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Thu, 23 Oct 2025 16:20:34 -0700 (PDT) Date: Thu, 23 Oct 2025 16:20:31 -0700 From: Deepak Gupta To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , Paul Walmsley , Palmer Dabbelt , Albert Ou , Conor Dooley , Rob Herring , Krzysztof Kozlowski , Arnd Bergmann , Christian Brauner , Peter Zijlstra , Oleg Nesterov , Eric Biederman , Kees Cook , Jonathan Corbet , Shuah Khan , Jann Horn , Conor Dooley , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Andreas Hindborg , Alice Ryhl , Trevor Gross , Benno Lossin , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, alistair.francis@wdc.com, richard.henderson@linaro.org, jim.shu@sifive.com, andybnac@gmail.com, kito.cheng@sifive.com, charlie@rivosinc.com, atishp@rivosinc.com, evan@rivosinc.com, cleger@rivosinc.com, alexghiti@rivosinc.com, samitolvanen@google.com, broonie@kernel.org, rick.p.edgecombe@intel.com, rust-for-linux@vger.kernel.org, Zong Li , David Hildenbrand , Charles Mirabile Subject: Re: [PATCH v22 00/28] riscv control-flow integrity for usermode Message-ID: References: <20251023-v5_user_cfi_series-v22-0-1935270f7636@rivosinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251023-v5_user_cfi_series-v22-0-1935270f7636@rivosinc.com> X-Stat-Signature: rpnnpbo3rpuxeap47or5sh18mxk3djjo X-Rspamd-Queue-Id: 29ED5180008 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1761261636-442068 X-HE-Meta: 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 gS/ZFsIt 7E4UxKq8H571BDiUax0OcY7PwovylsNns5YpyE8fWvsbS27YB+N8EI+A8G8Qg7POu8I9o1Y05ppMFzaxpGzD0bPvv4j/CvNw1+5vW X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Anyone looking to test this and don't want to bother with building cfi enabled toolchain. You can get this docker image https://github.com/orgs/linux-riscv/packages/container/package/linaro-tuxrun-dispatcher-riscv64 and toolchain is at "/build/INSTALL_June" -Deepak On Thu, Oct 23, 2025 at 09:51:05AM -0700, Deepak Gupta via B4 Relay wrote: >v22: fixing build error due to -march=zicfiss being picked in gcc-13 and above >but not actually doing any codegen or recognizing instruction for zicfiss. >Change in v22 makes dependence on `-fcf-protection=full` compiler flag to >ensure that toolchain has support and then only CONFIG_RISCV_USER_CFI will be >visible in menuconfig. > >v21: fixed build errors. > >Basics and overview >=================== > >Software with larger attack surfaces (e.g. network facing apps like databases, >browsers or apps relying on browser runtimes) suffer from memory corruption >issues which can be utilized by attackers to bend control flow of the program >to eventually gain control (by making their payload executable). Attackers are >able to perform such attacks by leveraging call-sites which rely on indirect >calls or return sites which rely on obtaining return address from stack memory. > >To mitigate such attacks, risc-v extension zicfilp enforces that all indirect >calls must land on a landing pad instruction `lpad` else cpu will raise software >check exception (a new cpu exception cause code on riscv). >Similarly for return flow, risc-v extension zicfiss extends architecture with > >- `sspush` instruction to push return address on a shadow stack >- `sspopchk` instruction to pop return address from shadow stack > and compare with input operand (i.e. return address on stack) >- `sspopchk` to raise software check exception if comparision above > was a mismatch >- Protection mechanism using which shadow stack is not writeable via > regular store instructions > >More information an details can be found at extensions github repo [1]. > >Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel >CET [3] and branch target identification (BTI) [4] on arm. >Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control >stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. > >x86 and arm64 support for user mode shadow stack is already in mainline. > >Kernel awareness for user control flow integrity >================================================ > >This series picks up Samuel Holland's envcfg changes [2] as well. So if those are >being applied independently, they should be removed from this series. > >Enabling: > >In order to maintain compatibility and not break anything in user mode, kernel >doesn't enable control flow integrity cpu extensions on binary by default. >Instead exposes a prctl interface to enable, disable and lock the shadow stack >or landing pad feature for a task. This allows userspace (loader) to enumerate >if all objects in its address space are compiled with shadow stack and landing >pad support and accordingly enable the feature. Additionally if a subsequent >`dlopen` happens on a library, user mode can take a decision again to disable >the feature (if incoming library is not compiled with support) OR terminate the >task (if user mode policy is strict to have all objects in address space to be >compiled with control flow integirty cpu feature). prctl to enable shadow stack >results in allocating shadow stack from virtual memory and activating for user >address space. x86 and arm64 are also following same direction due to similar >reason(s). > >clone/fork: > >On clone and fork, cfi state for task is inherited by child. Shadow stack is >part of virtual memory and is a writeable memory from kernel perspective >(writeable via a restricted set of instructions aka shadow stack instructions) >Thus kernel changes ensure that this memory is converted into read-only when >fork/clone happens and COWed when fault is taken due to sspush, sspopchk or >ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, >kernel will automatically allocate a shadow stack for that clone call. > >map_shadow_stack: > >x86 introduced `map_shadow_stack` system call to allow user space to explicitly >map shadow stack memory in its address space. It is useful to allocate shadow >for different contexts managed by a single thread (green threads or contexts) >risc-v implements this system call as well. > >signal management: > >If shadow stack is enabled for a task, kernel performs an asynchronous control >flow diversion to deliver the signal and eventually expects userspace to issue >sigreturn so that original execution can be resumed. Even though resume context >is prepared by kernel, it is in user space memory and is subject to memory >corruption and corruption bugs can be utilized by attacker in this race window >to perform arbitrary sigreturn and eventually bypass cfi mechanism. >Another issue is how to ensure that cfi related state on sigcontext area is not >trampled by legacy apps or apps compiled with old kernel headers. > >In order to mitigate control-flow hijacting, kernel prepares a token and place >it on shadow stack before signal delivery and places address of token in >sigcontext structure. During sigreturn, kernel obtains address of token from >sigcontext struture, reads token from shadow stack and validates it and only >then allow sigreturn to succeed. Compatiblity issue is solved by adopting >dynamic sigcontext management introduced for vector extension. This series >re-factor the code little bit to allow future sigcontext management easy (as >proposed by Andy Chiu from SiFive) > >config and compilation: > >Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this >config option picks the kernel support for user control flow integrity. This >optin is presented only if toolchain has shadow stack and landing pad support. >And is on purpose guarded by toolchain support. Reason being that eventually >vDSO also needs to be compiled in with shadow stack and landing pad support. >vDSO compile patches are not included as of now because landing pad labeling >scheme is yet to settle for usermode runtime. > >To get more information on kernel interactions with respect to >zicfilp and zicfiss, patch series adds documentation for >`zicfilp` and `zicfiss` in following: >Documentation/arch/riscv/zicfiss.rst >Documentation/arch/riscv/zicfilp.rst > >How to test this series >======================= > >Toolchain >--------- >$ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev >$ riscv-gnu-toolchain/configure --prefix= --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" >$ make -j$(nproc) > >Qemu >---- >Get the lastest qemu >$ cd qemu >$ mkdir build >$ cd build >$ ../configure --target-list=riscv64-softmmu >$ make -j$(nproc) > >Opensbi >------- >$ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi >$ make CROSS_COMPILE= -j$(nproc) PLATFORM=generic > >Linux >----- >Running defconfig is fine. CFI is enabled by default if the toolchain >supports it. > >$ make ARCH=riscv CROSS_COMPILE=/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig >$ make ARCH=riscv CROSS_COMPILE=/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) > >Running >------- > >Modify your qemu command to have: >-bios /build/platform/generic/firmware/fw_dynamic.bin >-cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true > >References >========== >[1] - https://github.com/riscv/riscv-cfi >[2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.com/ >[3] - https://lwn.net/Articles/889475/ >[4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identification >[5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-introduction-intel-cet-844137.pdf >[6] - https://lwn.net/Articles/940403/ > >To: Thomas Gleixner >To: Ingo Molnar >To: Borislav Petkov >To: Dave Hansen >To: x86@kernel.org >To: H. Peter Anvin >To: Andrew Morton >To: Liam R. Howlett >To: Vlastimil Babka >To: Lorenzo Stoakes >To: Paul Walmsley >To: Palmer Dabbelt >To: Albert Ou >To: Conor Dooley >To: Rob Herring >To: Krzysztof Kozlowski >To: Arnd Bergmann >To: Christian Brauner >To: Peter Zijlstra >To: Oleg Nesterov >To: Eric Biederman >To: Kees Cook >To: Jonathan Corbet >To: Shuah Khan >To: Jann Horn >To: Conor Dooley >To: Miguel Ojeda >To: Alex Gaynor >To: Boqun Feng >To: Gary Guo >To: Björn Roy Baron >To: Benno Lossin >To: Andreas Hindborg >To: Alice Ryhl >To: Trevor Gross >Cc: linux-kernel@vger.kernel.org >Cc: linux-fsdevel@vger.kernel.org >Cc: linux-mm@kvack.org >Cc: linux-riscv@lists.infradead.org >Cc: devicetree@vger.kernel.org >Cc: linux-arch@vger.kernel.org >Cc: linux-doc@vger.kernel.org >Cc: linux-kselftest@vger.kernel.org >Cc: alistair.francis@wdc.com >Cc: richard.henderson@linaro.org >Cc: jim.shu@sifive.com >Cc: andybnac@gmail.com >Cc: kito.cheng@sifive.com >Cc: charlie@rivosinc.com >Cc: atishp@rivosinc.com >Cc: evan@rivosinc.com >Cc: cleger@rivosinc.com >Cc: alexghiti@rivosinc.com >Cc: samitolvanen@google.com >Cc: broonie@kernel.org >Cc: rick.p.edgecombe@intel.com >Cc: rust-for-linux@vger.kernel.org > >changelog >--------- >v22: >- CONFIG_RISCV_USER_CFI was by default "n". With dual vdso support it is > default "y" (if toolchain supports it). Fixing build error due to > "-march=zicfiss" being picked in gcc-13 partially. gcc-13 only recognizes the > flag but not actually doing any codegen or recognizing instruction for zicfiss. > Change in v22 makes dependence on `-fcf-protection=full` compiler flag to > ensure that toolchain has support and then only CONFIG_RISCV_USER_CFI will be > visible in menuconfig. >- picked up tags and some cosmetic changes in commit message for dual vdso > patch. > > >v21: >- Fixing build errors due to changes in arch/riscv/include/asm/vdso.h > Using #ifdef instead of IS_ENABLED in arch/riscv/include/asm/vdso.h > vdso-cfi-offsets.h should be included only when CONFIG_RISCV_USER_CFI > is selected. > >v20: >- rebased on v6.18-rc1. >- Added two vDSO support. If `CONFIG_RISCV_USER_CFI` is selected > two vDSOs are compiled (one for hardware prior to RVA23 and one > for RVA23 onwards). Kernel exposes RVA23 vDSO if hardware/cpu > implements zimop else exposes existing vDSO to userspace. >- default selection for `CONFIG_RISCV_USER_CFI` is "Yes". >- replaced "__ASSEMBLY__" with "__ASSEMBLER__" > >v19: >- riscv_nousercfi was `int`. changed it to unsigned long. > Thanks to Alex Ghiti for reporting it. It was a bug. >- ELP is cleared on trap entry only when CONFIG_64BIT. >- restore ssp back on return to usermode was being done > before `riscv_v_context_nesting_end` on trap exit path. > If kernel shadow stack were enabled this would result in > kernel operating on user shadow stack and panic (as I found > in my testing of kcfi patch series). So fixed that. > >v18: >- rebased on 6.16-rc1 >- uprobe handling clears ELP in sstatus image in pt_regs >- vdso was missing shadow stack elf note for object files. > added that. Additional asm file for vdso needed the elf marker > flag. toolchain should complain if `-fcf-protection=full` and > marker is missing for object generated from asm file. Asked > toolchain folks to fix this. Although no reason to gate the merge > on that. >- Split up compile options for march and fcf-protection in vdso > Makefile >- CONFIG_RISCV_USER_CFI option is moved under "Kernel features" menu > Added `arch/riscv/configs/hardening.config` fragment which selects > CONFIG_RISCV_USER_CFI > >v17: >- fixed warnings due to empty macros in usercfi.h (reported by alexg) >- fixed prefixes in commit titles reported by alexg >- took below uprobe with fcfi v2 patch from Zong Li and squashed it with > "riscv/traps: Introduce software check exception and uprobe