From ab21d6063c01180a8e9b22a37b847e5819525d9f Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Thu, 21 Jul 2022 15:42:33 +0200 Subject: [PATCH] bpf: Introduce 8-byte BTF set 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 Link: https://lore.kernel.org/r/20220721134245.2450-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- 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 /* 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 */