86/mce: Increase maximum number of banks to 64 x86/mce: Delay clearing IA32_MCG_STATUS to the end of do_machine_check() x86/MCE/AMD, EDAC/mce_amd: Remove struct smca_hwid.xec_bitmap RAS/CEC: Fix cec_init() prototype
2020-10-09Merge branch 'kcsan' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/core Pull KCSAN updates for v5.10 from Paul E. McKenney: - Improve kernel messages. - Be more permissive with bitops races under KCSAN_ASSUME_PLAIN_WRITES_ATOMIC=y. - Optimize debugfs stat counters. - Introduce the instrument_*read_write() annotations, to provide a finer description of certain ops - using KCSAN's compound instrumentation. Use them for atomic RNW and bitops, where appropriate. Doing this might find new races. (Depends on the compiler having tsan-compound-read-before-write=1 support.) - Support atomic built-ins, which will help certain architectures, such as s390. - Misc enhancements and smaller fixes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-10-06objtool: Allow nested externs to enable BUILD_BUG()Vasily Gorbik
Currently BUILD_BUG() macro is expanded to smth like the following: do { extern void __compiletime_assert_0(void) __attribute__((error("BUILD_BUG failed"))); if (!(!(1))) __compiletime_assert_0(); } while (0); If used in a function body this obviously would produce build errors with -Wnested-externs and -Werror. Build objtool with -Wno-nested-externs to enable BUILD_BUG() usage. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-10-06x86/copy_mc: Introduce copy_mc_enhanced_fast_string()Dan Williams
The motivations to go rework memcpy_mcsafe() are that the benefit of doing slow and careful copies is obviated on newer CPUs, and that the current opt-in list of CPUs to instrument recovery is broken relative to those CPUs. There is no need to keep an opt-in list up to date on an ongoing basis if pmem/dax operations are instrumented for recovery by default. With recovery enabled by default the old "mcsafe_key" opt-in to careful copying can be made a "fragile" opt-out. Where the "fragile" list takes steps to not consume poison across cachelines. The discussion with Linus made clear that the current "_mcsafe" suffix was imprecise to a fault. The operations that are needed by pmem/dax are to copy from a source address that might throw #MC to a destination that may write-fault, if it is a user page. So copy_to_user_mcsafe() becomes copy_mc_to_user() to indicate the separate precautions taken on source and destination. copy_mc_to_kernel() is introduced as a non-SMAP version that does not expect write-faults on the destination, but is still prepared to abort with an error code upon taking #MC. The original copy_mc_fragile() implementation had negative performance implications since it did not use the fast-string instruction sequence to perform copies. For this reason copy_mc_to_kernel() fell back to plain memcpy() to preserve performance on platforms that did not indicate the capability to recover from machine check exceptions. However, that capability detection was not architectural and now that some platforms can recover from fast-string consumption of memory errors the memcpy() fallback now causes these more capable platforms to fail. Introduce copy_mc_enhanced_fast_string() as the fast default implementation of copy_mc_to_kernel() and finalize the transition of copy_mc_fragile() to be a platform quirk to indicate 'copy-carefully'. With this in place, copy_mc_to_kernel() is fast and recovery-ready by default regardless of hardware capability. Thanks to Vivek for identifying that copy_user_generic() is not suitable as the copy_mc_to_user() backend since the #MC handler explicitly checks ex_has_fault_handler(). Thanks to the 0day robot for catching a performance bug in the x86/copy_mc_to_user implementation. [ bp: Add the "why" for this change from the 0/2th message, massage. ] Fixes: 92b0729c34ca ("x86/mm, x86/mce: Add memcpy_mcsafe()") Reported-by: Erwin Tsaur <erwin.tsaur@intel.com> Reported-by: 0day robot <lkp@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Erwin Tsaur <erwin.tsaur@intel.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/160195562556.2163339.18063423034951948973.stgit@dwillia2-desk3.amr.corp.intel.com
2020-10-06x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()Dan Williams
In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: <stable@vger.kernel.org> Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
2020-10-02objtool: Permit __kasan_check_{read,write} under UACCESSJann Horn
