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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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444b46a128
The third argument in wrmsr(msr, low, 0) is unnecessary. Instead, use wrmsrq(msr, low), which automatically sets the higher 32 bits of the MSR value to 0. Signed-off-by: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lore.kernel.org/r/20250427092027.1598740-15-xin@zytor.com
92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_SWITCH_TO_H
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#define _ASM_X86_SWITCH_TO_H
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#include <linux/sched/task_stack.h>
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struct task_struct; /* one of the stranger aspects of C forward declarations */
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struct task_struct *__switch_to_asm(struct task_struct *prev,
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struct task_struct *next);
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__visible struct task_struct *__switch_to(struct task_struct *prev,
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struct task_struct *next);
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asmlinkage void ret_from_fork_asm(void);
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__visible void ret_from_fork(struct task_struct *prev, struct pt_regs *regs,
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int (*fn)(void *), void *fn_arg);
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/*
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* This is the structure pointed to by thread.sp for an inactive task. The
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* order of the fields must match the code in __switch_to_asm().
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*/
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struct inactive_task_frame {
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#ifdef CONFIG_X86_64
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unsigned long r15;
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unsigned long r14;
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unsigned long r13;
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unsigned long r12;
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#else
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unsigned long flags;
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unsigned long si;
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unsigned long di;
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#endif
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unsigned long bx;
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/*
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* These two fields must be together. They form a stack frame header,
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* needed by get_frame_pointer().
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*/
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unsigned long bp;
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unsigned long ret_addr;
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};
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struct fork_frame {
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struct inactive_task_frame frame;
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struct pt_regs regs;
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};
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#define switch_to(prev, next, last) \
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do { \
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((last) = __switch_to_asm((prev), (next))); \
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} while (0)
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#ifdef CONFIG_X86_32
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#include <asm/msr.h>
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static inline void refresh_sysenter_cs(struct thread_struct *thread)
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{
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/* Only happens when SEP is enabled, no need to test "SEP"arately: */
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if (unlikely(this_cpu_read(cpu_tss_rw.x86_tss.ss1) == thread->sysenter_cs))
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return;
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this_cpu_write(cpu_tss_rw.x86_tss.ss1, thread->sysenter_cs);
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wrmsrq(MSR_IA32_SYSENTER_CS, thread->sysenter_cs);
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}
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#endif
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/* This is used when switching tasks or entering/exiting vm86 mode. */
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static inline void update_task_stack(struct task_struct *task)
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{
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/* sp0 always points to the entry trampoline stack, which is constant: */
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#ifdef CONFIG_X86_32
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this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
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#else
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if (!cpu_feature_enabled(X86_FEATURE_FRED) && cpu_feature_enabled(X86_FEATURE_XENPV))
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/* Xen PV enters the kernel on the thread stack. */
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load_sp0(task_top_of_stack(task));
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#endif
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}
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static inline void kthread_frame_init(struct inactive_task_frame *frame,
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int (*fun)(void *), void *arg)
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{
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frame->bx = (unsigned long)fun;
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#ifdef CONFIG_X86_32
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frame->di = (unsigned long)arg;
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#else
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frame->r12 = (unsigned long)arg;
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#endif
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}
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#endif /* _ASM_X86_SWITCH_TO_H */
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