runtime: port assembly files for aix/ppc64

This commit adds the change on asm_ppc64.s and tls_ppc64.s files for AIX
operating system.

R2 does not need to be set for aix/ppc64 since it should remain valid
througout Go execution, except after a call to a C function.
Moreover, g must always be saved on the tls as syscalls are made with
C functions.

Some modifications on asm_ppc64.s are due to AIX stack layout.

It also removes a useless part in asmcgocall which was done twice.

Change-Id: Ie037ab73da00562bb978f2d0f17fcdabd4a40aa2
Reviewed-on: https://go-review.googlesource.com/c/138735
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index b180cb06ab9d0b3a5001f27f92aa098222729f31..e77c7179354927903875f4646e6d45011c88e987 100644 (file)
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -140,7 +140,9 @@ TEXT runtime·gogo(SB), NOSPLIT, $16-8
        MOVD    0(g), R4
        MOVD    gobuf_sp(R5), R1
        MOVD    gobuf_lr(R5), R31
+#ifndef GOOS_aix
        MOVD    24(R1), R2      // restore R2
+#endif
        MOVD    R31, LR
        MOVD    gobuf_ret(R5), R3
        MOVD    gobuf_ctxt(R5), R11
@@ -257,7 +259,9 @@ switch:
        MOVD    g_m(g), R3
        MOVD    m_curg(R3), g
        MOVD    (g_sched+gobuf_sp)(g), R3
+#ifndef GOOS_aix
        MOVD    24(R3), R2
+#endif
        // switch back to g
        MOVD    g_m(g), R3
        MOVD    m_curg(R3), g
@@ -274,7 +278,9 @@ noswitch:
        MOVD    0(R11), R12     // code pointer
        MOVD    R12, CTR
        BL      (CTR)
+#ifndef GOOS_aix
        MOVD    24(R1), R2
+#endif
        RET
 
 /*
@@ -422,11 +428,20 @@ tail: \
 callfn: \
        /* call function */                     \
        MOVD    f+8(FP), R11;                   \
+#ifdef GOOS_aix                                \
+       /* AIX won't trigger a SIGSEGV if R11 = nil */  \
+       /* So it manually triggers it */        \
+       CMP     R0, R11                         \
+       BNE     2(PC)                           \
+       MOVD    R0, 0(R0)                       \
+#endif                                         \
        MOVD    (R11), R12;                     \
        MOVD    R12, CTR;                       \
        PCDATA  $PCDATA_StackMapIndex, $0;      \
        BL      (CTR);                          \
+#ifndef GOOS_aix                               \
        MOVD    24(R1), R2;                     \
+#endif                                         \
        /* copy return values back */           \
        MOVD    argtype+0(FP), R7;              \
        MOVD    arg+16(FP), R3;                 \
@@ -504,12 +519,22 @@ again:
 // the BL deferreturn and jmpdefer rewinds to that.
 TEXT runtime·jmpdefer(SB), NOSPLIT|NOFRAME, $0-16
        MOVD    0(R1), R31
+#ifdef GOOS_aix
+       MOVD    16(R31), R31    // caller LR is on the previous stack frame on AIX
+#endif
        SUB     $8, R31
        MOVD    R31, LR
 
        MOVD    fv+0(FP), R11
        MOVD    argp+8(FP), R1
        SUB     $FIXED_FRAME, R1
+#ifdef GOOS_aix
+       // AIX won't trigger a SIGSEGV if R11 = nil
+       // So it manually triggers it
+       CMP     R0, R11
+       BNE     2(PC)
+       MOVD    R0, 0(R0)
+#endif
        MOVD    0(R11), R12
        MOVD    R12, CTR
        BR      (CTR)
@@ -542,8 +567,13 @@ TEXT ·asmcgocall(SB),NOSPLIT,$0-20
        // Figure out if we need to switch to m->g0 stack.
        // We get called to create new OS threads too, and those
        // come in on the m->g0 stack already.
-       MOVD    g_m(g), R6
-       MOVD    m_g0(R6), R6
+       // Moreover, if it's called inside the signal handler, it must not switch
+       // to g0 as it can be in use by another syscall.
+       MOVD    g_m(g), R8
+       MOVD    m_gsignal(R8), R6
+       CMP     R6, g
+       BEQ     g0
+       MOVD    m_g0(R8), R6
        CMP     R6, g
        BEQ     g0
        BL      gosave<>(SB)
@@ -555,13 +585,22 @@ TEXT ·asmcgocall(SB),NOSPLIT,$0-20
 g0:
        // Save room for two of our pointers, plus 32 bytes of callee
        // save area that lives on the caller stack.
+#ifdef GOOS_aix
+       // Create a fake LR to improve backtrace.
+       MOVD    $runtime·asmcgocall(SB), R6
+       MOVD    R6, 16(R1)
+#endif
        SUB     $48, R1
        RLDCR   $0, R1, $~15, R1        // 16-byte alignment for gcc ABI
        MOVD    R5, 40(R1)      // save old g on stack
        MOVD    (g_stack+stack_hi)(R5), R5
        SUB     R7, R5
        MOVD    R5, 32(R1)      // save depth in old g stack (can't just save SP, as stack might be copied during a callback)
+#ifdef GOOS_aix
+       MOVD    R7, 0(R1)       // Save frame pointer to allow manual backtrace with gdb
+#else
        MOVD    R0, 0(R1)       // clear back chain pointer (TODO can we give it real back trace information?)
+#endif
        // This is a "global call", so put the global entry point in r12
        MOVD    R3, R12
        MOVD    R12, CTR
@@ -574,15 +613,14 @@ g0:
        // Restore g, stack pointer, toc pointer.
        // R3 is errno, so don't touch it
        MOVD    40(R1), g
-       MOVD    (g_stack+stack_hi)(g), R5
-       MOVD    32(R1), R6
-       SUB     R6, R5
-       MOVD    24(R5), R2
-       BL      runtime·save_g(SB)
        MOVD    (g_stack+stack_hi)(g), R5
        MOVD    32(R1), R6
        SUB     R6, R5
+#ifndef GOOS_aix
+       MOVD    24(R5), R2
+#endif
        MOVD    R5, R1
+       BL      runtime·save_g(SB)
 
        MOVW    R3, ret+16(FP)
        RET

diff --git a/src/runtime/tls_ppc64x.s b/src/runtime/tls_ppc64x.s
index ed94989b6914671da8c953785334e5c14386026d..82714853ee7a84f2794dbe0cdf575dcfcf9f2f4e 100644 (file)
--- a/src/runtime/tls_ppc64x.s
+++ b/src/runtime/tls_ppc64x.s
@@ -23,9 +23,11 @@
 //
 // NOTE: setg_gcc<> assume this clobbers only R31.
 TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
+#ifndef GOOS_aix
        MOVB    runtime·iscgo(SB), R31
        CMP     R31, $0
        BEQ     nocgo
+#endif
        MOVD    runtime·tls_g(SB), R31
        MOVD    g, 0(R13)(R31*1)