| Message ID | 20220910025214.1536510-1-yhs@fb.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 9f2f5d7830ddfeeca147595f473e14eadbeb3db1 |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] libbpf: Improve BPF_PROG2 macro code quality and description | expand |
On 09/09, Yonghong Song wrote: > Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 > macro for trampoline based programs with struct arguments. Andrii > made a few suggestions to improve code quality and description. > This patch implemented these suggestions including better internal > macro name, consistent usage pattern for __builtin_choose_expr(), > simpler macro definition for always-inline func arguments and > better macro description. Not sure if Andrii wants to take a look, if not feel free to use: Acked-by: Stanislav Fomichev <sdf@google.com> > Signed-off-by: Yonghong Song <yhs@fb.com> > --- > tools/lib/bpf/bpf_tracing.h | 77 ++++++++++++++++++++++--------------- > 1 file changed, 47 insertions(+), 30 deletions(-) > diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h > index 8d4bdd18cb3d..a71ca48ea479 100644 > --- a/tools/lib/bpf/bpf_tracing.h > +++ b/tools/lib/bpf/bpf_tracing.h > @@ -438,39 +438,45 @@ typeof(name(0)) name(unsigned long long *ctx) > \ > static __always_inline typeof(name(0)) \ > ____##name(unsigned long long *ctx, ##args) > -#ifndef ____bpf_nth > -#define ____bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, > _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N > +#ifndef ___bpf_nth2 > +#define ___bpf_nth2(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, > _12, _13, \ > + _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N > #endif > -#ifndef ____bpf_narg > -#define ____bpf_narg(...) ____bpf_nth(_, ##__VA_ARGS__, 12, 12, 11, 11, > 10, 10, 9, 9, 8, 8, 7, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) > +#ifndef ___bpf_narg2 > +#define ___bpf_narg2(...) \ > + ___bpf_nth2(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, > \ > + 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) > #endif > -#define BPF_REG_CNT(t) \ > - (__builtin_choose_expr(sizeof(t) == 1 || sizeof(t) == 2 || sizeof(t) == > 4 || sizeof(t) == 8, 1, \ > - __builtin_choose_expr(sizeof(t) == 16, 2, \ > - (void)0))) > +#define ___bpf_reg_cnt(t) \ > + __builtin_choose_expr(sizeof(t) == 1, 1, \ > + __builtin_choose_expr(sizeof(t) == 2, 1, \ > + __builtin_choose_expr(sizeof(t) == 4, 1, \ > + __builtin_choose_expr(sizeof(t) == 8, 1, \ > + __builtin_choose_expr(sizeof(t) == 16, 2, \ > + (void)0))))) > #define ____bpf_reg_cnt0() (0) > -#define ____bpf_reg_cnt1(t, x) (____bpf_reg_cnt0() + BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt2(t, x, args...) (____bpf_reg_cnt1(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt3(t, x, args...) (____bpf_reg_cnt2(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt4(t, x, args...) (____bpf_reg_cnt3(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt5(t, x, args...) (____bpf_reg_cnt4(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt6(t, x, args...) (____bpf_reg_cnt5(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt7(t, x, args...) (____bpf_reg_cnt6(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt8(t, x, args...) (____bpf_reg_cnt7(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt9(t, x, args...) (____bpf_reg_cnt8(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt10(t, x, args...) (____bpf_reg_cnt9(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt11(t, x, args...) (____bpf_reg_cnt10(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt12(t, x, args...) (____bpf_reg_cnt11(args) + > BPF_REG_CNT(t)) > -#define ____bpf_reg_cnt(args...) ___bpf_apply(____bpf_reg_cnt, > ____bpf_narg(args))(args) > +#define ____bpf_reg_cnt1(t, x) (____bpf_reg_cnt0() + ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt2(t, x, args...) (____bpf_reg_cnt1(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt3(t, x, args...) (____bpf_reg_cnt2(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt4(t, x, args...) (____bpf_reg_cnt3(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt5(t, x, args...) (____bpf_reg_cnt4(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt6(t, x, args...) (____bpf_reg_cnt5(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt7(t, x, args...) (____bpf_reg_cnt6(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt8(t, x, args...) (____bpf_reg_cnt7(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt9(t, x, args...) (____bpf_reg_cnt8(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt10(t, x, args...) (____bpf_reg_cnt9(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt11(t, x, args...) (____bpf_reg_cnt10(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt12(t, x, args...) (____bpf_reg_cnt11(args) + > ___bpf_reg_cnt(t)) > +#define ____bpf_reg_cnt(args...) ___bpf_apply(____bpf_reg_cnt, > ___bpf_narg2(args))(args) > #define ____bpf_union_arg(t, x, n) \ > - __builtin_choose_expr(sizeof(t) == 1, ({ union { struct { __u8 x; } > ___z; t x; } ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \ > - __builtin_choose_expr(sizeof(t) == 2, ({ union { struct { __u16 x; } > ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ > - __builtin_choose_expr(sizeof(t) == 4, ({ union { struct { __u32 x; } > ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ > - __builtin_choose_expr(sizeof(t) == 8, ({ union { struct { __u64 x; } > ___z; t x; } ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \ > - __builtin_choose_expr(sizeof(t) == 16, ({ union { struct { __u64 x, y; > } ___z; t x; } ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \ > + __builtin_choose_expr(sizeof(t) == 1, ({ union { __u8 ___z[1]; t x; } > ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \ > + __builtin_choose_expr(sizeof(t) == 2, ({ union { __u16 ___z[1]; t x; } > ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ > + __builtin_choose_expr(sizeof(t) == 4, ({ union { __u32 ___z[1]; t x; } > ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ > + __builtin_choose_expr(sizeof(t) == 8, ({ union { __u64 ___z[1]; t x; } > ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \ > + __builtin_choose_expr(sizeof(t) == 16, ({ union { __u64 ___z[2]; t x; } > ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \ > (void)0))))) > #define ____bpf_ctx_arg0(n, args...) > @@ -486,7 +492,7 @@ ____##name(unsigned long long *ctx, ##args) > #define ____bpf_ctx_arg10(n, t, x, args...) , ____bpf_union_arg(t, x, n > - ____bpf_reg_cnt10(t, x, args)) ____bpf_ctx_arg9(n, args) > #define ____bpf_ctx_arg11(n, t, x, args...) , ____bpf_union_arg(t, x, n > - ____bpf_reg_cnt11(t, x, args)) ____bpf_ctx_arg10(n, args) > #define ____bpf_ctx_arg12(n, t, x, args...) , ____bpf_union_arg(t, x, n > - ____bpf_reg_cnt12(t, x, args)) ____bpf_ctx_arg11(n, args) > -#define ____bpf_ctx_arg(n, args...) ___bpf_apply(____bpf_ctx_arg, > ____bpf_narg(args))(n, args) > +#define ____bpf_ctx_arg(args...) ___bpf_apply(____bpf_ctx_arg, > ___bpf_narg2(args))(____bpf_reg_cnt(args), args) > #define ____bpf_ctx_decl0() > #define ____bpf_ctx_decl1(t, x) , t x > @@ -501,10 +507,21 @@ ____##name(unsigned long long *ctx, ##args) > #define ____bpf_ctx_decl10(t, x, args...) , t x ____bpf_ctx_decl9(args) > #define ____bpf_ctx_decl11(t, x, args...) , t x ____bpf_ctx_decl10(args) > #define ____bpf_ctx_decl12(t, x, args...) , t x ____bpf_ctx_decl11(args) > -#define ____bpf_ctx_decl(args...) ___bpf_apply(____bpf_ctx_decl, > ____bpf_narg(args))(args) > +#define ____bpf_ctx_decl(args...) ___bpf_apply(____bpf_ctx_decl, > ___bpf_narg2(args))(args) > /* > - * BPF_PROG2 can handle struct arguments. > + * BPF_PROG2 is an enhanced version of BPF_PROG in order to handle struct > + * arguments. Since each struct argument might take one or two u64 values > + * in the trampoline stack, argument type size is needed to place proper > number > + * of u64 values for each argument. Therefore, BPF_PROG2 has different > + * syntax from BPF_PROG. For example, for the following BPF_PROG syntax, > + * int BPF_PROG(test2, int a, int b) > + * the corresponding BPF_PROG2 synx is, > + * int BPF_PROG2(test2, int, a, int, b) > + * where type and the corresponding argument name are separated by comma. > + * If one or more argument is of struct type, BPF_PROG2 macro should be > used, > + * int BPF_PROG2(test_struct_arg, struct bpf_testmod_struct_arg_1, a, > int, b, > + * int, c, int, d, struct bpf_testmod_struct_arg_2, e, int, ret) > */ > #define BPF_PROG2(name, args...) \ > name(unsigned long long *ctx); \ > @@ -512,7 +529,7 @@ static __always_inline typeof(name(0)) \ > ____##name(unsigned long long *ctx ____bpf_ctx_decl(args)); \ > typeof(name(0)) name(unsigned long long *ctx) \ > { \ > - return ____##name(ctx ____bpf_ctx_arg(____bpf_reg_cnt(args), args)); \ > + return ____##name(ctx ____bpf_ctx_arg(args)); \ > } \ > static __always_inline typeof(name(0)) \ > ____##name(unsigned long long *ctx ____bpf_ctx_decl(args)) > -- > 2.30.2
