mbox series

[REVIEW,ONLY,0/3] UNRATIFIED RISC-V: Add 'Zisslpcfi' extension and its TENTATIVE CSRs

Message ID cover.1669684988.git.research_trasio@irq.a4lg.com
Headers
Series UNRATIFIED RISC-V: Add 'Zisslpcfi' extension and its TENTATIVE CSRs |

Message

Tsukasa OI Nov. 29, 2022, 1:23 a.m. UTC 
  *** WAIT FOR SPECIFICATION FREEZE ***
This is an implementation for unratified and not frozen RISC-V extension
and not intended to be merged for now.
The only intent to submit this patchset is to test new instructions for
your (possibly virtual) environment and early review for fast adoption
after ratification.


This patchset adds following unratified extension to GNU Binutils:

-   'Zisslpcfi' (Control-Flow Integrity - Shadow Stacks and Landing Pads)
    version 0.1 (may change on ratification)

which adds 11 instructions (all are MOPs [a type of instruction defined in
the 'Zimop' extension as rd=0 by default but allowed to change architectural
state if certain features are supported and optionally enabled; unlike
HINTs, changing the state is allowed]) and 4 CSRs.

This extension is a part of Control-Flow Integrity (CFI) and with this, many
types of control-flow attacks usually caused by a buffer overflow (including
ROP/JOP/COP) can be prevented/mitigated.  Since landing pads come with tags,
targeting certain address is harder than Intel's Indirect Branch Tracking.


This is based on the commit 6400f27c3742 of:
<https://github.com/riscv/riscv-cfi>
and following change not reflected in the documentation yet:
-   Extension name: 'Zimop', not 'Zimops'
    This is told by the author of the upcoming 'Zimop' extension,
    Dr. Andrew Waterman himself.


Note that all (4) CSR values are not allocated yet.
So, these CSRs are assigned with custom range values and this patchset comes
with an instantiation script ("$(srcdir)/instantiate-zisslpcfi.sh") to
assign custom values (overwrites all related files and removes itself).

Because of dependency to the 'Zimop' extension (which documentation is not
available yet [upcoming]), this patchset is NEVER going to be committed as
is (even if a maintainer approves).  Be careful.




Tsukasa OI (3):
  RISC-V: Add "XUN@S" operand type
  UNRATIFIED RISC-V: Add 'Zisslpcfi' extension and its TENTATIVE CSRs
  TEST: Add instantiation script on CSR allocation

 bfd/elfxx-riscv.c                           |   8 ++
 gas/config/tc-riscv.c                       |   6 +
 gas/testsuite/gas/riscv/csr-dw-regnums.d    |   2 +
 gas/testsuite/gas/riscv/csr-dw-regnums.s    |   3 +
 gas/testsuite/gas/riscv/csr-version-1p10.d  |   4 +
 gas/testsuite/gas/riscv/csr-version-1p10.l  |   4 +
 gas/testsuite/gas/riscv/csr-version-1p11.d  |   4 +
 gas/testsuite/gas/riscv/csr-version-1p11.l  |   4 +
 gas/testsuite/gas/riscv/csr-version-1p12.d  |   4 +
 gas/testsuite/gas/riscv/csr-version-1p12.l  |   4 +
 gas/testsuite/gas/riscv/csr-version-1p9p1.d |   4 +
 gas/testsuite/gas/riscv/csr-version-1p9p1.l |   4 +
 gas/testsuite/gas/riscv/csr.s               |   4 +
 gas/testsuite/gas/riscv/zisslpcfi-fail.d    |   2 +
 gas/testsuite/gas/riscv/zisslpcfi-fail.l    |  19 +++
 gas/testsuite/gas/riscv/zisslpcfi-fail.s    |  26 ++++
 gas/testsuite/gas/riscv/zisslpcfi-noarch.d  |   3 +
 gas/testsuite/gas/riscv/zisslpcfi-noarch.l  |  24 ++++
 gas/testsuite/gas/riscv/zisslpcfi.d         |  31 +++++
 gas/testsuite/gas/riscv/zisslpcfi.s         |  26 ++++
 include/opcode/riscv-opc.h                  |  41 +++++++
 include/opcode/riscv.h                      |   1 +
 instantiate-zisslpcfi.sh                    | 127 ++++++++++++++++++++
 opcodes/riscv-dis.c                         |   9 +-
 opcodes/riscv-opc.c                         |  19 +++
 25 files changed, 380 insertions(+), 3 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi-fail.d
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi-fail.l
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi-fail.s
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi-noarch.d
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi-noarch.l
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi.d
 create mode 100644 gas/testsuite/gas/riscv/zisslpcfi.s
 create mode 100755 instantiate-zisslpcfi.sh


base-commit: cb44f89ce977b1ab2d4063f2487950bddfb75bc7