kernel/linux.git/include/linux/module.h, branch v5.10.240

x86/its: Use dynamic thunks for indirect branches

2025-07-17T16:27:56+00:00

commit 872df34d7c51a79523820ea6a14860398c639b87 upstream. ITS mitigation moves the unsafe indirect branches to a safe thunk. This could degrade the prediction accuracy as the source address of indirect branches becomes same for different execution paths. To improve the predictions, and hence the performance, assign a separate thunk for each indirect callsite. This is also a defense-in-depth measure to avoid indirect branches aliasing with each other. As an example, 5000 dynamic thunks would utilize around 16 bits of the address space, thereby gaining entropy. For a BTB that uses 32 bits for indexing, dynamic thunks could provide better prediction accuracy over fixed thunks. Have ITS thunks be variable sized and use EXECMEM_MODULE_TEXT such that they are both more flexible (got to extend them later) and live in 2M TLBs, just like kernel code, avoiding undue TLB pressure. [ pawan: CONFIG_EXECMEM and CONFIG_EXECMEM_ROX are not supported on backport kernel, made changes to use module_alloc() and set_memory_*() for dynamic thunks. ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Dave Hansen Reviewed-by: Alexandre Chartre Signed-off-by: Pawan Gupta Signed-off-by: Greg Kroah-Hartman

kallsyms: Make module_kallsyms_on_each_symbol generally available

2024-10-17T13:08:29+00:00

commit 73feb8d5fa3b755bb51077c0aabfb6aa556fd498 upstream. Making module_kallsyms_on_each_symbol generally available, so it can be used outside CONFIG_LIVEPATCH option in following changes. Rather than adding another ifdef option let's make the function generally available (when CONFIG_KALLSYMS and CONFIG_MODULES options are defined). Cc: Christoph Hellwig Acked-by: Song Liu Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20221025134148.3300700-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 926fe783c8a6 ("tracing/kprobes: Fix symbol counting logic by looking at modules as well") Signed-off-by: Markus Boehme Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 329197033bb0 ("tracing/kprobes: Fix symbol counting logic by looking at modules as well") Signed-off-by: Sherry Yang Signed-off-by: Sasha Levin

exit: Rename module_put_and_exit to module_put_and_kthread_exit

2024-06-21T12:53:29+00:00

[ Upstream commit ca3574bd653aba234a4b31955f2778947403be16 ] Update module_put_and_exit to call kthread_exit instead of do_exit. Change the name to reflect this change in functionality. All of the users of module_put_and_exit are causing the current kthread to exit so this change makes it clear what is happening. There is no functional change. Signed-off-by: "Eric W. Biederman" Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

kallsyms: only build {,module_}kallsyms_on_each_symbol when required

2024-06-21T12:52:58+00:00

[ Upstream commit 3e3552056ab42f883d7723eeb42fed712b66bacf ] kallsyms_on_each_symbol and module_kallsyms_on_each_symbol are only used by the livepatching code, so don't build them if livepatching is not enabled. Reviewed-by: Miroslav Benes Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

module: use RCU to synchronize find_module

2024-06-21T12:52:58+00:00

[ Upstream commit a006050575745ca2be25118b90f1c37f454ac542 ] Allow for a RCU-sched critical section around find_module, following the lower level find_module_all helper, and switch the two callers outside of module.c to use such a RCU-sched critical section instead of module_mutex. Reviewed-by: Petr Mladek Acked-by: Miroslav Benes Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

module: use hidden visibility for weak symbol references

2020-10-28T14:08:54+00:00

Geert reports that commit be2881824ae9eb92 ("arm64/build: Assert for unwanted sections") results in build errors on arm64 for configurations that have CONFIG_MODULES disabled. The commit in question added ASSERT()s to the arm64 linker script to ensure that linker generated sections such as .got.plt etc are empty, but as it turns out, there are corner cases where the linker does emit content into those sections. More specifically, weak references to function symbols (which can remain unsatisfied, and can therefore not be emitted as relative references) will be emitted as GOT and PLT entries when linking the kernel in PIE mode (which is the case when CONFIG_RELOCATABLE is enabled, which is on by default). What happens is that code such as struct device *(*fn)(struct device *dev); struct device *iommu_device; fn = symbol_get(mdev_get_iommu_device); if (fn) { iommu_device = fn(dev); essentially gets converted into the following when CONFIG_MODULES is off: struct device *iommu_device; if (&mdev_get_iommu_device) { iommu_device = mdev_get_iommu_device(dev); where mdev_get_iommu_device is emitted as a weak symbol reference into the object file. The first reference is decorated with an ordinary ABS64 data relocation (which yields 0x0 if the reference remains unsatisfied). However, the indirect call is turned into a direct call covered by a R_AARCH64_CALL26 relocation, which is converted into a call via a PLT entry taking the target address from the associated GOT entry. Given that such GOT and PLT entries are unnecessary for fully linked binaries such as the kernel, let's give these weak symbol references hidden visibility, so that the linker knows that the weak reference via R_AARCH64_CALL26 can simply remain unsatisfied. Signed-off-by: Ard Biesheuvel Tested-by: Geert Uytterhoeven Reviewed-by: Fangrui Song Acked-by: Jessica Yu Cc: Jessica Yu Cc: Kees Cook Cc: Geert Uytterhoeven Cc: Nick Desaulniers Link: https://lore.kernel.org/r/20201027151132.14066-1-ardb@kernel.org Signed-off-by: Will Deacon

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49+00:00

Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches Reviewed-by: Nick Desaulniers Reviewed-by: Miguel Ojeda Signed-off-by: Linus Torvalds

static_call: Add inline static call infrastructure

2020-09-01T07:58:04+00:00

Add infrastructure for an arch-specific CONFIG_HAVE_STATIC_CALL_INLINE option, which is a faster version of CONFIG_HAVE_STATIC_CALL. At runtime, the static call sites are patched directly, rather than using the out-of-line trampolines. Compared to out-of-line static calls, the performance benefits are more modest, but still measurable. Steven Rostedt did some tracepoint measurements: https://lkml.kernel.org/r/20181126155405.72b4f718@gandalf.local.home This code is heavily inspired by the jump label code (aka "static jumps"), as some of the concepts are very similar. For more details, see the comments in include/linux/static_call.h. [peterz: simplified interface; merged trampolines] Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Steven Rostedt (VMware) Cc: Linus Torvalds Link: https://lore.kernel.org/r/20200818135804.684334440@infradead.org

modules: inherit TAINT_PROPRIETARY_MODULE

2020-08-05T08:31:28+00:00

If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag for all modules importing these symbols, and don't allow loading symbols from TAINT_PROPRIETARY_MODULE modules if the module previously imported gplonly symbols. Add a anti-circumvention devices so people don't accidentally get themselves into trouble this way. Comment from Greg: "Ah, the proven-to-be-illegal "GPL Condom" defense :)" [jeyu: pr_info -> pr_err and pr_warn as per discussion] Link: http://lore.kernel.org/r/20200730162957.GA22469@lst.de Acked-by: Daniel Vetter Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu

modules: return licensing information from find_symbol

2020-08-01T14:05:02+00:00

Report the GPLONLY status through a new argument. Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu