On Sun, 2 Mar 2025, Alvin Wong wrote:
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%)
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.
Thanks, this is a very valuable point!
I guess there's no prepreocessor define we can check in loadcfg.S, so we'd
need to pass one from the build system, when building with
--enable-cfguard, which can be used to switch between including or
omitting these pointers in the load config, irght?
// Martin
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