ARM: multi_v7_defconfig: Enable debugging symbols by default

Similarly to the ARM64 defconfig, enable debugging symbols and rely upon the toolchain's default DWARF implementation.

---
 arch/arm/configs/multi_v7_defconfig | 3 +++
 1 file changed, 3 insertions(+)

index 62734530a3d6..eee71f6ae131 100644
@@ -1322,5 +1322,8 @@ CONFIG_CRYPTO_DEV_STM32_HASH=m
 CONFIG_CRYPTO_DEV_STM32_CRYP=m
 CONFIG_CMA_SIZE_MBYTES=64
 CONFIG_PRINTK_TIME=y
+CONFIG_DEBUG_KERNEL=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_DEBUG_INFO_REDUCED=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_FS=y

2.43.0

I usually build with debug info disabled when I'm build testing, but turn it on explicitly when I try to actually debug a problem.

Depending on the configuration, adding debug info can significantly increase the build time and file size. I've tried to record exact data here, building the arm defconfig on gcc-14 with and without debug info, which doesn't seem too bad, especially with the reduced debug info:

config         vmlinux time    total time   vmlinux size
disabled-gcc9  49s             81s          35MB
reduced-gcc9   55s             98s          148MB
full-gcc9      66s             105s         443MB
disabled-gcc14 55s             90s          34MB
reduced-gcc14  60s             99s          124MB
full-gcc14     68s             115s         349MB

There is still added disk usage for build testing, but the time overhead seems fine. I'd like to hear what others think about the tradeoff.

Arnd