summaryrefslogtreecommitdiff
path: root/arch/riscv/kernel/traps_misaligned.c
AgeCommit message (Collapse)Author
10 daysriscv: traps_misaligned: properly sign extend value in misaligned load handlerAndreas Schwab
[ Upstream commit b3510183ab7d63c71a3f5c89043d31686a76a34c ] Add missing cast to signed long. Signed-off-by: Andreas Schwab <schwab@suse.de> Fixes: 956d705dd279 ("riscv: Unaligned load/store handling for M_MODE") Tested-by: Clément Léger <cleger@rivosinc.com> Link: https://lore.kernel.org/r/mvmikk0goil.fsf@suse.de Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-06Revert "riscv: misaligned: fix sleeping function called during misaligned ↵Nam Cao
access handling" commit 2f73c62d4e13df67380ff6faca39eec2bf08dd93 upstream. This reverts commit 61a74ad25462 ("riscv: misaligned: fix sleeping function called during misaligned access handling"). The commit addresses a sleeping in atomic context problem, but it is not the correct fix as explained by Clément: "Using nofault would lead to failure to read from user memory that is paged out for instance. This is not really acceptable, we should handle user misaligned access even at an address that would generate a page fault." This bug has been properly fixed by commit 453805f0a28f ("riscv: misaligned: enable IRQs while handling misaligned accesses"). Revert this improper fix. Link: https://lore.kernel.org/linux-riscv/b779beed-e44e-4a5e-9551-4647682b0d21@rivosinc.com/ Signed-off-by: Nam Cao <namcao@linutronix.de> Cc: stable@vger.kernel.org Reviewed-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Fixes: 61a74ad25462 ("riscv: misaligned: fix sleeping function called during misaligned access handling") Link: https://lore.kernel.org/r/20250620110939.1642735-1-namcao@linutronix.de Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19riscv: misaligned: fix sleeping function called during misaligned access ↵Nylon Chen
handling [ Upstream commit 61a74ad254628ccd9e88838c3c622885dfb6c588 ] Use copy_from_user_nofault() and copy_to_user_nofault() instead of copy_from/to_user functions in the misaligned access trap handlers. The following bug report was found when executing misaligned memory accesses: BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:162 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 115, name: two preempt_count: 0, expected: 0 CPU: 0 UID: 0 PID: 115 Comm: two Not tainted 6.14.0-rc5 #24 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff800160ea>] dump_backtrace+0x1c/0x24 [<ffffffff80002304>] show_stack+0x28/0x34 [<ffffffff80010fae>] dump_stack_lvl+0x4a/0x68 [<ffffffff80010fe0>] dump_stack+0x14/0x1c [<ffffffff8004e44e>] __might_resched+0xfa/0x104 [<ffffffff8004e496>] __might_sleep+0x3e/0x62 [<ffffffff801963c4>] __might_fault+0x1c/0x24 [<ffffffff80425352>] _copy_from_user+0x28/0xaa [<ffffffff8000296c>] handle_misaligned_store+0x204/0x254 [<ffffffff809eae82>] do_trap_store_misaligned+0x24/0xee [<ffffffff809f4f1a>] handle_exception+0x146/0x152 Fixes: b686ecdeacf6 ("riscv: misaligned: Restrict user access to kernel memory") Fixes: 441381506ba7 ("riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code") Signed-off-by: Zong Li <zong.li@sifive.com> Signed-off-by: Nylon Chen <nylon.chen@sifive.com> Link: https://lore.kernel.org/r/20250411073850.3699180-3-nylon.chen@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18riscv: misaligned: Add handling for ZCB instructionsNylon Chen
[ Upstream commit eb16b3727c05ed36420c90eca1e8f0e279514c1c ] Add support for the Zcb extension's compressed half-word instructions (C.LHU, C.LH, and C.SH) in the RISC-V misaligned access trap handler. Signed-off-by: Zong Li <zong.li@sifive.com> Signed-off-by: Nylon Chen <nylon.chen@sifive.com> Fixes: 956d705dd279 ("riscv: Unaligned load/store handling for M_MODE") Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20250411073850.3699180-2-nylon.chen@sifive.com Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05RISC-V: Check scalar unaligned access on all CPUsJesse Taube
commit 8d20a739f17a2de9e269db72330f5655d6545dd4 upstream. Originally, the check_unaligned_access_emulated_all_cpus function only checked the boot hart. This fixes the function to check all harts. Fixes: 71c54b3d169d ("riscv: report misaligned accesses emulation to hwprobe") Signed-off-by: Jesse Taube <jesse@rivosinc.com> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Reviewed-by: Evan Green <evan@rivosinc.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241017-jesse_unaligned_vector-v10-1-5b33500160f8@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-25riscv: Remove duplicated GET_RMChunyan Zhang
The macro GET_RM defined twice in this file, one can be removed. Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Signed-off-by: Chunyan Zhang <zhangchunyan@iscas.ac.cn> Fixes: 956d705dd279 ("riscv: Unaligned load/store handling for M_MODE") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241008094141.549248-3-zhangchunyan@iscas.ac.cn Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-08-31riscv: misaligned: Restrict user access to kernel memorySamuel Holland
raw_copy_{to,from}_user() do not call access_ok(), so this code allowed userspace to access any virtual memory address. Cc: stable@vger.kernel.org Fixes: 7c83232161f6 ("riscv: add support for misaligned trap handling in S-mode") Fixes: 441381506ba7 ("riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code") Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20240815005714.1163136-1-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-08-14RISC-V: hwprobe: Add SCALAR to misaligned perf definesEvan Green
