
/*--------------------------------------------------------------------*/
/*--- A minimal setjmp/longjmp implementation.      m_libcsetjmp.c ---*/
/*--------------------------------------------------------------------*/
 
/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2010-2012 Mozilla Inc

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/

/* Contributed by Julian Seward <jseward@acm.org> */


#include "pub_core_basics.h"
#include "pub_core_libcsetjmp.h"    /* self */


/* See include/pub_tool_libcsetjmp.h for background and rationale. */

/* The alternative implementations are for ppc{32,64}-linux and
   {amd64,x86}-{linux,darwin}.  See #259977.  That leaves only
   {arm,s390x}-linux using the gcc builtins now.
*/

/* ------------ ppc32-linux ------------ */

#if defined(VGP_ppc32_linux)

__asm__(
".text"  "\n"
""       "\n"
".global VG_MINIMAL_SETJMP"  "\n"  // r3 = jmp_buf
"VG_MINIMAL_SETJMP:"  "\n"
"        stw     0, 0(3)"  "\n"
"        stw     1, 4(3)"  "\n"
"        stw     2, 8(3)"  "\n"
"        stw     3, 12(3)"  "\n"
"        stw     4, 16(3)"  "\n"
"        stw     5, 20(3)"  "\n"
"        stw     6, 24(3)"  "\n"
"        stw     7, 28(3)"  "\n"
"        stw     8, 32(3)"  "\n"
"        stw     9, 36(3)"  "\n"
"        stw     10, 40(3)"  "\n"
"        stw     11, 44(3)"  "\n"
"        stw     12, 48(3)"  "\n"
"        stw     13, 52(3)"  "\n"
"        stw     14, 56(3)"  "\n"
"        stw     15, 60(3)"  "\n"
"        stw     16, 64(3)"  "\n"
"        stw     17, 68(3)"  "\n"
"        stw     18, 72(3)"  "\n"
"        stw     19, 76(3)"  "\n"
"        stw     20, 80(3)"  "\n"
"        stw     21, 84(3)"  "\n"
"        stw     22, 88(3)"  "\n"
"        stw     23, 92(3)"  "\n"
"        stw     24, 96(3)"  "\n"
"        stw     25, 100(3)"  "\n"
"        stw     26, 104(3)"  "\n"
"        stw     27, 108(3)"  "\n"
"        stw     28, 112(3)"  "\n"
"        stw     29, 116(3)"  "\n"
"        stw     30, 120(3)"  "\n"
"        stw     31, 124(3)"  "\n"
         // must use a caller-save register here as scratch, hence r4
"        mflr    4"  "\n"
"        stw     4, 128(3)"  "\n"
"        mfcr    4"  "\n"
"        stw     4, 132(3)"  "\n"
"        li      3, 0"  "\n"
"        blr"  "\n"
""       "\n"


".global VG_MINIMAL_LONGJMP"  "\n"
"VG_MINIMAL_LONGJMP:"  "\n"    // r3 = jmp_buf
         // do r4 = 1
         // and park it in the restore slot for r3 (the ret reg)
"        li      4, 1"  "\n"
"        stw     4, 12(3)"  "\n"
         // restore everything except r3
         // then r3 last of all
         // then blr
"        lwz     0, 128(3)"  "\n"
"        mtlr    0"  "\n"
"        lwz     0, 132(3)"  "\n"
"        mtcr    0"  "\n"
"        lwz     0, 0(3)"  "\n"
"        lwz     1, 4(3)"  "\n"
"        lwz     2, 8(3)"  "\n"
         // r3 is done at the end
"        lwz     4, 16(3)"  "\n"
"        lwz     5, 20(3)"  "\n"
"        lwz     6, 24(3)"  "\n"
"        lwz     7, 28(3)"  "\n"
"        lwz     8, 32(3)"  "\n"
"        lwz     9, 36(3)"  "\n"
"        lwz     10, 40(3)"  "\n"
"        lwz     11, 44(3)"  "\n"
"        lwz     12, 48(3)"  "\n"
"        lwz     13, 52(3)"  "\n"
"        lwz     14, 56(3)"  "\n"
"        lwz     15, 60(3)"  "\n"
"        lwz     16, 64(3)"  "\n"
"        lwz     17, 68(3)"  "\n"
"        lwz     18, 72(3)"  "\n"
"        lwz     19, 76(3)"  "\n"
"        lwz     20, 80(3)"  "\n"
"        lwz     21, 84(3)"  "\n"
"        lwz     22, 88(3)"  "\n"
"        lwz     23, 92(3)"  "\n"
"        lwz     24, 96(3)"  "\n"
"        lwz     25, 100(3)"  "\n"
"        lwz     26, 104(3)"  "\n"
"        lwz     27, 108(3)"  "\n"
"        lwz     28, 112(3)"  "\n"
"        lwz     29, 116(3)"  "\n"
"        lwz     30, 120(3)"  "\n"
"        lwz     31, 124(3)"  "\n"
"        lwz     3, 12(3)"  "\n"
"        blr"  "\n"
""       "\n"

