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authorRoland McGrath <roland@hack.frob.com>2012-05-22 16:00:50 -0700
committerRoland McGrath <roland@hack.frob.com>2012-05-24 13:13:46 -0700
commitc14874927b499ddfdbb03745bb32bfc778b8595f (patch)
treea07ace4f46694be67780cdf4765044f80ac4f729
parentd6c33fda03457ca8ca87a562fa2681af16ca4ea5 (diff)
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syscalls.list support for vDSO IFUNCs, use it for x32 gettimeofday and time.
-rw-r--r--ChangeLog13
-rw-r--r--Makeconfig4
-rw-r--r--Makerules4
-rw-r--r--sysdeps/unix/make-syscalls.sh142
-rw-r--r--sysdeps/unix/sysv/linux/dl-vdso.h11
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list2
6 files changed, 128 insertions, 48 deletions
diff --git a/ChangeLog b/ChangeLog
index 7c94fce..983ffe6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,18 @@
2012-05-24 Roland McGrath <roland@hack.frob.com>
+ * sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list: New file.
+
+ * sysdeps/unix/make-syscalls.sh: Support "syscall:vdso_name@VDSOVER"
+ in the third column, to generate for the shared library an IFUNC
+ that uses _dl_vdso_vsym.
+ * Makerules (COMPILE.c, compile-stdin.c): New variables.
+ * Makeconfig (object-suffixes-noshared): New variable.
+
+ * sysdeps/unix/sysv/linux/dl-vdso.h (PREPARE_VERSION_KNOWN): New macro.
+ (VDSO_NAME_LINUX_2_6, VDSO_HASH_LINUX_2_6): New macros.
+ (VDSO_NAME_LINUX_2_6_15, VDSO_HASH_LINUX_2_6_15): New macros.
+ (VDSO_NAME_LINUX_2_6_29, VDSO_HASH_LINUX_2_6_29): New macros.
+
[BZ #14132]
* include/sys/time.h (__gettimeofday): Remove macro.
(__gettimeofday, gettimeofday): Add libc_hidden_proto.
diff --git a/Makeconfig b/Makeconfig
index 3a09764..b4b2963 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -720,6 +720,10 @@ CFLAGS-.op = -pg
libtype.op = lib%_p.a
endif
+# Convenience variable for when we want to treat shared-library cases
+# differently from the rest.
+object-suffixes-noshared := $(filter-out .os,$(object-suffixes))
+
bppfx = BP-
ifeq (yes,$(build-bounded))
# Under --enable-bounded, we build the library with `-fbounded-pointers -g'
diff --git a/Makerules b/Makerules
index 0fd1b5b..685b1b8 100644
--- a/Makerules
+++ b/Makerules
@@ -366,6 +366,7 @@ compile.c = $(CC) $< -c $(CFLAGS) $(CPPFLAGS)
compile.cc = $(CXX) $< -c $(CXXFLAGS) $(CPPFLAGS)
compile.S = $(CC) $< -c $(CPPFLAGS) $(S-CPPFLAGS) \
$(ASFLAGS) $(ASFLAGS-$(suffix $@))
+COMPILE.c = $(CC) -c $(CFLAGS) $(CPPFLAGS)
COMPILE.S = $(CC) -c $(CPPFLAGS) $(S-CPPFLAGS) \
$(ASFLAGS) $(ASFLAGS-$(suffix $@))
@@ -374,6 +375,9 @@ COMPILE.S = $(CC) -c $(CPPFLAGS) $(S-CPPFLAGS) \
# together. You can't compile the C library with such a compiler.
OUTPUT_OPTION = -o $@
+# This is the end of the pipeline for compiling generated C code.
+compile-stdin.c = $(COMPILE.c) -o $@ -x c - $(compile-mkdep-flags)
+
# We need the $(CFLAGS) to be in there to have the right predefines during
# the dependency run for C sources. But having it for assembly sources can
# get the wrong predefines.
diff --git a/sysdeps/unix/make-syscalls.sh b/sysdeps/unix/make-syscalls.sh
index 48aab62..cedce31 100644
--- a/sysdeps/unix/make-syscalls.sh
+++ b/sysdeps/unix/make-syscalls.sh
@@ -64,10 +64,67 @@ done`
# Any calls left?
test -n "$calls" || exit 0
+# This uses variables $weak and $strong.
