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The LFS support is implemented on xstat64.c, instead of xstat.c for
64-bit architectures. The xstat.c implements the non-LFS it is
no-op for !XSTAT_IS_XSTAT64.
The generic non-LFS implementation handle two cases:
1. New kABIs which uses generic pre 64-bit time Linux ABI (csky and
nios): it issues __NR_fstat64 plus handle the overflow on st_ino,
st_size, or st_blocks. It only handles _STAT_VER_KERNEL.
2. Old KABIs with old non-LFS support (arm, i386, hppa, m68k,
microblaze, s390, sh, powerpc, and sparc32). For _STAT_VER_KERNEL
it issues __NR_stat, otherwise it issues __NR_stat64 and convert
to non-LFS stat struct handling possible overflows on st_ino,
st_size, or st_blocks.
Also the non-LFS mips is an outlier and it has its own implementation
since _STAT_VER_LINUX requires a different conversion function (it uses
the kernel_stat as the syscall argument since its exported ABI is
different than the kernel one for both non-LFS and LFS implementation).
The generic LFS implementation handles multiple cases:
1. XSTAT_IS_XSTAT64 being 1:
1.1. Old 64-bit kABI (ia64, powerpc64*, s390x, x86_64): it
issues __NR_stat for _STAT_VER_KERNEL or _STAT_VER_LINUX.
1.2. Old 64-bit kABI with defines __NR_stat64 instead of __NR_stat
(sparc64): it issues __NR_stat for _STAT_VER_KERNEL or
__NR_stat64 and convert to struct stat64.
1.3. New kABIs which uses generic 64-bit Linux ABI (aarch64 and
riscv64): it issues __NR_newfstatat and only for
_STAT_VER_KERNEL.
1.4. New 32-bit kABIs with only 64-bit time_t support (arc and
riscv32): it issues __NR_statx and covert to struct stat64.
2. Old ABIs with XSTAT_IS_XSTAT64 being 0:
2.1. New kABIs which uses generic pre 64-bit time Linux ABI (csky
and nios2): it issues __NR_fstatat64 for _STAT_VER_KERNEL.
2.2. Old kABIs with old non-LFS support (arm, i386, hppa, m68k,
microblaze, s390, sh, mips32, powerpc32, and sparc32): it
issues __NR_stat64.
Also, two special cases requires specific LFS implementations:
1. alpha: it requires to handle _STAT_VER_KERNEL64 to call __NR_stat64
or use the kernel_stat with __NR_stat otherwise.
2. mips64: as for non-LFS implementation its ABIs differ from glibc
exported one, which requires an specific conversion function to
handle the kernel_stat.
Checked with a build for all affected ABIs. I also checked on x86_64,
i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
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|---|---|---|
| .. | ||
| bits | ||
| wordsize-32 | ||
| ____longjmp_chk.c | ||
| brk.c | ||
| chmod.c | ||
| chown.c | ||
| dl-origin.c | ||
| dup2.c | ||
| epoll_create.c | ||
| futimesat.c | ||
| inotify_init.c | ||
| kernel_stat.h | ||
| lchown.c | ||
| link.c | ||
| lxstat.c | ||
| Makefile | ||
| mkdir.c | ||
| pipe.c | ||
| readlink.c | ||
| README | ||
| rmdir.c | ||
| stat-check.c | ||
| symlink.c | ||
| syscalls.list | ||
| sysdep.h | ||
| unlink.c | ||
| utimes.c | ||
| xmknod.c | ||
This hierarchy supports Linux systems using the new asm-generic/unistd.h, which removes many familiar old syscalls. For example, to implement open(), newer Linux architectures require glibc to invoke the __NR_openat syscall with AT_FDCWD. This hierarchy provides all those implementations. It also provides support for 32-bit platforms using the 64-bit kernel syscall APIs, as the 32-bit ones are no longer provided. Note that newer ILP32 environments (x32 or AArch64:ILP32, for example) are converting to use more 64-bit types in kernel syscalls, so that aspect of this support is in more flux as of this writing.