1 files changed, 223 insertions, 0 deletions
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
new file mode 100644
index 000000000..b8d40ddea
--- /dev/null
+++ b/arch/x86/include/asm/mmu_context.h
@@ -0,0 +1,223 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_MMU_CONTEXT_H
+#define _ASM_X86_MMU_CONTEXT_H
+
+#include <asm/desc.h>
+#include <linux/atomic.h>
+#include <linux/mm_types.h>
+#include <linux/pkeys.h>
+
+#include <trace/events/tlb.h>
+
+#include <asm/tlbflush.h>
+#include <asm/paravirt.h>
+#include <asm/debugreg.h>
+
+extern atomic64_t last_mm_ctx_id;
+
+#ifndef CONFIG_PARAVIRT_XXL
+static inline void paravirt_activate_mm(struct mm_struct *prev,
+					struct mm_struct *next)
+{
+}
+#endif	/* !CONFIG_PARAVIRT_XXL */
+
+#ifdef CONFIG_PERF_EVENTS
+DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key);
+DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key);
+void cr4_update_pce(void *ignored);
+#endif
+
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
+/*
+ * ldt_structs can be allocated, used, and freed, but they are never
+ * modified while live.
+ */
+struct ldt_struct {
+	/*
+	 * Xen requires page-aligned LDTs with special permissions.  This is
+	 * needed to prevent us from installing evil descriptors such as
+	 * call gates.  On native, we could merge the ldt_struct and LDT
+	 * allocations, but it's not worth trying to optimize.
+	 */
+	struct desc_struct	*entries;
+	unsigned int		nr_entries;
+
+	/*
+	 * If PTI is in use, then the entries array is not mapped while we're
+	 * in user mode.  The whole array will be aliased at the addressed
+	 * given by ldt_slot_va(slot).  We use two slots so that we can allocate
+	 * and map, and enable a new LDT without invalidating the mapping
+	 * of an older, still-in-use LDT.
+	 *
+	 * slot will be -1 if this LDT doesn't have an alias mapping.
+	 */
+	int			slot;
+};
+
+/*
+ * Used for LDT copy/destruction.
+ */
+static inline void init_new_context_ldt(struct mm_struct *mm)
+{
+	mm->context.ldt = NULL;
+	init_rwsem(&mm->context.ldt_usr_sem);
+}
+int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm);
+void destroy_context_ldt(struct mm_struct *mm);
+void ldt_arch_exit_mmap(struct mm_struct *mm);
+#else	/* CONFIG_MODIFY_LDT_SYSCALL */
+static inline void init_new_context_ldt(struct mm_struct *mm) { }
+static inline int ldt_dup_context(struct mm_struct *oldmm,
+				  struct mm_struct *mm)
+{
+	return 0;
+}
+static inline void destroy_context_ldt(struct mm_struct *mm) { }
+static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { }
+#endif
+
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
+extern void load_mm_ldt(struct mm_struct *mm);
+extern void switch_ldt(struct mm_struct *prev, struct mm_struct *next);
+#else
+static inline void load_mm_ldt(struct mm_struct *mm)
+{
+	clear_LDT();
+}
+static inline void switch_ldt(struct mm_struct *prev, struct mm_struct *next)
+{
+	DEBUG_LOCKS_WARN_ON(preemptible());
+}
+#endif
+
+#define enter_lazy_tlb enter_lazy_tlb
+extern void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk);
+
+/*
+ * Init a new mm.  Used on mm copies, like at fork()
+ * and on mm's that are brand-new, like at execve().
+ */
+#define init_new_context init_new_context
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	mutex_init(&mm->context.lock);
+
+	mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id);
+	atomic64_set(&mm->context.tlb_gen, 0);
+
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+	if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
+		/* pkey 0 is the default and allocated implicitly */
+		mm->context.pkey_allocation_map = 0x1;
+		/* -1 means unallocated or invalid */
+		mm->context.execute_only_pkey = -1;
+	}
+#endif
+	init_new_context_ldt(mm);
+	return 0;
+}
+
+#define destroy_context destroy_context
+static inline void destroy_context(struct mm_struct *mm)
+{
+	destroy_context_ldt(mm);
+}
+
+extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+		      struct task_struct *tsk);
+
+extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
+			       struct task_struct *tsk);
+#define switch_mm_irqs_off switch_mm_irqs_off
+
+#define activate_mm(prev, next)			\
+do {						\
+	paravirt_activate_mm((prev), (next));	\
+	switch_mm((prev), (next), NULL);	\
+} while (0);
+
+#ifdef CONFIG_X86_32
+#define deactivate_mm(tsk, mm)			\
+do {						\
+	loadsegment(gs, 0);			\
+} while (0)
+#else
+#define deactivate_mm(tsk, mm)			\
+do {						\
+	load_gs_index(0);			\
+	loadsegment(fs, 0);			\
+} while (0)
+#endif
+
+static inline void arch_dup_pkeys(struct mm_struct *oldmm,
+				  struct mm_struct *mm)
+{
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+	if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
+		return;
+
+	/* Duplicate the oldmm pkey state in mm: */
+	mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map;
+	mm->context.execute_only_pkey   = oldmm->context.execute_only_pkey;
+#endif
+}
+
+static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+	arch_dup_pkeys(oldmm, mm);
+	paravirt_arch_dup_mmap(oldmm, mm);
+	return ldt_dup_context(oldmm, mm);
+}
+
+static inline void arch_exit_mmap(struct mm_struct *mm)
+{
+	paravirt_arch_exit_mmap(mm);
+	ldt_arch_exit_mmap(mm);
+}
+
+#ifdef CONFIG_X86_64
+static inline bool is_64bit_mm(struct mm_struct *mm)
+{
+	return	!IS_ENABLED(CONFIG_IA32_EMULATION) ||
+		!(mm->context.flags & MM_CONTEXT_UPROBE_IA32);
+}
+#else
+static inline bool is_64bit_mm(struct mm_struct *mm)
+{
+	return false;
+}
+#endif
+
+static inline void arch_unmap(struct mm_struct *mm, unsigned long start,
+			      unsigned long end)
+{
+}
+
+/*
+ * We only want to enforce protection keys on the current process
+ * because we effectively have no access to PKRU for other
+ * processes or any way to tell *which * PKRU in a threaded
+ * process we could use.
+ *
+ * So do not enforce things if the VMA is not from the current
+ * mm, or if we are in a kernel thread.
+ */
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+		bool write, bool execute, bool foreign)
+{
+	/* pkeys never affect instruction fetches */
+	if (execute)
+		return true;
+	/* allow access if the VMA is not one from this process */
+	if (foreign || vma_is_foreign(vma))
+		return true;
+	return __pkru_allows_pkey(vma_pkey(vma), write);
+}
+
+unsigned long __get_current_cr3_fast(void);
+
+#include <asm-generic/mmu_context.h>
+
+#endif /* _ASM_X86_MMU_CONTEXT_H */