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bbc46b23af
With the introduction of clone3 in commit7f192e3cd3("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:c5febea095("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>
56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_FPU_SCHED_H
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#define _ASM_X86_FPU_SCHED_H
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#include <linux/sched.h>
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#include <asm/cpufeature.h>
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#include <asm/fpu/types.h>
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#include <asm/trace/fpu.h>
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extern void save_fpregs_to_fpstate(struct fpu *fpu);
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extern void fpu__drop(struct task_struct *tsk);
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extern int fpu_clone(struct task_struct *dst, u64 clone_flags, bool minimal,
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unsigned long shstk_addr);
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extern void fpu_flush_thread(void);
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/*
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* FPU state switching for scheduling.
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*
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* switch_fpu() saves the old state and sets TIF_NEED_FPU_LOAD if
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* TIF_NEED_FPU_LOAD is not set. This is done within the context
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* of the old process.
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*
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* Once TIF_NEED_FPU_LOAD is set, it is required to load the
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* registers before returning to userland or using the content
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* otherwise.
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*
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* The FPU context is only stored/restored for a user task and
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* PF_KTHREAD is used to distinguish between kernel and user threads.
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*/
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static inline void switch_fpu(struct task_struct *old, int cpu)
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{
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if (!test_tsk_thread_flag(old, TIF_NEED_FPU_LOAD) &&
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cpu_feature_enabled(X86_FEATURE_FPU) &&
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!(old->flags & (PF_KTHREAD | PF_USER_WORKER))) {
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struct fpu *old_fpu = x86_task_fpu(old);
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set_tsk_thread_flag(old, TIF_NEED_FPU_LOAD);
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save_fpregs_to_fpstate(old_fpu);
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/*
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* The save operation preserved register state, so the
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* fpu_fpregs_owner_ctx is still @old_fpu. Store the
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* current CPU number in @old_fpu, so the next return
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* to user space can avoid the FPU register restore
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* when is returns on the same CPU and still owns the
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* context. See fpregs_restore_userregs().
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*/
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old_fpu->last_cpu = cpu;
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trace_x86_fpu_regs_deactivated(old_fpu);
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}
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}
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#endif /* _ASM_X86_FPU_SCHED_H */
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