On Sat, Sep 10, 2022 at 1:35 PM <sdf@google.com> wrote: > > On 09/09, Yonghong Song wrote: > > Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 > > macro for trampoline based programs with struct arguments. Andrii > > made a few suggestions to improve code quality and description. > > This patch implemented these suggestions including better internal > > macro name, consistent usage pattern for __builtin_choose_expr(), > > simpler macro definition for always-inline func arguments and > > better macro description. > > Not sure if Andrii wants to take a look, if not feel free to use: > Andrii wanted to :) But thanks for looking and acking as well. I've slightly reformatted the "doccomment" for BPF_PROG2 and also removed other uses of quadruple underscore for consistency. Thanks. Applied to bpf-next. > Acked-by: Stanislav Fomichev <sdf@google.com> > > > Signed-off-by: Yonghong Song <yhs@fb.com> > > --- > > tools/lib/bpf/bpf_tracing.h | 77 ++++++++++++++++++++++--------------- > > 1 file changed, 47 insertions(+), 30 deletions(-) > > > diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h > > index 8d4bdd18cb3d..a71ca48ea479 100644 > > --- a/tools/lib/bpf/bpf_tracing.h > > +++ b/tools/lib/bpf/bpf_tracing.h > > @@ -438,39 +438,45 @@ typeof(name(0)) name(unsigned long long *ctx) > > \ > > static __always_inline typeof(name(0)) \ > > ____##name(unsigned long long *ctx, ##args) >
Hello: This patch was applied to bpf/bpf-next.git (master) by Andrii Nakryiko <andrii@kernel.org>: On Fri, 9 Sep 2022 19:52:14 -0700 you wrote: > Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 > macro for trampoline based programs with struct arguments. Andrii > made a few suggestions to improve code quality and description. > This patch implemented these suggestions including better internal > macro name, consistent usage pattern for __builtin_choose_expr(), > simpler macro definition for always-inline func arguments and > better macro description. > > [...] Here is the summary with links: - [bpf-next] libbpf: Improve BPF_PROG2 macro code quality and description https://git.kernel.org/bpf/bpf-next/c/9f2f5d7830dd You are awesome, thank you!
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index 8d4bdd18cb3d..a71ca48ea479 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -438,39 +438,45 @@ typeof(name(0)) name(unsigned long long *ctx) \ static __always_inline typeof(name(0)) \ ____##name(unsigned long long *ctx, ##args) -#ifndef ____bpf_nth -#define ____bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N +#ifndef ___bpf_nth2 +#define ___bpf_nth2(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, \ + _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N #endif -#ifndef ____bpf_narg -#define ____bpf_narg(...) ____bpf_nth(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) +#ifndef ___bpf_narg2 +#define ___bpf_narg2(...) \ + ___bpf_nth2(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, \ + 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) #endif -#define BPF_REG_CNT(t) \ - (__builtin_choose_expr(sizeof(t) == 1 || sizeof(t) == 2 || sizeof(t) == 4 || sizeof(t) == 8, 1, \ - __builtin_choose_expr(sizeof(t) == 16, 2, \ - (void)0))) +#define ___bpf_reg_cnt(t) \ + __builtin_choose_expr(sizeof(t) == 1, 1, \ + __builtin_choose_expr(sizeof(t) == 2, 1, \ + __builtin_choose_expr(sizeof(t) == 4, 1, \ + __builtin_choose_expr(sizeof(t) == 8, 1, \ + __builtin_choose_expr(sizeof(t) == 16, 2, \ + (void)0))))) #define ____bpf_reg_cnt0() (0) -#define ____bpf_reg_cnt1(t, x) (____bpf_reg_cnt0() + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt2(t, x, args...) (____bpf_reg_cnt1(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt3(t, x, args...) (____bpf_reg_cnt2(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt4(t, x, args...) (____bpf_reg_cnt3(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt5(t, x, args...) (____bpf_reg_cnt4(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt6(t, x, args...) (____bpf_reg_cnt5(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt7(t, x, args...) (____bpf_reg_cnt6(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt8(t, x, args...) (____bpf_reg_cnt7(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt9(t, x, args...) (____bpf_reg_cnt8(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt10(t, x, args...) (____bpf_reg_cnt9(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt11(t, x, args...) (____bpf_reg_cnt10(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt12(t, x, args...) (____bpf_reg_cnt11(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt(args...) ___bpf_apply(____bpf_reg_cnt, ____bpf_narg(args))(args) +#define ____bpf_reg_cnt1(t, x) (____bpf_reg_cnt0() + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt2(t, x, args...) (____bpf_reg_cnt1(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt3(t, x, args...) (____bpf_reg_cnt2(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt4(t, x, args...) (____bpf_reg_cnt3(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt5(t, x, args...) (____bpf_reg_cnt4(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt6(t, x, args...) (____bpf_reg_cnt5(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt7(t, x, args...) (____bpf_reg_cnt6(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt8(t, x, args...) (____bpf_reg_cnt7(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt9(t, x, args...) (____bpf_reg_cnt8(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt10(t, x, args...) (____bpf_reg_cnt9(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt11(t, x, args...) (____bpf_reg_cnt10(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt12(t, x, args...) (____bpf_reg_cnt11(args) + ___bpf_reg_cnt(t)) +#define ____bpf_reg_cnt(args...) ___bpf_apply(____bpf_reg_cnt, ___bpf_narg2(args))(args) #define ____bpf_union_arg(t, x, n) \ - __builtin_choose_expr(sizeof(t) == 1, ({ union { struct { __u8 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 2, ({ union { struct { __u16 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 4, ({ union { struct { __u32 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 8, ({ union { struct { __u64 x; } ___z; t x; } ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 16, ({ union { struct { __u64 x, y; } ___z; t x; } ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 1, ({ union { __u8 ___z[1]; t x; } ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 2, ({ union { __u16 ___z[1]; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 4, ({ union { __u32 ___z[1]; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 8, ({ union { __u64 ___z[1]; t x; } ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 16, ({ union { __u64 ___z[2]; t x; } ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \ (void)0))))) #define ____bpf_ctx_arg0(n, args...) @@ -486,7 +492,7 @@ ____##name(unsigned long long *ctx, ##args) #define ____bpf_ctx_arg10(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt10(t, x, args)) ____bpf_ctx_arg9(n, args) #define ____bpf_ctx_arg11(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt11(t, x, args)) ____bpf_ctx_arg10(n, args) #define ____bpf_ctx_arg12(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt12(t, x, args)) ____bpf_ctx_arg11(n, args) -#define ____bpf_ctx_arg(n, args...) ___bpf_apply(____bpf_ctx_arg, ____bpf_narg(args))(n, args) +#define ____bpf_ctx_arg(args...) ___bpf_apply(____bpf_ctx_arg, ___bpf_narg2(args))(____bpf_reg_cnt(args), args) #define ____bpf_ctx_decl0() #define ____bpf_ctx_decl1(t, x) , t x @@ -501,10 +507,21 @@ ____##name(unsigned long long *ctx, ##args) #define ____bpf_ctx_decl10(t, x, args...) , t x ____bpf_ctx_decl9(args) #define ____bpf_ctx_decl11(t, x, args...) , t x ____bpf_ctx_decl10(args) #define ____bpf_ctx_decl12(t, x, args...) , t x ____bpf_ctx_decl11(args) -#define ____bpf_ctx_decl(args...) ___bpf_apply(____bpf_ctx_decl, ____bpf_narg(args))(args) +#define ____bpf_ctx_decl(args...) ___bpf_apply(____bpf_ctx_decl, ___bpf_narg2(args))(args) /* - * BPF_PROG2 can handle struct arguments. + * BPF_PROG2 is an enhanced version of BPF_PROG in order to handle struct + * arguments. Since each struct argument might take one or two u64 values + * in the trampoline stack, argument type size is needed to place proper number + * of u64 values for each argument. Therefore, BPF_PROG2 has different + * syntax from BPF_PROG. For example, for the following BPF_PROG syntax, + * int BPF_PROG(test2, int a, int b) + * the corresponding BPF_PROG2 synx is, + * int BPF_PROG2(test2, int, a, int, b) + * where type and the corresponding argument name are separated by comma. + * If one or more argument is of struct type, BPF_PROG2 macro should be used, + * int BPF_PROG2(test_struct_arg, struct bpf_testmod_struct_arg_1, a, int, b, + * int, c, int, d, struct bpf_testmod_struct_arg_2, e, int, ret) */ #define BPF_PROG2(name, args...) \ name(unsigned long long *ctx); \ @@ -512,7 +529,7 @@ static __always_inline typeof(name(0)) \ ____##name(unsigned long long *ctx ____bpf_ctx_decl(args)); \ typeof(name(0)) name(unsigned long long *ctx) \ { \ - return ____##name(ctx ____bpf_ctx_arg(____bpf_reg_cnt(args), args)); \ + return ____##name(ctx ____bpf_ctx_arg(args)); \ } \ static __always_inline typeof(name(0)) \ ____##name(unsigned long long *ctx ____bpf_ctx_decl(args))
Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 macro for trampoline based programs with struct arguments. Andrii made a few suggestions to improve code quality and description. This patch implemented these suggestions including better internal macro name, consistent usage pattern for __builtin_choose_expr(), simpler macro definition for always-inline func arguments and better macro description. Signed-off-by: Yonghong Song <yhs@fb.com> --- tools/lib/bpf/bpf_tracing.h | 77 ++++++++++++++++++++++--------------- 1 file changed, 47 insertions(+), 30 deletions(-)