| Message ID | 1446507046-24604-2-git-send-email-ynorov@caviumnetworks.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tuesday 03 November 2015 02:30:30 Yury Norov wrote: > 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. > > 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> > Reviewed-by: David Daney <david.daney@cavium.com> Thanks for the updated version, I'm much happier with this, and only have some comments on a few details to the later patches. > +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. Right, makes sense. > +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 As I commented, we might want to change this for 'stat', which doesn't really time_t anyway. > + * semid64_ds uses time_t. > + * msqid64_ds uses time_t. > + * shmid64_ds uses time_t. These use the arm32 layout, right? That's good for consistency. Fixing these for y2038 will be a bit ugly, but that code can be shared across all architectures. > + * 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 these LP64 syscalls reused by ILP32 clients is: > + * fcntl > + * statfs > + * fstatfs Did you forget to edit this list? I see fcntl and {f,}statfs use the compat implementation, not the native one in your patches. > + * truncate > + * ftruncate > + * lseek > + * sendfile > + * fadvise64 Makes sense. I think using the normal compat syscalls would have been just as good here, to save a few lines in the syscall table, but I agree that the calling conventions are rather silly when you pass a 64-bit number in two registers. > + * newfstatat > + * fstat This contradicts what you write above regarding separate 'struct stat'. > + * mmap Not direct reuse because of the wrapper to check the page size I guess. Aside from the wrapper, the 32-bit and 64-bit system calls are basically identical. Arnd
diff --git a/Documentation/arm64/ilp32.txt b/Documentation/arm64/ilp32.txt new file mode 100644 index 0000000..4f6860b --- /dev/null +++ b/Documentation/arm64/ilp32.txt @@ -0,0 +1,55 @@ +ILP32 AARCH64 SYSCALL ABI +========================= +Written by Andrew Pinski <apinski@cavium.com> +Updated by Philipp Tomsich <philipp.tomsich@theobroma-systems.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 these LP64 syscalls reused by ILP32 clients is: + * fcntl + * statfs + * fstatfs + * truncate + * ftruncate + * lseek + * sendfile + * newfstatat + * fstat + * mmap + * fadvise64 +