From 840c5e79e31877a48931440e52a430c25d42fd20 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Fri, 29 Jul 1994 15:46:10 +0000 Subject: [PATCH] Don't set up args on the stack; pass them in registers. --- sysdeps/mach/hurd/mips/trampoline.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-) diff --git a/sysdeps/mach/hurd/mips/trampoline.c b/sysdeps/mach/hurd/mips/trampoline.c index a6c9cec..856cce6 100644 --- a/sysdeps/mach/hurd/mips/trampoline.c +++ b/sysdeps/mach/hurd/mips/trampoline.c @@ -40,15 +40,6 @@ _hurd_setup_sighandler (int flags, struct mips_thread_state *ts; void *sigsp; struct sigcontext *scp; - struct - { - void *retaddr; /* Never used. */ - __sighandler_t handler; - int signo; - int sigcode; - struct sigcontext *scp; /* Points to ctx, below. */ - struct sigcontext ctx; - } *stackframe; ts = state; @@ -61,18 +52,16 @@ _hurd_setup_sighandler (int flags, else sigsp = (char *) ts->r29; - /* Push the arguments to call `trampoline' on the stack. */ - sigsp -= sizeof (*stackframe); - stackframe = sigsp; - stackframe->handler = handler; - stackframe->signo = signo; - stackframe->sigcode = sigcode; - stackframe->scp = scp = &stackframe->ctx; + /* Set up the sigcontext structure on the stack. This is all the stack + needs, since the args are passed in registers (below). */ + sigsp -= sizeof (*scp); + scp = sigsp; /* Set up the sigcontext from the current state of the thread. */ scp->sc_onstack = sigaltstack->ss_flags & SA_ONSTACK ? 1 : 0; + scp->sc_gpr[2] = ts->r2; scp->sc_gpr[16] = ts->r16; scp->sc_gpr[17] = ts->r17; scp->sc_gpr[18] = ts->r18; @@ -89,7 +78,16 @@ _hurd_setup_sighandler (int flags, scp->sc_fp = ts->r30; /* Modify the thread state to call `trampoline' on the new stack. */ - ts->r29 = (int) sigsp; + + /* These registers are used for passing the first four arguments to a + function (the rest go on the stack). Fortunately `trampoline' takes + just four arguments, so they all fit in registers. */ + ts->r4 = (int) handler; + ts->r5 = signo; + ts->r6 = sigcode; + ts->r7 = (int) scp; + + ts->r29 = (int) sigsp; /* r29 is the stack pointer register. */ ts->pc = (int) &trampoline; return scp; -- 2.7.4