Use osigreturn(2) instead of sigreturn(2) plus broken magic for returning

from old signal handlers.  This is simpler and faster, and fixes (new)
sigreturn(2) when %eip in the new signal context happens to match the
magic value (0x1d516).  0x1d516 is below the default ELF text section,
so this probably never broken anything in practice.

locore.s:
In addition, don't build the signal trampoline for old signal handlers
when it is not used.

alpha:
Not fixed, but seems to be even less broken in practice due to more
advanced magic. A false match occurs for register #32 in mc_regs[].
Since there is no hardware register #32, a false match is only possible
for direct calls to sigreturn(2) that happen to have the magic number
in the spare mc_regs[32] field.

2 files changed, 0 insertions, 18 deletions

diff --git a/sys/pc98/i386/machdep.c b/sys/pc98/i386/machdep.c
index 0c0243d..71d2098 100644
--- a/sys/pc98/i386/machdep.c
+++ b/sys/pc98/i386/machdep.c
@@ -723,19 +723,10 @@ sigreturn(td, uap)
 	} */ *uap;
 {
 	struct proc *p = td->td_proc;
-	struct osigcontext *oscp;
-	struct osigreturn_args *ouap;
 	struct trapframe *regs;
 	ucontext_t *ucp;
 	int cs, eflags;
 
-#ifdef COMPAT_43
-	ouap = (struct osigreturn_args *)uap;
-	oscp = ouap->sigcntxp;
-	if (fuword(&oscp->sc_trapno) == 0x01d516)
-		return (osigreturn(td, ouap));
-#endif
-
 	ucp = uap->sigcntxp;
 	if (!useracc((caddr_t)ucp, sizeof(*ucp), VM_PROT_READ))
 		return (EFAULT);
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index 0c0243d..71d2098 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -723,19 +723,10 @@ sigreturn(td, uap)
 	} */ *uap;
 {
 	struct proc *p = td->td_proc;
-	struct osigcontext *oscp;
-	struct osigreturn_args *ouap;
 	struct trapframe *regs;
 	ucontext_t *ucp;
 	int cs, eflags;
 
-#ifdef COMPAT_43
-	ouap = (struct osigreturn_args *)uap;
-	oscp = ouap->sigcntxp;
-	if (fuword(&oscp->sc_trapno) == 0x01d516)
-		return (osigreturn(td, ouap));
-#endif
-
 	ucp = uap->sigcntxp;
 	if (!useracc((caddr_t)ucp, sizeof(*ucp), VM_PROT_READ))
 		return (EFAULT);