[src/trunk]: src/lib/libc/arch/powerpc64 Replace the branch to __cerror() in ...

[dennis <dennis%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4b7e4f056d18
branches:  trunk
changeset: 335536:4b7e4f056d18
user:      dennis <dennis%NetBSD.org@localhost>
date:      Mon Jan 12 02:48:20 2015 +0000

description:
Replace the branch to __cerror() in powerpc64 syscall stubs
with inline code which does what __cerror() was doing.  #ifdef
that code (i.e. all code) out of cerror.S; __cerror() is no more.
This seems to be necessary to fix the link of rescue/rescue, and
should have the pleasant side effect of making all other workarounds
done to keep the 'b __cerror' working unnecessary.

diffstat:

 lib/libc/arch/powerpc64/SYS.h        |  42 +++++++++++++++++++++++++++++------
 lib/libc/arch/powerpc64/sys/cerror.S |  23 ++++++++++---------
 2 files changed, 46 insertions(+), 19 deletions(-)

diffs (115 lines):

diff -r 8c1f6e112b18 -r 4b7e4f056d18 lib/libc/arch/powerpc64/SYS.h
--- a/lib/libc/arch/powerpc64/SYS.h     Mon Jan 12 02:32:33 2015 +0000
+++ b/lib/libc/arch/powerpc64/SYS.h     Mon Jan 12 02:48:20 2015 +0000
@@ -1,13 +1,39 @@
-/*     $NetBSD: SYS.h,v 1.3 2014/08/23 02:24:22 matt Exp $     */
+/*     $NetBSD: SYS.h,v 1.4 2015/01/12 02:48:20 dennis Exp $   */
 
 #include <machine/asm.h>
 #include <sys/syscall.h>
 
-#ifdef _CALL_AIX
-#define        BRANCH_TO_CERROR()      b       ._C_LABEL(__cerror); nop
-#else
-#define        BRANCH_TO_CERROR()      b       _C_LABEL(__cerror)
-#endif
+/*
+ * Inline what __cerror() is generally used to do since branching
+ * to __cerror() can't be done reliably with the powerpc64 ABI.
+ */
+#ifdef _REENTRANT
+#define        _DO_CERROR_SF_SZ        (SF_SZ + SF_ALIGN(8))
+#define        _DO_CERROR()            mflr    %r0                             ;\
+                               streg   %r31,-8(%r1)                    ;\
+                               streg   %r0,SF_LR(%r1)                  ;\
+                               stptru  %r1,-_DO_CERROR_SF_SZ(%r1)      ;\
+                               mr      %r31,%r3                        ;\
+                               bl      PIC_PLT(_C_LABEL(__errno))      ;\
+                               nop                                     ;\
+                               stint   %r31,0(%r3)                     ;\
+                               addi    %r1,%r1,_DO_CERROR_SF_SZ        ;\
+                               ldreg   %r0,SF_LR(%r1)                  ;\
+                               ldreg   %r31,-8(%r1)                    ;\
+                               mtlr    %r0                             ;\
+                               li      %r3,-1                          ;\
+                               li      %r4,-1                          ;\
+                               blr
+#else  /* !_REENTRANT */
+#define        _DO_CERROR()            lwz     %r4,_C_LABEL(errno)@got(%r2)    ;\
+                               stw     %r3,0(%r4)                      ;\
+                               li      %r3,-1                          ;\
+                               li      %r4,-1                          ;\
+                               blr
+#endif /* _REENTRANT */
+
+/* Clearly BRANCH_TO_CERROR() no longer does that... */
+#define        BRANCH_TO_CERROR()      _DO_CERROR()
 
 #define        _DOSYSCALL(x)           li      %r0,(SYS_ ## x)         ;\
                                sc
@@ -19,7 +45,7 @@
 
 #define _SYSCALL(x,y)          .text                           ;\
                                .p2align 2                      ;\
-                       2:      BRANCH_TO_CERROR()              ;\
+                       2:      _DO_CERROR()                    ;\
                                _SYSCALL_NOERROR(x,y)           ;\
                                bso     2b
 
@@ -33,7 +59,7 @@
 
 #define PSEUDO(x,y)            _SYSCALL_NOERROR(x,y)           ;\
                                bnslr                           ;\
-                               BRANCH_TO_CERROR()              ;\
+                               _DO_CERROR()                    ;\
                                END(x)
 
 #define RSYSCALL_NOERROR(x)    PSEUDO_NOERROR(x,x)
diff -r 8c1f6e112b18 -r 4b7e4f056d18 lib/libc/arch/powerpc64/sys/cerror.S
--- a/lib/libc/arch/powerpc64/sys/cerror.S      Mon Jan 12 02:32:33 2015 +0000
+++ b/lib/libc/arch/powerpc64/sys/cerror.S      Mon Jan 12 02:48:20 2015 +0000
@@ -1,5 +1,8 @@
-/*     $NetBSD: cerror.S,v 1.6 2014/08/23 02:24:22 matt Exp $  */
+/*     $NetBSD: cerror.S,v 1.7 2015/01/12 02:48:20 dennis Exp $        */
 
+/* Now inlined in the syscall stubs.  Keep code for a while for mind changes. */
+
+#if 0
 #include <machine/asm.h>
 #include "SYS.h"
 
@@ -13,26 +16,24 @@
 ENTRY(__cerror)
 #ifdef _REENTRANT
        mflr    %r0
-       streg   %r0,__SIZEOF_POINTER__(%r1)
-       stptru  %r1,-(4*__SIZEOF_POINTER__)(%r1) # allocate new stack frame
-       streg   %r31,(3*__SIZEOF_POINTER__)(%r1)
+       streg   %r0,SF_LR(%r1)
+       streg   %r31,-8(%r1)
+       stptru  %r1,-(SF_SZ+16)(%r1)    # allocate new stack frame
        mr      %r31,%r3                # stash away in callee-saved register
        bl      PIC_PLT(_C_LABEL(__errno))
        nop
        stint   %r31,0(%r3)
 
-       ldreg   %r31,(3*__SIZEOF_POINTER__)(%r1)
-       addi    %r1,%r1,4*__SIZEOF_POINTER__
-       ldreg   %r0,__SIZEOF_POINTER__(%r1)
+       addi    %r1,%r1,(SF_SZ+16)
+       ldreg   %r31,-8(%r1)
+       ldreg   %r0,SF_LR(%r1)
        mtlr    %r0
 #else
-       .pushsection ".toc", "aw"
-.Lerrno:.tc    errno[TC], errno
-       .popsection
-       lwz     %r4,_C_LABEL(.Lerrno)@toc(%r2)
+       lwz     %r4,_C_LABEL(errno)@got(%r2)
        stw     %r3,0(%r4)
 #endif /* _REENTRANT */
        li      %r3,-1
        li      %r4,-1
        blr
 END(__cerror)
+#endif /* 0 */