Building linux-next with JUMP_LABEL=n and KASAN=y, I got this objtool warning: arch/x86/lib/copy_mc.o: warning: objtool: copy_mc_to_user()+0x22: call to __kasan_check_read() with UACCESS enabled What happens here is that copy_mc_to_user() branches on a static key in a UACCESS region:         __uaccess_begin();         if (static_branch_unlikely(&copy_mc_fragile_key))                 ret = copy_mc_fragile(to, from, len);         ret = copy_mc_generic(to, from, len);         __uaccess_end(); and the !CONFIG_JUMP_LABEL version of static_branch_unlikely() uses static_key_enabled(), which uses static_key_count(), which uses atomic_read(), which calls instrument_atomic_read(), which uses kasan_check_read(), which is __kasan_check_read(). Let's permit these KASAN helpers in UACCESS regions - static keys should probably work under UACCESS, I think. PeterZ adds: It's not a matter of permitting, it's a matter of being safe and correct. In this case it is, because it's a thin wrapper around check_memory_region() which was already marked safe. check_memory_region() is correct because the only thing it ends up calling is kasa_report() and that is also marked safe because that is annotated with user_access_save/restore() before it does anything else. On top of that, all of KASAN is noinstr, so nothing in here will end up in tracing and/or call schedule() before the user_access_save(). Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-21objtool: Ignore unreachable trap after call to noreturn functionsIlie Halip
With CONFIG_UBSAN_TRAP enabled, the compiler may insert a trap instruction after a call to a noreturn function. In this case, objtool warns that the UD2 instruction is unreachable. This is a behavior seen with Clang, from the oldest version capable of building the mainline x64_64 kernel (9.0), to the latest experimental version (12.0). Objtool silences similar warnings (trap after dead end instructions), so so expand that check to include dead end functions. Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Rong Chen <rong.a.chen@intel.com> Cc: Marco Elver <elver@google.com> Cc: Philip Li <philip.li@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: kasan-dev@googlegroups.com Cc: x86@kernel.org Cc: clang-built-linux@googlegroups.com BugLink: https://github.com/ClangBuiltLinux/linux/issues/1148 Link: https://lore.kernel.org/lkml/CAKwvOdmptEpi8fiOyWUo=AiZJiX+Z+VHJOM2buLPrWsMTwLnyw@mail.gmail.com Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-21objtool: Handle calling non-function symbols in other sectionsJulien Thierry
Relocation for a call destination could point to a symbol that has type STT_NOTYPE. Lookup such a symbol when no function is available. Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-18objtool: Fix noreturn detection for ignored functionsJosh Poimboeuf
When a function is annotated with STACK_FRAME_NON_STANDARD, objtool doesn't validate its code paths. It also skips sibling call detection within the function. But sibling call detection is actually needed for the case where the ignored function doesn't have any return instructions. Otherwise objtool naively marks the function as implicit static noreturn, which affects the reachability of its callers, resulting in "unreachable instruction" warnings. Fix it by just enabling sibling call detection for ignored functions. The 'insn->ignore' check in add_jump_destinations() is no longer needed after e6da9567959e ("objtool: Don't use ignore flag for fake jumps"). Fixes the following warning: arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x142: unreachable instruction which triggers on an allmodconfig with CONFIG_GCOV_KERNEL unset. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com
2020-09-18objtool: Ignore unreachable fake jumpsJulien Thierry
It is possible for alternative code to unconditionally jump out of the alternative region. In such a case, if a fake jump is added at the end of the alternative instructions, the fake jump will never be reached. Since the fake jump is just a mean to make sure code validation does not go beyond the set of alternatives, reaching it is not a requirement. Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-18objtool: Remove useless tests before save_reg()Julien Thierry
save_reg already checks that the register being saved does not already have a saved state. Remove redundant checks before processing a register storing operation. Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Decode unwind hint register depending on architectureJulien Thierry
The set of registers that can be included in an unwind hint and their encoding will depend on the architecture. Have arch specific code to decode that register. Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Make unwind hint definitions available to other architecturesJulien Thierry
Unwind hints are useful to provide objtool with information about stack states in non-standard functions/code. While the type of information being provided might be very arch specific, the mechanism to provide the information can be useful for other architectures. Move the relevant unwint hint definitions for all architectures to see. [ jpoimboe: REGS_IRET -> REGS_PARTIAL ] Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Refactor jump table code to support other architecturesRaphael Gault
