diff mbox series

[v2,bpf-next,3/5] bpftool: Generalize light skeleton generation.

Message ID 20220208191306.6136-4-alexei.starovoitov@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf: Light skeleton for the kernel. | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR fail PR summary
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 7 maintainers not CCed: kpsingh@kernel.org john.fastabend@gmail.com kafai@fb.com songliubraving@fb.com ast@kernel.org yhs@fb.com netdev@vger.kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: Avoid line continuations in quoted strings WARNING: line length of 107 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns WARNING: line length of 96 exceeds 80 columns WARNING: quoted string split across lines WARNING: unnecessary whitespace before a quoted newline
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next fail VM_Test

Commit Message

Alexei Starovoitov Feb. 8, 2022, 7:13 p.m. UTC 
From: Alexei Starovoitov <ast@kernel.org>

Generealize light skeleton by hiding mmap details in skel_internal.h
In this form generated lskel.h is usable both by user space and by the kernel.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 tools/bpf/bpftool/gen.c | 45 ++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 18 deletions(-)

Comments

Yonghong Song Feb. 9, 2022, 12:25 a.m. UTC | #1 
On 2/8/22 11:13 AM, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.org>
> 
> Generealize light skeleton by hiding mmap details in skel_internal.h
> In this form generated lskel.h is usable both by user space and by the kernel.
> 
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---
>   tools/bpf/bpftool/gen.c | 45 ++++++++++++++++++++++++-----------------
>   1 file changed, 27 insertions(+), 18 deletions(-)
> 
> diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
> index eacfc6a2060d..903abbf077ce 100644
> --- a/tools/bpf/bpftool/gen.c
> +++ b/tools/bpf/bpftool/gen.c
> @@ -472,7 +472,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
>   			continue;
>   		if (bpf_map__is_internal(map) &&
>   		    (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
> -			printf("\tmunmap(skel->%1$s, %2$zd);\n",
> +			printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
>   			       ident, bpf_map_mmap_sz(map));
>   		codegen("\
>   			\n\
> @@ -481,7 +481,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
>   	}
>   	codegen("\
>   		\n\
> -			free(skel);					    \n\
> +			skel_free(skel);				    \n\
>   		}							    \n\
>   		",
>   		obj_name);
> @@ -525,7 +525,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>   		{							    \n\
>   			struct %1$s *skel;				    \n\
>   									    \n\
> -			skel = calloc(sizeof(*skel), 1);		    \n\
> +			skel = skel_alloc(sizeof(*skel));		    \n\
>   			if (!skel)					    \n\
>   				goto cleanup;				    \n\
>   			skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
> @@ -544,18 +544,12 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>   
>   		codegen("\
>   			\n\
> -				skel->%1$s =					 \n\
> -					mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
> -					     MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
> -				if (skel->%1$s == (void *) -1)			 \n\
> -					goto cleanup;				 \n\
> -				memcpy(skel->%1$s, (void *)\"\\			 \n\
> -			", ident, bpf_map_mmap_sz(map));
> +				skel->%1$s = skel_prep_map_data((void *)\"\\	 \n\
> +			", ident);
>   		mmap_data = bpf_map__initial_value(map, &mmap_size);
>   		print_hex(mmap_data, mmap_size);
> -		printf("\", %2$zd);\n"
> -		       "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
> -		       ident, mmap_size);
> +		printf("\", %1$zd, %2$zd);\n",
> +		       bpf_map_mmap_sz(map), mmap_size);
>   	}
>   	codegen("\
>   		\n\
> @@ -592,6 +586,24 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>   	codegen("\
>   		\n\
>   		\";							    \n\
> +		");
> +	bpf_object__for_each_map(map, obj) {
> +		size_t mmap_size = 0;
> +
> +		if (!get_map_ident(map, ident, sizeof(ident)))
> +			continue;
> +
> +		if (!bpf_map__is_internal(map) ||
> +		    !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
> +			continue;
> +
> +		bpf_map__initial_value(map, &mmap_size);
> +		printf("\tskel->maps.%1$s.initial_value ="
> +		       " skel_prep_init_value((void **)&skel->%1$s, %2$zd, %3$zd);\n",
> +		       ident, bpf_map_mmap_sz(map), mmap_size);
> +	}
> +	codegen("\
> +		\n\
>   			err = bpf_load_and_run(&opts);			    \n\
>   			if (err < 0)					    \n\
>   				return err;				    \n\
> @@ -611,9 +623,8 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>   		else
>   			mmap_flags = "PROT_READ | PROT_WRITE";
>   
> -		printf("\tskel->%1$s =\n"
> -		       "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
> -		       "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
> +		printf("\tskel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value,\n"
> +		       "\t\t\t%2$zd, %3$s, skel->maps.%1$s.map_fd);\n",
>   		       ident, bpf_map_mmap_sz(map), mmap_flags);
>   	}
>   	codegen("\
> @@ -751,8 +762,6 @@ static int do_skeleton(int argc, char **argv)
>   		#ifndef %2$s						    \n\
>   		#define %2$s						    \n\
>   									    \n\
> -		#include <stdlib.h>					    \n\
> -		#include <bpf/bpf.h>					    \n\

