Based on Andrew Pinski's patch-series. Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx> --- Documentation/arm64/ilp32.txt | 54 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 Documentation/arm64/ilp32.txt diff --git a/Documentation/arm64/ilp32.txt b/Documentation/arm64/ilp32.txt new file mode 100644 index 0000000..d5faa31 --- /dev/null +++ b/Documentation/arm64/ilp32.txt @@ -0,0 +1,54 @@ +ILP32 AARCH64 SYSCALL ABI +========================= + +This document describes the ILP32 syscall ABI and where it differs +from the generic compat linux syscall interface. + +AARCH64/ILP32 userspace can potentially access top halves of registers that +are passed as syscall arguments, so such registers (w0-w7) are deloused. + +AARCH64/ILP32 provides next types turned to 64-bit (comparing to AARCH32): +ino_t is u64 type. +off_t is s64 type. +blkcnt_t is s64 type. +fsblkcnt_t is u64 type. +fsfilcnt_t is u64 type. + +AARCH64/ILP32 ABI uses standard syscall table which can be found at +include/uapi/asm-generic/unistd.h, with the exceptions listed below. + +Syscalls which pass 64bit values are handled by the code shared from +AARCH32 and pass that value as a pair. Next syscalls are affected: +fadvise64_64() +fallocate() +ftruncate64() +pread64 () +pwrite64() +readahead() +sync_file_range() +truncate64() +sys_mmap() + +ptrace() syscall is handled by compat version. + +fcntl64() syscall is handled by non-compat handler as struct flock for ilp32 +is the same as for lp64 + +shmat() syscall is handled by non-compat handler as aarch64/ilp32 has no +limitation on 4-pages alignement for shared memory. + +Syscalls which take a pointer to stat, stat64, statfs, statfs64 +structures are now routed to native handlers directly, as aarch64/ilp32 +defines userspace ino_t, off_t, blkcnt_t, fsblkcnt_t, fsfilcnt_t types +as 64-bit and it makes that structures have same layout as lp64. +Next syscalls are affected: +fstatat64() +fstat64() +statfs64() +fstatfs64() + +struct rt_sigframe is redefined and contains struct compat_siginfo, +as compat syscalls expects, and struct ilp32_sigframe, to handle +AARCH64 register set and 32-bit userspace register representation.h + +elf_gregset_t is taken from lp64 to handle registers properly. -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