handling" > https://lore.kernel.org/all/20250604093403.10916-1-zong.li@sifive.com/ > >v16: >- If FWFT is not implemented or returns error for shadow stack activation, then > no_usercfi is set to disable shadow stack. Although this should be picked up > by extension validation and activation. Fixed this bug for zicfilp and zicfiss > both. Thanks to Charlie Jenkins for reporting this. >- If toolchain doesn't support cfi, cfi kselftest shouldn't build. Suggested by > Charlie Jenkins. >- Default for CONFIG_RISCV_USER_CFI is set to no. Charlie/Atish suggested to > keep it off till we have more hardware availibility with RVA23 profile and > zimop/zcmop implemented. Else this will start breaking people's workflow >- Includes the fix if "!RV64 and !SBI" then definitions for FWFT in > asm-offsets.c error. > >v15: >- Toolchain has been updated to include `-fcf-protection` flag. This > exists for x86 as well. Updated kernel patches to compile vDSO and > selftest to compile with `fcf-protection=full` flag. >- selecting CONFIG_RISCV_USERCFI selects CONFIG_RISCV_SBI. >- Patch to enable shadow stack for kernel wasn't hidden behind > CONFIG_RISCV_USERCFI and CONFIG_RISCV_SBI. fixed that. > >v14: >- rebased on top of palmer/sbi-v3. Thus dropped clement's FWFT patches > Updated RISCV_ISA_EXT_XXXX in hwcap and hwprobe constants. >- Took Radim's suggestions on bitfields. >- Placed cfi_state at the end of thread_info block so that current situation > is not disturbed with respect to member fields of thread_info in single > cacheline. > >v13: >- cpu_supports_shadow_stack/cpu_supports_indirect_br_lp_instr uses > riscv_has_extension_unlikely() >- uses nops(count) to create nop slide >- RISCV_ACQUIRE_BARRIER is not needed in `amo_user_shstk`. Removed it >- changed ternaries to simply use implicit casting to convert to bool. >- kernel command line allows to disable zicfilp and zicfiss independently. > updated kernel-parameters.txt. >- ptrace user abi for cfi uses bitmasks instead of bitfields. Added ptrace > kselftest. >- cosmetic and grammatical changes to documentation. > >v12: >- It seems like I had accidently squashed arch agnostic indirect branch > tracking prctl and riscv implementation of those prctls. Split them again. >- set_shstk_status/set_indir_lp_status perform CSR writes only when CPU > support is available. As suggested by Zong Li. >- Some minor clean up in kselftests as suggested by Zong Li. > >v11: >- patch "arch/riscv: compile vdso with landing pad" was unconditionally > selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to > to `lpad 0`. >v10: >- dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch > is not that interesting to this patch series for risc-v. There are instances in > arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch > to expedite merging in riscv tree. >- Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to > validate presence of cfi based on config. >- Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure > we add single vdso object with cfi enabled. But a vdso object with scheme of > zero labeled landing pad is least common denominator and should work with all > objects of zero labeled as well as function-signature labeled objects. > >v9: >- rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") >- dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) >- dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) > >v8: >- rebased on palmer/for-next >- dropped samuel holland's `envcfg` context switch patches. > they are in parlmer/for-next > >v7: >- Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" > Instead using `deactivate_mm` flow to clean up. > see here for more context > https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.com/#t >- Changed the header include in `kselftest`. Hopefully this fixes compile > issue faced by Zong Li at SiFive. >- Cleaned up an orphaned change to `mm/mmap.c` in below patch > "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" >- Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 > Any future evolution of this interface should accordingly define how arg should > be setup. >- `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper > `is_shadow_stack_vma`. >- Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@rivosinc.com > >v6: >- Picked up Samuel Holland's changes as is with `envcfg` placed in > `thread` instead of `thread_info` >- fixed unaligned newline escapes in kselftest >- cleaned up messages in