I noticed that in patch2, the "bpf.h" is used instead of <bpf/bpf.h>.
Any particular reason for this or it is a bug fix?


>   		#include <bpf/skel_internal.h>				    \n\
>   									    \n\
>   		struct %1$s {						    \n\
Alexei Starovoitov Feb. 9, 2022, 12:52 a.m. UTC | #2 
On Tue, Feb 08, 2022 at 04:25:15PM -0800, Yonghong Song wrote:
> 
> 
> On 2/8/22 11:13 AM, Alexei Starovoitov wrote:
> > From: Alexei Starovoitov <ast@kernel.org>
> > 
> > Generealize light skeleton by hiding mmap details in skel_internal.h
> > In this form generated lskel.h is usable both by user space and by the kernel.
> > 
> > Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> > ---
> >   tools/bpf/bpftool/gen.c | 45 ++++++++++++++++++++++++-----------------
> >   1 file changed, 27 insertions(+), 18 deletions(-)
> > 
> > diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
> > index eacfc6a2060d..903abbf077ce 100644
> > --- a/tools/bpf/bpftool/gen.c
> > +++ b/tools/bpf/bpftool/gen.c
> > @@ -472,7 +472,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
> >   			continue;
> >   		if (bpf_map__is_internal(map) &&
> >   		    (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
> > -			printf("\tmunmap(skel->%1$s, %2$zd);\n",
> > +			printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
> >   			       ident, bpf_map_mmap_sz(map));
> >   		codegen("\
> >   			\n\
> > @@ -481,7 +481,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
> >   	}
> >   	codegen("\
> >   		\n\
> > -			free(skel);					    \n\
> > +			skel_free(skel);				    \n\
> >   		}							    \n\
> >   		",
> >   		obj_name);
> > @@ -525,7 +525,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
> >   		{							    \n\
> >   			struct %1$s *skel;				    \n\
> >   									    \n\
> > -			skel = calloc(sizeof(*skel), 1);		    \n\
> > +			skel = skel_alloc(sizeof(*skel));		    \n\
> >   			if (!skel)					    \n\
> >   				goto cleanup;				    \n\
> >   			skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
> > @@ -544,18 +544,12 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
> >   		codegen("\
> >   			\n\
> > -				skel->%1$s =					 \n\
> > -					mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
> > -					     MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
> > -				if (skel->%1$s == (void *) -1)			 \n\
> > -					goto cleanup;				 \n\
> > -				memcpy(skel->%1$s, (void *)\"\\			 \n\
> > -			", ident, bpf_map_mmap_sz(map));
> > +				skel->%1$s = skel_prep_map_data((void *)\"\\	 \n\
> > +			", ident);
> >   		mmap_data = bpf_map__initial_value(map, &mmap_size);
> >   		print_hex(mmap_data, mmap_size);
> > -		printf("\", %2$zd);\n"
> > -		       "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
> > -		       ident, mmap_size);
> > +		printf("\", %1$zd, %2$zd);\n",
> > +		       bpf_map_mmap_sz(map), mmap_size);
> >   	}
> >   	codegen("\
> >   		\n\
> > @@ -592,6 +586,24 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
> >   	codegen("\
> >   		\n\
> >   		\";							    \n\
> > +		");
> > +	bpf_object__for_each_map(map, obj) {
> > +		size_t mmap_size = 0;
> > +
> > +		if (!get_map_ident(map, ident, sizeof(ident)))
> > +			continue;
> > +
> > +		if (!bpf_map__is_internal(map) ||
> > +		    !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
> > +			continue;
> > +
> > +		bpf_map__initial_value(map, &mmap_size);
> > +		printf("\tskel->maps.%1$s.initial_value ="
> > +		       " skel_prep_init_value((void **)&skel->%1$s, %2$zd, %3$zd);\n",
> > +		       ident, bpf_map_mmap_sz(map), mmap_size);
> > +	}
> > +	codegen("\
> > +		\n\
> >   			err = bpf_load_and_run(&opts);			    \n\
> >   			if (err < 0)					    \n\
> >   				return err;				    \n\
> > @@ -611,9 +623,8 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
> >   		else
> >   			mmap_flags = "PROT_READ | PROT_WRITE";
> > -		printf("\tskel->%1$s =\n"
> > -		       "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
> > -		       "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
> > +		printf("\tskel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value,\n"
> > +		       "\t\t\t%2$zd, %3$s, skel->maps.%1$s.map_fd);\n",
> >   		       ident, bpf_map_mmap_sz(map), mmap_flags);
> >   	}
> >   	codegen("\
> > @@ -751,8 +762,6 @@ static int do_skeleton(int argc, char **argv)
> >   		#ifndef %2$s						    \n\
> >   		#define %2$s						    \n\
> >   									    \n\
> > -		#include <stdlib.h>					    \n\
> > -		#include <bpf/bpf.h>					    \n\
> 
> I noticed that in patch2, the "bpf.h" is used instead of <bpf/bpf.h>.
> Any particular reason for this or it is a bug fix?

