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authorAndrey Konovalov <andrey.konovalov@linaro.org>2015-03-31 21:01:08 +0300
committerAndrey Konovalov <andrey.konovalov@linaro.org>2015-03-31 21:01:08 +0300
commitcd81b0ac5de5f0d6e87bbe726c3fbc17b1d15d16 (patch)
treec89eeab16d6c1f547915274c1e8b4786303f912c /Documentation/arm64/ilp32.txt
parentf08976ec5730d9ff85aded9f4d904ef1b321bdd2 (diff)
parent9b4db147ac19c2320edec431d93193f42e32d425 (diff)
Merge branch 'tracking-ilp32' into merge-linux-linaroll-20150331.0
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+ 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