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653650c4 |
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26-Mar-2024 |
Sami Tolvanen <samitolvanen@google.com> |
riscv: Mark __se_sys_* functions __used Clang doesn't think ___se_sys_* functions used even though they are aliased to __se_sys_*, resulting in -Wunused-function warnings when building rv32. For example: mm/oom_kill.c:1195:1: warning: unused function '___se_sys_process_mrelease' [-Wunused-function] 1195 | SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/syscalls.h:221:36: note: expanded from macro 'SYSCALL_DEFINE2' 221 | #define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/syscalls.h:231:2: note: expanded from macro 'SYSCALL_DEFINEx' 231 | __SYSCALL_DEFINEx(x, sname, __VA_ARGS__) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/riscv/include/asm/syscall_wrapper.h:81:2: note: expanded from macro '__SYSCALL_DEFINEx' 81 | __SYSCALL_SE_DEFINEx(x, sys, name, __VA_ARGS__) \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/riscv/include/asm/syscall_wrapper.h:40:14: note: expanded from macro '__SYSCALL_SE_DEFINEx' 40 | static long ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__)) | ^~~~~~~~~~~~~~~~~~~~ <scratch space>:30:1: note: expanded from here 30 | ___se_sys_process_mrelease | ^~~~~~~~~~~~~~~~~~~~~~~~~~ 1 warning generated. Mark the functions __used explicitly to fix the Clang warnings. Fixes: a9ad73295cc1 ("riscv: Fix syscall wrapper for >word-size arguments") Reported-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20240326153712.1839482-2-samitolvanen@google.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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a9ad7329 |
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11-Mar-2024 |
Sami Tolvanen <samitolvanen@google.com> |
riscv: Fix syscall wrapper for >word-size arguments The current syscall wrapper macros break 64-bit arguments on rv32 because they only guarantee the first N input registers are passed to syscalls that accept N arguments. According to the calling convention, values twice the word size reside in register pairs and as a result, syscall arguments don't always have a direct register mapping on rv32. Instead of using `__MAP(x,__SC_LONG,__VA_ARGS__)` to declare the type of the `__se(_compat)_sys_*` functions on rv32, change the function declarations to accept `ulong` arguments and alias them to the actual syscall implementations, similarly to the existing macros in include/linux/syscalls.h. This matches previous behavior and ensures registers are passed to syscalls as-is, no matter which argument types they expect. Fixes: 08d0ce30e0e4 ("riscv: Implement syscall wrappers") Reported-by: Khem Raj <raj.khem@gmail.com> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20240311193143.2981310-2-samitolvanen@google.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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a4aebe93 |
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19-Dec-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
posix-timers: Get rid of [COMPAT_]SYS_NI() uses Only the posix timer system calls use this (when the posix timer support is disabled, which does not actually happen in any normal case), because they had debug code to print out a warning about missing system calls. Get rid of that special case, and just use the standard COND_SYSCALL interface that creates weak system call stubs that return -ENOSYS for when the system call does not exist. This fixes a kCFI issue with the SYS_NI() hackery: CFI failure at int80_emulation+0x67/0xb0 (target: sys_ni_posix_timers+0x0/0x70; expected type: 0xb02b34d9) WARNING: CPU: 0 PID: 48 at int80_emulation+0x67/0xb0 Reported-by: kernel test robot <oliver.sang@intel.com> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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08d0ce30 |
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10-Jul-2023 |
Sami Tolvanen <samitolvanen@google.com> |
riscv: Implement syscall wrappers Commit f0bddf50586d ("riscv: entry: Convert to generic entry") moved syscall handling to C code, which exposed function pointer type mismatches that trip fine-grained forward-edge Control-Flow Integrity (CFI) checks as syscall handlers are all called through the same syscall_t pointer type. To fix the type mismatches, implement pt_regs based syscall wrappers similarly to x86 and arm64. This patch is based on arm64 syscall wrappers added in commit 4378a7d4be30 ("arm64: implement syscall wrappers"), where the main goal was to minimize the risk of userspace-controlled values being used under speculation. This may be a concern for riscv in future as well. Following other architectures, the syscall wrappers generate three functions for each syscall; __riscv_<compat_>sys_<name> takes a pt_regs pointer and extracts arguments from registers, __se_<compat_>sys_<name> is a sign-extension wrapper that casts the long arguments to the correct types for the real syscall implementation, which is named __do_<compat_>sys_<name>. Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20230710183544.999540-9-samitolvanen@google.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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