[PATCH v5 2/7] module: add kflagstab section to vmlinux and modules

Siddharth Nayyar
2026-03-26T21:25:26Z

This section will contain read-only data for values of kernel symbol
flags in the form of an 8-bit bitsets for each kernel symbol. Each bit
in the bitset represents a flag value defined by ksym_flags enumeration.

The kflagstab section introduces a 1-byte overhead for each symbol
exported in the ksymtab. Given that typical kernel builds contain
roughly a few thousand exported symbols, the resulting memory increase
is negligible.

Signed-off-by: Siddharth Nayyar <sidnayyar@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
---
include/asm-generic/vmlinux.lds.h | 7 +++++++
scripts/module.lds.S | 1 +
2 files changed, 8 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 1e1580febe4b..d64a475c468a 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -536,6 +536,13 @@
__stop___kcrctab_gpl = .; \
} \
\
+ /* Kernel symbol flags table */ \
+ __kflagstab : AT(ADDR(__kflagstab) - LOAD_OFFSET) { \
+ __start___kflagstab = .; \
+ KEEP(*(SORT(___kflagstab+*))) \
+ __stop___kflagstab = .; \
+ } \
+ \
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
*(__ksymtab_strings) \
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 054ef99e8288..d7a8ba278dfc 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -23,6 +23,7 @@ SECTIONS {
__ksymtab_gpl 0 : ALIGN(8) { *(SORT(___ksymtab_gpl+*)) }
__kcrctab 0 : ALIGN(4) { *(SORT(___kcrctab+*)) }
__kcrctab_gpl 0 : ALIGN(4) { *(SORT(___kcrctab_gpl+*)) }
+ __kflagstab 0 : ALIGN(1) { *(SORT(___kflagstab+*)) }

.ctors 0 : ALIGN(8) { *(SORT(.ctors.*)) *(.ctors) }
.init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }

--
2.53.0.1018.g2bb0e51243-goog