skel_internal.h didn't include bpf.h directly.
gen_loader.c needs it. It does:
#include "skel_internal.h"
because gen_loader.c is part of libbpf.
libbpf sources cannot do #include <bpf/...>

If skel_internal.h did
#include <bpf/bpf.h>
there would be a build error:
In file included from gen_loader.c:15:
skel_internal.h:17:10: fatal error: bpf/bpf.h: No such file or directory
 #include <bpf/bpf.h>

Hence #include "bpf.h" in skel_internal.h
So it works for libbpf's gen_loader.c and for generated lskel.h too.
Yonghong Song Feb. 9, 2022, 1:38 a.m. UTC | #3 
On 2/8/22 4:52 PM, Alexei Starovoitov wrote:
> On Tue, Feb 08, 2022 at 04:25:15PM -0800, Yonghong Song wrote:
>>
>>
>> On 2/8/22 11:13 AM, Alexei Starovoitov wrote:
>>> From: Alexei Starovoitov <ast@kernel.org>
>>>
>>> Generealize light skeleton by hiding mmap details in skel_internal.h
>>> In this form generated lskel.h is usable both by user space and by the kernel.
>>>
>>> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
>>> ---
>>>    tools/bpf/bpftool/gen.c | 45 ++++++++++++++++++++++++-----------------
>>>    1 file changed, 27 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
>>> index eacfc6a2060d..903abbf077ce 100644
>>> --- a/tools/bpf/bpftool/gen.c
>>> +++ b/tools/bpf/bpftool/gen.c
>>> @@ -472,7 +472,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
>>>    			continue;
>>>    		if (bpf_map__is_internal(map) &&
>>>    		    (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
>>> -			printf("\tmunmap(skel->%1$s, %2$zd);\n",
>>> +			printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
>>>    			       ident, bpf_map_mmap_sz(map));
>>>    		codegen("\
>>>    			\n\
>>> @@ -481,7 +481,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
>>>    	}
>>>    	codegen("\
>>>    		\n\
>>> -			free(skel);					    \n\
>>> +			skel_free(skel);				    \n\
>>>    		}							    \n\
>>>    		",
>>>    		obj_name);
>>> @@ -525,7 +525,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>>>    		{							    \n\
>>>    			struct %1$s *skel;				    \n\
>>>    									    \n\
>>> -			skel = calloc(sizeof(*skel), 1);		    \n\
>>> +			skel = skel_alloc(sizeof(*skel));		    \n\
>>>    			if (!skel)					    \n\
>>>    				goto cleanup;				    \n\
>>>    			skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
>>> @@ -544,18 +544,12 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>>>    		codegen("\
>>>    			\n\
>>> -				skel->%1$s =					 \n\
>>> -					mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
>>> -					     MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
>>> -				if (skel->%1$s == (void *) -1)			 \n\
>>> -					goto cleanup;				 \n\
>>> -				memcpy(skel->%1$s, (void *)\"\\			 \n\
>>> -			", ident, bpf_map_mmap_sz(map));