".previous"  "\n"
);

#endif /* VGP_ppc32_linux */


/* ------------ ppc64-linux ------------ */

#if defined(VGP_ppc64_linux)

__asm__(
".section \".toc\",\"aw\""          "\n"

".section \".text\""                "\n"
".align 2"                          "\n"
".p2align 4,,15"                    "\n"
".globl VG_MINIMAL_SETJMP"          "\n"

".section \".opd\",\"aw\""          "\n"
".align 3"                          "\n"
"VG_MINIMAL_SETJMP:"                "\n"
".quad .L.VG_MINIMAL_SETJMP,.TOC.@tocbase,0"   "\n"
".previous"                         "\n"

".type VG_MINIMAL_SETJMP, @function"   "\n"
".L.VG_MINIMAL_SETJMP:"   "\n"
"        std     0, 0(3)"  "\n"
"        std     1, 8(3)"  "\n"
"        std     2, 16(3)"  "\n"
"        std     3, 24(3)"  "\n"
"        std     4, 32(3)"  "\n"
"        std     5, 40(3)"  "\n"
"        std     6, 48(3)"  "\n"
"        std     7, 56(3)"  "\n"
"        std     8, 64(3)"  "\n"
"        std     9, 72(3)"  "\n"
"        std     10, 80(3)"  "\n"
"        std     11, 88(3)"  "\n"
"        std     12, 96(3)"  "\n"
"        std     13, 104(3)"  "\n"
"        std     14, 112(3)"  "\n"
"        std     15, 120(3)"  "\n"
"        std     16, 128(3)"  "\n"
"        std     17, 136(3)"  "\n"
"        std     18, 144(3)"  "\n"
"        std     19, 152(3)"  "\n"
"        std     20, 160(3)"  "\n"
"        std     21, 168(3)"  "\n"
"        std     22, 176(3)"  "\n"
"        std     23, 184(3)"  "\n"
"        std     24, 192(3)"  "\n"
"        std     25, 200(3)"  "\n"
"        std     26, 208(3)"  "\n"
"        std     27, 216(3)"  "\n"
"        std     28, 224(3)"  "\n"
"        std     29, 232(3)"  "\n"
"        std     30, 240(3)"  "\n"
"        std     31, 248(3)"  "\n"
         // must use a caller-save register here as scratch, hence r4
"        mflr    4"  "\n"
"        std     4, 256(3)"  "\n"
"        mfcr    4"  "\n"
"        std     4, 264(3)"  "\n"
"        li      3, 0"  "\n"
"        blr"  "\n"
""       "\n"


".globl VG_MINIMAL_LONGJMP"         "\n"

".section \".opd\",\"aw\""          "\n"
".align 3"                          "\n"
"VG_MINIMAL_LONGJMP:"               "\n"
".quad .L.VG_MINIMAL_LONGJMP,.TOC.@tocbase,0"   "\n"
".previous" "\n"

