[PPC64] Add ifunc support in libcsu

When ifuncs are used in statically linked binaries, the C runtime
must perform the needed dynamic relocations, to make calls to ifuncs
work correctly.

Reviewed by:	jhibbits
Differential Revision:	https://reviews.freebsd.org/D21070

diff --git a/lib/csu/powerpc64/Makefile b/lib/csu/powerpc64/Makefile
index a1e0c19eeb1e589700e16b20bd0708223e5409e7..ee1d7606575680e3f4a7c66acc419acafa48a5d5 100644 (file)
--- a/lib/csu/powerpc64/Makefile
+++ b/lib/csu/powerpc64/Makefile
@@ -5,9 +5,9 @@
 SRCS=          crt1.c crti.S crtn.S
 OBJS=          ${SRCS:N*.h:R:S/$/.o/g}
 OBJS+=         crtsavres.o Scrt1.o gcrt1.o
-CFLAGS+=       -I${.CURDIR:H}/common \
+CFLAGS+=       -I${.CURDIR} -I${.CURDIR:H}/common \
                -I${SRCTOP}/lib/libc/include \
-               -mlongcall -DCRT_IRELOC_SUPPRESS
+               -mlongcall -DCRT_IRELOC_RELA
 
 FILES=         ${OBJS}
 FILESMODE=     ${LIBMODE}

diff --git a/lib/csu/powerpc64/crt1.c b/lib/csu/powerpc64/crt1.c
index 869530749012773011f5a5fc82c7efd0e564e724..1d1d170f6e06acac66c295bd9597624358d389b9 100644 (file)
--- a/lib/csu/powerpc64/crt1.c
+++ b/lib/csu/powerpc64/crt1.c
@@ -45,6 +45,11 @@
 __FBSDID("$FreeBSD$");
 
 #include <stdlib.h>
+#include <stdint.h>
+#include <sys/elf.h>
+
+static uint32_t cpu_features;
+static uint32_t cpu_features2;
 
 #include "libc_private.h"
 #include "crtbrand.c"
@@ -65,6 +70,30 @@ extern int etext;
 
 struct ps_strings *__ps_strings;
 
+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:
+                       cpu_features = (uint32_t)aux->a_un.a_val;
+                       break;
+               case AT_HWCAP2:
+                       cpu_features2 = (uint32_t)aux->a_un.a_val;
+                       break;
+               }
+       }
+}
+
+
 /* The entry function. */
 /*
  * First 5 arguments are specified by the PowerPC SVR4 ABI.
@@ -84,8 +113,11 @@ _start(int argc, char **argv, char **env,
 
        if (&_DYNAMIC != NULL)
                atexit(cleanup);
-       else
+       else {
+               init_cpu_features(env);
+               process_irelocs();
                _init_tls();
+       }
 
 #ifdef GCRT
        atexit(_mcleanup);

diff --git a/lib/csu/powerpc64/reloc.c b/lib/csu/powerpc64/reloc.c
new file mode 100644 (file)
index 0000000..afa3f2f
--- /dev/null
+++ b/lib/csu/powerpc64/reloc.c
@@ -0,0 +1,43 @@
+/*-
+ * Copyright (c) 2019 Leandro Lupori
+ *
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+static void
+crt1_handle_rela(const Elf_Rela *r)
+{
+       typedef Elf_Addr (*ifunc_resolver_t)(
+           uint32_t, uint32_t, uint64_t, uint64_t,
+           uint64_t, uint64_t, uint64_t, uint64_t);
+       Elf_Addr *ptr, *where, target;
+
+       switch (ELF_R_TYPE(r->r_info)) {
+       case R_PPC_IRELATIVE:
+               ptr = (Elf_Addr *)r->r_addend;
+               where = (Elf_Addr *)r->r_offset;
+               target = ((ifunc_resolver_t)ptr)(cpu_features, cpu_features2,
+                   0, 0, 0, 0, 0, 0);
+               *where = target;
+               break;
+       }
+}