From 5d1a09b4996c5bdf4350bca4673ea7c9327bbfa5 Mon Sep 17 00:00:00 2001 From: jmallett Date: Thu, 29 Mar 2012 02:04:15 +0000 Subject: [PATCH] Disable FP instruction emulation by default on !o32 because of ABI concerns. Note that in practice this isn't needed because we get a coprocessor unusable exception first, but that's actually something like a bug. --- sys/mips/mips/trap.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/sys/mips/mips/trap.c b/sys/mips/mips/trap.c index f2b343a5109..27d3a481113 100644 --- a/sys/mips/mips/trap.c +++ b/sys/mips/mips/trap.c @@ -290,6 +290,20 @@ static int allow_unaligned_acc = 1; SYSCTL_INT(_vm, OID_AUTO, allow_unaligned_acc, CTLFLAG_RW, &allow_unaligned_acc, 0, "Allow unaligned accesses"); +/* + * FP emulation is assumed to work on O32, but the code is outdated and crufty + * enough that it's a more sensible default to have it disabled when using + * other ABIs. At the very least, it needs a lot of help in using + * type-semantic ABI-oblivious macros for everything it does. + */ +#if defined(__mips_o32) +static int emulate_fp = 1; +#else +static int emulate_fp = 0; +#endif +SYSCTL_INT(_machdep, OID_AUTO, emulate_fp, CTLFLAG_RW, + &allow_unaligned_acc, 0, "Emulate unimplemented FPU instructions"); + static int emulate_unaligned_access(struct trapframe *frame, int mode); extern void fswintrberr(void); /* XXX */ @@ -988,6 +1002,11 @@ trap(struct trapframe *trapframe) #endif case T_FPE + T_USER: + if (!emulate_fp) { + i = SIGILL; + addr = trapframe->pc; + break; + } MipsFPTrap(trapframe->sr, trapframe->cause, trapframe->pc); goto out; -- 2.45.2