+emit_weak_aliases()
+{
+ # A shortcoming in the current gas is that it will only allow one
+ # version-alias per symbol. So we create new strong aliases as needed.
+ vcount=""
+
+ for name in $weak; do
+ case $name in
+ *@@*)
+ base=`echo $name | sed 's/@@.*//'`
+ ver=`echo $name | sed 's/.*@@//'`
+ if test -z "$vcount" ; then
+ source=$strong
+ vcount=1
+ else
+ source="${strong}_${vcount}"
+ vcount=`expr $vcount + 1`
+ echo " echo 'strong_alias ($strong, $source)'; \\"
+ fi
+ echo " echo 'default_symbol_version($source, $base, $ver)'; \\"
+ ;;
+ *@*)
+ base=`echo $name | sed 's/@.*//'`
+ ver=`echo $name | sed 's/.*@//'`
+ if test -z "$vcount" ; then
+ source=$strong
+ vcount=1
+ else
+ source="${strong}_${vcount}"
+ vcount=`expr $vcount + 1`
+ echo " echo 'strong_alias ($strong, $source)'; \\"
+ fi
+ echo " echo 'symbol_version ($source, $base, $ver)'; \\"
+ ;;
+ !*)
+ name=`echo $name | sed 's/.//'`
+ echo " echo 'strong_alias ($strong, $name)'; \\"
+ echo " echo 'libc_hidden_def ($name)'; \\"
+ ;;
+ *)
+ echo " echo 'weak_alias ($strong, $name)'; \\"
+ echo " echo 'libc_hidden_weak ($name)'; \\"
+ ;;
+ esac
+ done
+}
+
+
# Emit rules to compile the syscalls remaining in $calls.
echo "$calls" |
while read file srcfile caller syscall args strong weak; do
+ vdso_syscall=
+ case x"$syscall" in
+ *:*@*)
+ vdso_syscall="${syscall#*:}"
+ syscall="${syscall%:*}"
+ ;;
+ esac
+
case x"$syscall" in
x-) callnum=_ ;;
*)
@@ -144,13 +201,14 @@ while read file srcfile caller syscall args strong weak; do
# Emit a compilation rule for this syscall.
if test $shared_only = t; then
# The versioned symbols are only in the shared library.
- echo "\
-shared-only-routines += $file
-\$(objpfx)${file}.os: \\"
+ echo "shared-only-routines += $file"
+ test -n "$vdso_syscall" || echo "\$(objpfx)${file}.os: \\"
else
+ object_suffixes='$(object-suffixes)'
+ test -z "$vdso_syscall" || object_suffixes='$(object-suffixes-noshared)'
echo "\
\$(foreach p,\$(sysd-rules-targets),\
-\$(foreach o,\$(object-suffixes),\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
+\$(foreach o,${object_suffixes},\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
fi
echo " \$(..)sysdeps/unix/make-syscalls.sh"
@@ -178,55 +236,43 @@ shared-only-routines += $file
esac
# Append any weak aliases or versions defined for this syscall function.
-
- # A shortcoming in the current gas is that it will only allow one
- # version-alias per symbol. So we create new strong aliases as needed.
- vcount=""
-
- for name in $weak; do
- case $name in
- *@@*)
- base=`echo $name | sed 's/@@.*//'`
- ver=`echo $name | sed 's/.*@@//'`
- if test -z "$vcount" ; then
- source=$strong
- vcount=1
- else
- source="${strong}_${vcount}"
- vcount=`expr $vcount + 1`
- echo " echo 'strong_alias ($strong, $source)'; \\"
- fi
- echo " echo 'default_symbol_version($source, $base, $ver)'; \\"
- ;;
- *@*)
- base=`echo $name | sed 's/@.*//'`
- ver=`echo $name | sed 's/.*@//'`
- if test -z "$vcount" ; then
- source=$strong
- vcount=1
- else
- source="${strong}_${vcount}"
- vcount=`expr $vcount + 1`
- echo " echo 'strong_alias ($strong, $source)'; \\"
- fi
- echo " echo 'symbol_version ($source, $base, $ver)'; \\"
- ;;
- !*)
- name=`echo $name | sed 's/.//'`
- echo " echo 'strong_alias ($strong, $name)'; \\"
- echo " echo 'libc_hidden_def ($name)'; \\"
- ;;
- *)
- echo " echo 'weak_alias ($strong, $name)'; \\"
- echo " echo 'libc_hidden_weak ($name)'; \\"
- ;;
- esac
- done
+ emit_weak_aliases
# And finally, pipe this all into the compiler.
echo ' ) | $(compile-syscall) '"\
\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
+ if test -n "$vdso_syscall"; then
+ # In the shared library, we're going to emit an IFUNC using a vDSO function.
