linux内核配置裁减问题
内核下载地址：可能需要
www.kernel.org
1、执行make menuconfig过程中会遇到的问题，可以根据提示安装对应缺少的软件包；本人遇到过的有如下三点：
*** Unable to find the ncurses libraries or the
*** required header files.
*** 'make menuconfig' requires the ncurses libraries.
*** Install ncurses (ncurses-devel) and try again.
sudo apt-get install ncurses-dev
/bin/sh: 1: flex: not found
scripts/Makefile.lib:194: recipe for target 'scripts/kconfig/lexer.lex.c' failed
make[1]: *** [scripts/kconfig/lexer.lex.c] Error 127
Makefile:552: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2
sudo apt-get install flex
LEX scripts/kconfig/lexer.lex.c
YACC scripts/kconfig/parser.tab.h
/bin/sh: 1: bison: not found
scripts/Makefile.lib:208: recipe for target 'scripts/kconfig/parser.tab.h' failed
make[1]: *** [scripts/kconfig/parser.tab.h] Error 127
Makefile:552: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2
sudo apt-get install bison
scripts/sign-file.c:25:10: fatal error: openssl/opensslv.h: 没有那个文件或目录
#include
^~~~~~~~~~~~~~~~~~~~
compilation terminated.
scripts/Makefile.host:92: recipe for target 'scripts/sign-file' failed
make[1]: *** [scripts/sign-file] Error 1
Makefile:1065: recipe for target 'scripts' failed
make: *** [scripts] Error 2
sudo apt-get install libssl-dev
Can't use 'defined(@array)' (Maybe you should just omit the defined()?) at kernel/timeconst.pl line 373.
/home/howe/iTop4412_Kernel_3.0/kernel/Makefile:140: recipe for target 'kernel/timeconst.h' failed
make[1]: *** [kernel/timeconst.h] Error 255
Makefile:954: recipe for target 'kernel' failed
make: *** [kernel] Error 2
解决方法:https://blog.csdn.net/abc87891842/article/details/55051042
参考：编译kernel perl版本bug
最近升级了一下MAC系统，突然发现android的Linux kernel无法编译通过了，报了如下错误：
Can’t use ‘!defined(@array)’ (Maybe you should just omit the defined()?) at kernel/timeconst.pl line 373.
其实，提示的错误信息已经明确告诉你了，你应该省略defined().
这里，我们打开 kernel/timeconst.pl
@val = @{KaTeX parse error: Expected '}', got 'EOF' at end of input: canned_values{hz}};
if (!defined(@val)) {
@val = compute_values(KaTeX parse error: Expected 'EOF', got '}' at position 6: hz); }̲ output(hz, @val);
将if (!defined(@val)) 改为if (!(@val))，再次编译就可以通过了。
查了一下更新，发现其中有一项是perl版本升级到了 v5.22.1，然后查了perl官方文档，发现官网因为一个bug，该版本将defined(@array)去掉了。可以直接使用数组判断非空。
kernel 3.0
警告1：
fs/cifs/cifssmb.c: In function ‘CIFSSMBSetFileInfo’:
fs/cifs/cifssmb.c:5318:8: warning: array subscript is above array bounds [-Warray-bounds]
memcpy(data_offset, data, sizeof(FILE_BASIC_INFO));
^
fs/cifs/cifssmb.c: In function ‘CIFSSMBUnixSetFileInfo’:
fs/cifs/cifssmb.c:5608:25: warning: array subscript is above array bounds [-Warray-bounds]
cifs_fill_unix_set_info(data_offset, args);
警告2：
fs/xfs/xfs_dir2_block.c: In function ‘xfs_dir2_sf_to_block’:
fs/xfs/xfs_dir2_block.c:1151:26: warning: array subscript is above array bounds [-Warray-bounds]
dep->name[0] = dep->name[1] = '.';
^
CC [M] fs/xfs/xfs_dir2_data.o
CC [M] fs/xfs/xfs_dir2_leaf.o
fs/xfs/xfs_dir2_leaf.c: In function ‘xfs_dir2_leaf_compact’:
fs/xfs/xfs_dir2_leaf.c:622:31: warning: array subscript is above array bounds [-Warray-bounds]
leaf->ents[to] = leaf->ents[from];
^
警告3：
In file included from /home/howe/iTop4412_Kernel_3.0/arch/arm/include/asm/xor.h:10:0,
from crypto/xor.c:24:
include/asm-generic/xor.h:696:34: warning: ‘xor_block_8regs_p’ defined but not used [-Wunused-variable]
static struct xor_block_template xor_block_8regs_p = {
^
include/asm-generic/xor.h:704:34: warning: ‘xor_block_32regs_p’ defined but not used [-Wunused-variable]
static struct xor_block_template xor_block_32regs_p = {
^
警告4：
drivers/ata/sata_sil.c: In function ‘sil_interrupt’:
drivers/ata/sata_sil.c:453:14: warning: ‘serror’ may be used uninitialized in this function [-Wmaybe-uninitialized]
if (serror & SERR_PHYRDY_CHG) {
^
drivers/ata/sata_sil.c:441:7: note: ‘serror’ was declared here
