Introduce support for defining flags for kfuncs using a new set of
macros, BTF_SET8_START/BTF_SET8_END, which define a set which contains
8 byte elements (each of which consists of a pair of BTF ID and flags),
using a new BTF_ID_FLAGS macro.
This will be used to tag kfuncs registered for a certain program type
as acquire, release, sleepable, ret_null, etc. without having to create
more and more sets which was proving to be an unscalable solution.
Now, when looking up whether a kfunc is allowed for a certain program,
we can also obtain its kfunc flags in the same call and avoid further
lookups.
The resolve_btfids change is split into a separate patch.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
include/linux/btf_ids.h | 68 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 64 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 252a4befeab1..3cb0741e71d7 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -8,6 +8,15 @@ struct btf_id_set {
u32 ids[];
};
+struct btf_id_set8 {
+ u32 cnt;
+ u32 flags;
+ struct {
+ u32 id;
+ u32 flags;
+ } pairs[];
+};
+
#ifdef CONFIG_DEBUG_INFO_BTF
#include <linux/compiler.h> /* for __PASTE */
@@ -25,7 +34,7 @@ struct btf_id_set {
#define BTF_IDS_SECTION ".BTF_ids"
-#define ____BTF_ID(symbol) \
+#define ____BTF_ID(symbol, word) \
asm( \
".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
".local " #symbol " ; \n" \
@@ -33,10 +42,11 @@ asm( \
".size " #symbol ", 4; \n" \
#symbol ": \n" \
".zero 4 \n" \
+word \
".popsection; \n");
-#define __BTF_ID(symbol) \
- ____BTF_ID(symbol)
+#define __BTF_ID(symbol, word) \
+ ____BTF_ID(symbol, word)
#define __ID(prefix) \
__PASTE(prefix, __COUNTER__)
@@ -46,7 +56,14 @@ asm( \
* to 4 zero bytes.
*/
#define BTF_ID(prefix, name) \
- __BTF_ID(__ID(__BTF_ID__##prefix##__##name##__))
+ __BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), "")
+
+#define ____BTF_ID_FLAGS(prefix, name, flags) \
+ __BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), ".long " #flags "\n")
+#define __BTF_ID_FLAGS(prefix, name, flags, ...) \
+ ____BTF_ID_FLAGS(prefix, name, flags)
+#define BTF_ID_FLAGS(prefix, name, ...) \
+ __BTF_ID_FLAGS(prefix, name, ##__VA_ARGS__, 0)
/*
* The BTF_ID_LIST macro defines pure (unsorted) list
@@ -145,10 +162,51 @@ asm( \
".popsection; \n"); \
extern struct btf_id_set name;
+/*
+ * The BTF_SET8_START/END macros pair defines sorted list of
+ * BTF IDs and their flags plus its members count, with the
+ * following layout:
+ *
+ * BTF_SET8_START(list)
+ * BTF_ID_FLAGS(type1, name1, flags)
+ * BTF_ID_FLAGS(type2, name2, flags)
+ * BTF_SET8_END(list)
+ *
+ * __BTF_ID__set8__list:
+ * .zero 8
+ * list:
+ * __BTF_ID__type1__name1__3:
+ * .zero 4
+ * .word (1 << 0) | (1 << 2)
+ * __BTF_ID__type2__name2__5:
+ * .zero 4
+ * .word (1 << 3) | (1 << 1) | (1 << 2)
+ *
+ */
+#define __BTF_SET8_START(name, scope) \
+asm( \
+".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
+"." #scope " __BTF_ID__set8__" #name "; \n" \
+"__BTF_ID__set8__" #name ":; \n" \
+".zero 8 \n" \
+".popsection; \n");
+
+#define BTF_SET8_START(name) \
+__BTF_ID_LIST(name, local) \
+__BTF_SET8_START(name, local)
+
+#define BTF_SET8_END(name) \
+asm( \
+".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
+".size __BTF_ID__set8__" #name ", .-" #name " \n" \
+".popsection; \n"); \
+extern struct btf_id_set8 name;
+
#else
#define BTF_ID_LIST(name) static u32 __maybe_unused name[5];
#define BTF_ID(prefix, name)
+#define BTF_ID_FLAGS(prefix, name, flags)
#define BTF_ID_UNUSED
#define BTF_ID_LIST_GLOBAL(name, n) u32 __maybe_unused name[n];
#define BTF_ID_LIST_SINGLE(name, prefix, typename) static u32 __maybe_unused name[1];
@@ -156,6 +214,8 @@ extern struct btf_id_set name;
#define BTF_SET_START(name) static struct btf_id_set __maybe_unused name = { 0 };
#define BTF_SET_START_GLOBAL(name) static struct btf_id_set __maybe_unused name = { 0 };
#define BTF_SET_END(name)
+#define BTF_SET8_START(name) static struct btf_id_set8 __maybe_unused name = { 0 };
+#define BTF_SET8_END(name) static struct btf_id_set8 __maybe_unused name = { 0 };
#endif /* CONFIG_DEBUG_INFO_BTF */
--
2.34.1
