[Bug libc/19371] Wrong error return on syscall ()

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=19371

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The branch, hjl/pr19371/master has been created
        at  bf0e161423748feb7950110d6074ebbcd102cb7e (commit)

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=bf0e161423748feb7950110d6074ebbcd102cb7e

commit bf0e161423748feb7950110d6074ebbcd102cb7e
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Dec 16 06:50:42 2015 -0800

    Properly handle x32 syscall

    X32 syscall() may return 64-bit integer as lseek, time and times.  Its
    return type should be __syscall_slong_t instead of long int.  We need
    to properly return 64-bit error value.

    Before the patch:

    Dump of assembler code for function syscall:
       0x000dab20 <+0>: mov    %rdi,%rax
       0x000dab23 <+3>: mov    %rsi,%rdi
       0x000dab26 <+6>: mov    %rdx,%rsi
       0x000dab29 <+9>: mov    %rcx,%rdx
       0x000dab2c <+12>:        mov    %r8,%r10
       0x000dab2f <+15>:        mov    %r9,%r8
       0x000dab32 <+18>:        mov    0x8(%rsp),%r9
       0x000dab37 <+23>:        syscall
       0x000dab39 <+25>:        cmp    $0xfffffffffffff001,%rax
       0x000dab3f <+31>:        jae    0xdab42 <syscall+34>
       0x000dab41 <+33>:        retq
       0x000dab42 <+34>:        mov    0x2b3367(%rip),%rcx        # 0x38deb0
       0x000dab49 <+41>:        neg    %eax
       0x000dab4b <+43>:        mov    %eax,%fs:(%rcx)
       0x000dab4e <+46>:        or     $0xffffffff,%eax
                            ^^^^^^^^^^^^^^^^^^ This is 32-bit error return.
       0x000dab51 <+49>:        retq
    End of assembler dump.

    After the patch:

    Dump of assembler code for function syscall:
       0x000daaf0 <+0>: mov    %rdi,%rax
       0x000daaf3 <+3>: mov    %rsi,%rdi
       0x000daaf6 <+6>: mov    %rdx,%rsi
       0x000daaf9 <+9>: mov    %rcx,%rdx
       0x000daafc <+12>:        mov    %r8,%r10
       0x000daaff <+15>:        mov    %r9,%r8
       0x000dab02 <+18>:        mov    0x8(%rsp),%r9
       0x000dab07 <+23>:        syscall
       0x000dab09 <+25>:        cmp    $0xfffffffffffff001,%rax
       0x000dab0f <+31>:        jae    0xdab12 <syscall+34>
       0x000dab11 <+33>:        retq
       0x000dab12 <+34>:        mov    0x2b3397(%rip),%rcx        # 0x38deb0
       0x000dab19 <+41>:        neg    %eax
       0x000dab1b <+43>:        mov    %eax,%fs:(%rcx)
       0x000dab1e <+46>:        or     $0xffffffffffffffff,%rax
       0x000dab22 <+50>:        retq
    End of assembler dump.

        [BZ #19371]
        * posix/unistd.h (syscall): Use __syscall_slong_t for return
        type.
        * sysdeps/unix/sysv/linux/x86_64/x32/syscall.S: New file.

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