擁有運行嵌入式 Linux (OpenWrt) 的客製化硬體就像一個魅力。 CPU - 是 IMX6ULL (ArmV7),因此 Jlink 支援透過 JTAG 介面進行偵錯。啟動 GDB 伺服器並逐步偵錯 Linux 核心會顯示大量optimized out
訊息,因為核心是使用KBUILD_CFLAGS += -O2 -fno-reorder-blocks -fno-tree-ch $(EXTRA_OPTIMIZATION)
標誌編譯的。所以我嘗試編譯它,-O0
它為我提供了以下選項:
$ make -j64 V=s all
CHK include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CC scripts/mod/empty.o
....
AR built-in.o
LD vmlinux.o
MODPOST vmlinux.o
WARNING: modpost: Found 4 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
arm-openwrt-linux-muslgnueabi-ld: arch/arm/kernel/setup.o: in function `setup_arch':
/opt/eclipse/imx6ull-openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-imx6ull_cortexa7/linux-4.14.199/arch/arm/kernel/setup.c:1134: undefined reference to `psci_smp_ops'
arm-openwrt-linux-muslgnueabi-ld: /opt/eclipse/imx6ull-openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-imx6ull_cortexa7/linux-4.14.199/arch/arm/kernel/setup.c:1134: undefined reference to `psci_smp_ops'
arm-openwrt-linux-muslgnueabi-ld: kernel/panic.o: in function `__xchg':
/opt/eclipse/imx6ull-openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-imx6ull_cortexa7/linux-4.14.199/./arch/arm/include/asm/cmpxchg.h:110: undefined reference to `__bad_xchg'
arm-openwrt-linux-muslgnueabi-ld: kernel/exit.o: in function `__xchg':
檢查了WARNING: modpost: Found x section mismatch(es).
這裡。似乎生成的二進位檔案比透過某些設定配置的空間佔用更多的空間。vmlinux
使用選項建構的尺寸-O2
為39Mb
。使用-O1
給了我37Mb
圖像,所以我希望我的 DDR3 RAM (128Mb) 有足夠的空間來容納透過-O0
配置編譯的更大圖像。所以我想知道如何為部分提供更多空間?有人可以指出我可以做的地方嗎?對 Linux 核心的了解有限,因此無法找到用於此目的的任何連結器腳本。