The way to identify jump tables and retrieve all the data necessary to handle the different execution branches is not the same on all architectures. In order to be able to add other architecture support, define an arch-dependent function to process jump-tables. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Raphael Gault <raphael.gault@arm.com> [J.T.: Move arm64 bits out of this patch, Have only one function to find the start of the jump table, for now assume that the jump table format will be the same as x86] Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Make relocation in alternative handling arch dependentJulien Thierry
As pointed out by the comment in handle_group_alt(), support of relocation for instructions in an alternative group depends on whether arch specific kernel code handles it. So, let objtool arch specific code decide whether a relocation for the alternative section should be accepted. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Abstract alternative special case handlingJulien Thierry
Some alternatives associated with a specific feature need to be treated in a special way. Since the features and how to treat them vary from one architecture to another, move the special case handling to arch specific code. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Move macros describing structures to arch-dependent codeJulien Thierry
Some macros are defined to describe the size and layout of structures exception_table_entry, jump_entry and alt_instr. These values can vary from one architecture to another. Have the values be defined by arch specific code. Suggested-by: Raphael Gault <raphael.gault@arm.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Make sync-check consider the target architectureJulien Thierry
Do not take into account outdated headers unrelated to the build of the current architecture. [ jpoimboe: use $SRCARCH directly ] Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Group headers to check in a single listJulien Thierry
In order to support multiple architectures and potentially different sets of headers to compare against their kernel equivalent, it is simpler to have all headers to check in a single list. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-01objtool: Define 'struct orc_entry' only when neededJulien Thierry
Implementation of ORC requires some definitions that are currently provided by the target architecture headers. Do not depend on these definitions when the orc subcommand is not implemented. This avoid requiring arches with no orc implementation to provide dummy orc definitions. Signed-off-by: Julien Thierry <jthierry@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-01objtool: Skip ORC entry creation for non-text sectionsJulien Thierry
Orc generation is only done for text sections, but some instructions can be found in non-text sections (e.g. .discard.text sections). Skip setting their orc sections since their whole sections will be skipped for orc generation. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-01objtool: Move ORC logic out of check()Julien Thierry
Now that the objtool_file can be obtained outside of the check function, orc generation builtin no longer requires check to explicitly call its orc related functions. Signed-off-by: Julien Thierry <jthierry@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-01objtool: Move object file loading out of check()Julien Thierry
Structure objtool_file can be used by different subcommands. In fact it already is, by check and orc. Provide a function that allows to initialize objtool_file, that builtin can call, without relying on check to do the correct setup for them and explicitly hand the objtool_file to them. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-01static_call: Handle tail-callsPeter Zijlstra
GCC can turn our static_call(name)(args...) into a tail call, in which case we get a JMP.d32 into the trampoline (which then does a further tail-call). Teach objtool to recognise and mark these in .static_call_sites and adjust the code patching to deal with this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20200818135805.101186767@infradead.org
2020-09-01x86/static_call: Add inline static call implementation for x86-64Josh Poimboeuf
Add the inline static call implementation for x86-64. The generated code is identical to the out-of-line case, except we move the trampoline into it's own section. Objtool uses the trampoline naming convention to detect all the call sites. It then annotates those call sites in the .static_call_sites section. During boot (and module init), the call sites are patched to call directly into the destination function. The temporary trampoline is then no longer used. [peterz: merged trampolines, put trampoline in section] Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20200818135804.864271425@infradead.org
