[ARM] 3499/1: Fix VFP FPSCR corruption for double exception case

Patch from George G. Davis

The ARM VFP FPSCR register is corrupted when a condition flags modifying
VFP instruction is followed by a non-condition flags modifying VFP
instruction and both instructions raise exceptions.  The fix is to
read the current FPSCR in between emulation of these two instructions
and use the current FPSCR value when handling the second exception.

Signed-off-by: George G. Davis <gdavis@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 37ff8145b5b50bf52ea9f22f5212068764167e5f..03486be04193e0497f8258d45d4be1ef02656258 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -245,7 +245,7 @@ void VFP9_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
         */
        barrier();
        trigger = fmrx(FPINST2);
-       fpscr = fmrx(FPSCR);
+       orig_fpscr = fpscr = fmrx(FPSCR);
 
  emulate:
        exceptions = vfp_emulate_instruction(trigger, fpscr, regs);