u32 serror;
^
警告5：
drivers/atm/ambassador.c: In function ‘do_loader_command’:
drivers/atm/ambassador.c:1765:3: warning: passing argument 1 of ‘virt_to_bus’ discards ‘volatile’ qualifier from pointer target type [enabled by default]
wr_mem (dev, offsetof(amb_mem, doorbell), virt_to_bus (lb) & ~onegigmask);
^
In file included from /home/howe/iTop4412_Kernel_3.0/arch/arm/include/asm/system.h:165:0,
from /home/howe/iTop4412_Kernel_3.0/arch/arm/include/asm/bitops.h:27,
from include/linux/bitops.h:22,
from include/linux/kernel.h:17,
from include/linux/cache.h:4,
from include/linux/time.h:7,
from include/linux/stat.h:60,
from include/linux/module.h:10,
from drivers/atm/ambassador.c:25:
/home/howe/iTop4412_Kernel_3.0/arch/arm/include/asm/memory.h:264:42: note: expected ‘void *’ but argument is of type ‘volatile struct loader_block *’
static inline __deprecated unsigned long virt_to_bus(void *x)
^
drivers/atm/ambassador.c: In function ‘amb_probe’:
drivers/atm/ambassador.c:1975:19: warning: ‘fw’ may be used uninitialized in this function [-Wmaybe-uninitialized]
release_firmware(fw);
^
drivers/atm/ambassador.c:1926:26: note: ‘fw’ was declared here
const struct firmware *fw;
^
警告6：
drivers/block/DAC960.c: In function ‘DAC960_V2_ProcessCompletedCommand’:
drivers/block/DAC960.c:5095:30: warning: comparison between ‘DAC960_V2_IOCTL_Opcode_T’ and ‘enum ’ [-Wenum-compare]
else if (CommandOpcode == DAC960_V2_SCSI_10_Passthru)
^
In file included from include/linux/bio.h:29:0,
from include/linux/blkdev.h:16,
from drivers/block/DAC960.c:27:
drivers/block/DAC960.c: In function ‘DAC960_V1_EnableMemoryMailboxInterface’:
/home/howe/iTop4412_Kernel_3.0/arch/arm/include/asm/io.h:50:43: warning: ‘CommandMailbox.Bytes[12]’ may be used uninitialized in this function [-Wmaybe-uninitialized]
#define __raw_writeb(v,a) (__chk_io_ptr(a), *(volatile unsigned char __force *)(a) = (v))
^
drivers/block/DAC960.c:1175:30: note: ‘CommandMailbox.Bytes[12]’ was declared here
DAC960_V1_CommandMailbox_T CommandMailbox;
^
警告7：
drivers/block/drbd/drbd_main.c: In function ‘drbd_buildtag’:
drivers/block/drbd/drbd_main.c:4187:19: warning: the comparison will always evaluate as ‘true’ for the address of ‘__this_module’ will never be NULL [-Waddress]
if (THIS_MODULE != NULL)
^
警告8：
drivers/char/tpm/tpm_tis.c:96:12: warning: ‘is_itpm’ defined but not used [-Wunused-function]
static int is_itpm(struct pnp_dev *dev)
^
linux kernel 5.1
警告1：
warning: Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel
警告2：
arch/x86/hyperv/hv_apic.c: In function ‘__send_ipi_one’:
arch/x86/hyperv/hv_apic.c:196:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
arch/x86/hyperv/hv_apic.c: In function ‘hv_send_ipi_mask_allbutself’:
arch/x86/hyperv/hv_apic.c:221:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
警告3：
arch/x86/kernel/kvm.c: In function ‘kvm_send_ipi_mask_allbutself’:
arch/x86/kernel/kvm.c:519:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
警告4：
mm/memcontrol.c: In function ‘memcg_stat_show’:
mm/memcontrol.c:3485:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
mm/memcontrol.c: In function ‘memory_stat_show’:
mm/memcontrol.c:5638:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
警告5：
fs/jffs2/xattr.c: In function ‘jffs2_build_xattr_subsystem’:
fs/jffs2/xattr.c:887:1: warning: the frame size of 1120 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
警告6：
drivers/cpufreq/cpufreq_ondemand.c: In function ‘od_set_powersave_bias’:
drivers/cpufreq/cpufreq_ondemand.c:449:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
}
^
2、menuconfig菜单栏的说明
menuconfig界面的运行脚本在内核目录下的scripts文件夹下，而界面相关都与内核文件夹下的Kconfig文件有关，可自行查看，比如菜单、选择栏等，需要链接到其他文件夹下的Kconfig，则通过source来实现。
配置完menuconfig之后，会在内核根目录下生成一个.config文件，给编译内核时使用。
3、make编译内核说明
编译过程，是调用各个文件夹下的makefile文件，而makefile文件依赖于.config中的宏定义。