Commit 903922cf authored by Ihor Solodrai's avatar Ihor Solodrai Committed by Andrii Nakryiko
Browse files

lib/Kconfig.debug: Set the minimum required pahole version to v1.22 

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: default avatarIhor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Tested-by: default avatarAlan Maguire <alan.maguire@oracle.com>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Acked-by: default avatarNicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/bpf/20251219181825.1289460-1-ihor.solodrai@linux.dev
parent 90e5b38a

Documentation/process/changes.rst

+2 −2
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ bash 4.2 bash --version 
binutils               2.30             ld -v

flex                   2.5.35           flex --version

bison                  2.0              bison --version

pahole                 1.16             pahole --version

pahole                 1.22             pahole --version

util-linux             2.10o            mount --version

kmod                   13               depmod -V

e2fsprogs              1.41.4           e2fsck -V
@@ -143,7 +143,7 @@ pahole 


Since Linux 5.2, if CONFIG_DEBUG_INFO_BTF is selected, the build system

generates BTF (BPF Type Format) from DWARF in vmlinux, a bit later from kernel

modules as well.  This requires pahole v1.16 or later.

modules as well.  This requires pahole v1.22 or later.



It is found in the 'dwarves' or 'pahole' distro packages or from

https://fedorapeople.org/~acme/dwarves/.

Documentation/scheduler/sched-ext.rst

+0 −1
Original line number Diff line number Diff line
@@ -43,7 +43,6 @@ options should be enabled to use sched_ext: 
    CONFIG_DEBUG_INFO_BTF=y

    CONFIG_BPF_JIT_ALWAYS_ON=y

    CONFIG_BPF_JIT_DEFAULT_ON=y

    CONFIG_PAHOLE_HAS_SPLIT_BTF=y

    CONFIG_PAHOLE_HAS_BTF_TAG=y



sched_ext is used only when the BPF scheduler is loaded and running.

lib/Kconfig.debug

+4 −9
Original line number Diff line number Diff line
@@ -388,18 +388,13 @@ 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
@@ -421,7 +416,7 @@ 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.

scripts/Makefile.btf

+1 −8
Original line number Diff line number Diff line
@@ -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-y                                  	+= --btf_gen_floats -j$(JOBS)



pahole-flags-$(call test-ge, $(pahole-ver), 125)	+= --skip_encoding_btf_inconsistent_proto --btf_gen_optimized

tools/sched_ext/README.md

+0 −1
Original line number Diff line number Diff line
@@ -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

```