linux-stable.git/arch/riscv/kernel/process.c, branch linux-rolling-lts Linux kernel stable tree riscv: Reset pmm when PR_TAGGED_ADDR_ENABLE is not set 2026-04-11T12:26:33+00:00 Zishun Yi vulab@iscas.ac.cn 2026-03-22T16:00:22+00:00 50392cdfe95e0cd40b03ed95b50d3d53be3fa624 [ Upstream commit 3033b2b1e3949274f33a140e2a97571b5a307298 ] In set_tagged_addr_ctrl(), when PR_TAGGED_ADDR_ENABLE is not set, pmlen is correctly set to 0, but it forgets to reset pmm. This results in the CPU pmm state not corresponding to the software pmlen state. Fix this by resetting pmm along with pmlen. Fixes: 2e1743085887 ("riscv: Add support for the tagged address ABI") Signed-off-by: Zishun Yi <vulab@iscas.ac.cn> Reviewed-by: Samuel Holland <samuel.holland@sifive.com> Link: https://patch.msgid.link/20260322160022.21908-1-vulab@iscas.ac.cn Signed-off-by: Paul Walmsley <pjw@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3033b2b1e3949274f33a140e2a97571b5a307298 ]

In set_tagged_addr_ctrl(), when PR_TAGGED_ADDR_ENABLE is not set, pmlen
is correctly set to 0, but it forgets to reset pmm. This results in the
CPU pmm state not corresponding to the software pmlen state.

Fix this by resetting pmm along with pmlen.

Fixes: 2e1743085887 ("riscv: Add support for the tagged address ABI")
Signed-off-by: Zishun Yi <vulab@iscas.ac.cn>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://patch.msgid.link/20260322160022.21908-1-vulab@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch: copy_thread: pass clone_flags as u64 2025-09-01T13:31:34+00:00 Simon Schuster schuster.simon@siemens-energy.com 2025-09-01T13:09:52+00:00 bbc46b23af5bb934cd1cf066ef4342cee457a24e With the introduction of clone3 in commit 7f192e3cd316 ("fork: add clone3") the effective bit width of clone_flags on all architectures was increased from 32-bit to 64-bit, with a new type of u64 for the flags. However, for most consumers of clone_flags the interface was not changed from the previous type of unsigned long. While this works fine as long as none of the new 64-bit flag bits (CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still undesirable in terms of the principle of least surprise. Thus, this commit fixes all relevant interfaces of the copy_thread function that is called from copy_process to consistently pass clone_flags as u64, so that no truncation to 32-bit integers occurs on 32-bit architectures. Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com> Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-3-53fcf5577d57@siemens-energy.com Fixes: c5febea0956fd387 ("fork: Pass struct kernel_clone_args into copy_thread") Acked-by: Guo Ren (Alibaba Damo Academy) <guoren@kernel.org> Acked-by: Andreas Larsson <andreas@gaisler.com> # sparc Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Christian Brauner <brauner@kernel.org> 
With the introduction of clone3 in commit 7f192e3cd316 ("fork: add
clone3") the effective bit width of clone_flags on all architectures was
increased from 32-bit to 64-bit, with a new type of u64 for the flags.
However, for most consumers of clone_flags the interface was not
changed from the previous type of unsigned long.

While this works fine as long as none of the new 64-bit flag bits
(CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still
undesirable in terms of the principle of least surprise.

Thus, this commit fixes all relevant interfaces of the copy_thread
function that is called from copy_process to consistently pass
clone_flags as u64, so that no truncation to 32-bit integers occurs on
32-bit architectures.

Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com>
Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-3-53fcf5577d57@siemens-energy.com
Fixes: c5febea0956fd387 ("fork: Pass struct kernel_clone_args into copy_thread")
Acked-by: Guo Ren (Alibaba Damo Academy) <guoren@kernel.org>
Acked-by: Andreas Larsson <andreas@gaisler.com> # sparc
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Merge tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux 2025-06-07T01:05:18+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-06-07T01:05:18+00:00 119b1e61a769aa98e68599f44721661a4d8c55f3 Pull RISC-V updates from Palmer Dabbelt: - Support for the FWFT SBI extension, which is part of SBI 3.0 and a dependency for many new SBI and ISA extensions - Support for getrandom() in the VDSO - Support for mseal - Optimized routines for raid6 syndrome and recovery calculations - kexec_file() supports loading Image-formatted kernel binaries - Improvements to the instruction patching framework to allow for atomic instruction patching, along with rules as to how systems need to behave in order to function correctly - Support for a handful of new ISA extensions: Svinval, Zicbop, Zabha, some SiFive vendor extensions - Various fixes and cleanups, including: misaligned access handling, perf symbol mangling, module loading, PUD THPs, and improved uaccess routines * tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (69 commits) riscv: uaccess: Only restore the CSR_STATUS SUM bit RISC-V: vDSO: Wire up getrandom() vDSO implementation riscv: enable mseal sysmap for RV64 raid6: Add RISC-V SIMD syndrome and recovery calculations riscv: mm: Add support for Svinval extension RISC-V: Documentation: Add enough title underlines to CMODX riscv: Improve Kconfig help for RISCV_ISA_V_PREEMPTIVE MAINTAINERS: Update Atish's email address riscv: uaccess: do not do misaligned accesses in get/put_user() riscv: process: use unsigned int instead of unsigned long for put_user() riscv: make unsafe user copy routines use existing assembly routines riscv: hwprobe: export Zabha extension riscv: Make regs_irqs_disabled() more clear perf symbols: Ignore mapping symbols on riscv RISC-V: Kconfig: Fix help text of CMDLINE_EXTEND riscv: module: Optimize PLT/GOT entry counting riscv: Add support for PUD THP riscv: xchg: Prefetch the destination word for sc.w riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop riscv: Add support for Zicbop ... 
Pull RISC-V updates from Palmer Dabbelt:

