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Wong" To: Deepak Gupta Cc: 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: <20251020211342.GG6174@frogsfrogsfrogs> References: <20251020-v5_user_cfi_series-v22-0-66732256ad8f@rivosinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Stat-Signature: 8n1q9kj16j4p67uiggcdhdcfigfati9c X-Rspamd-Queue-Id: B7CEF1C0014 X-Rspamd-Server: rspam09 X-HE-Tag: 1760994824-691117 X-HE-Meta: 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 3JrgNvdU 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 zREdENUw Crozt2lWovy482i0VRFysw8XB7FEJw1t6h1v5Da7cK1A4gfDp/p63yN+dxy/We1C1i4JXQMsDvqvi2bLUMR9I/RZq5j/PnsRZqo4k52WK/eduLMjhIObrrhP9Tb5kt0YRK+oYDaD/aiqrOFKWI+8F42+82+gbwIPxb/htpQzOoIcRoSuJWqMnf/jEqLdNAM4i27FbetjU0pQglXKU8Mvj+6ca2jsJ1M/KcMICuxx9+IH3wkzdYNVCfArN52XNW4weabF8mmAIRTFhZl1AH8/ynmSnzV2nDP26aYpuzz+LbRC14lw9E7dl00DqBLQNZQPjlwRnF3GYEEOk5panjQKQHeV9sS+23Er5Sp0jaUGJrKXB4D6jSY4zG82gVsf96kT58dl+KWR6Tk= 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: On Mon, Oct 20, 2025 at 01:53:06PM -0700, Deepak Gupta wrote: > I am getting below error on my end for all recipients. That's the reason for > partial delivery. I have to figure out issue and then I'll re-send. > > """ > The user you are trying to contact is receiving mail at a rate that\n > 4.2.1 prevents additional messages from being delivered. Please resend your\n > 4.2.1 message at a later time. If the user is able to receive mail at that\n > 4.2.1 time, your message will be delivered. For more information, go to\n > 4.2.1 https://support.google.com/mail/?p=ReceivingRate 98e67ed59e1d1-33dfb7f8310sm153460a91.5 - gsmtp') > """ A MTA says "You're sending too much email too fast, please stop" and your response is to send everyone the entire patchset A SECOND TIME?! Please stop. --D > On Mon, Oct 20, 2025 at 01:22:29PM -0700, Deepak Gupta 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 > > >