git: 2e7cf772a411 - main - amd64: add amd64_set_tlsbase(3)

From: Konstantin Belousov <kib_at_FreeBSD.org>
Date: Wed, 28 May 2025 11:11:44 UTC
The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=2e7cf772a4114b78eb0ab2687d91d563de89e206

commit 2e7cf772a4114b78eb0ab2687d91d563de89e206
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2025-05-22 04:32:03 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2025-05-28 11:11:23 +0000

    amd64: add amd64_set_tlsbase(3)
    
    Tested by:      pho
    Reviewed by:    olce
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D50482
---
 lib/libsys/amd64/Makefile.sys        |  1 +
 lib/libsys/amd64/Symbol.sys.map      |  4 +++
 lib/libsys/amd64/amd64_set_tlsbase.c | 51 ++++++++++++++++++++++++++++++++++++
 sys/x86/include/sysarch.h            |  1 +
 4 files changed, 57 insertions(+)

diff --git a/lib/libsys/amd64/Makefile.sys b/lib/libsys/amd64/Makefile.sys
index 09947d998480..8134bdc422a6 100644
--- a/lib/libsys/amd64/Makefile.sys
+++ b/lib/libsys/amd64/Makefile.sys
@@ -3,6 +3,7 @@ SRCS+=	\
 	amd64_get_gsbase.c \
 	amd64_set_fsbase.c \
 	amd64_set_gsbase.c \
+	amd64_set_tlsbase.c \
 	rfork_thread.S
 
 MDASM=	vfork.S cerror.S getcontext.S
diff --git a/lib/libsys/amd64/Symbol.sys.map b/lib/libsys/amd64/Symbol.sys.map
index 5f463c85f872..11e0507b6613 100644
--- a/lib/libsys/amd64/Symbol.sys.map
+++ b/lib/libsys/amd64/Symbol.sys.map
@@ -13,6 +13,10 @@ FBSD_1.6 {
 	 x86_pkru_unprotect_range;
 };
 
+FBSD_1.8 {
+	amd64_set_tlsbase;
+};
+
 FBSDprivate_1.0 {
 	_vfork;
 };
diff --git a/lib/libsys/amd64/amd64_set_tlsbase.c b/lib/libsys/amd64/amd64_set_tlsbase.c
new file mode 100644
index 000000000000..a28441fbfc5d
--- /dev/null
+++ b/lib/libsys/amd64/amd64_set_tlsbase.c
@@ -0,0 +1,51 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#define _WANT_P_OSREL
+#include <sys/param.h>
+#include <machine/cpufunc.h>
+#include <machine/specialreg.h>
+#include <machine/sysarch.h>
+#include <x86/ifunc.h>
+#include "libc_private.h"
+
+static int
+amd64_set_tlsbase_syscall(void *addr)
+{
+	return (sysarch(AMD64_SET_TLSBASE, &addr));
+}
+
+DEFINE_UIFUNC(, int, amd64_set_tlsbase, (void *))
+{
+	if (__getosreldate() >= P_OSREL_TLSBASE)
+		return (amd64_set_tlsbase_syscall);
+	return (amd64_set_fsbase);
+}
diff --git a/sys/x86/include/sysarch.h b/sys/x86/include/sysarch.h
index 61f559f4bd23..a67e5c2265a3 100644
--- a/sys/x86/include/sysarch.h
+++ b/sys/x86/include/sysarch.h
@@ -142,6 +142,7 @@ int amd64_get_fsbase(void **);
 int amd64_get_gsbase(void **);
 int amd64_set_fsbase(void *);
 int amd64_set_gsbase(void *);
+int amd64_set_tlsbase(void *);
 int x86_pkru_get_perm(unsigned int keyidx, int *access, int *modify);
 int x86_pkru_set_perm(unsigned int keyidx, int access, int modify);
 int x86_pkru_protect_range(void *addr, unsigned long len, unsigned int keyidx,