diff options
| author | Sami Tolvanen <samitolvanen@google.com> | 2025-05-07 23:14:07 +0000 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2025-05-25 18:12:23 +0900 |
| commit | c9083467f7b97e7c06b7a9038c4f18095329bd37 (patch) | |
| tree | ea6e74c8041c837d58e3f10c7a171337a22c3b8d /scripts/gendwarfksyms/examples/kabi.h | |
| parent | db59d74e5da144111fc133fb1bf72e6392bdb04e (diff) | |
gendwarfksyms: Add a kABI rule to override type strings
In rare situations where distributions must make significant
changes to otherwise opaque data structures that have
inadvertently been included in the published ABI, keeping
symbol versions stable using the existing kABI macros can
become tedious.
For example, Android decided to switch to a newer io_uring
implementation in the 5.10 GKI kernel "to resolve a huge number
of potential, and known, problems with the codebase," requiring
"horrible hacks" with genksyms:
"A number of the io_uring structures get used in other core
kernel structures, only as "opaque" pointers, so there is
not any real ABI breakage. But, due to the visibility of
the structures going away, the CRC values of many scheduler
variables and functions were changed."
-- https://r.android.com/2425293
While these specific changes probably could have been hidden
from gendwarfksyms using the existing kABI macros, this may not
always be the case.
Add a last resort kABI rule that allows distribution
maintainers to fully override a type string for a symbol or a
type. Also add a more informative error message in case we find
a non-existent type references when calculating versions.
Suggested-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/gendwarfksyms/examples/kabi.h')
| -rw-r--r-- | scripts/gendwarfksyms/examples/kabi.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/scripts/gendwarfksyms/examples/kabi.h b/scripts/gendwarfksyms/examples/kabi.h index 86f4428e0479..170733a3fba4 100644 --- a/scripts/gendwarfksyms/examples/kabi.h +++ b/scripts/gendwarfksyms/examples/kabi.h @@ -37,11 +37,14 @@ #define __stringify(x...) __stringify_1(x) #endif -#define __KABI_RULE(hint, target, value) \ +#define ___KABI_RULE(hint, target, value) \ static const char __PASTE(__gendwarfksyms_rule_, \ __COUNTER__)[] __used __aligned(1) \ __section(".discard.gendwarfksyms.kabi_rules") = \ - "1\0" #hint "\0" #target "\0" #value + "1\0" #hint "\0" target "\0" value + +#define __KABI_RULE(hint, target, value) \ + ___KABI_RULE(hint, #target, #value) #define __KABI_NORMAL_SIZE_ALIGN(_orig, _new) \ union { \ @@ -97,6 +100,13 @@ #define KABI_BYTE_SIZE(fqn, value) __KABI_RULE(byte_size, fqn, value) /* + * KABI_TYPE_STRING(type, str) + * For the given type, override the type string used in symtypes + * output and version calculation with str. + */ +#define KABI_TYPE_STRING(type, str) ___KABI_RULE(type_string, type, str) + +/* * KABI_RESERVE * Reserve some "padding" in a structure for use by LTS backports. * This is normally placed at the end of a structure. |