ARM: 5909/1: ARM: Correct the FPSCR bits setting when raising exceptions

Commit c98929c0 removed the clearing of the FPSCR[31:28] bits from the
vfp_raise_exceptions() function and the new bits are or'ed with the old
FPSCR bits leading to unexpected results (the original commit was
referring to the cumulative bits - FPSCR[4:0]).
Reported-by: Tom Hameenanttila <tmhameen@marvell.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/vfp/vfpmodule.c

@@ -197,10 +197,13 @@ static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_
 	}
 
 	/*
-	 * Update the FPSCR with the additional exception flags.
+	 * If any of the status flags are set, update the FPSCR.
 	 * Comparison instructions always return at least one of
 	 * these flags set.
 	 */
+	if (exceptions & (FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V))
+		fpscr &= ~(FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V);
+
 	fpscr |= exceptions;
 
 	fmxr(FPSCR, fpscr);