kernel/linux.git/include/linux/kallsyms.h, branch v6.6.132

module: Extend the preempt disabled section in dereference_symbol_descriptor().

2025-02-08T08:52:27+00:00

[ Upstream commit a145c848d69f9c6f32008d8319edaa133360dd74 ] dereference_symbol_descriptor() needs to obtain the module pointer belonging to pointer in order to resolve that pointer. The returned mod pointer is obtained under RCU-sched/ preempt_disable() guarantees and needs to be used within this section to ensure that the module is not removed in the meantime. Extend the preempt_disable() section to also cover dereference_module_function_descriptor(). Fixes: 04b8eb7a4ccd9 ("symbol lookup: introduce dereference_symbol_descriptor()") Cc: James E.J. Bottomley Cc: Christophe Leroy Cc: Helge Deller Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Naveen N Rao Cc: Nicholas Piggin Cc: Sergey Senozhatsky Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Reviewed-by: Sergey Senozhatsky Acked-by: Peter Zijlstra (Intel) Signed-off-by: Sebastian Andrzej Siewior Link: https://lore.kernel.org/r/20250108090457.512198-2-bigeasy@linutronix.de Signed-off-by: Petr Pavlu Signed-off-by: Sasha Levin

kallsyms: make kallsyms_show_value() as generic function

2023-06-08T19:27:20+00:00

This change makes function kallsyms_show_value() as generic function without dependency on CONFIG_KALLSYMS. Now module address will be displayed with lsmod and /proc/modules. Earlier: ======= / # insmod test.ko / # lsmod test 12288 0 - Live 0x0000000000000000 (O) // No Module Load address / # With change: ========== / # insmod test.ko / # lsmod test 12288 0 - Live 0xffff800000fc0000 (O) // Module address / # cat /proc/modules test 12288 0 - Live 0xffff800000fc0000 (O) Co-developed-by: Onkarnath Signed-off-by: Onkarnath Signed-off-by: Maninder Singh Reviewed-by: Zhen Lei Signed-off-by: Luis Chamberlain

kallsyms: remove unsed API lookup_symbol_attrs

2023-05-26T22:10:18+00:00

with commit '7878c231dae0 ("slab: remove /proc/slab_allocators")' lookup_symbol_attrs usage is removed. Thus removing redundant API. Signed-off-by: Maninder Singh Reviewed-by: Kees Cook Signed-off-by: Luis Chamberlain

kallsyms: Delete an unused parameter related to {module_}kallsyms_on_each_symbol()

2023-03-19T20:27:19+00:00

The parameter 'struct module *' in the hook function associated with {module_}kallsyms_on_each_symbol() is no longer used. Delete it. Suggested-by: Petr Mladek Signed-off-by: Zhen Lei Reviewed-by: Vincenzo Palazzo Acked-by: Jiri Olsa Acked-by: Steven Rostedt (Google) Signed-off-by: Luis Chamberlain

kallsyms: Add self-test facility

2022-11-15T08:42:02+00:00

Added test cases for basic functions and performance of functions kallsyms_lookup_name(), kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol(). It also calculates the compression rate of the kallsyms compression algorithm for the current symbol set. The basic functions test begins by testing a set of symbols whose address values are known. Then, traverse all symbol addresses and find the corresponding symbol name based on the address. It's impossible to determine whether these addresses are correct, but we can use the above three functions along with the addresses to test each other. Due to the traversal operation of kallsyms_on_each_symbol() is too slow, only 60 symbols can be tested in one second, so let it test on average once every 128 symbols. The other two functions validate all symbols. If the basic functions test is passed, print only performance test results. If the test fails, print error information, but do not perform subsequent performance tests. Start self-test automatically after system startup if CONFIG_KALLSYMS_SELFTEST=y. Example of output content: (prefix 'kallsyms_selftest:' is omitted start --------------------------------------------------------- | nr_symbols | compressed size | original size | ratio(%) | |---------------------------------------------------------| | 107543 | 1357912 | 2407433 | 56.40 | --------------------------------------------------------- kallsyms_lookup_name() looked up 107543 symbols The time spent on each symbol is (ns): min=630, max=35295, avg=7353 kallsyms_on_each_symbol() traverse all: 11782628 ns kallsyms_on_each_match_symbol() traverse all: 9261 ns finish Signed-off-by: Zhen Lei Signed-off-by: Luis Chamberlain

kallsyms: Add helper kallsyms_on_each_match_symbol()

2022-11-13T02:47:36+00:00

Function kallsyms_on_each_symbol() traverses all symbols and submits each symbol to the hook 'fn' for judgment and processing. For some cases, the hook actually only handles the matched symbol, such as livepatch. Because all symbols are currently sorted by name, all the symbols with the same name are clustered together. Function kallsyms_lookup_names() gets the start and end positions of the set corresponding to the specified name. So we can easily and quickly traverse all the matches. The test results are as follows (twice): (x86) kallsyms_on_each_match_symbol: 7454, 7984 kallsyms_on_each_symbol : 11733809, 11785803 kallsyms_on_each_match_symbol() consumes only 0.066% of kallsyms_on_each_symbol()'s time. In other words, 1523x better performance. Signed-off-by: Zhen Lei Signed-off-by: Luis Chamberlain

kallsyms: increase maximum kernel symbol length to 512

2022-09-28T06:56:25+00:00

Rust symbols can become quite long due to namespacing introduced by modules, types, traits, generics, etc. For instance, the following code: pub mod my_module { pub struct MyType; pub struct MyGenericType(T); pub trait MyTrait { fn my_method() -> u32; } impl MyTrait for MyGenericType { fn my_method() -> u32 { 42 } } } generates a symbol of length 96 when using the upcoming v0 mangling scheme: _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method At the moment, Rust symbols may reach up to 300 in length. Setting 512 as the maximum seems like a reasonable choice to keep some headroom. Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Signed-off-by: Miguel Ojeda

kallsyms: Make kallsyms_on_each_symbol generally available

2022-05-10T21:42:06+00:00

Making 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 option is defined). Cc: Christoph Hellwig Reviewed-by: Masami Hiramatsu Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20220510122616.2652285-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov

asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS

2022-02-16T12:25:11+00:00

Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of 'dereference_function_descriptor' macro to know whether an arch has function descriptors. To limit churn in one of the following patches, use an #ifdef/#else construct with empty first part instead of an #ifndef in asm-generic/sections.h On powerpc, make sure the config option matches the ABI used by the compiler with a BUILD_BUG_ON() and add missing _CALL_ELF=2 when calling 'sparse' so that sparse sees the same piece of code as GCC. And include a helper to check whether an arch has function descriptors or not : have_function_descriptors() Signed-off-by: Christophe Leroy Reviewed-by: Kees Cook Reviewed-by: Nicholas Piggin Acked-by: Helge Deller Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/4a0f11fb0ea74a3197bc44dd7ba25e53a24fd03d.1644928018.git.christophe.leroy@csgroup.eu

sections: provide internal __is_kernel() and __is_kernel_text() helper

2021-11-09T18:02:51+00:00

An internal __is_kernel() helper which only check the kernel address ranges, and an internal __is_kernel_text() helper which only check text section ranges. Link: https://lkml.kernel.org/r/20210930071143.63410-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Sergey Senozhatsky Cc: Alexander Potapenko Cc: Alexei Starovoitov Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Christophe Leroy Cc: "David S. Miller" Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Ellerman Cc: Michal Simek Cc: Paul Mackerras Cc: Petr Mladek Cc: Richard Henderson Cc: Steven Rostedt Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds