/* sssus8.c: SPARC STACK SCANNING
*
* $Id: //info.ravenbrook.com/project/mps/version/1.103/code/sssus8.c#1 $
* Copyright (c) 2001 Ravenbrook Limited. See end of file for license.
* Portions copyright (c) 2002 Global Graphics Software.
*
* This scans the stack and fixes the registers which may contain
* roots. See <design/thread-manager/>.
*
* .roots: The non-global registers are preserved into the stackframe
* by the "ta 3" instruction. This leaves the global registers.
* According to the Sparc Architecture Manual:
* %g1 is assumed to be volatile across procedure calls
* %g2...%g4 are "reserved for use by application programmer"
* %g5...%g7 are "nonvolatile and reserved for (as-yet-undefined)
* use by the execution environment"
* To be safe %g2 to %g7 are pushed onto the stack before scanning
* it just in case.
*
* ASSUMPTIONS
*
* .assume.align: The stack pointer is assumed to be aligned on a word
* boundary.
*
* .assume.asm.stack: The compiler must not do wacky things with the
* stack pointer around a call since we need to ensure that the
* callee-save regs are visible during TraceScanArea.
*
* .assume.asm.order: The volatile modifier should prevent movement
* of code, which might break .assume.asm.stack.
*/
#include "mpm.h"
#include <alloca.h>
SRCID(sssus8, "$Id: //info.ravenbrook.com/project/mps/version/1.103/code/sssus8.c#1 $");
/* .assume.asm.order */
#define ASMV(x) __asm__ volatile (x)
Res StackScan(ScanState ss, Addr *stackBot)
{
Addr *stackTop;
Res res;
void *globals;
/* We expect C will save the caller's window, but we don't really care, */
/* because it's bound to be an MPS window. */
globals = alloca(24); /* for 6 globals */
ASMV("std %%g2, [%0]" : : "r" (globals)); /* double stores */
ASMV("std %%g4, [%0 + 8]" : : "r" (globals));
ASMV("std %%g6, [%0 + 16]" : : "r" (globals));
ASMV("ta 3"); /* flushes register windows onto stack */
ASMV("mov %%sp, %0" : "=r" (stackTop)); /* stackTop = sp */
AVER(AddrIsAligned((Addr)stackTop, sizeof(Addr))); /* .assume.align */
res = TraceScanArea(ss, stackTop, stackBot);
return res;
}
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
* All rights reserved. This is an open source license. Contact
* Ravenbrook for commercial licensing options.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Redistributions in any form must be accompanied by information on how
* to obtain complete source code for this software and any accompanying
* software that uses this software. The source code must either be
* included in the distribution or be available for no more than the cost
* of distribution plus a nominal fee, and must be freely redistributable
* under reasonable conditions. For an executable file, complete source
* code means the source code for all modules it contains. It does not
* include source code for modules or files that typically accompany the
* major components of the operating system on which the executable file
* runs.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
* PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/