Messages in this thread Patch in this message | | | From | Yury Norov <> | Subject | [PATCH v6 01/19] arm64:ilp32: add documentation on the ILP32 ABI for ARM64 | Date | Wed, 18 Nov 2015 00:16:41 +0300 |
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From: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Based on Andrew Pinski's original patch-series and adapted with changes to reduce the duplication of code-paths and resolve issue found during LTP testing.
Reviewed-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com> Signed-off-by: Yury Norov <ynorov@caviumnetworks.com> Signed-off-by: Andrew Pinski <Andrew.Pinski@caviumnetworks.com> --- Documentation/arm64/ilp32.txt | 47 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 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..93c09f2 --- /dev/null +++ b/Documentation/arm64/ilp32.txt @@ -0,0 +1,47 @@ +ILP32 AARCH64 SYSCALL ABI +========================= +Written by Andrew Pinski <apinski@cavium.com> +Updated by Philipp Tomsich <philipp.tomsich@theobroma-systems.com> +Updated by Yury Norov <ynorov@caviumnetworks.com> + + +This document describes the ILP32 syscall ABI and where it differs +from the generic linux syscall interface. + +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, including: + * 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 Conversion is handled in the userland (glibc), as the + userland data structures are defined in glibc anyway. + +A number of structures differ between ILP32 and LP64, including: + * 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 + * fd_set This is done to avoid endian issues between ILP32 and + LP64. Syscalls consuming fd_set use timespec. + * struct msgbuf The specification of 'struct msgbuf' defines the 'mtype' + field as a 'long' (i.e. 32bit for ILP32, but 64bit for + LP64). Functions that operate on 'struct msgbuf' need + to be passed through the compat-syscalls to resolve + this. + * stack_t contains pointers (handled in the compatibility layer) + +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 LP64 syscalls reused by ILP32 clients, and syscalls having +ILP32-specific handlers is in arch/arm64/kernel/sys_ilp32.c + -- 2.1.4
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