tunables: Simplify TUNABLE_SET interface

The TUNABLE_SET interface took a primitive C type argument, which
resulted in inconsistent type conversions internally due to incorrect
dereferencing of types, especialy on 32-bit architectures.  This
change simplifies the TUNABLE setting logic along with the interfaces.

Now all numeric tunable values are stored as signed numbers in
tunable_num_t, which is intmax_t.  All calls to set tunables cast the
input value to its primitive type and then to tunable_num_t for
storage.  This relies on gcc-specific (although I suspect other
compilers woul also do the same) unsigned to signed integer conversion
semantics, i.e. the bit pattern is conserved.  The reverse conversion
is guaranteed by the standard.

1 files changed, 1 insertions, 1 deletions

diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
index fe52b6308e..db6aa3516c 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
@@ -104,7 +104,7 @@ init_cpu_features (struct cpu_features *cpu_features)
   cpu_features->mte_state = (GLRO (dl_hwcap2) & HWCAP2_MTE) ? mte_state : 0;
   /* If we lack the MTE feature, disable the tunable, since it will
      otherwise cause instructions that won't run on this CPU to be used.  */
-  TUNABLE_SET (glibc, mem, tagging, unsigned, cpu_features->mte_state);
+  TUNABLE_SET (glibc, mem, tagging, cpu_features->mte_state);
 # endif
 
   if (cpu_features->mte_state & 2)