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![Alexey Kardashevskiy](/assets/img/avatar_default.png)
LoPAPR defines guest visible IOMMU with hypercalls to use it - H_PUT_TCE/etc. Implemented first on POWER7 where hypercalls would trap in the KVM in the real mode (with MMU off). The problem with the real mode is some memory is not available and some API usage crashed the host but enabling MMU was an expensive operation. The problems with the real mode handlers are: 1. Occasionally these cannot complete the request so the code is copied+modified to work in the virtual mode, very little is shared; 2. The real mode handlers have to be linked into vmlinux to work; 3. An exception in real mode immediately reboots the machine. If the small DMA window is used, the real mode handlers bring better performance. However since POWER8, there has always been a bigger DMA window which VMs use to map the entire VM memory to avoid calling H_PUT_TCE. Such 1:1 mapping happens once and uses H_PUT_TCE_INDIRECT (a bulk version of H_PUT_TCE) which virtual mode handler is even closer to its real mode version. On POWER9 hypercalls trap straight to the virtual mode so the real mode handlers never execute on POWER9 and later CPUs. So with the current use of the DMA windows and MMU improvements in POWER9 and later, there is no point in duplicating the code. The 32bit passed through devices may slow down but we do not have many of these in practice. For example, with this applied, a 1Gbit ethernet adapter still demostrates above 800Mbit/s of actual throughput. This removes the real mode handlers from KVM and related code from the powernv platform. This updates the list of implemented hcalls in KVM-HV as the realmode handlers are removed. This changes ABI - kvmppc_h_get_tce() moves to the KVM module and kvmppc_find_table() is static now. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220506053755.3820702-1-aik@ozlabs.ru
305 lines
9.1 KiB
C
305 lines
9.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_POWERPC_MMU_CONTEXT_H
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#define __ASM_POWERPC_MMU_CONTEXT_H
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#ifdef __KERNEL__
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <asm/mmu.h>
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#include <asm/cputable.h>
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#include <asm/cputhreads.h>
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/*
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* Most if the context management is out of line
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*/
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#define init_new_context init_new_context
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extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
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#define destroy_context destroy_context
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extern void destroy_context(struct mm_struct *mm);
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#ifdef CONFIG_SPAPR_TCE_IOMMU
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struct mm_iommu_table_group_mem_t;
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extern bool mm_iommu_preregistered(struct mm_struct *mm);
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extern long mm_iommu_new(struct mm_struct *mm,
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unsigned long ua, unsigned long entries,
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struct mm_iommu_table_group_mem_t **pmem);
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extern long mm_iommu_newdev(struct mm_struct *mm, unsigned long ua,
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unsigned long entries, unsigned long dev_hpa,
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struct mm_iommu_table_group_mem_t **pmem);
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extern long mm_iommu_put(struct mm_struct *mm,
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struct mm_iommu_table_group_mem_t *mem);
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extern void mm_iommu_init(struct mm_struct *mm);
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extern void mm_iommu_cleanup(struct mm_struct *mm);
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extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
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unsigned long ua, unsigned long size);
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extern struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
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unsigned long ua, unsigned long entries);
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extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
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unsigned long ua, unsigned int pageshift, unsigned long *hpa);
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extern bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa,
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unsigned int pageshift, unsigned long *size);
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extern long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem);
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extern void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem);
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#else
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static inline bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa,
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unsigned int pageshift, unsigned long *size)
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{
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return false;
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}
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static inline void mm_iommu_init(struct mm_struct *mm) { }
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#endif
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extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm);
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#ifdef CONFIG_PPC_BOOK3S_64
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extern void radix__switch_mmu_context(struct mm_struct *prev,
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struct mm_struct *next);
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static inline void switch_mmu_context(struct mm_struct *prev,
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struct mm_struct *next,
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struct task_struct *tsk)
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{
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if (radix_enabled())
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return radix__switch_mmu_context(prev, next);
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return switch_slb(tsk, next);
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}
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extern int hash__alloc_context_id(void);
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void __init hash__reserve_context_id(int id);
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extern void __destroy_context(int context_id);
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static inline void mmu_context_init(void) { }
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#ifdef CONFIG_PPC_64S_HASH_MMU
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static inline int alloc_extended_context(struct mm_struct *mm,
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unsigned long ea)
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{
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int context_id;
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int index = ea >> MAX_EA_BITS_PER_CONTEXT;
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context_id = hash__alloc_context_id();
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if (context_id < 0)
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return context_id;
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VM_WARN_ON(mm->context.extended_id[index]);
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mm->context.extended_id[index] = context_id;
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return context_id;
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}
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static inline bool need_extra_context(struct mm_struct *mm, unsigned long ea)
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{
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int context_id;
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context_id = get_user_context(&mm->context, ea);
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if (!context_id)
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return true;
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return false;
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}
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#endif
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#else
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extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk);
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extern unsigned long __init_new_context(void);
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extern void __destroy_context(unsigned long context_id);
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extern void mmu_context_init(void);
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static inline int alloc_extended_context(struct mm_struct *mm,
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unsigned long ea)
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{
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/* non book3s_64 should never find this called */
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WARN_ON(1);
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return -ENOMEM;
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}
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static inline bool need_extra_context(struct mm_struct *mm, unsigned long ea)
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{
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return false;
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}
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#endif
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extern void switch_cop(struct mm_struct *next);
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extern int use_cop(unsigned long acop, struct mm_struct *mm);
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extern void drop_cop(unsigned long acop, struct mm_struct *mm);
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#ifdef CONFIG_PPC_BOOK3S_64
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static inline void inc_mm_active_cpus(struct mm_struct *mm)
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{
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atomic_inc(&mm->context.active_cpus);
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}
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static inline void dec_mm_active_cpus(struct mm_struct *mm)
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{
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atomic_dec(&mm->context.active_cpus);
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}
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static inline void mm_context_add_copro(struct mm_struct *mm)
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{
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/*
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* If any copro is in use, increment the active CPU count
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* in order to force TLB invalidations to be global as to
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* propagate to the Nest MMU.