 - Support for the FWFT SBI extension, which is part of SBI 3.0 and a
   dependency for many new SBI and ISA extensions

 - Support for getrandom() in the VDSO

 - Support for mseal

 - Optimized routines for raid6 syndrome and recovery calculations

 - kexec_file() supports loading Image-formatted kernel binaries

 - Improvements to the instruction patching framework to allow for
   atomic instruction patching, along with rules as to how systems need
   to behave in order to function correctly

 - Support for a handful of new ISA extensions: Svinval, Zicbop, Zabha,
   some SiFive vendor extensions

 - Various fixes and cleanups, including: misaligned access handling,
   perf symbol mangling, module loading, PUD THPs, and improved uaccess
   routines

* tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (69 commits)
  riscv: uaccess: Only restore the CSR_STATUS SUM bit
  RISC-V: vDSO: Wire up getrandom() vDSO implementation
  riscv: enable mseal sysmap for RV64
  raid6: Add RISC-V SIMD syndrome and recovery calculations
  riscv: mm: Add support for Svinval extension
  RISC-V: Documentation: Add enough title underlines to CMODX
  riscv: Improve Kconfig help for RISCV_ISA_V_PREEMPTIVE
  MAINTAINERS: Update Atish's email address
  riscv: uaccess: do not do misaligned accesses in get/put_user()
  riscv: process: use unsigned int instead of unsigned long for put_user()
  riscv: make unsafe user copy routines use existing assembly routines
  riscv: hwprobe: export Zabha extension
  riscv: Make regs_irqs_disabled() more clear
  perf symbols: Ignore mapping symbols on riscv
  RISC-V: Kconfig: Fix help text of CMDLINE_EXTEND
  riscv: module: Optimize PLT/GOT entry counting
  riscv: Add support for PUD THP
  riscv: xchg: Prefetch the destination word for sc.w
  riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
  riscv: Add support for Zicbop
  ...
Merge patch series "riscv: misaligned: fix misaligned accesses handling in put/get_user()" 2025-06-05T21:03:18+00:00 Palmer Dabbelt palmer@dabbelt.com 2025-06-05T18:39:22+00:00 a921f0753a4c152ba6ebb215b224dd1d04420d26 Clément Léger <cleger@rivosinc.com> says: While debugging a few problems with the misaligned access kselftest, Alexandre discovered some crash with the current code. Indeed, some misaligned access was done by the kernel using put_user(). This was resulting in trap and a kernel crash since. The path was the following: user -> kernel -> access to user memory -> misaligned trap -> trap -> kernel -> misaligned handling -> memcpy -> crash due to failed page fault while in interrupt disabled section. Last discussion about kernel misaligned handling and interrupt reenabling were actually not to reenable interrupt when handling misaligned access being done by kernel. The best solution being not to do any misaligned accesses to userspace memory, we considered a few options: - Remove any call to put/get_user() potentially doing misaligned accesses - Do not do any misaligned accesses in put/get_user() itself The second solution was the one chosen as there are too many callsites to put/get_user() that could potentially do misaligned accesses. We tried two approaches for that, either split access in two aligned accesses (and do RMW for put_user()) or call copy_from/to_user() which does not do any misaligned accesses. The later one was the simpler to implement (although the performances are probably lower than split aligned accesses but still way better than doing misaligned access emulation) and allows to support what we wanted. These commits are based on top of Alex dev/alex/get_user_misaligned_v1 branch. [Palmer: No idea what that branch is, so I'm basing it on the uaccess optimizations patch series which is the last thing to touch these.] * b4-shazam-merge riscv: uaccess: do not do misaligned accesses in get/put_user() riscv: process: use unsigned int instead of unsigned long for put_user() riscv: make unsafe user copy routines use existing assembly routines Link: https://lore.kernel.org/r/20250602193918.868962-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> 
Clément Léger <cleger@rivosinc.com> says:

While debugging a few problems with the misaligned access kselftest,
Alexandre discovered some crash with the current code. Indeed, some
misaligned access was done by the kernel using put_user(). This
was resulting in trap and a kernel crash since. The path was the
following:
user -> kernel -> access to user memory -> misaligned trap -> trap ->
kernel -> misaligned handling -> memcpy -> crash due to failed page fault
while in interrupt disabled section.

