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authorWaldemar Brodkorb <wbx@uclibc-ng.org>2016-04-23 12:17:56 +0200
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2016-04-26 19:41:08 +0200
commit2b3cdadee36b0445ed799932358dd94a1e839b46 (patch)
tree88120c5bcbf0a5420b3407bc5b0ccc1f0eae1456 /libc/sysdeps/linux/sparc/makecontext.c
parentf1dcb9beedc5d05238e90cfbad026736d6efe891 (diff)
sparc: add deprecated context switching functions
Ported over from glibc mostly without changes. Lightly tested with mongrel2 in qemu-system-sparc.
Diffstat (limited to 'libc/sysdeps/linux/sparc/makecontext.c')
-rw-r--r--libc/sysdeps/linux/sparc/makecontext.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/sparc/makecontext.c b/libc/sysdeps/linux/sparc/makecontext.c
new file mode 100644
index 000000000..3a9f70cc5
--- /dev/null
+++ b/libc/sysdeps/linux/sparc/makecontext.c
@@ -0,0 +1,92 @@
+/* Create new context.
+ Copyright (C) 2008-2016 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by David S. Miller <davem@davemloft.net>, 2008.
+
+ 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, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <ucontext.h>
+
+/* Sets up the outgoing arguments and the program counter for a user
+ context for the requested function call.
+
+ Returning to the correct parent context is pretty simple on
+ Sparc. We only need to link up the register windows correctly.
+ Since global registers are clobbered by calls, we need not be
+ concerned about those, and thus is all could be worked out without
+ using a trampoline.
+
+ Except that we must deal with the signal mask, thus a trampoline
+ is unavoidable. 32-bit stackframe layout:
+ +-----------------------------------------+
+ | 7th and further parameters |
+ +-----------------------------------------+
+ | backup storage for initial 6 parameters |
+ +-----------------------------------------+
+ | struct return pointer |
+ +-----------------------------------------+
+ | 8 incoming registers |
+ +-----------------------------------------+
+ | 8 local registers |
+ %sp --> +-----------------------------------------+
+
+*/
+
+void
+__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
+{
+ extern void __start_context (void);
+ unsigned long int *sp;
+ va_list ap;
+ int i;
+
+ sp = (unsigned long int *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+ sp -= 16 + 7 + argc;
+ sp = (unsigned long int *) (((uintptr_t) sp) & ~(8 - 1));
+
+ for (i = 0; i < 8; i++)
+ sp[i + 8] = ucp->uc_mcontext.gregs[REG_O0 + i];
+
+ /* The struct return pointer is essentially unused, so we can
+ place the link there. */
+ sp[16] = (unsigned long int) ucp->uc_link;
+
+ va_start (ap, argc);
+
+ /* Fill in outgoing arguments, including those which will
+ end up being passed on the stack. */
+ for (i = 0; i < argc; i++)
+ {
+ unsigned long int arg = va_arg (ap, unsigned long int);
+ if (i < 6)
+ ucp->uc_mcontext.gregs[REG_O0 + i] = arg;
+ else
+ sp[i + 23 - 6] = arg;
+ }
+
+ va_end (ap);
+
+ ucp->uc_mcontext.gregs[REG_O6] = (unsigned long int) sp;
+
+ ucp->uc_mcontext.gregs[REG_O7] = ((unsigned long int) __start_context) - 8;
+
+ ucp->uc_mcontext.gregs[REG_PC] = (unsigned long int) func;
+ ucp->uc_mcontext.gregs[REG_nPC] = ucp->uc_mcontext.gregs[REG_PC] + 4;
+}
+
+weak_alias (__makecontext, makecontext)