".type   VG_MINIMAL_LONGJMP, @function"    "\n"
".L.VG_MINIMAL_LONGJMP:"            "\n"
         // do r4 = 1
         // and park it in the restore slot for r3 (the ret reg)
"        li      4, 1"  "\n"
"        std     4, 24(3)"  "\n"
         // restore everything except r3
         // then r3 last of all
         // then blr
"        ld      0, 256(3)"  "\n"
"        mtlr    0"  "\n"
"        ld      0, 264(3)"  "\n"
"        mtcr    0"  "\n"
"        ld      0, 0(3)"  "\n"
"        ld      1, 8(3)"  "\n"
"        ld      2, 16(3)"  "\n"
         // r3 is done at the end
"        ld      4, 32(3)"  "\n"
"        ld      5, 40(3)"  "\n"
"        ld      6, 48(3)"  "\n"
"        ld      7, 56(3)"  "\n"
"        ld      8, 64(3)"  "\n"
"        ld      9, 72(3)"  "\n"
"        ld      10, 80(3)"  "\n"
"        ld      11, 88(3)"  "\n"
"        ld      12, 96(3)"  "\n"
"        ld      13, 104(3)"  "\n"
"        ld      14, 112(3)"  "\n"
"        ld      15, 120(3)"  "\n"
"        ld      16, 128(3)"  "\n"
"        ld      17, 136(3)"  "\n"
"        ld      18, 144(3)"  "\n"
"        ld      19, 152(3)"  "\n"
"        ld      20, 160(3)"  "\n"
"        ld      21, 168(3)"  "\n"
"        ld      22, 176(3)"  "\n"
"        ld      23, 184(3)"  "\n"
"        ld      24, 192(3)"  "\n"
"        ld      25, 200(3)"  "\n"
"        ld      26, 208(3)"  "\n"
"        ld      27, 216(3)"  "\n"
"        ld      28, 224(3)"  "\n"
"        ld      29, 232(3)"  "\n"
"        ld      30, 240(3)"  "\n"
"        ld      31, 248(3)"  "\n"
"        ld      3, 24(3)"  "\n"
"        blr"               "\n"
""       "\n"

".previous"  "\n"
".previous"  "\n"
);

#endif /* VGP_ppc64_linux */


/* ------------ amd64-{linux,darwin} ------------ */

#if defined(VGP_amd64_linux) || defined(VGP_amd64_darwin)

__asm__(
".text"  "\n"
""       "\n"

#if defined(VGP_amd64_linux)
".global VG_MINIMAL_SETJMP"  "\n"  // rdi = jmp_buf
"VG_MINIMAL_SETJMP:"  "\n"

#elif defined(VGP_amd64_darwin)
".globl _VG_MINIMAL_SETJMP"  "\n"  // rdi = jmp_buf
"_VG_MINIMAL_SETJMP:"  "\n"

#else
#   error "Huh?"
#endif

"        movq   %rax,   0(%rdi)"   "\n"
"        movq   %rbx,   8(%rdi)"   "\n"
"        movq   %rcx,  16(%rdi)"   "\n"
"        movq   %rdx,  24(%rdi)"   "\n"
"        movq   %rdi,  32(%rdi)"   "\n"
"        movq   %rsi,  40(%rdi)"   "\n"
"        movq   %rbp,  48(%rdi)"   "\n"
"        movq   %rsp,  56(%rdi)"   "\n"
"        movq   %r8,   64(%rdi)"   "\n"
"        movq   %r9,   72(%rdi)"   "\n"
"        movq   %r10,  80(%rdi)"   "\n"
"        movq   %r11,  88(%rdi)"   "\n"
"        movq   %r12,  96(%rdi)"   "\n"
"        movq   %r13, 104(%rdi)"   "\n"
"        movq   %r14, 112(%rdi)"   "\n"
"        movq   %r15, 120(%rdi)"   "\n"
         // store the return address
"        movq   0(%rsp), %rax"     "\n"
"        movq   %rax, 128(%rdi)"   "\n"
         // and return zero
"        movq   $0, %rax"          "\n"
"        ret"                      "\n"
""       "\n"


#if defined(VGP_amd64_linux)
".global VG_MINIMAL_LONGJMP"  "\n"
"VG_MINIMAL_LONGJMP:"  "\n"    // rdi = jmp_buf

#elif defined(VGP_amd64_darwin)
".globl _VG_MINIMAL_LONGJMP"  "\n"
"_VG_MINIMAL_LONGJMP:"  "\n"    // rdi = jmp_buf

