[PATCH] ARM: 2837/2: Re: ARM: Make NWFPE preempt safe

Patch from Richard Purdie

NWFPE used global variables which meant it wasn't safe for use with
preemptive kernels. This patch removes them and communicates the
information between functions in a preempt safe manner. Generation
of some exceptions was broken and this has also been corrected.
Tests with glibc's maths test suite show no change in the results
before/after this patch.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 11 insertions, 19 deletions

diff --git a/arch/arm/nwfpe/fpa11.c b/arch/arm/nwfpe/fpa11.c
index bf61696865ec..7690f731ee87 100644
--- a/arch/arm/nwfpe/fpa11.c
+++ b/arch/arm/nwfpe/fpa11.c
@@ -51,48 +51,42 @@ static void resetFPA11(void)
         fpa11->fpsr = FP_EMULATOR | BIT_AC;
 }
 
-void SetRoundingMode(const unsigned int opcode)
+int8 SetRoundingMode(const unsigned int opcode)
 {
         switch (opcode & MASK_ROUNDING_MODE) {
         default:
         case ROUND_TO_NEAREST:
-                float_rounding_mode = float_round_nearest_even;
-                break;
+                return float_round_nearest_even;
 
         case ROUND_TO_PLUS_INFINITY:
-                float_rounding_mode = float_round_up;
-                break;
+                return float_round_up;
 
         case ROUND_TO_MINUS_INFINITY:
-                float_rounding_mode = float_round_down;
-                break;
+                return float_round_down;
 
         case ROUND_TO_ZERO:
-                float_rounding_mode = float_round_to_zero;
-                break;
+                return float_round_to_zero;
         }
 }
 
-void SetRoundingPrecision(const unsigned int opcode)
+int8 SetRoundingPrecision(const unsigned int opcode)
 {
 #ifdef CONFIG_FPE_NWFPE_XP
         switch (opcode & MASK_ROUNDING_PRECISION) {
         case ROUND_SINGLE:
-                floatx80_rounding_precision = 32;
-                break;
+                return 32;
 
         case ROUND_DOUBLE:
-                floatx80_rounding_precision = 64;
-                break;
+                return 64;
 
         case ROUND_EXTENDED:
-                floatx80_rounding_precision = 80;
-                break;
+                return 80;
 
         default:
-                floatx80_rounding_precision = 80;
+                return 80;
         }
 #endif
+        return 80;
 }
 
 void nwfpe_init_fpa(union fp_state *fp)
@@ -103,8 +97,6 @@ void nwfpe_init_fpa(union fp_state *fp)
 #endif
         memset(fpa11, 0, sizeof(FPA11));
         resetFPA11();
-        SetRoundingMode(ROUND_TO_NEAREST);
-        SetRoundingPrecision(ROUND_EXTENDED);
         fpa11->initflag = 1;
 }