On 11/11/22 02:26, liuhongt via Gcc-patches wrote:
2 years ago, ARM folks support HWASAN[1] in GCC[2], and introduced several
target hooks(Many thanks to their work) so other backends can do similar
things if they have similar feature.
Intel LAM(linear Address Masking)[3 Charpter 14] supports similar feature
with
the upper bits of pointers can be used as metadata, LAM support two modes:
LAM_U48:bits 48-62 can be used as metadata
LAM_U57:bits 57-62 can be used as metedata.
These 2 patches mainly support those target hooks, but HWASAN is not really
enabled until the final decision for the LAM kernel interface which may take
quite a long time. We have verified our patches with a "fake" interface
locally[4], and
decided to push the backend patches to the GCC13 to make other HWASAN
developper's work
easy.
Hello.
A few random comments I noticed:
1) please document the new target -mlam in extend.texi
2) the description speaks about bits [48-62] or [57-62], can explain why the
patch contains:
+ /* Mask off bit63 when LAM_U57. */
+ if (ix86_lam_type == lam_u57)
?
3) Shouldn't the -lman option emit GNU_PROPERTY_X86_FEATURE_1_LAM_U57 or
GNU_PROPERTY_X86_FEATURE_1_LAM_U48
.gnu.property note?
4) Can you please explain Florian's comment here:
https://gitlab.com/x86-psABIs/x86-64-ABI/-/merge_requests/13#note_1181396487
Thanks,
Martin
[1] https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
[2] https://gcc.gnu.org/pipermail/gcc-patches/2020-November/557857.html
[3]
https://www.intel.com/content/dam/develop/external/us/en/documents/architecture-instruction-set-extensions-programming-reference.pdf
[4] https://gitlab.com/x86-gcc/gcc/-/tree/users/intel/lam/master
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk?
liuhongt (2):
Implement hwasan target_hook.
Enable hwasan for x86-64.
gcc/config/i386/i386-expand.cc | 12 ++++
gcc/config/i386/i386-options.cc | 3 +
gcc/config/i386/i386-opts.h | 6 ++
gcc/config/i386/i386-protos.h | 2 +
gcc/config/i386/i386.cc | 123 ++++++++++++++++++++++++++++++++
gcc/config/i386/i386.opt | 16 +++++
libsanitizer/configure.tgt | 1 +
7 files changed, 163 insertions(+)
