The use of the .hidden directive to avoid going via the PLT for
__set_errno had the side-effect of actually making __set_errno
hidden (which is odd because assembler directives don't usually
affect symbols defined in a different file --- you can't even
create a weak reference to a symbol that's defined in a different
file).
This change switches the system call stubs over to a new always-hidden
__set_errno_internal and has a visible __set_errno on LP32 just for
binary compatibility with old NDK apps.
(cherry-pick of 7efad83d430f4d824f2aaa75edea5106f6ff8aae.)
Bug: 17423135
Change-Id: I6b6d7a05dda85f923d22e5ffd169a91e23499b7b
bionic/libc/arch-arm64/syscalls/read.S ends with:
b.hi __set_errno
ret
END(read)
If __set_errno returns int, it will set w0 to 0xFFFFFFFF, which means
x0 is 0x00000000FFFFFFFF. When interpreted as a ssize_t that is
INT_MAX, not -1.
Change __set_errno to return long, which will cause x0 to be set instead
of w0.
Change-Id: I9f9ea0f2995928d2ea240eb2ff7758ecdf0ff412
