Control-flow Enforcement Technology (CET), published by Intel, Introduces the Shadow Stack feature, which ensures a return from a function is done to exactly the same location from where the function was called. When EH is present the control-flow transfer may skip some stack frames and the shadow stack has to be adjusted not to signal a violation of a control-flow transfer. It's done by counting a number of skipping frames and adjusting shadow stack pointer by this number.
gcc/
* config/i386/i386.c (ix86_expand_epilogue): Change simple
return to indirect jump for EH return. Change explicit 'false'
argument in pro_epilogue_adjust_stack with a value of
flag_cf_protection.
* config/i386/i386.md (simple_return_indirect_internal): Remove
SImode restriction to support 64-bit.
libgcc/
* config/i386/linux-unwind.h: Include
config/i386/shadow-stack-unwind.h.
* config/i386/shadow-stack-unwind.h: New file.
* unwind-dw2.c: (uw_install_context): Add a FRAMES argument and
pass it to _Unwind_Frames_Extra.
* unwind-generic.h (FRAMES_P_DECL): New.
(FRAMES_VAR): Likewise.
(FRAMES_VAR_P): Likewise.
(FRAMES_VAR_DECL): Likewise.
(FRAMES_VAR_DECL_1): Likewise.
(FRAMES_VAR_INC): Likewise.
(FRAMES_P_UPDATE): Likewise.
(_Unwind_Frames_Extra): Likewise.
* unwind.inc (_Unwind_RaiseException_Phase2): Use FRAMES_P_DECL,
FRAMES_VAR_DECL_1, FRAMES_VAR_INC and FRAMES_P_UPDATE.
(_Unwind_RaiseException): Use FRAMES_VAR_DECL, FRAMES_VAR_P and
FRAMES_VAR.
(_Unwind_ForcedUnwind_Phase2): Use FRAMES_P_DECL,
FRAMES_VAR_DECL_1, FRAMES_VAR_INC, FRAMES_P_UPDATE.
(_Unwind_ForcedUnwind): Use FRAMES_VAR_DECL, FRAMES_VAR_P and
FRAMES_VAR.
(_Unwind_Resume): Use FRAMES_VAR_DECL, FRAMES_VAR_P and
FRAMES_VAR.
(_Unwind_Resume_or_Rethrow): Use FRAMES_VAR_DECL, FRAMES_VAR_P
and FRAMES_VAR.
Igor
0008-Add-Intel-CET-support-for-EH-in-libgcc.patch
Description: 0008-Add-Intel-CET-support-for-EH-in-libgcc.patch
