[PATCH bpf-next v3 4/6] lib/Kconfig.debug: Set the minimum required pahole version to v1.22

[Ihor Solodrai <ihor.solodrai@linux.dev>]

Subsequent patches in the series change vmlinux linking scripts to
unconditionally pass --btf_encode_detached to pahole, which was
introduced in v1.22 [1][2].

This change allows to remove PAHOLE_HAS_SPLIT_BTF Kconfig option and
other checks of older pahole versions.

[1] https://github.com/acmel/dwarves/releases/tag/v1.22
[2] https://lore.kernel.org/bpf/cbafbf4e-9073-4383-8ee6-1353f9e5869c@oracle.com/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
 lib/Kconfig.debug         | 13 ++++---------
 scripts/Makefile.btf      |  9 +--------
 tools/sched_ext/README.md |  1 -
 3 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 742b23ef0d8b..3abf3ae554b6 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -389,18 +389,13 @@ config DEBUG_INFO_BTF
 	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
 	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
 	depends on BPF_SYSCALL
-	depends on PAHOLE_VERSION >= 116
-	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
+	depends on PAHOLE_VERSION >= 122
 	# pahole uses elfutils, which does not have support for Hexagon relocations
 	depends on !HEXAGON
 	help
 	  Generate deduplicated BTF type information from DWARF debug info.
-	  Turning this on requires pahole v1.16 or later (v1.21 or later to
-	  support DWARF 5), which will convert DWARF type info into equivalent
-	  deduplicated BTF type info.
-
-config PAHOLE_HAS_SPLIT_BTF
-	def_bool PAHOLE_VERSION >= 119
+	  Turning this on requires pahole v1.22 or later, which will convert
+	  DWARF type info into equivalent deduplicated BTF type info.
 
 config PAHOLE_HAS_BTF_TAG
 	def_bool PAHOLE_VERSION >= 123
@@ -422,7 +417,7 @@ config PAHOLE_HAS_LANG_EXCLUDE
 config DEBUG_INFO_BTF_MODULES
 	bool "Generate BTF type information for kernel modules"
 	default y
-	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
+	depends on DEBUG_INFO_BTF && MODULES
 	help
 	  Generate compact split BTF type information for kernel modules.
 
diff --git a/scripts/Makefile.btf b/scripts/Makefile.btf
index db76335dd917..7c1cd6c2ff75 100644
--- a/scripts/Makefile.btf
+++ b/scripts/Makefile.btf
@@ -7,14 +7,7 @@ JOBS := $(patsubst -j%,%,$(filter -j%,$(MAKEFLAGS)))
 
 ifeq ($(call test-le, $(pahole-ver), 125),y)
 
-# pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars
-ifeq ($(call test-le, $(pahole-ver), 121),y)
-pahole-flags-$(call test-ge, $(pahole-ver), 118)	+= --skip_encoding_btf_vars
-endif
-
-pahole-flags-$(call test-ge, $(pahole-ver), 121)	+= --btf_gen_floats
-
-pahole-flags-$(call test-ge, $(pahole-ver), 122)	+= -j$(JOBS)
+pahole-flags-$(call test-ge, $(pahole-ver), 122)	+= --btf_gen_floats -j$(JOBS)
 
 pahole-flags-$(call test-ge, $(pahole-ver), 125)	+= --skip_encoding_btf_inconsistent_proto --btf_gen_optimized
 
diff --git a/tools/sched_ext/README.md b/tools/sched_ext/README.md
index 16a42e4060f6..56a9d1557ac4 100644
--- a/tools/sched_ext/README.md
+++ b/tools/sched_ext/README.md
@@ -65,7 +65,6 @@ It's also recommended that you also include the following Kconfig options:
 ```
 CONFIG_BPF_JIT_ALWAYS_ON=y
 CONFIG_BPF_JIT_DEFAULT_ON=y
-CONFIG_PAHOLE_HAS_SPLIT_BTF=y
 CONFIG_PAHOLE_HAS_BTF_TAG=y
 ```
 
-- 
2.52.0