> On Jul 1, 2014, at 8:07 AM, "Catalin Marinas" <catalin.mari...@arm.com> wrote: > >> On Sat, May 24, 2014 at 12:02:17AM -0700, Andrew Pinski wrote: >> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S >> index 1e1ebfc..8241ffe 100644 >> --- a/arch/arm64/kernel/entry.S >> +++ b/arch/arm64/kernel/entry.S >> @@ -620,9 +620,14 @@ ENDPROC(ret_from_fork) >> */ >> .align 6 >> el0_svc: >> - adrp stbl, sys_call_table // load syscall table pointer >> uxtw scno, w8 // syscall number in w8 >> mov sc_nr, #__NR_syscalls >> +#ifdef CONFIG_ARM64_ILP32 >> + get_thread_info tsk >> + ldr x16, [tsk, #TI_FLAGS] >> + tbnz x16, #TIF_32BIT_AARCH64, el0_ilp32_svc // We are using ILP32 >> +#endif >> + adrp stbl, sys_call_table // load syscall table pointer > > This adds a slight penalty on the AArch64 SVC entry path. I can't tell > whether that's visible or not but I think the x86 guys decided to set an > extra bit to the syscall number to distinguish it from native calls. > >> diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c >> new file mode 100644 >> index 0000000..1da1d11 >> --- /dev/null >> +++ b/arch/arm64/kernel/sys_ilp32.c > [...] >> +/* >> + * Wrappers to pass the pt_regs argument. >> + */ >> +#define sys_rt_sigreturn sys_rt_sigreturn_wrapper >> + >> + >> +/* Using Compat syscalls where necessary */ >> +#define sys_ioctl compat_sys_ioctl >> +/* iovec */ >> +#define sys_readv compat_sys_readv >> +#define sys_writev compat_sys_writev >> +#define sys_preadv compat_sys_preadv64 >> +#define sys_pwritev compat_sys_pwritev64 >> +#define sys_vmsplice compat_sys_vmsplice > > Do these actually work? compat_iovec has two members of 32-bit each > while the ILP32 iovec has a void * (32-bit) and a __kernel_size_t which > is 64-bit.
size_t should be unsigned long in ilp32 so a 32bit unsigned integer type. That part of the abi was already defined in the arm abi documents. Now are saying we should pass size_t different between user and kernel space? > >> +/* robust_list_head */ >> +#define sys_set_robust_list compat_sys_set_robust_list >> +#define sys_get_robust_list compat_sys_get_robust_list > > Same here, we have a size_t * argument. The compat function would write > back 32-bit but size_t is 64-bit for ILP32. See above. Size_t is 32bits. > >> +/* kexec_segment */ >> +#define sys_kexec_load compat_sys_kexec_load > > More size_t members in the kexec_segment structure (but we don't yet > have kexec on arm64). See above. Size_t is 32bits. > >> +/* struct msghdr */ >> +#define sys_recvfrom compat_sys_recvfrom > > Why compat here? struct sockaddr seems to be the same as the native one. > >> +#define sys_recvmmsg compat_sys_recvmmsg >> +#define sys_sendmmsg compat_sys_sendmmsg >> +#define sys_sendmsg compat_sys_sendmsg >> +#define sys_recvmsg compat_sys_recvmsg > > These get messier as well with a different size_t affecting struct > msghdr. See above about size_t. > >> +#define sys_setsockopt compat_sys_setsockopt >> +#define sys_getsockopt compat_sys_getsockopt > > Looking at the sock_getsockopt() function, we have a union v copied > to/from user. However, such a union contains a struct timeval which for > ILP32 would be different than the compat one. I will look into this one but it might already be taken care of due to the compact uses 64bit time spec define. I will add a comment saying that if it is true. > >> +/* iovec */ >> +#define sys_process_vm_readv compat_sys_process_vm_readv >> +#define sys_process_vm_writev compat_sys_process_vm_writev > > See above for iovec. See above for my size_t question. > >> +/* Pointer in struct */ >> +#define sys_mount compat_sys_mount > > Which structure is this? NFS structure, I can expand out the comment if needed. > >> +/* Scheduler */ >> +/* unsigned long bitmaps */ >> +#define sys_sched_setaffinity compat_sys_sched_setaffinity >> +#define sys_sched_getaffinity compat_sys_sched_getaffinity > > Does the long bitmask matter here? I can see the length is passed in > bytes. Yes for big endian. If we were only supporting little endian, bit fields would not matter. > >> +/* iov usage */ >> +#define sys_keyctl compat_sys_keyctl > > Same problem as iovec above. > >> +/* aio */ >> +/* Pointer to Pointer */ >> +#define sys_io_setup compat_sys_io_setup > > sys_io_setup takes a pointer to aio_context_t which is defined as > __kernel_ulong_t (same as LP64). Let me look at why I did this one, I think the code which used aio was not in glibc which is why I used the compat version. Thanks, Andrew > > -- > Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/