2020-08-24objtool, kcsan: Add __tsan_read_write to uaccess whitelistMarco Elver
Adds the new __tsan_read_write compound instrumentation to objtool's uaccess whitelist. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24objtool: Add atomic builtin TSAN instrumentation to uaccess whitelistMarco Elver
Adds the new TSAN functions that may be emitted for atomic builtins to objtool's uaccess whitelist. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
2020-08-03Merge tag 'objtool-core-2020-08-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - Add support for non-rela relocations, in preparation to merge 'recordmcount' functionality into objtool - Fix assumption that broke under --ffunction-sections (LTO) builds - Misc cleanups * tag 'objtool-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Add support for relocations without addends objtool: Rename rela to reloc objtool: Use sh_info to find the base for .rela sections objtool: Do not assume order of parent/child functions
2020-06-28Merge tag 'objtool_urgent_for_5.8_rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool fixes from Borislav Petkov: "Three fixes from Peter Zijlstra suppressing KCOV instrumentation in noinstr sections. Peter Zijlstra says: "Address KCOV vs noinstr. There is no function attribute to selectively suppress KCOV instrumentation, instead teach objtool to NOP out the calls in noinstr functions" This cures a bunch of KCOV crashes (as used by syzcaller)" * tag 'objtool_urgent_for_5.8_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Fix noinstr vs KCOV objtool: Provide elf_write_{insn,reloc}() objtool: Clean up elf_write() condition
2020-06-25objtool: Don't consider vmlinux a C-filePeter Zijlstra
Avoids issuing C-file warnings for vmlinux. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200618144801.701257527@infradead.org
2020-06-18Merge branch 'objtool/urgent' into objtool/corePeter Zijlstra
Conflicts: tools/objtool/elf.c tools/objtool/elf.h tools/objtool/orc_gen.c tools/objtool/check.c Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-06-18objtool: Fix noinstr vs KCOVPeter Zijlstra
Since many compilers cannot disable KCOV with a function attribute, help it to NOP out any __sanitizer_cov_*() calls injected in noinstr code. This turns: 12: e8 00 00 00 00 callq 17 <lockdep_hardirqs_on+0x17> 13: R_X86_64_PLT32 __sanitizer_cov_trace_pc-0x4 into: 12: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 13: R_X86_64_NONE __sanitizer_cov_trace_pc-0x4 Just like recordmcount does. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Dmitry Vyukov <dvyukov@google.com>
2020-06-18objtool: Provide elf_write_{insn,reloc}()Peter Zijlstra
This provides infrastructure to rewrite instructions; this is immediately useful for helping out with KCOV-vs-noinstr, but will also come in handy for a bunch of variable sized jump-label patches that are still on ice. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-06-18objtool: Clean up elf_write() conditionPeter Zijlstra
With there being multiple ways to change the ELF data, let's more concisely track modification. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-06-17Merge branch 'objtool/core' of ↵Peter Zijlstra
git://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux into objtool/core
2020-06-15x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*()Peter Zijlstra
The UBSAN instrumentation only inserts external CALLs when things go 'BAD', much like WARN(). So treat them similar to WARN()s for noinstr, that is: allow them, at the risk of taking the machine down, to get their message out. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Marco Elver <elver@google.com>
2020-06-11Rebase locking/kcsan to locking/urgentThomas Gleixner
Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-02objtool: Add support for relocations without addendsMatt Helsley
Currently objtool only collects information about relocations with addends. In recordmcount, which we are about to merge into objtool, some supported architectures do not use rela relocations. Signed-off-by: Matt Helsley <mhelsley@vmware.com> Reviewed-by: Julien Thierry <jthierry@redhat.com> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-06-01objtool: Rename rela to relocMatt Helsley
