x86/fpu/math-emu: Fix function cast warning

Building with 'make W=1', gcc points out that casting between
incompatible function types can be dangerous:

  arch/x86/math-emu/fpu_trig.c:1638:60: error: cast between incompatible function types from ‘int (*)(FPU_REG *, u_char)’ {aka ‘int (*)(struct fpu__reg *, unsigned char)’} to ‘void (*)(FPU_REG *, u_char)’ {aka ‘void (*)(struct fpu__reg *, unsigned char)’} [-Werror=cast-function-type]
   1638 |         fprem, fyl2xp1, fsqrt_, fsincos, frndint_, fscale, (FUNC_ST0) fsin, fcos
        |                                                            ^

This one seems harmless, but it is easy enough to work around it by
adding an intermediate function that adjusts the return type.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210322214824.974323-1-arnd@kernel.org

diff --git a/arch/x86/math-emu/fpu_trig.c b/arch/x86/math-emu/fpu_trig.c
index 4a9887851ad8ab05e11fb427df846721bd66ff43..990d847ae902c6e032462e55914dbc680a3959bd 100644 (file)
--- a/arch/x86/math-emu/fpu_trig.c
+++ b/arch/x86/math-emu/fpu_trig.c
@@ -547,7 +547,7 @@ static void frndint_(FPU_REG *st0_ptr, u_char st0_tag)
                single_arg_error(st0_ptr, st0_tag);
 }
 
-static int fsin(FPU_REG *st0_ptr, u_char tag)
+static int f_sin(FPU_REG *st0_ptr, u_char tag)
 {
        u_char arg_sign = getsign(st0_ptr);
 
@@ -608,6 +608,11 @@ static int fsin(FPU_REG *st0_ptr, u_char tag)
        }
 }
 
+static void fsin(FPU_REG *st0_ptr, u_char tag)
+{
+       f_sin(st0_ptr, tag);
+}
+
 static int f_cos(FPU_REG *st0_ptr, u_char tag)
 {
        u_char st0_sign;
@@ -724,7 +729,7 @@ static void fsincos(FPU_REG *st0_ptr, u_char st0_tag)
        }
 
        reg_copy(st0_ptr, &arg);
-       if (!fsin(st0_ptr, st0_tag)) {
+       if (!f_sin(st0_ptr, st0_tag)) {
                push();
                FPU_copy_to_reg0(&arg, st0_tag);
                f_cos(&st(0), st0_tag);
@@ -1635,7 +1640,7 @@ void FPU_triga(void)
 }
 
 static FUNC_ST0 const trig_table_b[] = {
-       fprem, fyl2xp1, fsqrt_, fsincos, frndint_, fscale, (FUNC_ST0) fsin, fcos
+       fprem, fyl2xp1, fsqrt_, fsincos, frndint_, fscale, fsin, fcos
 };
 
 void FPU_trigb(void)