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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2020-08-18 15:57:41 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-09-01 09:58:04 +0200 |
| commit | 115284d89a436e9b66da0c6c4f6efded806874b2 (patch) | |
| tree | 32a7cea5ea8b3669e7ba38532c3e229cb13331c6 /arch/Kconfig | |
| parent | 563a02b0c9704f69c0364befedd451f57fe88092 (diff) | |
| download | linux-115284d89a436e9b66da0c6c4f6efded806874b2.tar.gz linux-115284d89a436e9b66da0c6c4f6efded806874b2.tar.bz2 linux-115284d89a436e9b66da0c6c4f6efded806874b2.zip | |
static_call: Add basic static call infrastructure
Static calls are a replacement for global function pointers. They use
code patching to allow direct calls to be used instead of indirect
calls. They give the flexibility of function pointers, but with
improved performance. This is especially important for cases where
retpolines would otherwise be used, as retpolines can significantly
impact performance.
The concept and code are an extension of previous work done by Ard
Biesheuvel and Steven Rostedt:
https://lkml.kernel.org/r/20181005081333.15018-1-ard.biesheuvel@linaro.org
https://lkml.kernel.org/r/20181006015110.653946300@goodmis.org
There are two implementations, depending on arch support:
1) out-of-line: patched trampolines (CONFIG_HAVE_STATIC_CALL)
2) basic function pointers
For more details, see the comments in include/linux/static_call.h.
[peterz: simplified interface]
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>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20200818135804.623259796@infradead.org
Diffstat (limited to 'arch/Kconfig')
| -rw-r--r-- | arch/Kconfig | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index af14a567b493..806e6df7b47c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -975,6 +975,9 @@ config HAVE_SPARSE_SYSCALL_NR config ARCH_HAS_VDSO_DATA bool +config HAVE_STATIC_CALL + bool + source "kernel/gcov/Kconfig" source "scripts/gcc-plugins/Kconfig" |