Before supporting additional relocation types rename the relevant types and functions from "rela" to "reloc". This work be done with the following regex: sed -e 's/struct rela/struct reloc/g' \ -e 's/\([_\*]\)rela\(s\{0,1\}\)/\1reloc\2/g' \ -e 's/tmprela\(s\{0,1\}\)/tmpreloc\1/g' \ -e 's/relasec/relocsec/g' \ -e 's/rela_list/reloc_list/g' \ -e 's/rela_hash/reloc_hash/g' \ -e 's/add_rela/add_reloc/g' \ -e 's/rela->/reloc->/g' \ -e '/rela[,\.]/{ s/\([^\.>]\)rela\([\.,]\)/\1reloc\2/g ; }' \ -e 's/rela =/reloc =/g' \ -e 's/relas =/relocs =/g' \ -e 's/relas\[/relocs[/g' \ -e 's/relaname =/relocname =/g' \ -e 's/= rela\;/= reloc\;/g' \ -e 's/= relas\;/= relocs\;/g' \ -e 's/= relaname\;/= relocname\;/g' \ -e 's/, rela)/, reloc)/g' \ -e 's/\([ @]\)rela\([ "]\)/\1reloc\2/g' \ -e 's/ rela$/ reloc/g' \ -e 's/, relaname/, relocname/g' \ -e 's/sec->rela/sec->reloc/g' \ -e 's/(\(!\{0,1\}\)rela/(\1reloc/g' \ -i \ arch.h \ arch/x86/decode.c \ check.c \ check.h \ elf.c \ elf.h \ orc_gen.c \ special.c Notable exceptions which complicate the regex include gelf_* library calls and standard/expected section names which still use "rela" because they encode the type of relocation expected. Also, keep "rela" in the struct because it encodes a specific type of relocation we currently expect. It will eventually turn into a member of an anonymous union when a susequent patch adds implicit addend, or "rel", relocation support. Signed-off-by: Matt Helsley <mhelsley@vmware.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-05-28objtool: Use sh_info to find the base for .rela sectionsSami Tolvanen
ELF doesn't require .rela section names to match the base section. Use the section index in sh_info to find the section instead of looking it up by name. LLD, for example, generates a .rela section that doesn't match the base section name when we merge sections in a linker script for a binary compiled with -ffunction-sections. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org>
2020-05-28objtool: Do not assume order of parent/child functionsKristen Carlson Accardi
If a .cold function is examined prior to it's parent, the link to the parent/child function can be overwritten when the parent is examined. Only update pfunc and cfunc if they were previously nil to prevent this from happening. This fixes an issue seen when compiling with -ffunction-sections. Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-05-20objtool: Enable compilation of objtool for all architecturesMatt Helsley
Objtool currently only compiles for x86 architectures. This is fine as it presently does not support tooling for other architectures. However, we would like to be able to convert other kernel tools to run as objtool sub commands because they too process ELF object files. This will allow us to convert tools such as recordmcount to use objtool's ELF code. Since much of recordmcount's ELF code is copy-paste code to/from a variety of other kernel tools (look at modpost for example) this means that if we can convert recordmcount we can convert more. We define weak definitions for subcommand entry functions and other weak definitions for shared functions critical to building existing subcommands. These return 127 when the command is missing which signify tools that do not exist on all architectures. In this case the "check" and "orc" tools do not exist on all architectures so we only add them for x86. Future changes adding support for "check", to arm64 for example, can then modify the SUBCMD_CHECK variable when building for arm64. Objtool is not currently wired in to KConfig to be built for other architectures because it's not needed for those architectures and there are no commands it supports other than those for x86. As more command support is enabled on various architectures the necessary KConfig changes can be made (e.g. adding "STACK_VALIDATION") to trigger building objtool. [ jpoimboe: remove aliases, add __weak macro, add error messages ] Cc: Julien Thierry <jthierry@redhat.com> Signed-off-by: Matt Helsley <mhelsley@vmware.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-05-20objtool: Move struct objtool_file into arch-independent headerMatt Helsley
The objtool_file structure describes the files objtool works on, is used by the check subcommand, and the check.h header is included by the orc subcommands so it's presently used by all subcommands. Since the structure will be useful in all subcommands besides check, and some subcommands may not want to include check.h to get the definition, split the structure out into a new header meant for use by all objtool subcommands. Signed-off-by: Matt Helsley <mhelsley@vmware.com> Reviewed-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-05-20objtool: Exit successfully when requesting helpMatt Helsley
When the user requests help it's not an error so do not exit with a non-zero exit code. This is not especially useful for a user but any script that might wish to check that objtool --help is at least available can't rely on the exit code to crudely check that, for example, building an objtool executable succeeds. Signed-off-by: Matt Helsley <mhelsley@vmware.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-28 16:29:47 +0000