Last discussion about kernel misaligned handling and interrupt reenabling
were actually not to reenable interrupt when handling misaligned access
being done by kernel. The best solution being not to do any misaligned
accesses to userspace memory, we considered a few options:

- Remove any call to put/get_user() potentially doing misaligned
  accesses
- Do not do any misaligned accesses in put/get_user() itself

The second solution was the one chosen as there are too many callsites to
put/get_user() that could potentially do misaligned accesses. We tried
two approaches for that, either split access in two aligned accesses
(and do RMW for put_user()) or call copy_from/to_user() which does not
do any misaligned accesses. The later one was the simpler to implement
(although the performances are probably lower than split aligned
accesses but still way better than doing misaligned access emulation)
and allows to support what we wanted.

These commits are based on top of Alex dev/alex/get_user_misaligned_v1
branch.

[Palmer: No idea what that branch is, so I'm basing it on the uaccess
optimizations patch series which is the last thing to touch these.]

* b4-shazam-merge
  riscv: uaccess: do not do misaligned accesses in get/put_user()
  riscv: process: use unsigned int instead of unsigned long for put_user()
  riscv: make unsafe user copy routines use existing assembly routines

Link: https://lore.kernel.org/r/20250602193918.868962-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
riscv: process: use unsigned int instead of unsigned long for put_user() 2025-06-05T18:39:16+00:00 Clément Léger cleger@rivosinc.com 2025-06-02T19:39:15+00:00 020667d661f9be65167174d28a6eda7102f7293f The specification of prctl() for GET_UNALIGN_CTL states that the value is returned in an unsigned int * address passed as an unsigned long. Change the type to match that and avoid an unaligned access as well. Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20250602193918.868962-3-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> 
The specification of prctl() for GET_UNALIGN_CTL states that the value is
returned in an unsigned int * address passed as an unsigned long. Change
the type to match that and avoid an unaligned access as well.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250602193918.868962-3-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Merge tag 'core-entry-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2025-05-27T14:44:22+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-05-27T14:44:22+00:00 0c1494015fea0935fbf6cd9d99c008fcbe1e4165 Pull core entry code updates from Thomas Gleixner: "Updates for the generic and architecture entry code: - Move LoongArch and RISC-V ret_from_fork() implementations to C code so that syscall_exit_user_mode() can be inlined - Split the RISC-V ret_from_fork() implementation into return to user and return to kernel, which gives a measurable performance improvement - Inline syscall_exit_user_mode() which benefits all architectures by avoiding a function call and letting the compiler do better optimizations" * tag 'core-entry-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: LoongArch: entry: Fix include order entry: Inline syscall_exit_to_user_mode() LoongArch: entry: Migrate ret_from_fork() to C riscv: entry: Split ret_from_fork() into user and kernel riscv: entry: Convert ret_from_fork() to C 
Pull core entry code updates from Thomas Gleixner:
 "Updates for the generic and architecture entry code:

   - Move LoongArch and RISC-V ret_from_fork() implementations to C code
     so that syscall_exit_user_mode() can be inlined

   - Split the RISC-V ret_from_fork() implementation into return to user
     and return to kernel, which gives a measurable performance
     improvement

   - Inline syscall_exit_user_mode() which benefits all architectures by
     avoiding a function call and letting the compiler do better
     optimizations"

