toolchain/uClibc/patches-0.9.33.2/611-mips_syscall_error_argument.patch

   1 commit 2952c70804b48bb5c87eea21df5e401969dc4ec1
   2 Author: Kevin Cernekee <cernekee@gmail.com>
   3 Date:   Tue Jun 5 15:05:20 2012 -0700
   4
   5     MIPS: Use $a0 instead of $v0 for __syscall_error() argument
   6
   7     $a0 is saved across _dl_runtime_resolve(); $v0 is not.  Unfortunately,
   8     __syscall_error() uses $v0 for its argument, not $a0 as is the MIPS ABI
   9     standard.  This means that if lazy binding was used for __syscall_error(),
  10     the errno value in $v0 could get corrupted.
  11
  12     The problem can be easily seen in testcases where syscalls in librt fail;
  13     when librt tries to call __syscall_error() in libc, the argument gets
  14     lost and errno gets set to a bogus value:
  15
  16         # ./tst-mqueue1 ; echo $?
  17         mq_receive on O_WRONLY mqd_t did not fail with EBADF: Unknown error 2004684208
  18         1
  19         # ./tst-mqueue2 ; echo $?
  20         mq_timedreceive with too small msg_len did not fail with EMSGSIZE: Unknown error 1997360560
  21         1
  22         # ./tst-mqueue4 ; echo $?
  23         mq_timedsend did not fail with ETIMEDOUT: Unknown error 2008747440
  24         1
  25
  26     When _dl_runtime_resolve() was taken out of the equation, the same test
  27     cases passed:
  28
  29         # LD_BIND_NOW=y ./tst-mqueue1 ; echo $?
  30         0
  31         # LD_BIND_NOW=y ./tst-mqueue2 ; echo $?
  32         0
  33         # LD_BIND_NOW=y ./tst-mqueue4 ; echo $?
  34         0
  35
  36     Changing __syscall_error() to look at $a0 instead of $v0 fixed the
  37     problem.
  38
  39     (Note that there is also a "__syscall_error.c" file which presumably
  40     uses the standard C calling conventions, but I do not think it is used
  41     on MIPS.)
  42
  43     Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
  44     Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
  45
  46 commit 3c58d95d918c7e2fda374c37a52f81b34b81e4ca
  47 Author: Kevin Cernekee <cernekee@gmail.com>
  48 Date:   Tue Jun 5 15:05:19 2012 -0700
  49
  50     MIPS: Convert __syscall_error() callers to use $a0 for argument
  51
  52     Some callers passed the first argument in $v0, while others used $a0.
  53     Change the callers to use $a0 consistently.
  54
  55     Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
  56     Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
  57
  58 --- a/libc/sysdeps/linux/mips/vfork.S
  59 +++ b/libc/sysdeps/linux/mips/vfork.S
  60 @@ -84,6 +84,7 @@ NESTED(__vfork,FRAMESZ,sp)
  61
  62         /* Something bad happened -- no child created.  */
  63  L(error):
  64 +       move    a0, v0
  65  #ifdef __PIC__
  66         PTR_LA          t9, __syscall_error
  67         RESTORE_GP64
  68 --- a/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/mips64/sysdep-cancel.h
  69 +++ b/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/mips64/sysdep-cancel.h
  70 @@ -31,7 +31,7 @@
  71  # undef PSEUDO
  72  # define PSEUDO(name, syscall_name, args)                                    \
  73    .align 2;                                                                  \
  74 -  99:                                                                        \
  75 +  99: move a0, v0;                                                           \
  76    PTR_LA t9,__syscall_error;                                                 \
  77    /* manual cpreturn.  */                                                    \
  78    REG_L gp, STKOFF_GP(sp);                                                   \
  79 --- a/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/vfork.S
  80 +++ b/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/vfork.S
  81 @@ -80,6 +80,7 @@ NESTED(__vfork,FRAMESZ,sp)
  82
  83         /* Something bad happened -- no child created.  */
  84  L(error):
  85 +       move            a0, v0
  86  #ifdef __PIC__
  87         PTR_LA          t9, __syscall_error
  88         RESTORE_GP64
  89 --- a/libc/sysdeps/linux/mips/syscall_error.S
  90 +++ b/libc/sysdeps/linux/mips/syscall_error.S
  91 @@ -43,7 +43,7 @@ ENTRY(__syscall_error)
  92  #ifdef __PIC__
  93         SAVE_GP(GPOFF)
  94  #endif
  95 -       REG_S   v0, V0OFF(sp)
  96 +       REG_S   a0, V0OFF(sp)
  97         REG_S   ra, RAOFF(sp)
  98
  99         /* Find our per-thread errno address  */