+ # $vdso_syscall looks like "name@KERNEL_X.Y" where "name" is the symbol
+ # name in the vDSO and KERNEL_X.Y is its symbol version.
+ vdso_symbol="${vdso_syscall%@*}"
+ vdso_symver="${vdso_syscall#*@}"
+ vdso_symver="${vdso_symver//./_}"
+ echo "\
+\$(foreach p,\$(sysd-rules-targets),\$(objpfx)\$(patsubst %,\$p,$file).os): \\
+ \$(..)sysdeps/unix/make-syscalls.sh\
+ \$(make-target-directory)
+ (echo '#include <dl-vdso.h>'; \\
+ echo 'extern void *${strong}_ifunc (void) __asm (\"${strong}\");'; \\
+ echo 'void *'; \\
+ echo '${strong}_ifunc (void)'; \\
+ echo '{'; \\
+ echo ' PREPARE_VERSION_KNOWN (symver, ${vdso_symver});'; \\
+ echo ' return _dl_vdso_vsym (\"${vdso_symbol}\", &symver);'; \\
+ echo '}'; \\
+ echo 'asm (\".type ${strong}, %gnu_indirect_function\");'; \\"
+ # This is doing "libc_hidden_def (${strong})", but the compiler
+ # doesn't know that we've defined ${strong} in the same file, so
+ # we can't do it the normal way.
+ echo "\
+ echo 'asm (\".globl __GI_${strong}\\n\"'; \\
+ echo ' \"__GI_${strong} = ${strong}\");'; \\"
+ emit_weak_aliases
+ echo ' ) | $(compile-stdin.c) '"\
+\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
+ fi
+
if test $shared_only = t; then
# The versioned symbols are only in the shared library.
echo endif
diff --git a/sysdeps/unix/sysv/linux/dl-vdso.h b/sysdeps/unix/sysv/linux/dl-vdso.h
index c30671d..4149bac 100644
--- a/sysdeps/unix/sysv/linux/dl-vdso.h
+++ b/sysdeps/unix/sysv/linux/dl-vdso.h
@@ -33,6 +33,17 @@
/* We don't have a specific file where the symbol can be found. */ \
var.filename = NULL
+/* Use this for the known version sets defined below, where we
+ record their precomputed hash values only once, in this file. */
+#define PREPARE_VERSION_KNOWN(var, vname) \
+ PREPARE_VERSION (var, VDSO_NAME_##vname, VDSO_HASH_##vname)
+
+#define VDSO_NAME_LINUX_2_6 "LINUX_2.6"
+#define VDSO_HASH_LINUX_2_6 61765110
+#define VDSO_NAME_LINUX_2_6_15 "LINUX_2.6.15"
+#define VDSO_HASH_LINUX_2_6_15 123718565
+#define VDSO_NAME_LINUX_2_6_29 "LINUX_2.6.29"
+#define VDSO_HASH_LINUX_2_6_29 123718585
/* Functions for resolving symbols in the VDSO link map. */
extern void *_dl_vdso_vsym (const char *name,
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
index 7edb6fd..2cc58af 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
@@ -1,6 +1,8 @@
# File name Caller Syscall name # args Strong name Weak names
fallocate - fallocate Ci:iiii fallocate fallocate64
+gettimeofday - gettimeofday:__vdso_gettimeofday@LINUX_2.6 i:pP __gettimeofday gettimeofday
posix_fadvise - fadvise64 Vi:iiii posix_fadvise posix_fadvise64
preadv - preadv Ci:ipii preadv preadv64
pwritev - pwritev Ci:ipii pwritev pwritev64
+time - time:__vdso_time@LINUX_2.6 Ei:P time