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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/include/asm/switch_to.h
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/include/asm/switch_to.h')
-rw-r--r--arch/x86/include/asm/switch_to.h91
1 files changed, 91 insertions, 0 deletions
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
new file mode 100644
index 000000000..c08eb0fdd
--- /dev/null
+++ b/arch/x86/include/asm/switch_to.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SWITCH_TO_H
+#define _ASM_X86_SWITCH_TO_H
+
+#include <linux/sched/task_stack.h>
+
+struct task_struct; /* one of the stranger aspects of C forward declarations */
+
+struct task_struct *__switch_to_asm(struct task_struct *prev,
+ struct task_struct *next);
+
+__visible struct task_struct *__switch_to(struct task_struct *prev,
+ struct task_struct *next);
+
+asmlinkage void ret_from_fork(void);
+
+/*
+ * This is the structure pointed to by thread.sp for an inactive task. The
+ * order of the fields must match the code in __switch_to_asm().
+ */
+struct inactive_task_frame {
+#ifdef CONFIG_X86_64
+ unsigned long r15;
+ unsigned long r14;
+ unsigned long r13;
+ unsigned long r12;
+#else
+ unsigned long flags;
+ unsigned long si;
+ unsigned long di;
+#endif
+ unsigned long bx;
+
+ /*
+ * These two fields must be together. They form a stack frame header,
+ * needed by get_frame_pointer().
+ */
+ unsigned long bp;
+ unsigned long ret_addr;
+};
+
+struct fork_frame {
+ struct inactive_task_frame frame;
+ struct pt_regs regs;
+};
+
+#define switch_to(prev, next, last) \
+do { \
+ ((last) = __switch_to_asm((prev), (next))); \
+} while (0)
+
+#ifdef CONFIG_X86_32
+static inline void refresh_sysenter_cs(struct thread_struct *thread)
+{
+ /* Only happens when SEP is enabled, no need to test "SEP"arately: */
+ if (unlikely(this_cpu_read(cpu_tss_rw.x86_tss.ss1) == thread->sysenter_cs))
+ return;
+
+ this_cpu_write(cpu_tss_rw.x86_tss.ss1, thread->sysenter_cs);
+ wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
+}
+#endif
+
+/* This is used when switching tasks or entering/exiting vm86 mode. */
+static inline void update_task_stack(struct task_struct *task)
+{
+ /* sp0 always points to the entry trampoline stack, which is constant: */
+#ifdef CONFIG_X86_32
+ if (static_cpu_has(X86_FEATURE_XENPV))
+ load_sp0(task->thread.sp0);
+ else
+ this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
+#else
+ /* Xen PV enters the kernel on the thread stack. */
+ if (static_cpu_has(X86_FEATURE_XENPV))
+ load_sp0(task_top_of_stack(task));
+#endif
+}
+
+static inline void kthread_frame_init(struct inactive_task_frame *frame,
+ int (*fun)(void *), void *arg)
+{
+ frame->bx = (unsigned long)fun;
+#ifdef CONFIG_X86_32
+ frame->di = (unsigned long)arg;
+#else
+ frame->r12 = (unsigned long)arg;
+#endif
+}
+
+#endif /* _ASM_X86_SWITCH_TO_H */