* tag 'core-entry-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  LoongArch: entry: Fix include order
  entry: Inline syscall_exit_to_user_mode()
  LoongArch: entry: Migrate ret_from_fork() to C
  riscv: entry: Split ret_from_fork() into user and kernel
  riscv: entry: Convert ret_from_fork() to C
riscv: Disallow PR_GET_TAGGED_ADDR_CTRL without Supm 2025-05-08T12:01:01+00:00 Samuel Holland samuel.holland@sifive.com 2025-05-07T14:52:18+00:00 7f1c3de1370bc6a8ad5157336b258067dac0ae9c When the prctl() interface for pointer masking was added, it did not check that the pointer masking ISA extension was supported, only the individual submodes. Userspace could still attempt to disable pointer masking and query the pointer masking state. commit 81de1afb2dd1 ("riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL") disallowed the former, as the senvcfg write could crash on older systems. PR_GET_TAGGED_ADDR_CTRL state does not crash, because it reads only kernel-internal state and not senvcfg, but it should still be disallowed for consistency. Fixes: 09d6775f503b ("riscv: Add support for userspace pointer masking") Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20250507145230.2272871-1-samuel.holland@sifive.com Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> 
When the prctl() interface for pointer masking was added, it did not
check that the pointer masking ISA extension was supported, only the
individual submodes. Userspace could still attempt to disable pointer
masking and query the pointer masking state. commit 81de1afb2dd1
("riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL") disallowed
the former, as the senvcfg write could crash on older systems.
PR_GET_TAGGED_ADDR_CTRL state does not crash, because it reads only
kernel-internal state and not senvcfg, but it should still be disallowed
for consistency.

Fixes: 09d6775f503b ("riscv: Add support for userspace pointer masking")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20250507145230.2272871-1-samuel.holland@sifive.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL 2025-05-08T12:01:01+00:00 Nam Cao namcao@linutronix.de 2025-05-04T10:19:20+00:00 ae08d55807c099357c047dba17624b09414635dd When userspace does PR_SET_TAGGED_ADDR_CTRL, but Supm extension is not available, the kernel crashes: Oops - illegal instruction [#1] [snip] epc : set_tagged_addr_ctrl+0x112/0x15a ra : set_tagged_addr_ctrl+0x74/0x15a epc : ffffffff80011ace ra : ffffffff80011a30 sp : ffffffc60039be10 [snip] status: 0000000200000120 badaddr: 0000000010a79073 cause: 0000000000000002 set_tagged_addr_ctrl+0x112/0x15a __riscv_sys_prctl+0x352/0x73c do_trap_ecall_u+0x17c/0x20c andle_exception+0x150/0x15c Fix it by checking if Supm is available. Fixes: 09d6775f503b ("riscv: Add support for userspace pointer masking") Signed-off-by: Nam Cao <namcao@linutronix.de> Cc: stable@vger.kernel.org Reviewed-by: Samuel Holland <samuel.holland@sifive.com> Link: https://lore.kernel.org/r/20250504101920.3393053-1-namcao@linutronix.de Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> 
When userspace does PR_SET_TAGGED_ADDR_CTRL, but Supm extension is not
available, the kernel crashes:

Oops - illegal instruction [#1]
    [snip]
epc : set_tagged_addr_ctrl+0x112/0x15a
 ra : set_tagged_addr_ctrl+0x74/0x15a
epc : ffffffff80011ace ra : ffffffff80011a30 sp : ffffffc60039be10
    [snip]
status: 0000000200000120 badaddr: 0000000010a79073 cause: 0000000000000002
    set_tagged_addr_ctrl+0x112/0x15a
    __riscv_sys_prctl+0x352/0x73c
    do_trap_ecall_u+0x17c/0x20c
    andle_exception+0x150/0x15c

Fix it by checking if Supm is available.

Fixes: 09d6775f503b ("riscv: Add support for userspace pointer masking")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20250504101920.3393053-1-namcao@linutronix.de
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
riscv: entry: Split ret_from_fork() into user and kernel 2025-04-29T06:27:10+00:00 Charlie Jenkins charlie@rivosinc.com 2025-03-20T17:29:22+00:00 5b3d6103b343d59e19bd641e4c31df519f4d250d This function was unified into a single function in commit ab9164dae273 ("riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork"). However that imposed a performance degradation. Partially reverting this commit to have ret_from_fork() split again, results in a 1% increase on the number of times fork is able to be called per second. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/all/20250320-riscv_optimize_entry-v6-2-63e187e26041@rivosinc.com 
This function was unified into a single function in commit ab9164dae273
("riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork").
However that imposed a performance degradation.

Partially reverting this commit to have ret_from_fork() split again,
results in a 1% increase on the number of times fork is able to be called
per second.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/all/20250320-riscv_optimize_entry-v6-2-63e187e26041@rivosinc.com
riscv: entry: Convert ret_from_fork() to C 2025-04-29T06:27:10+00:00 Charlie Jenkins charlie@rivosinc.com 2025-03-20T17:29:21+00:00 f955aa8723a65759e920d4de8e5d076cef412afc Move the main section of ret_from_fork() to C to allow inlining of syscall_exit_to_user_mode(). Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/all/20250320-riscv_optimize_entry-v6-1-63e187e26041@rivosinc.com 
Move the main section of ret_from_fork() to C to allow inlining of
syscall_exit_to_user_mode().

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/all/20250320-riscv_optimize_entry-v6-1-63e187e26041@rivosinc.com