#else
#   error "Huh?"
#endif
         // skip restoring rax; it's pointless
"        movq     8(%rdi),  %rbx"    "\n"
"        movq    16(%rdi),  %rcx"    "\n"
"        movq    24(%rdi),  %rdx"    "\n"
         // defer restoring rdi; we still need it
"        movq    40(%rdi),  %rsi"    "\n"
"        movq    48(%rdi),  %rbp"    "\n"
"        movq    56(%rdi),  %rsp"    "\n"
"        movq    64(%rdi),  %r8"     "\n"
"        movq    72(%rdi),  %r9"     "\n"
"        movq    80(%rdi),  %r10"    "\n"
"        movq    88(%rdi),  %r11"    "\n"
"        movq    96(%rdi),  %r12"    "\n"
"        movq   104(%rdi),  %r13"    "\n"
"        movq   112(%rdi),  %r14"    "\n"
"        movq   120(%rdi),  %r15"    "\n"
         // restore the return address
"        movq   128(%rdi), %rax"     "\n"
         // restore rdi; this is the last use
"        movq   32(%rdi), %rdi"      "\n"
         // make %rsp look like we really did a return
"        addq   $8, %rsp"            "\n"
         // continue at RA of original call.  Note: this is a
         // nasty trick.  We assume that %rax is nonzero, and so the
         // caller can differentiate this case from the normal _SETJMP
         // return case.  If the return address ever is zero, then
         // we're hosed; but that seems pretty unlikely given that it
         // would mean we'd be executing at the wraparound point of the
         // address space.
"        jmp *%rax"                  "\n"
""       "\n"

#if !defined(VGP_amd64_darwin)
".previous"       "\n"
#endif
);

#endif /* VGP_amd64_linux || VGP_amd64_darwin */


/* ------------ x86-{linux,darwin} ------------ */

#if defined(VGP_x86_linux) || defined(VGP_x86_darwin)

__asm__(
".text"  "\n"
""       "\n"

#if defined(VGP_x86_linux)
".global VG_MINIMAL_SETJMP"  "\n"  // eax = jmp_buf
"VG_MINIMAL_SETJMP:"  "\n"

#elif defined(VGP_x86_darwin)
".globl _VG_MINIMAL_SETJMP"  "\n"  // eax = jmp_buf
"_VG_MINIMAL_SETJMP:"  "\n"

#else
#   error "Huh?"
#endif

"        movl   %eax,   0(%eax)"   "\n"
"        movl   %ebx,   4(%eax)"   "\n"
"        movl   %ecx,   8(%eax)"   "\n"
"        movl   %edx,  12(%eax)"   "\n"
"        movl   %edi,  16(%eax)"   "\n"
"        movl   %esi,  20(%eax)"   "\n"
"        movl   %ebp,  24(%eax)"   "\n"
"        movl   %esp,  28(%eax)"   "\n"
         // store the return address
"        movl   0(%esp), %ebx"     "\n"
"        movl   %ebx, 32(%eax)"    "\n"
         // un-trash ebx (necessary?  i don't know)
"        movl   4(%eax), %ebx"     "\n"
         // and return zero
"        movl   $0, %eax"          "\n"
"        ret"                      "\n"
""       "\n"


#if defined(VGP_x86_linux)
".global VG_MINIMAL_LONGJMP"  "\n"
"VG_MINIMAL_LONGJMP:"  "\n"    // eax = jmp_buf

#elif defined(VGP_x86_darwin)
".globl _VG_MINIMAL_LONGJMP"  "\n"
"_VG_MINIMAL_LONGJMP:"  "\n"    // eax = jmp_buf

#else
#   error "Huh?"
#endif

         // skip restoring eax; it's pointless
"        movl     4(%eax),  %ebx"    "\n"
"        movl     8(%eax),  %ecx"    "\n"
"        movl    12(%eax),  %edx"    "\n"
"        movl    16(%eax),  %edi"    "\n"
"        movl    20(%eax),  %esi"    "\n"
"        movl    24(%eax),  %ebp"    "\n"
"        movl    28(%eax),  %esp"    "\n"
         // restore the return address
"        movl    32(%eax), %eax"     "\n"
         // make %esp look like we really did a return
"        addl    $4, %esp"           "\n"
         // continue at RA of original call.  Same zero-vs-nonzero
         // trick/assumption as documented for the amd64-linux case.
"        jmp *%eax"                  "\n"
""       "\n"

#if !defined(VGP_x86_darwin)
".previous"       "\n"
#endif
);

#endif /* VGP_x86_linux || VGP_x86_darwin */

/*--------------------------------------------------------------------*/
/*--- end                                                          ---*/
/*--------------------------------------------------------------------*/
