Merge tag 'riscv-for-linus-7.0-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Paul Walmsley:

- Add support for control flow integrity for userspace proc

Merge tag 'riscv-for-linus-7.0-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Paul Walmsley:

- Add support for control flow integrity for userspace processes.

This is based on the standard RISC-V ISA extensions Zicfiss and
Zicfilp

- Improve ptrace behavior regarding vector registers, and add some
selftests

- Optimize our strlen() assembly

- Enable the ISO-8859-1 code page as built-in, similar to ARM64, for
EFI volume mounting

- Clean up some code slightly, including defining copy_user_page() as
copy_page() rather than memcpy(), aligning us with other
architectures; and using max3() to slightly simplify an expression
in riscv_iommu_init_check()

* tag 'riscv-for-linus-7.0-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (42 commits)
riscv: lib: optimize strlen loop efficiency
selftests: riscv: vstate_exec_nolibc: Use the regular prctl() function
selftests: riscv: verify ptrace accepts valid vector csr values
selftests: riscv: verify ptrace rejects invalid vector csr inputs
selftests: riscv: verify syscalls discard vector context
selftests: riscv: verify initial vector state with ptrace
selftests: riscv: test ptrace vector interface
riscv: ptrace: validate input vector csr registers
riscv: csr: define vtype register elements
riscv: vector: init vector context with proper vlenb
riscv: ptrace: return ENODATA for inactive vector extension
kselftest/riscv: add kselftest for user mode CFI
riscv: add documentation for shadow stack
riscv: add documentation for landing pad / indirect branch tracking
riscv: create a Kconfig fragment for shadow stack and landing pad support
arch/riscv: add dual vdso creation logic and select vdso based on hw
arch/riscv: compile vdso with landing pad and shadow stack note
riscv: enable kernel access to shadow stack memory via the FWFT SBI call
riscv: add kernel command line option to opt out of user CFI
riscv/hwprobe: add zicfilp / zicfiss enumeration in hwprobe
...

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kselftest/riscv: add kselftest for user mode CFI

Add a kselftest for RISC-V control flow integrity implementation for
user mode. There is not a lot going on in the kernel to enable landing
pad for u

kselftest/riscv: add kselftest for user mode CFI

Add a kselftest for RISC-V control flow integrity implementation for
user mode. There is not a lot going on in the kernel to enable landing
pad for user mode. CFI selftests are intended to be compiled with a
zicfilp and zicfiss enabled compiler. This kselftest simply checks if
landing pads and shadow stacks for the process are enabled or not and
executes ptrace selftests on CFI. The selftest then registers a
SIGSEGV signal handler. Any control flow violations are reported as
SIGSEGV with si_code = SEGV_CPERR. The test will fail on receiving
any SEGV_CPERR. The shadow stack part has more changes in the kernel,
and thus there are separate tests for that.

- Exercise 'map_shadow_stack' syscall
- 'fork' test to make sure COW works for shadow stack pages
- gup tests
Kernel uses FOLL_FORCE when access happens to memory via
/proc/<pid>/mem. Not breaking that for shadow stack.
- signal test. Make sure signal delivery results in token creation on
shadow stack and consumes (and verifies) token on sigreturn
- shadow stack protection test. attempts to write using regular store
instruction on shadow stack memory must result in access faults
- ptrace test: adds landing pad violation, clears ELP and continues

In case the toolchain doesn't support the CFI extension, the CFI
kselftest won't be built.

Test output
===========

"""
TAP version 13
1..5
This is to ensure shadow stack is indeed enabled and working
This is to ensure shadow stack is indeed enabled and working
ok 1 shstk fork test
ok 2 map shadow stack syscall
ok 3 shadow stack gup tests
ok 4 shadow stack signal tests
ok 5 memory protections of shadow stack memory
"""

Suggested-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-28-b55691eacf4f@rivosinc.com
[pjw@kernel.org: updated to apply; cleaned up patch description, code comments]
Signed-off-by: Paul Walmsley <pjw@kernel.org>

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