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authorAndreas Jaeger <aj@suse.de>2002-08-31 08:04:45 +0000
committerAndreas Jaeger <aj@suse.de>2002-08-31 08:04:45 +0000
commitba1e2fe668361bd6887f237f70f47def96fa7bef (patch)
tree936c625a11b1cd7ebfecbc4d82d6673fd9c70806 /sysdeps
parentcc6d371de3af78fa6440c9f80d441e7c73115f23 (diff)
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Linux/x86-64 makecontext implementation.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/makecontext.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/x86_64/makecontext.c b/sysdeps/unix/sysv/linux/x86_64/makecontext.c
new file mode 100644
index 0000000..f859160
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/makecontext.c
@@ -0,0 +1,113 @@
+/* Create new context.
+ Copyright (C) 2002 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 2002.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <sysdep.h>
+#include <stdarg.h>
+#include <ucontext.h>
+
+#include "ucontext_i.h"
+
+/* This implementation can handle any ARGC value but only
+ normal integer parameters.
+ makecontext sets up a stack and the registers for the
+ user context. The stack looks like this:
+ +-----------------------+
+ | next context |
+ +-----------------------+
+ | parameter 7-n |
+ +-----------------------+
+ | trampoline address |
+ %rsp -> +-----------------------+
+
+ The registers are set up like this:
+ %rdi,%rsi,%rdx,%rcx,%r8,%r9: parameter 1 to 6
+ %rbx : address of next context
+ %rsp : stack pointer.
+*/
+
+/* XXX: This implementation currently only handles integer arguments.
+ To handle long int and pointer arguments the va_arg arguments needs
+ to be changed to long and also the stdlib/tst-setcontext.c file needs
+ to be changed to pass long arguments to makecontext. */
+
+
+void
+__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
+{
+ extern void __start_context (void);
+ unsigned long *sp, idx_uc_link;
+ va_list ap;
+ int i;
+
+ /* Generate room on stack for parameter if needed and uc_link. */
+ sp = (long *) ((long) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+ sp -= (argc > 6 ? argc : 0) + 1;
+ /* Align stack. */
+ sp = (long *) (((long) sp) & -16L);
+ /* Make space for trampoline address. */
+ sp -= 8;
+
+ idx_uc_link = (argc > 6 ? argc : 0) + 1;
+
+ /* Setup context ucp. */
+ /* Address to jump to. */
+ ucp->uc_mcontext.gregs[REG_RIP] = (long) func;
+ /* Setup rbx.*/
+ ucp->uc_mcontext.gregs[REG_RBX] = (long) &sp[idx_uc_link];
+ ucp->uc_mcontext.gregs[REG_RSP] = (long) sp;
+
+ /* Setup stack. */
+ sp[0] = (long) &__start_context;
+ sp[idx_uc_link] = (long) ucp->uc_link;
+
+ va_start (ap, argc);
+ /* Handle arguments. */
+ for (i = 0; i < argc; ++i)
+ switch (i)
+ {
+ case 0:
+ ucp->uc_mcontext.gregs [REG_RDI] = va_arg (ap, int);
+ break;
+ case 1:
+ ucp->uc_mcontext.gregs [REG_RSI] = va_arg (ap, int);
+ break;
+ case 2:
+ ucp->uc_mcontext.gregs [REG_RDX] = va_arg (ap, int);
+ break;
+ case 3:
+ ucp->uc_mcontext.gregs [REG_RCX] = va_arg (ap, int);
+ break;
+ case 4:
+ ucp->uc_mcontext.gregs [REG_R8] = va_arg (ap, int);
+ break;
+ case 5:
+ ucp->uc_mcontext.gregs [REG_R9] = va_arg (ap, int);
+ break;
+ default:
+ /* Put value on stack. */
+ sp[8 + (i - 5)] = va_arg (ap, int);
+ break;
+ }
+ va_end (ap);
+
+}
+
+
+weak_alias(__makecontext, makecontext)