[glibc] RISC-V: Add support for 32-bit vDSO calls

[glibc] RISC-V: Add support for 32-bit vDSO calls

[Alistair Francis]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=68efae739a3eae514dafb52c42d5e3295fd13903

commit 68efae739a3eae514dafb52c42d5e3295fd13903
Author: Alistair Francis <alistair.francis@wdc.com>
Date:   Wed Sep 18 08:41:59 2019 -0700

    RISC-V: Add support for 32-bit vDSO calls
    
    Reviewed-by: Maciej W. Rozycki <macro@wdc.com>

Diff:
---
 sysdeps/unix/sysv/linux/riscv/sysdep.h | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
index 430fa23a58..e94afbf106 100644
--- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
@@ -135,13 +135,24 @@
 
 #else /* !__ASSEMBLER__ */
 
-# define VDSO_NAME  "LINUX_4.15"
-# define VDSO_HASH  182943605
+# if __WORDSIZE == 64
+#  define VDSO_NAME	"LINUX_4.15"
+#  define VDSO_HASH	182943605
+
+/* List of system calls which are supported as vsyscalls only
+   for RV64.  */
+#  define HAVE_CLOCK_GETRES64_VSYSCALL	"__vdso_clock_getres"
+#  define HAVE_CLOCK_GETTIME64_VSYSCALL	"__vdso_clock_gettime"
+#  define HAVE_GETTIMEOFDAY_VSYSCALL	"__vdso_gettimeofday"
+# else
+#  define VDSO_NAME	"LINUX_5.4"
+#  define VDSO_HASH	61765876
+
+/* RV32 does not support the gettime VDSO syscalls.  */
+# endif
 
-/* List of system calls which are supported as vsyscalls.  */
-# define HAVE_CLOCK_GETRES64_VSYSCALL	"__vdso_clock_getres"
-# define HAVE_CLOCK_GETTIME64_VSYSCALL	"__vdso_clock_gettime"
-# define HAVE_GETTIMEOFDAY_VSYSCALL	"__vdso_gettimeofday"
+/* List of system calls which are supported as vsyscalls (for RV32 and
+   RV64).  */
 # define HAVE_GETCPU_VSYSCALL		"__vdso_getcpu"
 
 # define INTERNAL_SYSCALL(name, nr, args...) \