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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 /include/linux/static_call_types.h | |
| parent | 563a02b0c9704f69c0364befedd451f57fe88092 (diff) | |
| download | linux-115284d89a436e9b66da0c6c4f6efded806874b2.tar.bz2 | |
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 'include/linux/static_call_types.h')
| -rw-r--r-- | include/linux/static_call_types.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/static_call_types.h b/include/linux/static_call_types.h new file mode 100644 index 000000000000..5ed249dc47d3 --- /dev/null +++ b/include/linux/static_call_types.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _STATIC_CALL_TYPES_H +#define _STATIC_CALL_TYPES_H + +#include <linux/stringify.h> + +#define STATIC_CALL_KEY_PREFIX __SCK__ +#define STATIC_CALL_KEY(name) __PASTE(STATIC_CALL_KEY_PREFIX, name) + +#define STATIC_CALL_TRAMP_PREFIX __SCT__ +#define STATIC_CALL_TRAMP_PREFIX_STR __stringify(STATIC_CALL_TRAMP_PREFIX) +#define STATIC_CALL_TRAMP(name) __PASTE(STATIC_CALL_TRAMP_PREFIX, name) +#define STATIC_CALL_TRAMP_STR(name) __stringify(STATIC_CALL_TRAMP(name)) + +#endif /* _STATIC_CALL_TYPES_H */ |