Patch for Go1.6 to use set_thread_area instead of modify_ldt

go16_set_thread_area.patch

ec2-user@ip-10-1-8-251 go]$ diff -u src/runtime/sys_linux_386.s.orig src/runtime/sys_linux_386.s
--- src/runtime/sys_linux_386.s.orig    2016-03-26 02:42:51.537721466 +0000
+++ src/runtime/sys_linux_386.s 2016-03-26 02:44:37.973471872 +0000
@@ -407,7 +407,6 @@

 // setldt(int entry, int address, int limit)
 TEXT runtime·setldt(SB),NOSPLIT,$32
-       MOVL    entry+0(FP), BX // entry
        MOVL    address+4(FP), DX       // base address

 #ifdef GOOS_android
@@ -444,16 +443,14 @@

        // set up user_desc
        LEAL    16(SP), AX      // struct user_desc
-       MOVL    BX, 0(AX)
+       MOVL    $-1, 0(AX)
        MOVL    DX, 4(AX)
        MOVL    $0xfffff, 8(AX)
        MOVL    $(SEG_32BIT|LIMIT_IN_PAGES|USEABLE|CONTENTS_DATA), 12(AX)       // flag bits

-       // call modify_ldt
-       MOVL    $1, BX  // func = 1 (write)
-       MOVL    AX, CX  // user_desc
-       MOVL    $16, DX // sizeof(user_desc)
-       MOVL    $123, AX        // syscall - modify_ldt
+       // call set_thread_area
+       MOVL    AX, BX  // user_desc
+       MOVL    $243, AX        // syscall - set_thread_area
        // We can't call this via 0x10(GS) because this is called from setldt0 to set that up.
        INT     $0x80

@@ -463,9 +460,10 @@
        INT $3

        // compute segment selector - (entry*8+7)
-       MOVL    entry+0(FP), AX
+       LEAL    16(SP), AX      // get our user_desc back
+       MOVL    0(AX), AX
        SHLL    $3, AX
-       ADDL    $7, AX
+       ADDL    $3, AX
        MOVW    AX, GS

        RET