kernel/linux.git/tools/objtool/builtin-check.c, branch v6.18.21

objtool: Add action to check for absence of absolute relocations

2025-09-03T15:59:51+00:00

The x86 startup code must not use absolute references to code or data, as it executes before the kernel virtual mapping is up. Add an action to objtool to check all allocatable sections (with the exception of __patchable_function_entries, which uses absolute references for nebulous reasons) and raise an error if any absolute references are found. Note that debug sections typically contain lots of absolute references too, but those are not allocatable so they will be ignored. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/20250828102202.1849035-39-ardb+git@google.com

objtool: Change "warning:" to "error: " for fatal errors

2025-04-01T07:07:13+00:00

This is similar to GCC's behavior and makes it more obvious why the build failed. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/0ea76f4b0e7a370711ed9f75fd0792bb5979c2bf.1743481539.git.jpoimboe@kernel.org

objtool: Fix NULL printf() '%s' argument in builtin-check.c:save_argv()

2025-03-28T13:38:09+00:00

It's probably not the best idea to pass a string pointer to printf() right after confirming said pointer is NULL. Fix the typo and use argv[i] instead. Fixes: c5995abe1547 ("objtool: Improve error handling") Reported-by: Stephen Rothwell Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Tested-by: Stephen Rothwell Link: https://lore.kernel.org/r/a814ed8b08fb410be29498a20a5fbbb26e907ecf.1742952512.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/20250326103854.309e3c60@canb.auug.org.au

objtool: Reduce CONFIG_OBJTOOL_WERROR verbosity

2025-03-25T08:20:27+00:00

Remove the following from CONFIG_OBJTOOL_WERROR: * backtrace * "upgraded warnings to errors" message * cmdline args This makes the default output less cluttered and makes it easier to spot the actual warnings. Note the above options are still are available with --verbose or OBJTOOL_VERBOSE=1. Also, do the cmdline arg printing on all warnings, regardless of werror. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/d61df69f64b396fa6b2a1335588aad7a34ea9e71.1742852846.git.jpoimboe@kernel.org

objtool: Improve error handling

2025-03-25T08:20:27+00:00

Fix some error handling issues, improve error messages, properly distinguish betwee errors and warnings, and generally try to make all the error handling more consistent. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/3094bb4463dad29b6bd1bea03848d1571ace771c.1742852846.git.jpoimboe@kernel.org

objtool: Use O_CREAT with explicit mode mask

2025-03-17T11:24:02+00:00

Recent Ubuntu enforces 3-argument open() with O_CREAT: CC /home/mingo/tip/tools/objtool/builtin-check.o In file included from /usr/include/fcntl.h:341, from builtin-check.c:9: In function ‘open’, inlined from ‘copy_file’ at builtin-check.c:201:11: /usr/include/x86_64-linux-gnu/bits/fcntl2.h:52:11: error: call to ‘__open_missing_mode’ declared with attribute error: open with O_CREAT or O_TMPFILE in second argument needs 3 arguments 52 | __open_missing_mode (); | ^~~~~~~~~~~~~~~~~~~~~~ Use 0400 as the most restrictive mode for the new file. Signed-off-by: Ingo Molnar Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: linux-kernel@vger.kernel.org

objtool: Create backup on error and print args

2025-03-17T10:36:02+00:00

Recreating objtool errors can be a manual process. Kbuild removes the object, so it has to be compiled or linked again before running objtool. Then the objtool args need to be reversed engineered. Make that all easier by automatically making a backup of the object file on error, and print a modified version of the args which can be used to recreate. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/7571e30636359b3e173ce6e122419452bb31882f.1741975349.git.jpoimboe@kernel.org

objtool: Add --Werror option

2025-03-17T10:36:01+00:00

Any objtool warning has the potential of reflecting (or triggering) a major bug in the kernel or compiler which could result in crashing the kernel or breaking the livepatch consistency model. In preparation for failing the build on objtool errors/warnings, add a new --Werror option. [ jpoimboe: commit log, comments, error out on fatal errors too ] Co-developed-by: Brendan Jackman Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/e423ea4ec297f510a108aa6c78b52b9fe30fa8c1.1741975349.git.jpoimboe@kernel.org

objtool: Add --output option

2025-03-17T10:36:01+00:00

Add option to allow writing the changed binary to a separate file rather than changing it in place. Libelf makes this suprisingly hard, so take the easy way out and just copy the file before editing it. Also steal the -o short option from --orc. Nobody will notice ;-) Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/0da308d42d82b3bbed16a31a72d6bde52afcd6bd.1741975349.git.jpoimboe@kernel.org

objtool: Upgrade "Linked object detected" warning to error

2025-03-17T10:36:01+00:00

Force the user to fix their cmdline if they forget the '--link' option. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Brendan Jackman Link: https://lore.kernel.org/r/8380bbf3a0fa86e03fd63f60568ae06a48146bc1.1741975349.git.jpoimboe@kernel.org