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Diffstat (limited to 'Documentation/arm64/ilp32.txt')
| -rw-r--r-- | Documentation/arm64/ilp32.txt | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/Documentation/arm64/ilp32.txt b/Documentation/arm64/ilp32.txt new file mode 100644 index 000000000000..0863aa4eac36 --- /dev/null +++ b/Documentation/arm64/ilp32.txt @@ -0,0 +1,57 @@ + ILP32 AARCH64 SYSCALL ABI + ===================== + +Author: Andrew Pinski <apinski@cavium.com> +Date: May 23, 2014 + +This document describes the ILP32 syscall ABI and where it differs +from the generic linux syscall interface. +ILP32 sets __kernel_long_t and __kernel_ulong_t both to 64bit +(long long). This effects the following types: +* time_t: unsigned long long +* clock_t: unsigned long long +* fsword_t: long long +* suseconds_t: long long +* swblk_t: long long +* fd_mask_t: long long + +Some structures are changed to reduce the difference in the code path +for both ILP32 and LP64 ABIs for signal handling. + +The following structures have been changed so the layout of the structures are the same between ILP32 and LP64 ABIs. +* timespec: Uses time_t and suseconds_t +* timeval: Uses time_t and suseconds_t +* stat: Uses timespec/time_t. +* semid64_ds: Uses time_t. +* msqid64_ds: Uses time_t. +* shmid64_ds: Uses time_t. +* rt_sigframe: Uses siginfo and ucontext. +* siginfo_t: Uses clock_t and sigval_t +* ucontext: Uses stack_t and sigset_t +* stack_t: NOTE special handling inside the kernel is done to make sure + the pointers are zero extended +* sigval_t: Contains pointers +* sigevent: Uses sigval_t which causes it to be the same. Special + handing is needed for reading; in the mq_notify syscall +* sigaction: NOTE the userland structure inside glibc does + not match the kernel structure here (this causes issues with LTP). + Uses sigset_t. +* fd_set: This is done to avoid endian issues between ILP32 and LP64 + Also the syscall which uses fd_set uses timespec + + +Also the syscalls which normally would pass 64bit values as two +arguments; now pass the 64bit value as one argument. Also they have +been renamed (removing the 64 from the name) to avoid confusion. +The list of these syscalls: +* fcntl +* statfs +* fstatfs +* truncate +* ftruncate +* lseek +* sendfile +* newfstatat +* fstat +* mmap +* fadvise64 |