[PATCH v2 1/4] aarch64: Use 64-bit variable to access the special registers

Adhemerval Zanella adhemerval.zanella@linaro.org
Fri Jan 10 18:12:11 GMT 2025


clang issues:

  error: value size does not match register size specified by the
  constraint and modifier [-Werror,-Wasm-operand-widths]

while tryng to use 32 bit variables with 'mrs' to get/set the
fpsr, dczid_el0, and ctr.
---
 sysdeps/aarch64/fpu/fpu_control.h             | 36 +++++++++++++------
 sysdeps/aarch64/fpu/fraiseexcpt.c             |  3 +-
 sysdeps/aarch64/sfp-machine.h                 |  2 +-
 .../unix/sysv/linux/aarch64/cpu-features.c    |  2 +-
 sysdeps/unix/sysv/linux/aarch64/sysconf.c     |  2 +-
 5 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/sysdeps/aarch64/fpu/fpu_control.h b/sysdeps/aarch64/fpu/fpu_control.h
index 5df6da3ffc..a93dbf5efa 100644
--- a/sysdeps/aarch64/fpu/fpu_control.h
+++ b/sysdeps/aarch64/fpu/fpu_control.h
@@ -29,17 +29,31 @@
 # define _FPU_GETFPSR(fpsr) (fpsr = __builtin_aarch64_get_fpsr ())
 # define _FPU_SETFPSR(fpsr) __builtin_aarch64_set_fpsr (fpsr)
 #else
-# define _FPU_GETCW(fpcr) \
-  __asm__ __volatile__ ("mrs	%0, fpcr" : "=r" (fpcr))
-
-# define _FPU_SETCW(fpcr) \
-  __asm__ __volatile__ ("msr	fpcr, %0" : : "r" (fpcr))
-
-# define _FPU_GETFPSR(fpsr) \
-  __asm__ __volatile__ ("mrs	%0, fpsr" : "=r" (fpsr))
-
-# define _FPU_SETFPSR(fpsr) \
-  __asm__ __volatile__ ("msr	fpsr, %0" : : "r" (fpsr))
+# define _FPU_GETCW(fpcr)					\
+  ({ 								\
+   __uint64_t __fpcr;						\
+   __asm__ __volatile__ ("mrs	%0, fpcr" : "=r" (__fpcr));	\
+   fpcr = __fpcr;						\
+  })
+
+# define _FPU_SETCW(fpcr)					\
+  ({								\
+   __uint64_t __fpcr = fpcr;					\
+   __asm__ __volatile__ ("msr	fpcr, %0" : : "r" (__fpcr));    \
+  })
+
+# define _FPU_GETFPSR(fpsr)					\
+  ({								\
+   __uint64_t __fpsr;						\
+   __asm__ __volatile__ ("mrs	%0, fpsr" : "=r" (__fpsr));	\
+   fpsr = __fpsr;						\
+  })
+
+# define _FPU_SETFPSR(fpsr)					\
+  ({								\
+   __uint64_t __fpsr = fpsr;					\
+   __asm__ __volatile__ ("msr	fpsr, %0" : : "r" (__fpsr));    \
+  })
 #endif
 
 /* Reserved bits should be preserved when modifying register
diff --git a/sysdeps/aarch64/fpu/fraiseexcpt.c b/sysdeps/aarch64/fpu/fraiseexcpt.c
index bf5862a56e..518a6eb321 100644
--- a/sysdeps/aarch64/fpu/fraiseexcpt.c
+++ b/sysdeps/aarch64/fpu/fraiseexcpt.c
@@ -19,11 +19,12 @@
 #include <fenv.h>
 #include <fpu_control.h>
 #include <float.h>
+#include <stdint.h>
 
 int
 __feraiseexcept (int excepts)
 {
-  int fpsr;
+  uint64_t fpsr;
   const float fp_zero = 0.0;
   const float fp_one = 1.0;
   const float fp_max = FLT_MAX;
diff --git a/sysdeps/aarch64/sfp-machine.h b/sysdeps/aarch64/sfp-machine.h
index a9ecdbf961..b41a9462df 100644
--- a/sysdeps/aarch64/sfp-machine.h
+++ b/sysdeps/aarch64/sfp-machine.h
@@ -74,7 +74,7 @@ do {						\
     const float fp_1e32 = 1.0e32f;					\
     const float fp_zero = 0.0;						\
     const float fp_one = 1.0;						\
-    unsigned fpsr;							\
+    uint64_t fpsr;							\
     if (_fex & FP_EX_INVALID)						\
       {									\
         __asm__ __volatile__ ("fdiv\ts0, %s0, %s0"			\
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
index 26cf6d4a56..7ac228303f 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
@@ -128,7 +128,7 @@ init_cpu_features (struct cpu_features *cpu_features)
   cpu_features->midr_el1 = midr;
 
   /* Check if ZVA is enabled.  */
-  unsigned dczid;
+  uint64_t dczid;
   asm volatile ("mrs %0, dczid_el0" : "=r"(dczid));
 
   if ((dczid & DCZID_DZP_MASK) == 0)
diff --git a/sysdeps/unix/sysv/linux/aarch64/sysconf.c b/sysdeps/unix/sysv/linux/aarch64/sysconf.c
index c0df3af28c..bca2e0d286 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sysconf.c
+++ b/sysdeps/unix/sysv/linux/aarch64/sysconf.c
@@ -27,7 +27,7 @@ static long int linux_sysconf (int name);
 long int
 __sysconf (int name)
 {
-  unsigned ctr;
+  unsigned long int ctr;
 
   /* Unfortunately, the registers that contain the actual cache info
      (CCSIDR_EL1, CLIDR_EL1, and CSSELR_EL1) are protected by the Linux
-- 
2.43.0



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