In preparation for misaligned vector performance hwprobe keys, rename the hwprobe key values associated with misaligned scalar accesses to include the term SCALAR. Leave the old defines in place to maintain source compatibility. This change is intended to be a functional no-op. Signed-off-by: Evan Green <evan@rivosinc.com> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Link: https://lore.kernel.org/r/20240809214444.3257596-3-evan@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-04-28riscv: misaligned: remove CONFIG_RISCV_M_MODE specific codeClément Léger
While reworking code to fix sparse errors, it appears that the RISCV_M_MODE specific could actually be removed and use the one for normal mode. Even though RISCV_M_MODE can do direct user memory access, using the user uaccess helpers is also going to work. Since there is no need anymore for specific accessors (load_u8()/store_u8()), we can directly use memcpy()/copy_{to/from}_user() and get rid of the copy loop entirely. __read_insn() is also fixed to use an unsigned long instead of a pointer which was cast in __user address space. The insn_addr parameter is now cast from unsigned lnog to the correct address space directly. Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Link: https://lore.kernel.org/r/20240206154104.896809-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-03-13riscv: Set unaligned access speed at compile timeCharlie Jenkins
Introduce Kconfig options to set the kernel unaligned access support. These options provide a non-portable alternative to the runtime unaligned access probe. To support this, the unaligned access probing code is moved into it's own file and gated behind a new RISCV_PROBE_UNALIGNED_ACCESS_SUPPORT option. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Samuel Holland <samuel.holland@sifive.com> Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-4-a388770ba0ce@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-03-13riscv: Decouple emulated unaligned accesses from access speedCharlie Jenkins
Detecting if a system traps into the kernel on an unaligned access can be performed separately from checking the speed of unaligned accesses. This decoupling will make it possible to selectively enable or disable each of these checks. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Tested-by: Samuel Holland <samuel.holland@sifive.com> Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-3-a388770ba0ce@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-03-13riscv: Only check online cpus for emulated accessesCharlie Jenkins
The unaligned access checker only sets valid values for online cpus. Check for these values on online cpus rather than on present cpus. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Fixes: 71c54b3d169d ("riscv: report misaligned accesses emulation to hwprobe") Tested-by: Samuel Holland <samuel.holland@sifive.com> Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-2-a388770ba0ce@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-01-09Merge remote-tracking branch 'palmer/fixes' into for-nextPalmer Dabbelt
I don't usually merge these in, but I missed sending a PR due to the holidays. * palmer/fixes: riscv: Fix set_direct_map_default_noflush() to reset _PAGE_EXEC riscv: Fix module_alloc() that did not reset the linear mapping permissions riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping riscv: Check if the code to patch lies in the exit section riscv: errata: andes: Probe for IOCP only once in boot stage riscv: Fix SMP when shadow call stacks are enabled dt-bindings: perf: riscv,pmu: drop unneeded quotes riscv: fix misaligned access handling of C.SWSP and C.SDSP RISC-V: hwprobe: Always use u64 for extension bits Support rv32 ULEB128 test riscv: Correct type casting in module loading riscv: Safely remove entries from relocation list Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-01-09riscv: fix __user annotation in traps_misaligned.cBen Dooks
The instruction reading code can read from either user or kernel addresses and thus the use of __user on pointers to instructions depends on which context. Fix a few sparse warnings by using __user for user-accesses and remove it when not. Fixes: arch/riscv/kernel/traps_misaligned.c:361:21: warning: dereference of noderef expression arch/riscv/kernel/traps_misaligned.c:373:21: warning: dereference of noderef expression arch/riscv/kernel/traps_misaligned.c:381:21: warning: dereference of noderef expression arch/riscv/kernel/traps_misaligned.c:322:24: warning: incorrect type in initializer (different address spaces) arch/riscv/kernel/traps_misaligned.c:322:24: expected unsigned char const [noderef] __user *__gu_ptr arch/riscv/kernel/traps_misaligned.c:322:24: got unsigned char const [usertype] *addr arch/riscv/kernel/traps_misaligned.c:361:21: warning: dereference of noderef expression arch/riscv/kernel/traps_misaligned.c:373:21: warning: dereference of noderef expression arch/riscv/kernel/traps_misaligned.c:381:21: warning: dereference of noderef expression arch/riscv/kernel/traps_misaligned.c:332:24: warning: incorrect type in initializer (different address spaces) arch/riscv/kernel/traps_misaligned.c:332:24: expected unsigned char [noderef] __user *__gu_ptr arch/riscv/kernel/traps_misaligned.c:332:24: got unsigned char [usertype] *addr Fixes: 7c83232161f60 ("riscv: add support for misaligned trap handling in S-mode") Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Link: https://lore.kernel.org/r/20231123141617.259591-1-ben.dooks@codethink.co.uk Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-12-06riscv: fix misaligned access handling of C.SWSP and C.SDSPClément Léger
