On 1/3/2025 20:25, Jacek Caban wrote:
This is mandatory on ARM64EC and also required on AArch64 for ARM64X builds.
Instead of extending the existing logic, unify it by always including it in
mingwex.
In practice, this means load config will always be present in output images
when using
LLD. Since ld.bfd does not support load config, it remains unaffected.
---
mingw-w64-crt/Makefile.am | 7 +------
mingw-w64-crt/configure.ac | 4 +---
.../{cfguard/mingw_cfguard_loadcfg.S => crt/loadcfg.S} | 0
3 files changed, 2 insertions(+), 9 deletions(-)
rename mingw-w64-crt/{cfguard/mingw_cfguard_loadcfg.S => crt/loadcfg.S} (100%)
diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index 423e233ac..baf65badd 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -928,6 +928,7 @@ src_msvcr120_app=\
# These mingwex sources are target independent:
src_libmingwex=\
+ crt/loadcfg.S \
cfguard/mingw_cfguard_support.c \
\
misc/dllmain.c \
@@ -1015,12 +1016,6 @@ src_libmingwex=\
stdio/vsnprintf.c stdio/vsnwprintf.c \
stdio/wtoll.c stdio/mingw_asprintf.c stdio/mingw_vasprintf.c
-# Include the default load config struct only for Control Flow Guard support.
-if CFGUARD
-src_libmingwex+=\
- cfguard/mingw_cfguard_loadcfg.S
-endif
-
# these go into both 32 and 64 bit x86 versions:
src_libmingwex_x86=\
math/cbrtl.c math/erfl.c math/fdiml.c
math/fmal.c math/fmaxl.c \
diff --git a/mingw-w64-crt/configure.ac b/mingw-w64-crt/configure.ac
index 37851f605..03aa705d7 100644
--- a/mingw-w64-crt/configure.ac
+++ b/mingw-w64-crt/configure.ac
@@ -273,10 +273,8 @@ AC_ARG_ENABLE([cfguard],
AC_MSG_RESULT([$enable_cfguard])
AS_CASE([$enable_cfguard],
[no],[],
- [yes],[AS_VAR_SET([CFGUARD])
- AS_VAR_SET([CFGUARD_CFLAGS],[-mguard=cf])],
+ [yes],[AS_VAR_SET([CFGUARD_CFLAGS],[-mguard=cf])],
[AC_MSG_ERROR([invalid argument. Must be either yes or no.])])
-AM_CONDITIONAL([CFGUARD], [AS_VAR_TEST_SET([CFGUARD])])
AC_SUBST([CFGUARD_CFLAGS])
AC_MSG_CHECKING([whether to enable experimental features])
diff --git a/mingw-w64-crt/cfguard/mingw_cfguard_loadcfg.S
b/mingw-w64-crt/crt/loadcfg.S
similarity index 100%
rename from mingw-w64-crt/cfguard/mingw_cfguard_loadcfg.S
rename to mingw-w64-crt/crt/loadcfg.S
I am concerned that `loadcfg.S` currently always embed the symbols
related to control flow guard (`__guard_check_icall_fptr`,
`__guard_fids_table`, `__guard_flags`, etc.). In my opinion they should
not be included in the load config if mingw-w64 itself isn't compiled
with CFGuard, i.e. the fields should be hardcoded to 0 to reflect that.
The reason for this is that LLD has extra checks to make sure these
CFGuard-related fields are filled up with the correct symbols when
linking with CFGuard enabled. This gives users a warning as an
indication that their mingw-w64 has not been compiled with CFGuard. I
believe it is beneficial to keep this warning functional.
Best Regards,
Alvin
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