runtime: save registers in linux/{386,amd64} lib entry point

The callee-saved registers must be saved because for the c-shared case
this code is invoked from C code in the system library, and that code
expects the registers to be saved.  The tests were passing because in
the normal case the code calls a cgo function that naturally saves
callee-saved registers anyhow.  However, it fails when the code takes
the non-cgo path.

Change-Id: I9c1f5e884f5a72db9614478049b1863641c8b2b9
Reviewed-on: https://go-review.googlesource.com/9114
Reviewed-by: David Crawshaw <crawshaw@golang.org>

diff --git a/src/runtime/rt0_linux_386.s b/src/runtime/rt0_linux_386.s
index 14d9f548261c1d44d0f3d51aa1d9194fd303a44b..f98642bc03f86717290791e880000fd06b110f1f 100644 (file)
--- a/src/runtime/rt0_linux_386.s
+++ b/src/runtime/rt0_linux_386.s
@@ -14,12 +14,20 @@ TEXT _rt0_386_linux(SB),NOSPLIT,$8
 
 // When building with -buildmode=c-shared, this symbol is called when the shared
 // library is loaded.
-TEXT _rt0_386_linux_lib(SB),NOSPLIT,$12
-       MOVL    16(SP), AX
+TEXT _rt0_386_linux_lib(SB),NOSPLIT,$0
+       PUSHL   BP
+       MOVL    SP, BP
+       PUSHL   BX
+       PUSHL   SI
+       PUSHL   DI
+
+       MOVL    8(BP), AX
        MOVL    AX, _rt0_386_linux_lib_argc<>(SB)
-       MOVL    20(SP), AX
+       MOVL    12(BP), AX
        MOVL    AX, _rt0_386_linux_lib_argv<>(SB)
 
+       SUBL    $8, SP
+
        // Create a new thread to do the runtime initialization.
        MOVL    _cgo_sys_thread_create(SB), AX
        TESTL   AX, AX
@@ -28,7 +36,7 @@ TEXT _rt0_386_linux_lib(SB),NOSPLIT,$12
        MOVL    BX, 0(SP)
        MOVL    $0, 4(SP)
        CALL    AX
-       RET
+       JMP     restore
 
 nocgo:
        MOVL    $0x800000, 0(SP)                    // stacksize = 8192KB
@@ -37,6 +45,13 @@ nocgo:
        MOVL    $0, 8(SP)                           // fnarg
        MOVL    $runtime·newosproc0(SB), AX
        CALL    AX
+
+restore:
+       ADDL    $8, SP
+       POPL    DI
+       POPL    SI
+       POPL    BX
+       POPL    BP
        RET
 
 TEXT _rt0_386_linux_lib_go(SB),NOSPLIT,$12

diff --git a/src/runtime/rt0_linux_amd64.s b/src/runtime/rt0_linux_amd64.s
index 9010aba271e981246985f2f75f6cf16050eb8edf..ee1dbc6cd13280eb054be2174743071d8ff9d9e7 100644 (file)
--- a/src/runtime/rt0_linux_amd64.s
+++ b/src/runtime/rt0_linux_amd64.s
@@ -12,7 +12,14 @@ TEXT _rt0_amd64_linux(SB),NOSPLIT,$-8
 
 // When building with -buildmode=c-shared, this symbol is called when the shared
 // library is loaded.
-TEXT _rt0_amd64_linux_lib(SB),NOSPLIT,$40
+TEXT _rt0_amd64_linux_lib(SB),NOSPLIT,$0x58
+       MOVQ    BX, 0x18(SP)
+       MOVQ    BP, 0x20(SP)
+       MOVQ    R12, 0x28(SP)
+       MOVQ    R13, 0x30(SP)
+       MOVQ    R14, 0x38(SP)
+       MOVQ    R15, 0x40(SP)
+
        MOVQ    DI, _rt0_amd64_linux_lib_argc<>(SB)
        MOVQ    SI, _rt0_amd64_linux_lib_argv<>(SB)
 
@@ -23,14 +30,23 @@ TEXT _rt0_amd64_linux_lib(SB),NOSPLIT,$40
        MOVQ    $_rt0_amd64_linux_lib_go(SB), DI
        MOVQ    $0, SI
        CALL    AX
-       RET
+       JMP     restore
+
 nocgo:
        MOVQ    $8388608, 0(SP)                    // stacksize
        MOVQ    $_rt0_amd64_linux_lib_go(SB), AX
        MOVQ    AX, 8(SP)                          // fn
-       MOVQ    $0, 16(SP)                         // fnarg
+       MOVQ    $0, 0x10(SP)                       // fnarg
        MOVQ    $runtime·newosproc0(SB), AX
        CALL    AX
+
+restore:
+       MOVQ    0x18(SP), BX
+       MOVQ    0x20(SP), BP
+       MOVQ    0x28(SP), R12
+       MOVQ    0x30(SP), R13
+       MOVQ    0x38(SP), R14
+       MOVQ    0x40(SP), R15
        RET
 
 TEXT _rt0_amd64_linux_lib_go(SB),NOSPLIT,$0