>>> +				skel->%1$s = skel_prep_map_data((void *)\"\\	 \n\
>>> +			", ident);
>>>    		mmap_data = bpf_map__initial_value(map, &mmap_size);
>>>    		print_hex(mmap_data, mmap_size);
>>> -		printf("\", %2$zd);\n"
>>> -		       "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
>>> -		       ident, mmap_size);
>>> +		printf("\", %1$zd, %2$zd);\n",
>>> +		       bpf_map_mmap_sz(map), mmap_size);
>>>    	}
>>>    	codegen("\
>>>    		\n\
>>> @@ -592,6 +586,24 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>>>    	codegen("\
>>>    		\n\
>>>    		\";							    \n\
>>> +		");
>>> +	bpf_object__for_each_map(map, obj) {
>>> +		size_t mmap_size = 0;
>>> +
>>> +		if (!get_map_ident(map, ident, sizeof(ident)))
>>> +			continue;
>>> +
>>> +		if (!bpf_map__is_internal(map) ||
>>> +		    !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
>>> +			continue;
>>> +
>>> +		bpf_map__initial_value(map, &mmap_size);
>>> +		printf("\tskel->maps.%1$s.initial_value ="
>>> +		       " skel_prep_init_value((void **)&skel->%1$s, %2$zd, %3$zd);\n",
>>> +		       ident, bpf_map_mmap_sz(map), mmap_size);
>>> +	}
>>> +	codegen("\
>>> +		\n\
>>>    			err = bpf_load_and_run(&opts);			    \n\
>>>    			if (err < 0)					    \n\
>>>    				return err;				    \n\
>>> @@ -611,9 +623,8 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
>>>    		else
>>>    			mmap_flags = "PROT_READ | PROT_WRITE";
>>> -		printf("\tskel->%1$s =\n"
>>> -		       "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
>>> -		       "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
>>> +		printf("\tskel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value,\n"
>>> +		       "\t\t\t%2$zd, %3$s, skel->maps.%1$s.map_fd);\n",
>>>    		       ident, bpf_map_mmap_sz(map), mmap_flags);
>>>    	}
>>>    	codegen("\
>>> @@ -751,8 +762,6 @@ static int do_skeleton(int argc, char **argv)
>>>    		#ifndef %2$s						    \n\
>>>    		#define %2$s						    \n\
>>>    									    \n\
>>> -		#include <stdlib.h>					    \n\
>>> -		#include <bpf/bpf.h>					    \n\
>>
>> I noticed that in patch2, the "bpf.h" is used instead of <bpf/bpf.h>.
>> Any particular reason for this or it is a bug fix?
> 
> skel_internal.h didn't include bpf.h directly.
> gen_loader.c needs it. It does:
> #include "skel_internal.h"
> because gen_loader.c is part of libbpf.
> libbpf sources cannot do #include <bpf/...>
> 
> If skel_internal.h did
> #include <bpf/bpf.h>
> there would be a build error:
> In file included from gen_loader.c:15:
> skel_internal.h:17:10: fatal error: bpf/bpf.h: No such file or directory
>   #include <bpf/bpf.h>
> 
> Hence #include "bpf.h" in skel_internal.h
> So it works for libbpf's gen_loader.c and for generated lskel.h too.

