linux/tools/objtool/check.c, branch v5.8

Merge tag 'objtool_urgent_for_5.8_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-06-28T17:16:15Z

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

objtool: Don't consider vmlinux a C-file

2020-06-25T11:45:39Z

Avoids issuing C-file warnings for vmlinux. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200618144801.701257527@infradead.org

objtool: Fix noinstr vs KCOV

2020-06-18T15:36:33Z

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 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) Acked-by: Dmitry Vyukov

objtool: Clean up elf_write() condition

2020-06-18T15:36:33Z

With there being multiple ways to change the ELF data, let's more concisely track modification. Signed-off-by: Peter Zijlstra (Intel)

x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*()

2020-06-15T12:10:09Z

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 Signed-off-by: Peter Zijlstra (Intel) Acked-by: Marco Elver

Rebase locking/kcsan to locking/urgent

2020-06-11T18:02:46Z

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

objtool: Enable compilation of objtool for all architectures

2020-05-20T14:17:28Z

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 Signed-off-by: Matt Helsley Signed-off-by: Josh Poimboeuf

objtool: Add check_kcov_mode() to the uaccess safelist

2020-05-20T13:30:43Z

check_kcov_mode() is called by write_comp_data() and __sanitizer_cov_trace_pc(), which are already on the uaccess safe list. It's notrace and doesn't call out to anything else, so add it to the list too. This fixes the following warnings: kernel/kcov.o: warning: objtool: __sanitizer_cov_trace_pc()+0x15: call to check_kcov_mode() with UACCESS enabled kernel/kcov.o: warning: objtool: write_comp_data()+0x1b: call to check_kcov_mode() with UACCESS enabled Reported-by: Arnd Bergmann Signed-off-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel)

Merge tag 'v5.7-rc6' into objtool/core, to pick up fixes and resolve semantic conflict

2020-05-18T10:09:37Z

Resolve structural conflict between: 59566b0b622e: ("x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up") which introduced a new reference to 'ftrace_epilogue', and: 0298739b7983: ("x86,ftrace: Fix ftrace_regs_caller() unwind") Which renamed it to 'ftrace_caller_end'. Rename the new usage site in the merge commit. Signed-off-by: Ingo Molnar

objtool: optimize add_dead_ends for split sections

2020-05-15T08:35:13Z

Instead of iterating through all instructions to find the last instruction each time .rela.discard.(un)reachable points beyond the section, use find_insn to locate the last instruction by looking at the last bytes of the section instead. Suggested-by: Josh Poimboeuf Signed-off-by: Sami Tolvanen Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200421220843.188260-3-samitolvanen@google.com