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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/x86/include/asm/tlbflush.h
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/include/asm/tlbflush.h')
-rw-r--r--arch/x86/include/asm/tlbflush.h427
1 files changed, 427 insertions, 0 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
new file mode 100644
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+++ b/arch/x86/include/asm/tlbflush.h
@@ -0,0 +1,427 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_TLBFLUSH_H
+#define _ASM_X86_TLBFLUSH_H
+
+#include <linux/mm_types.h>
+#include <linux/mmu_notifier.h>
+#include <linux/sched.h>
+
+#include <asm/processor.h>
+#include <asm/cpufeature.h>
+#include <asm/special_insns.h>
+#include <asm/smp.h>
+#include <asm/invpcid.h>
+#include <asm/pti.h>
+#include <asm/processor-flags.h>
+#include <asm/pgtable.h>
+
+DECLARE_PER_CPU(u64, tlbstate_untag_mask);
+
+void __flush_tlb_all(void);
+
+#define TLB_FLUSH_ALL -1UL
+#define TLB_GENERATION_INVALID 0
+
+void cr4_update_irqsoff(unsigned long set, unsigned long clear);
+unsigned long cr4_read_shadow(void);
+
+/* Set in this cpu's CR4. */
+static inline void cr4_set_bits_irqsoff(unsigned long mask)
+{
+ cr4_update_irqsoff(mask, 0);
+}
+
+/* Clear in this cpu's CR4. */
+static inline void cr4_clear_bits_irqsoff(unsigned long mask)
+{
+ cr4_update_irqsoff(0, mask);
+}
+
+/* Set in this cpu's CR4. */
+static inline void cr4_set_bits(unsigned long mask)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ cr4_set_bits_irqsoff(mask);
+ local_irq_restore(flags);
+}
+
+/* Clear in this cpu's CR4. */
+static inline void cr4_clear_bits(unsigned long mask)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ cr4_clear_bits_irqsoff(mask);
+ local_irq_restore(flags);
+}
+
+#ifndef MODULE
+/*
+ * 6 because 6 should be plenty and struct tlb_state will fit in two cache
+ * lines.
+ */
+#define TLB_NR_DYN_ASIDS 6
+
+struct tlb_context {
+ u64 ctx_id;
+ u64 tlb_gen;
+};
+
+struct tlb_state {
+ /*
+ * cpu_tlbstate.loaded_mm should match CR3 whenever interrupts
+ * are on. This means that it may not match current->active_mm,
+ * which will contain the previous user mm when we're in lazy TLB
+ * mode even if we've already switched back to swapper_pg_dir.
+ *
+ * During switch_mm_irqs_off(), loaded_mm will be set to
+ * LOADED_MM_SWITCHING during the brief interrupts-off window
+ * when CR3 and loaded_mm would otherwise be inconsistent. This
+ * is for nmi_uaccess_okay()'s benefit.
+ */
+ struct mm_struct *loaded_mm;
+
+#define LOADED_MM_SWITCHING ((struct mm_struct *)1UL)
+
+ /* Last user mm for optimizing IBPB */
+ union {
+ struct mm_struct *last_user_mm;
+ unsigned long last_user_mm_spec;
+ };
+
+ u16 loaded_mm_asid;
+ u16 next_asid;
+
+ /*
+ * If set we changed the page tables in such a way that we
+ * needed an invalidation of all contexts (aka. PCIDs / ASIDs).
+ * This tells us to go invalidate all the non-loaded ctxs[]
+ * on the next context switch.
+ *
+ * The current ctx was kept up-to-date as it ran and does not
+ * need to be invalidated.
+ */
+ bool invalidate_other;
+
+#ifdef CONFIG_ADDRESS_MASKING
+ /*
+ * Active LAM mode.
+ *
+ * X86_CR3_LAM_U57/U48 shifted right by X86_CR3_LAM_U57_BIT or 0 if LAM
+ * disabled.
+ */
+ u8 lam;
+#endif
+
+ /*
+ * Mask that contains TLB_NR_DYN_ASIDS+1 bits to indicate
+ * the corresponding user PCID needs a flush next time we
+ * switch to it; see SWITCH_TO_USER_CR3.
+ */
+ unsigned short user_pcid_flush_mask;
+
+ /*
+ * Access to this CR4 shadow and to H/W CR4 is protected by
+ * disabling interrupts when modifying either one.
+ */
+ unsigned long cr4;
+
+ /*
+ * This is a list of all contexts that might exist in the TLB.
+ * There is one per ASID that we use, and the ASID (what the
+ * CPU calls PCID) is the index into ctxts.
+ *
+ * For each context, ctx_id indicates which mm the TLB's user
+ * entries came from. As an invariant, the TLB will never
+ * contain entries that are out-of-date as when that mm reached
+ * the tlb_gen in the list.
+ *
+ * To be clear, this means that it's legal for the TLB code to
+ * flush the TLB without updating tlb_gen. This can happen
+ * (for now, at least) due to paravirt remote flushes.
