From: Benjamin Berg benjamin.berg@intel.com
For a while now, we have discussed that it may be better to avoid using libc inside UML as it may be interfering in unexpected ways with kernel functionality. A major point of concern is that there is no guarantee that the libc is not using any address space that may conflict with kernel addresses.
This patchset is an attempt to start a nolibc port of UML. The goal is to port UML to use nolibc in smaller chunks to make the switch more manageable.
There are three parts to this patchset: * Two patches to use tools/include headers instead of kernel headers for userspace files. * A few nolibc fixes and a new NOLIBC_NO_STARTCODE compile flag for it * Finally nolibc build support for UML and switching two files
The first two parts could be merged independently. The last step to use nolibc inside UML obviously depends on the first two.
Benjamin
Benjamin Berg (9): tools compiler.h: fix __used definition um: use tools/include for user files tools/nolibc/stdio: remove perror if NOLIBC_IGNORE_ERRNO is set tools/nolibc/dirent: avoid errno in readdir_r tools/nolibc: use __fallthrough__ rather than fallthrough tools/nolibc: add option to disable startup code um: add infrastructure to build files using nolibc um: use nolibc for the --showconfig implementation um: switch ptrace FP register access to nolibc
arch/um/Makefile | 32 ++++++++++++++++--- .../um/include/shared/generated/asm-offsets.h | 1 + .../include/shared/generated/user_constants.h | 1 + arch/um/include/shared/init.h | 2 +- arch/um/include/shared/os.h | 2 ++ arch/um/include/shared/user.h | 5 --- arch/um/kernel/Makefile | 2 +- arch/um/kernel/skas/stub.c | 1 + arch/um/kernel/skas/stub_exe.c | 4 +-- arch/um/os-Linux/skas/process.c | 6 ++-- arch/um/os-Linux/start_up.c | 4 +-- arch/um/scripts/Makefile.rules | 10 ++++-- arch/x86/um/Makefile | 6 ++-- arch/x86/um/os-Linux/Makefile | 5 ++- arch/x86/um/os-Linux/registers.c | 22 +++++-------- arch/x86/um/user-offsets.c | 1 - tools/include/linux/compiler.h | 2 +- tools/include/nolibc/arch-arm.h | 2 ++ tools/include/nolibc/arch-arm64.h | 2 ++ tools/include/nolibc/arch-loongarch.h | 2 ++ tools/include/nolibc/arch-m68k.h | 2 ++ tools/include/nolibc/arch-mips.h | 2 ++ tools/include/nolibc/arch-powerpc.h | 2 ++ tools/include/nolibc/arch-riscv.h | 2 ++ tools/include/nolibc/arch-s390.h | 2 ++ tools/include/nolibc/arch-sh.h | 2 ++ tools/include/nolibc/arch-sparc.h | 2 ++ tools/include/nolibc/arch-x86.h | 4 +++ tools/include/nolibc/compiler.h | 4 +-- tools/include/nolibc/crt.h | 3 ++ tools/include/nolibc/dirent.h | 6 ++-- tools/include/nolibc/stackprotector.h | 2 ++ tools/include/nolibc/stdio.h | 2 ++ tools/include/nolibc/stdlib.h | 2 ++ tools/include/nolibc/sys.h | 3 +- tools/include/nolibc/sys/auxv.h | 3 ++ 36 files changed, 108 insertions(+), 47 deletions(-) create mode 120000 arch/um/include/shared/generated/asm-offsets.h create mode 120000 arch/um/include/shared/generated/user_constants.h