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

Commit c98929c07a 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>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index f60a5400a25b..a63c4be99b36 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/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);