This is a backport of a fix that was done in OpenSBI: ec0559eb315b ("lib: sbi_misaligned_ldst: Fix handling of C.SWSP and C.SDSP"). Unlike C.LWSP/C.LDSP, these encodings can be used with the zero register, so checking that the rs2 field is non-zero is unnecessary. Additionally, the previous check was incorrect since it was checking the immediate field of the instruction instead of the rs2 field. Fixes: 956d705dd279 ("riscv: Unaligned load/store handling for M_MODE") Signed-off-by: Clément Léger <cleger@rivosinc.com> Link: https://lore.kernel.org/r/20231103090223.702340-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-07RISC-V: Remove __init on unaligned_emulation_finish()Evan Green
This function shouldn't be __init, since it's called during hotplug. The warning says it well enough: WARNING: modpost: vmlinux: section mismatch in reference: check_unaligned_access_all_cpus+0x13a (section: .text) -> unaligned_emulation_finish (section: .init.text) Signed-off-by: Evan Green <evan@rivosinc.com> Fixes: 71c54b3d169d ("riscv: report misaligned accesses emulation to hwprobe") Link: https://lore.kernel.org/r/20231106231105.3141413-1-evan@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: add support for PR_SET_UNALIGN and PR_GET_UNALIGNClément Léger
Now that trap support is ready to handle misalignment errors in S-mode, allow the user to control the behavior of misaligned accesses using prctl(PR_SET_UNALIGN). Add an align_ctl flag in thread_struct which will be used to determine if we should SIGBUS the process or not on such fault. Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-9-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: report misaligned accesses emulation to hwprobeClément Léger
hwprobe provides a way to report if misaligned access are emulated. In order to correctly populate that feature, we can check if it actually traps when doing a misaligned access. This can be checked using an exception table entry which will actually be used when a misaligned access is done from kernel mode. Signed-off-by: Clément Léger <cleger@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-8-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: add support for sysctl unaligned_enabled controlClément Léger
This sysctl tuning option allows the user to disable misaligned access handling globally on the system. This will also be used by misaligned detection code to temporarily disable misaligned access handling. Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-6-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: add floating point insn support to misaligned access emulationClément Léger
This support is partially based of openSBI misaligned emulation floating point instruction support. It provides support for the existing floating point instructions (both for 32/64 bits as well as compressed ones). Since floating point registers are not part of the pt_regs struct, we need to modify them directly using some assembly. We also dirty the pt_regs status in case we modify them to be sure context switch will save FP state. With this support, Linux is on par with openSBI support. Signed-off-by: Clément Léger <cleger@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-5-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: report perf event for misaligned faultClément Léger
Add missing calls to account for misaligned fault event using perf_sw_event(). Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-4-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: add support for misaligned trap handling in S-modeClément Léger
Misalignment trap handling is only supported for M-mode and uses direct accesses to user memory. In S-mode, when handling usermode fault, this requires to use the get_user()/put_user() accessors. Implement load_u8(), store_u8() and get_insn() using these accessors for userspace and direct text access for kernel. Signed-off-by: Clément Léger <cleger@rivosinc.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-3-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-01riscv: remove unused functions in traps_misaligned.cClément Léger
Replace macros by the only two function calls that are done from this file, store_u8() and load_u8(). Signed-off-by: Clément Léger <cleger@rivosinc.com> Link: https://lore.kernel.org/r/20231004151405.521596-2-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-08-11riscv: traps_misaligned: do not duplicate stringifyKrzysztof Kozlowski
Use existing stringify macro from the kernel headers. Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20220623112905.253157-1-krzysztof.kozlowski@linaro.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2020-04-03riscv: Unaligned load/store handling for M_MODEDamien Le Moal
Add handlers for unaligned load and store traps that may be generated by applications. Code heavily inspired from the OpenSBI project. Handling of the unaligned access traps is suitable for applications compiled with or without compressed instructions and is independent of the kernel CONFIG_RISCV_ISA_C option value. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Anup Patel <anup.patel@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>