[PATCH 21/46] btf, lto: pass scope as strings

[PATCH 21/46] btf, lto: pass scope as strings

[Jiri Slaby (SUSE)]

From: Jiri Slaby <jslaby@suse.cz>

gcc LTO can put assembler top level statements into other assembler
files. The BTF IDs assumed that they are in the same file. We need to
make all BTF IDs global to work around this.

This is a preparation for that, as we will pass __global_on_lto as
scope. That is macro that expands either to "globl" or "local" depending
whether LTO is enabled.

That wouldn't work without this patch as we stringify scope at the
moment.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Cc: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 include/linux/btf_ids.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 2aea877d644f..3011757a48ef 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -83,16 +83,16 @@ word							\
 #define __BTF_ID_LIST(name, scope)			\
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
-"." #scope " " #name ";                        \n"	\
+"." scope " " #name ";                         \n"	\
 #name ":;                                      \n"	\
 ".popsection;                                  \n");
 
 #define BTF_ID_LIST(name)				\
-__BTF_ID_LIST(name, local)				\
+__BTF_ID_LIST(name, "local")				\
 extern u32 name[];
 
 #define BTF_ID_LIST_GLOBAL(name, n)			\
-__BTF_ID_LIST(name, globl)
+__BTF_ID_LIST(name, "globl")
 
 /* The BTF_ID_LIST_SINGLE macro defines a BTF_ID_LIST with
  * a single entry.
@@ -142,18 +142,18 @@ asm(							\
 #define __BTF_SET_START(name, scope)			\
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
-"." #scope " __BTF_ID__set__" #name ";         \n"	\
+"." scope " __BTF_ID__set__" #name ";          \n"	\
 "__BTF_ID__set__" #name ":;                    \n"	\
 ".zero 4                                       \n"	\
 ".popsection;                                  \n");
 
 #define BTF_SET_START(name)				\
-__BTF_ID_LIST(name, local)				\
-__BTF_SET_START(name, local)
+__BTF_ID_LIST(name, "local")				\
+__BTF_SET_START(name, "local")
 
 #define BTF_SET_START_GLOBAL(name)			\
-__BTF_ID_LIST(name, globl)				\
-__BTF_SET_START(name, globl)
+__BTF_ID_LIST(name, "globl")				\
+__BTF_SET_START(name, "globl")
 
 #define BTF_SET_END(name)				\
 asm(							\
@@ -186,14 +186,14 @@ extern struct btf_id_set name;
 #define __BTF_SET8_START(name, scope)			\
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
-"." #scope " __BTF_ID__set8__" #name ";        \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)
+__BTF_ID_LIST(name, "local")				\
+__BTF_SET8_START(name, "local")
 
 #define BTF_SET8_END(name)				\
 asm(							\
-- 
2.38.1

[PATCH 22/46] btf, lto: Make all BTF IDs global on LTO

[Jiri Slaby (SUSE)]

From: Andi Kleen <andi@firstfloor.org>

gcc LTO can put assembler top level statements into other assembler
files. The BTF IDs assumed that they are in the same file. So if we are
building with gcc LTO, make all BTF IDs global to work around this.

This is done by new __global_on_lto macro.

[js] do that for 8B BTF set too (commit ab21d6063c01)
[js] do global only in LTO case

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 include/linux/btf_ids.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 3011757a48ef..a2bef302e42c 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -37,7 +37,7 @@ struct btf_id_set8 {
 #define ____BTF_ID(symbol, word)			\
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
-".local " #symbol " ;                          \n"	\
+"." __global_on_lto " " #symbol " ;            \n"	\
 ".type  " #symbol ", STT_OBJECT;               \n"	\
 ".size  " #symbol ", 4;                        \n"	\
 #symbol ":                                     \n"	\
@@ -88,7 +88,7 @@ asm(							\
 ".popsection;                                  \n");
 
 #define BTF_ID_LIST(name)				\
-__BTF_ID_LIST(name, "local")				\
+__BTF_ID_LIST(name, __global_on_lto)			\
 extern u32 name[];
 
 #define BTF_ID_LIST_GLOBAL(name, n)			\
@@ -148,8 +148,8 @@ asm(							\
 ".popsection;                                  \n");
 
 #define BTF_SET_START(name)				\
-__BTF_ID_LIST(name, "local")				\
-__BTF_SET_START(name, "local")
+__BTF_ID_LIST(name, __global_on_lto)			\
+__BTF_SET_START(name, __global_on_lto)
 
 #define BTF_SET_START_GLOBAL(name)			\
 __BTF_ID_LIST(name, "globl")				\
@@ -192,8 +192,8 @@ asm(							\
 ".popsection;                                  \n");
 
 #define BTF_SET8_START(name)				\
-__BTF_ID_LIST(name, "local")				\
-__BTF_SET8_START(name, "local")
+__BTF_ID_LIST(name, __global_on_lto)			\
+__BTF_SET8_START(name, __global_on_lto)
 
 #define BTF_SET8_END(name)				\
 asm(							\
-- 
2.38.1

[PATCH 24/46] bpf, lto: mark interpreter jump table as __noreorder

[Jiri Slaby (SUSE)]

From: Andi Kleen <ak@linux.intel.com>

gcc LTO has a problem that can cause static variables containing &&
labels to be put into a different LTO partition and then fail the build.
This can happen with the jump table in the BPF interprer.

Mark the interpreter function and the jump table as __noreorder, this
guarantees they both end up in the first partition.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 kernel/bpf/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 25a54e04560e..d40ce00622f6 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1640,7 +1640,7 @@ u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
  *
  * Return: whatever value is in %BPF_R0 at program exit
  */
-static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
+static u64 __noreorder ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
 {
 #define BPF_INSN_2_LBL(x, y)    [BPF_##x | BPF_##y] = &&x##_##y
 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
-- 
2.38.1