Messages in this thread Patch in this message | | | Subject | Re: [PATCH 20/25] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it | From | "Zhangjian (Bamvor)" <> | Date | Thu, 12 May 2016 11:45:53 +0800 |
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Hi, Arnd
On 2016/5/11 22:50, Arnd Bergmann wrote: > On Wednesday 11 May 2016 19:16:44 Zhangjian wrote: >> Hi, >> >> On 2016/5/11 18:12, Zhangjian (Bamvor) wrote: >>> Hi, Arnd >>> >>> On 2016/5/11 16:09, Arnd Bergmann wrote: >>> > On Wednesday 11 May 2016 10:04:16 Zhangjian wrote: >>> >>> I don't remember. It's probably not important whether we have the shift >>> >>> in there, as long as it's independent of the actual kernel page size and >>> >>> user space and kernel agree on the calling conventions. >>> >> Well. I am ok with where to shift the pages size because we get the same >>> >> result. I was just thinking if we should get rid of the name of mmap2 in our >>> >> ILP32 porting. Actually, it is mmap but we name it as mmap2. User may confused >>> >> if they do not know the implementations. >>> > >>> > That is a good point: If the implementation matches the mmap() behavior rather than >>> > mmap2(), we should rename the macro by doing >>> > >>> > #undef __NR_mmap2 >>> > #define __NR_mmap 222 >>> > >>> > in the uapi/asm/unistd.h file for ilp32 mode. >>> Do you mean define the following things in kernel: >>> ``` >>> diff --git a/arch/arm64/include/uapi/asm/unistd.h b/arch/arm64/include/uapi/asm/unistd.h >>> index 1caadc2..3f79640 100644 >>> --- a/arch/arm64/include/uapi/asm/unistd.h >>> +++ b/arch/arm64/include/uapi/asm/unistd.h >>> @@ -14,3 +14,9 @@ >>> * along with this program. If not, see <http://www.gnu.org/licenses/>. >>> */ >>> #include <asm-generic/unistd.h> >>> + >>> +#ifdef __ILP32__ >>> +#undef __NR_mmap2 >>> +#define __NR_mmap 222 >>> +#endif /* #ifdef __ILP32__ */ >>> + >>> ``` >>> Then glibc could call mmap instead of mmap2. >>> I could not try it now. Because after change off_t to 64bit in glibc, stat >>> is fail. I may need to revert the stat relative patch. >> After revert stat relative patch in glibc, mmap01-mmap14 success. But mmap16 >> success with segfault. I will investigate it later. >> >> There is pointer and size_t in mmap, so, IIUC, we need to clear the top halves >> of register by using COMPAT_SYSCALL_WRAP6. > > Correct, good catch! > >> And after check the function in >> arch/s390/kernel/compat_linux.c, I feel that we need to do the same thing for >> pread64 and pwrite64. >> > >> But I got following error when I try to add >> COMPAT_SYSCALL_WRAP4(pread64, unsigned int, fd, char __user *, buf, >> size_t, count, loff_t, pos); >> COMPAT_SYSCALL_WRAP4(pwrite64, unsigned int, fd, const char __user *, buf, >> size_t, count, loff_t, pos); >> > > Hmm, that is indeed tricky. I think COMPAT_SYSCALL_WRAP4 rightfully > refuses the loff_t argument here, as the common case is that this is > not possible. It works if I apply the following patch, I defined the wrong `__TYPE_IS_xxx` yesterday. Should we merge this into ILP32 series or send the compat.h and syscalls.h individually? The current series of ILP32 is a little bit long and hard to review. diff --git a/include/linux/compat.h b/include/linux/compat.h index ba6ebe0..22a9565 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -747,7 +747,8 @@ asmlinkage long compat_sys_fanotify_mark(int, unsigned int, __u32, __u32, #ifndef __SC_COMPAT_CAST #define __SC_COMPAT_CAST(t, a) ({ \ BUILD_BUG_ON((sizeof(t) > 4) && !__TYPE_IS_L(t) && \ - !__TYPE_IS_UL(t) && !__TYPE_IS_PTR(t)); \ + !__TYPE_IS_UL(t) && !__TYPE_IS_PTR(t) && \ + !__TYPE_IS_LOFFT(t)); \ ((t) ((t)(-1) < 0 ? (s64)(s32)(a) : (u64)(u32)(a))); \ }) #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 6e57d9c..66eb85d 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -47,6 +47,7 @@ #define __TYPE_IS_L(t) (__same_type((t)0, 0L)) #define __TYPE_IS_UL(t) (__same_type((t)0, 0UL)) #define __TYPE_IS_LL(t) (__same_type((t)0, 0LL) || __same_type((t)0, 0ULL)) +#define __TYPE_IS_LOFFT(t) (__same_type((t)0, (loff_t)0)) #define __SC_LONG(t, a) __typeof(__builtin_choose_expr(__TYPE_IS_LL(t), 0LL, 0L)) a #define __SC_CAST(t, a) (t) a #define __SC_ARGS(t, a) a diff --git a/kernel/compat_wrapper.c b/kernel/compat_wrapper.c index 98b68b8..28f02d0 100644 --- a/kernel/compat_wrapper.c +++ b/kernel/compat_wrapper.c @@ -304,3 +304,7 @@ COMPAT_SYSCALL_WRAP3(getpeername, int, fd, struct sockaddr __user *, usockaddr, COMPAT_SYSCALL_WRAP6(sendto, int, fd, void __user *, buff, size_t, len, unsigned int, flags, struct sockaddr __user *, addr, int, addr_len); +COMPAT_SYSCALL_WRAP4(pread64, unsigned int, fd, char __user *, buf, + size_t, count, loff_t, pos); +COMPAT_SYSCALL_WRAP4(pwrite64, unsigned int, fd, const char __user *, buf, + size_t, count, loff_t, pos); > Can you open-code this using a COMPAT_SYSCALL4 definition similar to what > arch/tile has, but without the merging of the two halves of the argument? I am lost here. Tile do not use the wrapper, and it do not use the loff_t either: COMPAT_SYSCALL_DEFINE6(pread64, unsigned int, fd, char __user *, ubuf, size_t, count, u32, dummy, u32, low, u32, high)
Regards
Bamvor > Arnd >
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