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| author | Volodymyr Boyko <boyko.cxx@gmail.com> | 2018-11-23 02:19:55 +0200 |
|---|---|---|
| committer | Waldemar Brodkorb <wbx@openadk.org> | 2018-11-23 14:24:29 +0100 |
| commit | fa9cfbfcb70bd3736ec54eeeb4d0796aa4b9521f (patch) | |
| tree | d1c5c7599703f7024acf6769cdd378e1c0a58b77 | |
| parent | cbfdb7abf4790bac4da52b2161a12bf8abd9f174 (diff) | |
Defined INLINE_SYSCALL_NOERR_NCS in mips/bits/syscalls.h
On Linux/MIPS (O32 ABI) for system call we have two result registers - v0 and a3.
v0 contains actual syscall result on success or error number on fail, a3 set to 0/1
for indicating syscall success/fail. (if a3 == 1, v0 contains errno).
Now as we can see from definition of handle_sys (arch/mips/kernel/scall32-o32.S),
handler treats returned by syscall function (let's call "original") values in
range [-EMAXERRNO; 0[ as -errno, a3 is set to 1 and final returned (to userspace)
value is (-original).
INLINE_SYSCALL_NOERR_NCS defined in mips/bits/syscalls.h will handle
this behaviour.
Signed-off-by: Volodymyr Boyko <boyko.cxx@gmail.com>
| -rw-r--r-- | libc/sysdeps/linux/mips/bits/syscalls.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/mips/bits/syscalls.h b/libc/sysdeps/linux/mips/bits/syscalls.h index 787bb7d55..b8f80597e 100644 --- a/libc/sysdeps/linux/mips/bits/syscalls.h +++ b/libc/sysdeps/linux/mips/bits/syscalls.h @@ -29,6 +29,16 @@ } \ result_var; }) +#define INLINE_SYSCALL_NOERR_NCS(name, nr, args...) \ +({ \ + INTERNAL_SYSCALL_DECL(err); \ + long res = INTERNAL_SYSCALL_NCS(name, err, nr, args); \ + if (unlikely(INTERNAL_SYSCALL_ERROR_P(res, err))) { \ + res = -res; \ + } \ + res; \ +}) + #define INTERNAL_SYSCALL_DECL(err) long err attribute_unused #define INTERNAL_SYSCALL_ERROR_P(val, err) ((long) (err)) |