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home:gbelinassi:branches:home:Andreas_Schwab:glibc
glibc
ulp-prologue-into-asm-functions.patch
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File ulp-prologue-into-asm-functions.patch of Package glibc
From 322a7b6a9bad6ab6a985ea67f7bc65a434806061 Mon Sep 17 00:00:00 2001 From: Giuliano Belinassi <gbelinassi@suse.de> Date: Mon, 6 May 2024 20:09:55 -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 <gbelinassi@suse.de> --- Makeconfig | 5 +++ config.h.in | 3 ++ config.make.in | 1 + configure | 21 +++++++++ configure.ac | 13 ++++++ 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 | 54 ++++++++++++++++++++++-- 9 files changed, 96 insertions(+), 16 deletions(-) diff --git a/Makeconfig b/Makeconfig index a0abc2239b..1eb730a2f7 100644 --- a/Makeconfig +++ b/Makeconfig @@ -1017,6 +1017,11 @@ endif # Filter out 64 bit time_t flags if compiler defines it by default. +cflags += $(no-time-bits-source) +# Add flags for Userspace Livepatching support. +ifeq (yes,$(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 6c25c923fa..98e267d71c 100644 --- a/config.h.in +++ b/config.h.in @@ -211,6 +211,9 @@ /* 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 36096881b7..04cf873fad 100644 --- a/config.make.in +++ b/config.make.in @@ -81,6 +81,7 @@ mach-interface-list = @mach_interface_list@ memory-tagging = @memory_tagging@ # 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 9c0c0dce03..4b18c93595 100755 --- a/configure +++ b/configure @@ -615,6 +615,7 @@ LIBOBJS pthread_in_libc RELEASE VERSION +enable_userspace_livepatch mach_interface_list DEFINES static_nss @@ -811,6 +812,7 @@ enable_cet enable_scv enable_fortify_source with_cpu +enable_userspace_livepatch ' ac_precious_vars='build_alias host_alias @@ -1493,6 +1495,8 @@ Optional Features: Use -D_FORTIFY_SOURCE=[1|2|3] to control code hardening, defaults to highest possible value supported by the build compiler. + --enable-userspace-livepatch + build with userspace livepatch support [default=no] Optional Packages: --with-PACKAGE[=ARG] use PACKAGE [ARG=yes] @@ -8184,6 +8188,23 @@ libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` +# Check whether --enable-userspace-livepatch was given. +if test ${enable_userspace_livepatch+y} +then : + enableval=$enable_userspace_livepatch; enable_userspace_livepatch=$enableval +else $as_nop + enable_userspace_livepatch=no +fi + + +# Libpulp uses -fpatchable-function-entry to add padding NOPS to the +# prologue of all functions. +if test "x$enable_userspace_livepatch" = xyes; then + printf "%s\n" "#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' < $srcdir/version.h` diff --git a/configure.ac b/configure.ac index d5a00461ff..80f183a7b5 100644 --- a/configure.ac +++ b/configure.ac @@ -1813,6 +1813,19 @@ AC_SUBST(DEFINES) dnl See sysdeps/mach/configure.ac for this variable. AC_SUBST(mach_interface_list) +AC_ARG_ENABLE([userspace-livepatch], + AS_HELP_STRING([--enable-userspace-livepatch], + [build with userspace livepatch support @<:@default=no@:>@]), + [enable_userspace_livepatch=$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_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S index 5bc1d90078..3ea96c0aa3 100644 --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S @@ -201,10 +201,7 @@ END (STRCASECMP) # endif .p2align 4 -STRCMP: - cfi_startproc - _CET_ENDBR - CALL_MCOUNT +FUNCTION_START(STRCMP) # if defined USE_AS_STRCASECMP_L /* We have to fall back on the C implementation for locales with diff --git a/sysdeps/x86_64/multiarch/strcmp-evex.S