git: 1363acbf25de - main - libc/csu: Support IFUNCs on riscv

The branch main has been updated by jrtc27:

URL: https://cgit.FreeBSD.org/src/commit/?id=1363acbf25de4c36e183cfa0b0e801d4dd9bf2ad

commit 1363acbf25de4c36e183cfa0b0e801d4dd9bf2ad
Author:     Jessica Clarke <jrtc27@FreeBSD.org>
AuthorDate: 2024-10-18 18:14:58 +0000
Commit:     Jessica Clarke <jrtc27@FreeBSD.org>
CommitDate: 2024-10-18 18:14:58 +0000

    libc/csu: Support IFUNCs on riscv
    
    When adding support to rtld-elf I neglected the fact that static
    binaries can have IFUNCs. Add support for this too.
    
    Fixes:          729d2b16b74f ("rtld-elf: Support IFUNCs on riscv")
    MFC after:      1 week
---
 lib/libc/csu/riscv/Makefile.inc |  4 +--
 lib/libc/csu/riscv/reloc.c      | 63 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/lib/libc/csu/riscv/Makefile.inc b/lib/libc/csu/riscv/Makefile.inc
index 2534e6579f38..5d59d40eb393 100644
--- a/lib/libc/csu/riscv/Makefile.inc
+++ b/lib/libc/csu/riscv/Makefile.inc
@@ -1,4 +1,4 @@
 #
 
-CFLAGS+=	-DCRT_IRELOC_SUPPRESS \
-		-DINIT_IRELOCS=""
+CFLAGS+=	-DCRT_IRELOC_RELA \
+		-DINIT_IRELOCS="init_cpu_features(env)"
diff --git a/lib/libc/csu/riscv/reloc.c b/lib/libc/csu/riscv/reloc.c
new file mode 100644
index 000000000000..036ea3de8701
--- /dev/null
+++ b/lib/libc/csu/riscv/reloc.c
@@ -0,0 +1,63 @@
+/*-
+ * Copyright (c) 2019 Leandro Lupori
+ * Copyright (c) 2024 Jessica Clarke <jrtc27@FreeBSD.org>
+ *
+ * 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.
+ *
+ * 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.
+ */
+
+static unsigned long elf_hwcap;
+
+static void
+init_cpu_features(char **env)
+{
+	const Elf_Auxinfo *aux;
+
+	/* Find the auxiliary vector on the stack. */
+	while (*env++ != 0)	/* Skip over environment, and NULL terminator */
+		;
+	aux = (const Elf_Auxinfo *)env;
+
+	/* Digest the auxiliary vector. */
+	for (; aux->a_type != AT_NULL; aux++) {
+		switch (aux->a_type) {
+		case AT_HWCAP:
+			elf_hwcap = (uint32_t)aux->a_un.a_val;
+			break;
+		}
+	}
+}
+
+static void
+crt1_handle_rela(const Elf_Rela *r)
+{
+	typedef Elf_Addr (*ifunc_resolver_t)(
+	    unsigned long, unsigned long, unsigned long, unsigned long,
+	    unsigned long, unsigned long, unsigned long, unsigned long);
+	Elf_Addr *ptr, *where, target;
+
+	switch (ELF_R_TYPE(r->r_info)) {
+	case R_RISCV_IRELATIVE:
+		ptr = (Elf_Addr *)r->r_addend;
+		where = (Elf_Addr *)r->r_offset;
+		target = ((ifunc_resolver_t)ptr)(elf_hwcap,
+		    0, 0, 0, 0, 0, 0, 0);
+		*where = target;
+		break;
+	}
+}