+ *
+ * NB: context 0 is a bit special, since it's also used by
+ * various bits of init code. This is fine -- code that
+ * isn't aware of PCID will end up harmlessly flushing
+ * context 0.
+ */
+ struct tlb_context ctxs[TLB_NR_DYN_ASIDS];
+};
+DECLARE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate);
+
+struct tlb_state_shared {
+ /*
+ * We can be in one of several states:
+ *
+ * - Actively using an mm. Our CPU's bit will be set in
+ * mm_cpumask(loaded_mm) and is_lazy == false;
+ *
+ * - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit
+ * will not be set in mm_cpumask(&init_mm) and is_lazy == false.
+ *
+ * - Lazily using a real mm. loaded_mm != &init_mm, our bit
+ * is set in mm_cpumask(loaded_mm), but is_lazy == true.
+ * We're heuristically guessing that the CR3 load we
+ * skipped more than makes up for the overhead added by
+ * lazy mode.
+ */
+ bool is_lazy;
+};
+DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared);
+
+bool nmi_uaccess_okay(void);
+#define nmi_uaccess_okay nmi_uaccess_okay
+
+/* Initialize cr4 shadow for this CPU. */
+static inline void cr4_init_shadow(void)
+{
+ this_cpu_write(cpu_tlbstate.cr4, __read_cr4());
+}
+
+extern unsigned long mmu_cr4_features;
+extern u32 *trampoline_cr4_features;
+
+extern void initialize_tlbstate_and_flush(void);
+
+/*
+ * TLB flushing:
+ *
+ * - flush_tlb_all() flushes all processes TLBs
+ * - flush_tlb_mm(mm) flushes the specified mm context TLB's
+ * - flush_tlb_page(vma, vmaddr) flushes one page
+ * - flush_tlb_range(vma, start, end) flushes a range of pages
+ * - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
+ * - flush_tlb_multi(cpumask, info) flushes TLBs on multiple cpus
+ *
+ * ..but the i386 has somewhat limited tlb flushing capabilities,
+ * and page-granular flushes are available only on i486 and up.
+ */
+struct flush_tlb_info {
+ /*
+ * We support several kinds of flushes.
+ *
+ * - Fully flush a single mm. .mm will be set, .end will be
+ * TLB_FLUSH_ALL, and .new_tlb_gen will be the tlb_gen to
+ * which the IPI sender is trying to catch us up.
+ *
+ * - Partially flush a single mm. .mm will be set, .start and
+ * .end will indicate the range, and .new_tlb_gen will be set
+ * such that the changes between generation .new_tlb_gen-1 and
+ * .new_tlb_gen are entirely contained in the indicated range.
+ *
+ * - Fully flush all mms whose tlb_gens have been updated. .mm
+ * will be NULL, .end will be TLB_FLUSH_ALL, and .new_tlb_gen
+ * will be zero.
+ */
+ struct mm_struct *mm;
+ unsigned long start;
+ unsigned long end;
+ u64 new_tlb_gen;
+ unsigned int initiating_cpu;
+ u8 stride_shift;
+ u8 freed_tables;
+};
+
+void flush_tlb_local(void);
+void flush_tlb_one_user(unsigned long addr);
+void flush_tlb_one_kernel(unsigned long addr);
+void flush_tlb_multi(const struct cpumask *cpumask,
+ const struct flush_tlb_info *info);
+
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#endif
+
+#define flush_tlb_mm(mm) \
+ flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL, true)
+
+#define flush_tlb_range(vma, start, end) \
+ flush_tlb_mm_range((vma)->vm_mm, start, end, \
+ ((vma)->vm_flags & VM_HUGETLB) \
+ ? huge_page_shift(hstate_vma(vma)) \
+ : PAGE_SHIFT, false)
+
+extern void flush_tlb_all(void);
+extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
+ unsigned long end, unsigned int stride_shift,
+ bool freed_tables);
+extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
+
+static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a)
+{
+ flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false);
+}
+
+static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
+{
+ bool should_defer = false;
+
+ /* If remote CPUs need to be flushed then defer batch the flush */
+ if (cpumask_any_but(mm_cpumask(mm), get_cpu()) < nr_cpu_ids)
+ should_defer = true;
+ put_cpu();
+
+ return should_defer;
+}
+
+static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
+{
+ /*
+ * Bump the generation count. This also serves as a full barrier
+ * that synchronizes with switch_mm(): callers are required to order
+ * their read of mm_cpumask after their writes to the paging
+ * structures.
+ */
+ return atomic64_inc_return(&mm->context.tlb_gen);
+}
+
+static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
+ struct mm_struct *mm,
+ unsigned long uaddr)
+{
+ inc_mm_tlb_gen(mm);
+ cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm));
+ mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL);
+}
+
+static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm)
+{
+ flush_tlb_mm(mm);
+}
+
+extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
+
+static inline bool pte_flags_need_flush(unsigned long oldflags,
+ unsigned long newflags,
+ bool ignore_access)
+{
+ /*
+ * Flags that require a flush when cleared but not when they are set.
