From: Evan Green <evan@rivosinc.com>
Date: Tue, 27 Feb 2024 22:56:38 +0000 (-0800)
Subject: linux: Introduce INTERNAL_VSYSCALL
X-Git-Tag: glibc-2.40~353
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c6c33339b45281590f9db138ba6c9d79acb1da27;p=thirdparty%2Fglibc.git

linux: Introduce INTERNAL_VSYSCALL

Add an INTERNAL_VSYSCALL() macro that makes a vDSO call, falling back to
a regular syscall, but without setting errno. Instead, the return value
is plumbed straight out of the macro.

Signed-off-by: Evan Green <evan@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---

diff --git a/sysdeps/unix/sysv/linux/sysdep-vdso.h b/sysdeps/unix/sysv/linux/sysdep-vdso.h
index 189319ad98..2f53ada6e5 100644
--- a/sysdeps/unix/sysv/linux/sysdep-vdso.h
+++ b/sysdeps/unix/sysv/linux/sysdep-vdso.h
@@ -53,4 +53,16 @@
     sc_ret;								      \
   })
 
+#define INTERNAL_VSYSCALL(name, nr, args...)				      \
+  ({									      \
+    long int sc_ret = -ENOSYS;						      \
+									      \
+    __typeof (GLRO(dl_vdso_##name)) vdsop = GLRO(dl_vdso_##name);	      \
+    if (vdsop != NULL)							      \
+	sc_ret = INTERNAL_VSYSCALL_CALL (vdsop, nr, ##args);		      \
+    if (sc_ret == -ENOSYS)						      \
+	sc_ret = INTERNAL_SYSCALL_CALL (name, ##args);			      \
+    sc_ret;								      \
+  })
+
 #endif /* SYSDEP_VDSO_LINUX_H  */