Skip to content

[Clang][RISCV] Remove forced-sw-shadow-stack #115355

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Nov 8, 2024
Merged

[Clang][RISCV] Remove forced-sw-shadow-stack #115355

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 4 additions & 5 deletions clang/docs/ShadowCallStack.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,11 +59,10 @@ and destruction would need to be intercepted by the application.

The instrumentation makes use of the platform register ``x18`` on AArch64,
``x3`` (``gp``) on RISC-V with software shadow stack and ``ssp`` on RISC-V with
hardware shadow stack, which needs `Zicfiss`_ and ``-mno-forced-sw-shadow-stack``
(default option). Note that with ``Zicfiss``_ the RISC-V backend will default to
the hardware based shadow call stack. Users can force the RISC-V backend to
generate the software shadow call stack with ``Zicfiss``_ by passing
``-mforced-sw-shadow-stack``.
hardware shadow stack, which needs `Zicfiss`_ and ``-fcf-protection=return``.
Users can choose between the software and hardware based shadow stack
implementation on RISC-V backend by passing ``-fsanitize=shadowcallstack``
or ``Zicfiss`` with ``-fcf-protection=return``.
For simplicity we will refer to this as the ``SCSReg``. On some platforms,
``SCSReg`` is reserved, and on others, it is designated as a scratch register.
This generally means that any code that may run on the same thread as code
Expand Down
4 changes: 0 additions & 4 deletions clang/include/clang/Driver/Options.td
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4930,10 +4930,6 @@ def msave_restore : Flag<["-"], "msave-restore">, Group<m_riscv_Features_Group>,
HelpText<"Enable using library calls for save and restore">;
def mno_save_restore : Flag<["-"], "mno-save-restore">, Group<m_riscv_Features_Group>,
HelpText<"Disable using library calls for save and restore">;
def mforced_sw_shadow_stack : Flag<["-"], "mforced-sw-shadow-stack">, Group<m_riscv_Features_Group>,
HelpText<"Force using software shadow stack when shadow-stack enabled">;
def mno_forced_sw_shadow_stack : Flag<["-"], "mno-forced-sw-shadow-stack">, Group<m_riscv_Features_Group>,
HelpText<"Not force using software shadow stack when shadow-stack enabled">;
} // let Flags = [TargetSpecific]
let Flags = [TargetSpecific] in {
def menable_experimental_extensions : Flag<["-"], "menable-experimental-extensions">, Group<m_Group>,
Expand Down
6 changes: 0 additions & 6 deletions clang/test/Driver/riscv-features.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -29,12 +29,6 @@
// DEFAULT-NOT: "-target-feature" "-save-restore"
// DEFAULT-NOT: "-target-feature" "+save-restore"

// RUN: %clang --target=riscv32-unknown-elf -### %s -mforced-sw-shadow-stack 2>&1 | FileCheck %s -check-prefix=FORCE-SW-SCS
// RUN: %clang --target=riscv32-unknown-elf -### %s -mno-forced-sw-shadow-stack 2>&1 | FileCheck %s -check-prefix=NO-FORCE-SW-SCS
// FORCE-SW-SCS: "-target-feature" "+forced-sw-shadow-stack"
// NO-FORCE-SW-SCS: "-target-feature" "-forced-sw-shadow-stack"
// DEFAULT-NOT: "-target-feature" "+forced-sw-shadow-stack"

// RUN: %clang --target=riscv32-unknown-elf -### %s -mno-strict-align 2>&1 | FileCheck %s -check-prefixes=FAST-SCALAR-UNALIGNED-ACCESS,FAST-VECTOR-UNALIGNED-ACCESS
// RUN: %clang --target=riscv32-unknown-elf -### %s -mstrict-align 2>&1 | FileCheck %s -check-prefixes=NO-FAST-SCALAR-UNALIGNED-ACCESS,NO-FAST-VECTOR-UNALIGNED-ACCESS
// RUN: %clang --target=riscv32-unknown-elf -### %s -mno-scalar-strict-align 2>&1 | FileCheck %s -check-prefix=FAST-SCALAR-UNALIGNED-ACCESS
Expand Down
Loading