diff options
Diffstat (limited to 'sys/arch/m88k')
| -rw-r--r-- | sys/arch/m88k/m88k/m88k_machdep.c | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/sys/arch/m88k/m88k/m88k_machdep.c b/sys/arch/m88k/m88k/m88k_machdep.c index 737e888038c..4f276442de9 100644 --- a/sys/arch/m88k/m88k/m88k_machdep.c +++ b/sys/arch/m88k/m88k/m88k_machdep.c @@ -1,4 +1,4 @@ -/* $OpenBSD: m88k_machdep.c,v 1.32 2007/11/17 05:36:23 miod Exp $ */ +/* $OpenBSD: m88k_machdep.c,v 1.33 2007/11/20 21:47:12 miod Exp $ */ /* * Copyright (c) 1998, 1999, 2000, 2001 Steve Murphree, Jr. * Copyright (c) 1996 Nivas Madhur @@ -154,18 +154,33 @@ setregs(p, pack, stack, retval) /* * We want to start executing at pack->ep_entry. The way to - * do this is force the processor to fetch from ep_entry. Set - * NIP to something bogus and invalid so that it will be a NOOP. - * And set sfip to ep_entry with valid bit on so that it will be - * fetched. mc88110 - just set exip to pack->ep_entry. + * do this is force the processor to fetch from ep_entry. + * However, since we will return throug m{88100,88110}_syscall(), + * we need to setup registers so that the success return, when + * ``incrementing'' the instruction pointers, will cause the + * binary to start at the expected address. */ #ifdef M88110 if (CPU_IS88110) { - tf->tf_exip = pack->ep_entry & XIP_ADDR; + /* + * Delay slot in exip, so we'll start at enip + 4. + * This relies on the fact that binaries start with + * + * br.n 1f + * first instruction + * 1: second instruction + * + * So by pretending exip is a delay slot, m88110_syscall() + * will resume at enip + 4... which really is the first + * instruction we want to run. + */ + tf->tf_exip = (pack->ep_entry & XIP_ADDR) | 1; + tf->tf_enip = pack->ep_entry & XIP_ADDR; } #endif #ifdef M88100 if (CPU_IS88100) { + /* we'll start at sfip / sfip + 4 */ tf->tf_snip = pack->ep_entry & NIP_ADDR; tf->tf_sfip = (pack->ep_entry & FIP_ADDR) | FIP_V; } |