From e3a1c61d1a69c66a5635bb23318531d5ef651e15 Mon Sep 17 00:00:00 2001 From: Giuliano Belinassi Date: Wed, 24 May 2023 18:03:15 -0300 Subject: [PATCH] Add Userspace Livepatch prologue into ASM functions Userspace Live Patching (ULP) refers to the process of applying patches to the libraries used by a running process, without interrupting it. In order to archive this, functions must have the NOP prologue. This prologue is included automatically when compiled with -fpatchable-function-entry, but for ASM functions this have to be included manually. This patch does this. Signed-off-by: Giuliano Belinassi --- Makeconfig | 5 +++++ config.h.in | 3 +++ config.make.in | 1 + configure | 20 ++++++++++++++++++ configure.ac | 13 ++++++++++++ sysdeps/x86/sysdep.h | 22 ++++++++++++++++---- sysdeps/x86_64/multiarch/strcmp-avx2.S | 5 +---- sysdeps/x86_64/multiarch/strcmp-evex.S | 5 +---- sysdeps/x86_64/multiarch/strcmp-sse4_2.S | 5 +---- sysdeps/x86_64/sysdep.h | 26 ++++++++++++++++++++++++ 10 files changed, 89 insertions(+), 16 deletions(-) diff --git a/Makeconfig b/Makeconfig index 2514db35f6..37df019873 100644 --- a/Makeconfig +++ b/Makeconfig @@ -961,6 +961,11 @@ endif # $(+cflags) == "" $(+stack-protector) -fno-common +gcc-nowarn := -w +# Add flags for Userspace Livepatching support. +ifeq (yes,$(enable-userspace-livepatch)) ++cflags += -fpatchable-function-entry=16,14 +endif + # Each sysdeps directory can contain header files that both will be # used to compile and will be installed. Each can also contain an # include/ subdirectory, whose header files will be used to compile diff --git a/config.h.in b/config.h.in index 44a34072a4..430627dcaf 100644 --- a/config.h.in +++ b/config.h.in @@ -199,6 +199,9 @@ /* Define to 1 if libpthread actually resides in libc. */ #define PTHREAD_IN_LIBC 0 +/* Define to 1 if support for userspace livepatching is enabled. */ +#define ENABLE_USERSPACE_LIVEPATCH 0 + /* An integer used to scale the timeout of test programs. */ #define TIMEOUTFACTOR 1 diff --git a/config.make.in b/config.make.in index 4afd37feaf..84d957cb1c 100644 --- a/config.make.in +++ b/config.make.in @@ -83,6 +83,7 @@ nss-crypt = @libc_cv_nss_crypt@ static-nss-crypt = @libc_cv_static_nss_crypt@ # Configuration options. +enable-userspace-livepatch = @enable_userspace_livepatch@ build-shared = @shared@ build-profile = @profile@ build-static-nss = @static_nss@ diff --git a/configure b/configure index f84040644b..490800c75c 100755 --- a/configure +++ b/configure @@ -591,6 +591,7 @@ LIBOBJS pthread_in_libc RELEASE VERSION +enable_userspace_livepatch mach_interface_list DEFINES static_nss @@ -783,6 +784,7 @@ enable_mathvec enable_cet enable_scv with_cpu +enable_userspace_livepatch ' ac_precious_vars='build_alias host_alias @@ -1452,6 +1454,8 @@ Optional Features: (CET), x86 only --disable-scv syscalls will not use scv instruction, even if the kernel supports it, powerpc only + --enable-userspace-livepatch + build with userspace livepatch support [default=no] Optional Packages: --with-PACKAGE[=ARG] use PACKAGE [ARG=yes] @@ -6708,6 +6712,22 @@ libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` +# Check whether --enable-userspace-livepatch was given. +if test "${enable_userspace_livepatch+set}" = set; then : + enableval=$enable_userspace_livepatch; enable_userspace_livepatch=$enableval +else + enable_userspace_livepatch=no +fi + + +# Libpulp uses -fpatchable-function-entry to add padding NOPS to the +# prologue of all functions. +if test "x$enable_userspace_livepatch" = xyes; then + $as_echo "#define ENABLE_USERSPACE_LIVEPATCH 1" >>confdefs.h + +fi + + VERSION=`sed -n -e 's/^#define VERSION "\([^"]*\)"/\1/p' < $srcdir/version.h` RELEASE=`sed -n -e 's/^#define RELEASE "\([^"]*\)"/\1/p' < $srcdir/version.h` diff --git a/configure.ac b/configure.ac index 88df3e5eed..1c2983de75 100644 --- a/configure.ac +++ b/configure.ac @@ -1803,6 +1803,19 @@ AC_SUBST(DEFINES) dnl See sysdeps/mach/configure.ac for this variable. AC_SUBST(mach_interface_list) +AC_ARG_ENABLE([userspace-livepatch], + AS_HELP_STRING([--enable-userspace-livepatch], + [build with userspace livepatch support @<:@default=no@:>@]), + [enable_userspace_livepatch=$enableval], + [enable_userspace_livepatch=no]) + +# Libpulp uses -fpatchable-function-entry to add padding NOPS to the +# prologue of all functions. +if test "x$enable_userspace_livepatch" = xyes; then + AC_DEFINE(ENABLE_USERSPACE_LIVEPATCH) +fi +AC_SUBST(enable_userspace_livepatch) + VERSION=`sed -n -e 's/^#define VERSION "\([^"]*\)"/\1/p' < $srcdir/version.h` RELEASE=`sed -n -e 's/^#define RELEASE "\([^"]*\)"/\1/p' < $srcdir/version.h` AC_SUBST(VERSION) diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h index 0b3483a77a..329c16306e 100644 --- a/sysdeps/x86/sysdep.h +++ b/sysdeps/x86/sysdep.h @@ -77,15 +77,29 @@ enum cf_protection_level #define ALIGNARG(log2) 1<