+ * Only include flags that would not trigger spurious page-faults.
+ * Non-present entries are not cached. Hardware would set the
+ * dirty/access bit if needed without a fault.
+ */
+ const pteval_t flush_on_clear = _PAGE_DIRTY | _PAGE_PRESENT |
+ _PAGE_ACCESSED;
+ const pteval_t software_flags = _PAGE_SOFTW1 | _PAGE_SOFTW2 |
+ _PAGE_SOFTW3 | _PAGE_SOFTW4 |
+ _PAGE_SAVED_DIRTY;
+ const pteval_t flush_on_change = _PAGE_RW | _PAGE_USER | _PAGE_PWT |
+ _PAGE_PCD | _PAGE_PSE | _PAGE_GLOBAL | _PAGE_PAT |
+ _PAGE_PAT_LARGE | _PAGE_PKEY_BIT0 | _PAGE_PKEY_BIT1 |
+ _PAGE_PKEY_BIT2 | _PAGE_PKEY_BIT3 | _PAGE_NX;
+ unsigned long diff = oldflags ^ newflags;
+
+ BUILD_BUG_ON(flush_on_clear & software_flags);
+ BUILD_BUG_ON(flush_on_clear & flush_on_change);
+ BUILD_BUG_ON(flush_on_change & software_flags);
+
+ /* Ignore software flags */
+ diff &= ~software_flags;
+
+ if (ignore_access)
+ diff &= ~_PAGE_ACCESSED;
+
+ /*
+ * Did any of the 'flush_on_clear' flags was clleared set from between
+ * 'oldflags' and 'newflags'?
+ */
+ if (diff & oldflags & flush_on_clear)
+ return true;
+
+ /* Flush on modified flags. */
+ if (diff & flush_on_change)
+ return true;
+
+ /* Ensure there are no flags that were left behind */
+ if (IS_ENABLED(CONFIG_DEBUG_VM) &&
+ (diff & ~(flush_on_clear | software_flags | flush_on_change))) {
+ VM_WARN_ON_ONCE(1);
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * pte_needs_flush() checks whether permissions were demoted and require a
+ * flush. It should only be used for userspace PTEs.
+ */
+static inline bool pte_needs_flush(pte_t oldpte, pte_t newpte)
+{
+ /* !PRESENT -> * ; no need for flush */
+ if (!(pte_flags(oldpte) & _PAGE_PRESENT))
+ return false;
+
+ /* PFN changed ; needs flush */
+ if (pte_pfn(oldpte) != pte_pfn(newpte))
+ return true;
+
+ /*
+ * check PTE flags; ignore access-bit; see comment in
+ * ptep_clear_flush_young().
+ */
+ return pte_flags_need_flush(pte_flags(oldpte), pte_flags(newpte),
+ true);
+}
+#define pte_needs_flush pte_needs_flush
+
+/*
+ * huge_pmd_needs_flush() checks whether permissions were demoted and require a
+ * flush. It should only be used for userspace huge PMDs.
+ */
+static inline bool huge_pmd_needs_flush(pmd_t oldpmd, pmd_t newpmd)
+{
+ /* !PRESENT -> * ; no need for flush */
+ if (!(pmd_flags(oldpmd) & _PAGE_PRESENT))
+ return false;
+
+ /* PFN changed ; needs flush */
+ if (pmd_pfn(oldpmd) != pmd_pfn(newpmd))
+ return true;
+
+ /*
+ * check PMD flags; do not ignore access-bit; see
+ * pmdp_clear_flush_young().
+ */
+ return pte_flags_need_flush(pmd_flags(oldpmd), pmd_flags(newpmd),
+ false);
+}
+#define huge_pmd_needs_flush huge_pmd_needs_flush
+
+#ifdef CONFIG_ADDRESS_MASKING
+static inline u64 tlbstate_lam_cr3_mask(void)
+{
+ u64 lam = this_cpu_read(cpu_tlbstate.lam);
+
+ return lam << X86_CR3_LAM_U57_BIT;
+}
+
+static inline void set_tlbstate_lam_mode(struct mm_struct *mm)
+{
+ this_cpu_write(cpu_tlbstate.lam,
+ mm->context.lam_cr3_mask >> X86_CR3_LAM_U57_BIT);
+ this_cpu_write(tlbstate_untag_mask, mm->context.untag_mask);
+}
+
+#else
+
+static inline u64 tlbstate_lam_cr3_mask(void)
+{
+ return 0;
+}
+
+static inline void set_tlbstate_lam_mode(struct mm_struct *mm)
+{
+}
+#endif
+#endif /* !MODULE */
+
+static inline void __native_tlb_flush_global(unsigned long cr4)
+{
+ native_write_cr4(cr4 ^ X86_CR4_PGE);
+ native_write_cr4(cr4);
+}
+#endif /* _ASM_X86_TLBFLUSH_H */