kselftest and included test output in commit message >- fixed a bug in clone path reported by Zong Li >- fixed a build issue if CONFIG_RISCV_ISA_V is not selected > (this was introduced due to re-factoring signal context > management code) > >v5: >- rebased on v6.12-rc1 >- Fixed schema related issues in device tree file >- Fixed some of the documentation related issues in zicfilp/ss.rst > (style issues and added index) >- added `SHADOW_STACK_SET_MARKER` so that implementation can define base > of shadow stack. >- Fixed warnings on definitions added in usercfi.h when > CONFIG_RISCV_USER_CFI is not selected. >- Adopted context header based signal handling as proposed by Andy Chiu >- Added support for enabling kernel mode access to shadow stack using > FWFT > (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware-features.adoc) >- Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@rivosinc.com > (Note: I had an issue in my workflow due to which version number wasn't > picked up correctly while sending out patches) > >v4: >- rebased on 6.11-rc6 >- envcfg: Converged with Samuel Holland's patches for envcfg management on per- >thread basis. >- vma_is_shadow_stack is renamed to is_vma_shadow_stack >- picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch >- signal context: using extended context management to maintain compatibility. >- fixed `-Wmissing-prototypes` compiler warnings for prctl functions >- Documentation fixes and amending typos. >- Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ > >v3: >- envcfg > logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been > picked on per task basis, even though CPU didn't implement it. Fixed in > this series. > >- dt-bindings > As suggested, split into separate commit. fixed the messaging that spec is > in public review > >- arch_is_shadow_stack change > arch_is_shadow_stack changed to vma_is_shadow_stack > >- hwprobe > zicfiss / zicfilp if present will get enumerated in hwprobe > >- selftests > As suggested, added object and binary filenames to .gitignore > Selftest binary anyways need to be compiled with cfi enabled compiler which > will make sure that landing pad and shadow stack are enabled. Thus removed > separate enable/disable tests. Cleaned up tests a bit. > >- Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ > >v2: >- Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow > integrity for user mode programs can be compiled in the kernel. > >- Enabling of control flow integrity for user programs is left to user runtime > >- This patch series introduces arch agnostic `prctls` to enable shadow stack > and indirect branch tracking. And implements them on riscv. > >--- >Changes in v22: >- Link to v21: https://lore.kernel.org/r/20251015-v5_user_cfi_series-v21-0-6a07856e90e7@rivosinc.com > >Changes in v21: >- Link to v20: https://lore.kernel.org/r/20251013-v5_user_cfi_series-v20-0-b9de4be9912e@rivosinc.com > >Changes in v20: >- Link to v19: https://lore.kernel.org/r/20250731-v5_user_cfi_series-v19-0-09b468d7beab@rivosinc.com > >Changes in v19: >- Link to v18: https://lore.kernel.org/r/20250711-v5_user_cfi_series-v18-0-a8ee62f9f38e@rivosinc.com > >Changes in v18: >- Link to v17: https://lore.kernel.org/r/20250604-v5_user_cfi_series-v17-0-4565c2cf869f@rivosinc.com > >Changes in v17: >- Link to v16: https://lore.kernel.org/r/20250522-v5_user_cfi_series-v16-0-64f61a35eee7@rivosinc.com > >Changes in v16: >- Link to v15: https://lore.kernel.org/r/20250502-v5_user_cfi_series-v15-0-914966471885@rivosinc.com > >Changes in v15: >- changelog posted just below cover letter >- Link to v14: https://lore.kernel.org/r/20250429-v5_user_cfi_series-v14-0-5239410d012a@rivosinc.com > >Changes in v14: > >- changelog posted just below cover letter >- Link to v13: https://lore.kernel.org/r/20250424-v5_user_cfi_series-v13-0-971437de586a@rivosinc.com > >Changes in v13: >- changelog posted just below cover letter >- Link to v12: https://lore.kernel.org/r/20250314-v5_user_cfi_series-v12-0-e51202b53138@rivosinc.com > >Changes in v12: >- changelog posted just below cover letter >- Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@rivosinc.com > >Changes in v11: >- changelog posted just below cover letter >- Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@rivosinc.com > >--- >Andy Chiu (1): > riscv: signal: abstract header saving for setup_sigcontext > >Deepak Gupta (26): > mm: VM_SHADOW_STACK definition for riscv > dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) > riscv: zicfiss / zicfilp enumeration > riscv: zicfiss / zicfilp extension csr and bit definitions > riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit > riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE > riscv/mm: manufacture shadow stack pte > riscv/mm: teach pte_mkwrite to manufacture shadow stack PTEs > riscv/mm: write protect and shadow stack > riscv/mm: Implement map_shadow_stack() syscall > riscv/shstk: If needed allocate a new shadow stack on clone > riscv: Implements arch agnostic shadow stack prctls > prctl: arch-agnostic prctl for indirect branch tracking > riscv: Implements arch agnostic indirect branch tracking prctls > riscv/traps: Introduce software check exception and uprobe handling > riscv/signal: save and restore of shadow stack for signal > riscv/kernel: update __show_regs to print shadow stack register > riscv/ptrace: riscv cfi status and state via ptrace and in core files > riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe > riscv: kernel command line option to opt out of user cfi > riscv: enable kernel access to shadow stack memory via FWFT sbi call > arch/riscv: dual vdso creation logic and select vdso based on hw > riscv: create a config for shadow stack and landing pad instr support > riscv: Documentation for landing pad / indirect branch tracking > riscv: Documentation for shadow stack on riscv > kselftest/riscv: kselftest for user mode cfi > >Jim Shu (1): > arch/riscv: compile vdso with landing pad and shadow stack note > > Documentation/admin-guide/kernel-parameters.txt | 8 + > Documentation/arch/riscv/index.rst | 2 + > Documentation/arch/riscv/zicfilp.rst | 115 +++++ > Documentation/arch/riscv/zicfiss.rst | 179 +++++++ > .../devicetree/bindings/riscv/extensions.yaml | 14 + > arch/riscv/Kconfig | 22 + > arch/riscv/Makefile | 8 +- > arch/riscv/configs/hardening.config | 4 + > arch/riscv/include/asm/asm-prototypes.h | 1 + > arch/riscv/include/asm/assembler.h | 44 ++ > arch/riscv/include/asm/cpufeature.h | 12 + > arch/riscv/include/asm/csr.h | 16 + > arch/riscv/include/asm/entry-common.h | 2 + > arch/riscv/include/asm/hwcap.h | 2 + > arch/riscv/include/asm/mman.h | 26 + > arch/riscv/include/asm/mmu_context.h | 7 + > arch/riscv/include/asm/pgtable.h | 30 +- > arch/riscv/include/asm/processor.h | 1 + > arch/riscv/include/asm/thread_info.h | 3 + > arch/riscv/include/asm/usercfi.h | 95 ++++ > arch/riscv/include/asm/vdso.h | 13 +- > arch/riscv/include/asm/vector.h | 3 + > arch/riscv/include/uapi/asm/hwprobe.h | 2 + > arch/riscv/include/uapi/asm/ptrace.h | 34 ++ > arch/riscv/include/uapi/asm/sigcontext.h | 1 + > arch/riscv/kernel/Makefile | 2 + > arch/riscv/kernel/asm-offsets.c | 10 + > arch/riscv/kernel/cpufeature.c | 27 + > arch/riscv/kernel/entry.S | 38 ++ > arch/riscv/kernel/head.S | 27 + > arch/riscv/kernel/process.c | 27 +- > arch/riscv/kernel/ptrace.c | 95 ++++ > arch/riscv/kernel/signal.c | 148 +++++- > arch/riscv/kernel/sys_hwprobe.c | 2 + > arch/riscv/kernel/sys_riscv.c | 10 + > arch/riscv/kernel/traps.c | 54 ++ > arch/riscv/kernel/usercfi.c | 545 +++++++++++++++++++++ > arch/riscv/kernel/vdso.c | 7 + > arch/riscv/kernel/vdso/Makefile | 40 +- > arch/riscv/kernel/vdso/flush_icache.S | 4 + > arch/riscv/kernel/vdso/gen_vdso_offsets.sh | 4 +- > arch/riscv/kernel/vdso/getcpu.S | 4 + > arch/riscv/kernel/vdso/note.S | 3 + > arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + > arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + > arch/riscv/kernel/vdso/vgetrandom-chacha.S | 5 +- > arch/riscv/kernel/vdso_cfi/Makefile | 25 + > arch/riscv/kernel/vdso_cfi/vdso-cfi.S | 11 + > arch/riscv/mm/init.c | 2 +- > arch/riscv/mm/pgtable.c | 16 + > include/linux/cpu.h | 4 + > include/linux/mm.h | 7 + > include/uapi/linux/elf.h | 2 + > include/uapi/linux/prctl.h | 27 + > kernel/sys.c | 30 ++ > tools/testing/selftests/riscv/Makefile | 2 +- > tools/testing/selftests/riscv/cfi/.gitignore | 3 + > tools/testing/selftests/riscv/cfi/Makefile | 16 + > tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ > tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 173 +++++++ > tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ > tools/testing/selftests/riscv/cfi/shadowstack.h | 27 + > 62 files changed, 2475 insertions(+), 41 deletions(-) >--- >base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 >change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 >-- >- debug > >