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			100 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			100 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
commit 2952c70804b48bb5c87eea21df5e401969dc4ec1
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Author: Kevin Cernekee <cernekee@gmail.com>
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Date:   Tue Jun 5 15:05:20 2012 -0700
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    MIPS: Use $a0 instead of $v0 for __syscall_error() argument
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    $a0 is saved across _dl_runtime_resolve(); $v0 is not.  Unfortunately,
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    __syscall_error() uses $v0 for its argument, not $a0 as is the MIPS ABI
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    standard.  This means that if lazy binding was used for __syscall_error(),
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    the errno value in $v0 could get corrupted.
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    The problem can be easily seen in testcases where syscalls in librt fail;
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    when librt tries to call __syscall_error() in libc, the argument gets
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    lost and errno gets set to a bogus value:
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        # ./tst-mqueue1 ; echo $?
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        mq_receive on O_WRONLY mqd_t did not fail with EBADF: Unknown error 2004684208
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        1
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        # ./tst-mqueue2 ; echo $?
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        mq_timedreceive with too small msg_len did not fail with EMSGSIZE: Unknown error 1997360560
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        1
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        # ./tst-mqueue4 ; echo $?
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        mq_timedsend did not fail with ETIMEDOUT: Unknown error 2008747440
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        1
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    When _dl_runtime_resolve() was taken out of the equation, the same test
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    cases passed:
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        # LD_BIND_NOW=y ./tst-mqueue1 ; echo $?
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        0
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        # LD_BIND_NOW=y ./tst-mqueue2 ; echo $?
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        0
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        # LD_BIND_NOW=y ./tst-mqueue4 ; echo $?
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        0
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    Changing __syscall_error() to look at $a0 instead of $v0 fixed the
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    problem.
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    (Note that there is also a "__syscall_error.c" file which presumably
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    uses the standard C calling conventions, but I do not think it is used
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    on MIPS.)
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    Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
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    Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
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commit 3c58d95d918c7e2fda374c37a52f81b34b81e4ca
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Author: Kevin Cernekee <cernekee@gmail.com>
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Date:   Tue Jun 5 15:05:19 2012 -0700
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    MIPS: Convert __syscall_error() callers to use $a0 for argument
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    Some callers passed the first argument in $v0, while others used $a0.
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    Change the callers to use $a0 consistently.
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    Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
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    Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
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--- a/libc/sysdeps/linux/mips/vfork.S
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+++ b/libc/sysdeps/linux/mips/vfork.S
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@@ -84,6 +84,7 @@ NESTED(__vfork,FRAMESZ,sp)
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 	/* Something bad happened -- no child created.  */
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 L(error):
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+	move	a0, v0
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 #ifdef __PIC__
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 	PTR_LA		t9, __syscall_error
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 	RESTORE_GP64
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--- a/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/mips64/sysdep-cancel.h
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+++ b/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/mips64/sysdep-cancel.h
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@@ -31,7 +31,7 @@
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 # undef PSEUDO
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 # define PSEUDO(name, syscall_name, args)				      \
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   .align 2;								      \
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-  99:									      \
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+  99: move a0, v0; 							      \
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   PTR_LA t9,__syscall_error;					 	      \
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   /* manual cpreturn.  */						      \
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   REG_L gp, STKOFF_GP(sp);						      \
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--- a/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/vfork.S
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+++ b/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/vfork.S
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@@ -80,6 +80,7 @@ NESTED(__vfork,FRAMESZ,sp)
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 	/* Something bad happened -- no child created.  */
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 L(error):
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+	move		a0, v0
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 #ifdef __PIC__
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 	PTR_LA		t9, __syscall_error
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 	RESTORE_GP64
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--- a/libc/sysdeps/linux/mips/syscall_error.S
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+++ b/libc/sysdeps/linux/mips/syscall_error.S
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@@ -43,7 +43,7 @@ ENTRY(__syscall_error)
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 #ifdef __PIC__
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 	SAVE_GP(GPOFF)
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 #endif
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-	REG_S	v0, V0OFF(sp)
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+	REG_S	a0, V0OFF(sp)
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 	REG_S	ra, RAOFF(sp)
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 	/* Find our per-thread errno address  */
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