Okay, now I understand, previously <bpf/bpf.h> is in *.lskel.h file, 
which has nothing to do with gen_loader.c, and now the bpf.h header
needs to be in skel_internal.h which will impact gen_loader.c compilation.

Acked-by: Yonghong Song <yhs@fb.com>
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index eacfc6a2060d..903abbf077ce 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -472,7 +472,7 @@  static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
 			continue;
 		if (bpf_map__is_internal(map) &&
 		    (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
-			printf("\tmunmap(skel->%1$s, %2$zd);\n",
+			printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
 			       ident, bpf_map_mmap_sz(map));
 		codegen("\
 			\n\
@@ -481,7 +481,7 @@  static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
 	}
 	codegen("\
 		\n\
-			free(skel);					    \n\
+			skel_free(skel);				    \n\
 		}							    \n\
 		",
 		obj_name);
@@ -525,7 +525,7 @@  static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
 		{							    \n\
 			struct %1$s *skel;				    \n\
 									    \n\
-			skel = calloc(sizeof(*skel), 1);		    \n\
+			skel = skel_alloc(sizeof(*skel));		    \n\
 			if (!skel)					    \n\
 				goto cleanup;				    \n\
 			skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
@@ -544,18 +544,12 @@  static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
 
 		codegen("\
 			\n\
-				skel->%1$s =					 \n\
-					mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
-					     MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
-				if (skel->%1$s == (void *) -1)			 \n\
-					goto cleanup;				 \n\
-				memcpy(skel->%1$s, (void *)\"\\			 \n\
-			", ident, bpf_map_mmap_sz(map));
+				skel->%1$s = skel_prep_map_data((void *)\"\\	 \n\
+			", ident);
 		mmap_data = bpf_map__initial_value(map, &mmap_size);
 		print_hex(mmap_data, mmap_size);
-		printf("\", %2$zd);\n"
-		       "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
-		       ident, mmap_size);
+		printf("\", %1$zd, %2$zd);\n",
+		       bpf_map_mmap_sz(map), mmap_size);
 	}
 	codegen("\
 		\n\
@@ -592,6 +586,24 @@  static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
 	codegen("\
 		\n\
 		\";							    \n\
+		");
+	bpf_object__for_each_map(map, obj) {
+		size_t mmap_size = 0;
+
+		if (!get_map_ident(map, ident, sizeof(ident)))
+			continue;
+
+		if (!bpf_map__is_internal(map) ||
+		    !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
+			continue;
+
+		bpf_map__initial_value(map, &mmap_size);
+		printf("\tskel->maps.%1$s.initial_value ="
+		       " skel_prep_init_value((void **)&skel->%1$s, %2$zd, %3$zd);\n",
+		       ident, bpf_map_mmap_sz(map), mmap_size);
+	}
+	codegen("\
+		\n\
 			err = bpf_load_and_run(&opts);			    \n\
 			if (err < 0)					    \n\
 				return err;				    \n\
@@ -611,9 +623,8 @@  static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
 		else
 			mmap_flags = "PROT_READ | PROT_WRITE";
 
-		printf("\tskel->%1$s =\n"
-		       "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
-		       "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
+		printf("\tskel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value,\n"
+		       "\t\t\t%2$zd, %3$s, skel->maps.%1$s.map_fd);\n",
 		       ident, bpf_map_mmap_sz(map), mmap_flags);
 	}
 	codegen("\
@@ -751,8 +762,6 @@  static int do_skeleton(int argc, char **argv)
 		#ifndef %2$s						    \n\
 		#define %2$s						    \n\
 									    \n\
-		#include <stdlib.h>					    \n\
-		#include <bpf/bpf.h>					    \n\
 		#include <bpf/skel_internal.h>				    \n\
 									    \n\
 		struct %1$s {						    \n\