b/sysdeps/x86_64/multiarch/strcmp-evex.S index cea034f394..3ed55b7d66 100644 --- a/sysdeps/x86_64/multiarch/strcmp-evex.S +++ b/sysdeps/x86_64/multiarch/strcmp-evex.S @@ -226,10 +226,7 @@ END (STRCASECMP) # endif .p2align 4 -STRCMP: - cfi_startproc - _CET_ENDBR - CALL_MCOUNT +FUNCTION_START(STRCMP) # if defined USE_AS_STRCASECMP_L /* We have to fall back on the C implementation for locales with diff --git a/sysdeps/x86_64/multiarch/strcmp-sse4_2.S b/sysdeps/x86_64/multiarch/strcmp-sse4_2.S index 4e98da0246..2a2280c65f 100644 --- a/sysdeps/x86_64/multiarch/strcmp-sse4_2.S +++ b/sysdeps/x86_64/multiarch/strcmp-sse4_2.S @@ -103,10 +103,7 @@ END (STRCASECMP) # define arg arg -STRCMP: - cfi_startproc - _CET_ENDBR - CALL_MCOUNT +FUNCTION_START(STRCMP) /* * This implementation uses SSE to compare up to 16 bytes at a time. diff --git a/sysdeps/x86_64/sysdep.h b/sysdeps/x86_64/sysdep.h index db6e36b2dd..86a5d1b2be 100644 --- a/sysdeps/x86_64/sysdep.h +++ b/sysdeps/x86_64/sysdep.h @@ -49,6 +49,46 @@ enum cf_protection_level #ifdef __ASSEMBLER__ +/* Libpulp uses -fpatchable-function-entry to add padding NOPS to the + prologue of all functions. This works for C functions. For functions + written in ASM, the way we do this is by adding this prologue manually. */ + +#if ENABLE_USERSPACE_LIVEPATCH + +/* Instructions to be inserted before the function label. */ +# define ULP_NOPS_PRE_PROLOGUE .rept 14; nop; .endr + +/* Instruction to be inserted after the function label. */ +# define ULP_NOPS_POST_PROLOGUE .rept 2; nop; .endr + + +/* this macro expands according to the following condition: + * if name = _start, then the prologue is not inserted. + * if name = _dl_relocate_static_pie, then the prologue is not inserted. + * if name = anything else, then the prologue is inserted. + **/ +# define __ULP_POST_PROLOGUE_dl_relocate_static_pie , +# define __ULP_PRE_PROLOGUE_start , +# define __ULP_PRE_PROLOGUE(x, y,...) y +# define _ULP_PRE_PROLOGUE(x, ...) __ULP_PRE_PROLOGUE(x, __VA_ARGS__) +# define ULP_PRE_PROLOGUE(name) _ULP_PRE_PROLOGUE(__ULP_PRE_PROLOGUE##name, ULP_NOPS_PRE_PROLOGUE,) + +/* this macro expands according to the following condition: + * if name = _start, then the postlogue is not inserted. + * if name = _dl_relocate_static_pie, then the postlogue is not inserted. + * if name = anything else, then the postlogue is inserted. + **/ +# define __ULP_POST_PROLOGUE_dl_relocate_static_pie , +# define __ULP_POST_PROLOGUE_start , +# define __ULP_POST_PROLOGUE(x, y,...) y +# define _ULP_POST_PROLOGUE(x, ...) __ULP_POST_PROLOGUE(x, __VA_ARGS__) +# define ULP_POST_PROLOGUE(name) _ULP_POST_PROLOGUE(__ULP_POST_PROLOGUE##name, ULP_NOPS_POST_PROLOGUE,) + +#else +# define ULP_PRE_PROLOGUE(name) +# define ULP_POST_PROLOGUE(name) +#endif + /* Syntactic details of assembler. */ #ifdef _CET_ENDBR @@ -58,15 +98,21 @@ enum cf_protection_level # define _CET_NOTRACK #endif +/* Define the first instructions of a function. */ +#define FUNCTION_START(name) \ + ULP_PRE_PROLOGUE(name); \ + C_LABEL(name); \ + cfi_startproc; \ + _CET_ENDBR; \ + ULP_POST_PROLOGUE(name); \ + CALL_MCOUNT; + /* Define an entry point visible from C. */ #define ENTRY_P2ALIGN(name, alignment) \ .globl C_SYMBOL_NAME(name); \ .type C_SYMBOL_NAME(name),@function; \ .align ALIGNARG(alignment); \ - C_LABEL(name) \ - cfi_startproc; \ - _CET_ENDBR; \ - CALL_MCOUNT + FUNCTION_START(name) /* This macro is for setting proper CFI with DW_CFA_expression describing the register as saved relative to %rsp instead of relative to the CFA. -- 2.46.2
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