From 579648554acbd6c22d5cc2f03cf77cfc25332650 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 11 Jan 2018 13:25:39 +0000 Subject: linux-user/arm/nwfpe: Check coprocessor number for FPA emulation Our copy of the nwfpe code for emulating of the old FPA11 floating point unit doesn't check the coprocessor number in the instruction when it emulates it. This means that we might treat some instructions which should really UNDEF as being FPA11 instructions by accident. The kernel's copy of the nwfpe code doesn't make this error; I suspect the bug was noticed and fixed as part of the process of mainlining the nwfpe code more than a decade ago. Add a check that the coprocessor number (which is always in bits [11:8] of the instruction) is either 1 or 2, which is where the FPA11 lives. Reported-by: Richard Henderson Signed-off-by: Peter Maydell --- linux-user/arm/nwfpe/fpa11.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/linux-user/arm/nwfpe/fpa11.c b/linux-user/arm/nwfpe/fpa11.c index 441e3b1cf6..f6f8163eab 100644 --- a/linux-user/arm/nwfpe/fpa11.c +++ b/linux-user/arm/nwfpe/fpa11.c @@ -137,8 +137,17 @@ unsigned int EmulateAll(unsigned int opcode, FPA11* qfpa, CPUARMState* qregs) unsigned int nRc = 0; // unsigned long flags; FPA11 *fpa11; + unsigned int cp; // save_flags(flags); sti(); + /* Check that this is really an FPA11 instruction: the coprocessor + * field in bits [11:8] must be 1 or 2. + */ + cp = (opcode >> 8) & 0xf; + if (cp != 1 && cp != 2) { + return 0; + } + qemufpa=qfpa; user_registers=qregs; -- cgit v1.2.3