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*/
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if (atomic_inc_return(&mm->context.copros) == 1)
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inc_mm_active_cpus(mm);
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}
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static inline void mm_context_remove_copro(struct mm_struct *mm)
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{
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int c;
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/*
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* When removing the last copro, we need to broadcast a global
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* flush of the full mm, as the next TLBI may be local and the
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* nMMU and/or PSL need to be cleaned up.
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*
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* Both the 'copros' and 'active_cpus' counts are looked at in
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* flush_all_mm() to determine the scope (local/global) of the
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* TLBIs, so we need to flush first before decrementing
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* 'copros'. If this API is used by several callers for the
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* same context, it can lead to over-flushing. It's hopefully
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* not common enough to be a problem.
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*
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* Skip on hash, as we don't know how to do the proper flush
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* for the time being. Invalidations will remain global if
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* used on hash. Note that we can't drop 'copros' either, as
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* it could make some invalidations local with no flush
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* in-between.
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*/
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if (radix_enabled()) {
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flush_all_mm(mm);
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c = atomic_dec_if_positive(&mm->context.copros);
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/* Detect imbalance between add and remove */
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WARN_ON(c < 0);
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if (c == 0)
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dec_mm_active_cpus(mm);
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}
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}
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/*
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* vas_windows counter shows number of open windows in the mm
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* context. During context switch, use this counter to clear the
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* foreign real address mapping (CP_ABORT) for the thread / process
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* that intend to use COPY/PASTE. When a process closes all windows,
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* disable CP_ABORT which is expensive to run.
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*
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* For user context, register a copro so that TLBIs are seen by the
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* nest MMU. mm_context_add/remove_vas_window() are used only for user
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* space windows.
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*/
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static inline void mm_context_add_vas_window(struct mm_struct *mm)
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{
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atomic_inc(&mm->context.vas_windows);
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mm_context_add_copro(mm);
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}
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static inline void mm_context_remove_vas_window(struct mm_struct *mm)
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{
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int v;
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mm_context_remove_copro(mm);
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v = atomic_dec_if_positive(&mm->context.vas_windows);
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/* Detect imbalance between add and remove */
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WARN_ON(v < 0);
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}
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#else
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static inline void inc_mm_active_cpus(struct mm_struct *mm) { }
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static inline void dec_mm_active_cpus(struct mm_struct *mm) { }
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static inline void mm_context_add_copro(struct mm_struct *mm) { }
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static inline void mm_context_remove_copro(struct mm_struct *mm) { }
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#endif
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#if defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE) && defined(CONFIG_PPC_RADIX_MMU)
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void do_h_rpt_invalidate_prt(unsigned long pid, unsigned long lpid,
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unsigned long type, unsigned long pg_sizes,
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unsigned long start, unsigned long end);
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#else
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static inline void do_h_rpt_invalidate_prt(unsigned long pid,
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unsigned long lpid,
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unsigned long type,
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unsigned long pg_sizes,
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unsigned long start,
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unsigned long end) { }
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#endif
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extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk);
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static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk)
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{
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unsigned long flags;
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local_irq_save(flags);
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switch_mm_irqs_off(prev, next, tsk);
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local_irq_restore(flags);
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}
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#define switch_mm_irqs_off switch_mm_irqs_off
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/*
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* After we have set current->mm to a new value, this activates
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* the context for the new mm so we see the new mappings.
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*/
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#define activate_mm activate_mm
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static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
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{
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switch_mm_irqs_off(prev, next, current);
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}
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/* We don't currently use enter_lazy_tlb() for anything */
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#ifdef CONFIG_PPC_BOOK3E_64
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#define enter_lazy_tlb enter_lazy_tlb
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static inline void enter_lazy_tlb(struct mm_struct *mm,
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struct task_struct *tsk)
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{
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/* 64-bit Book3E keeps track of current PGD in the PACA */
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get_paca()->pgd = NULL;
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}
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#endif
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extern void arch_exit_mmap(struct mm_struct *mm);
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static inline void arch_unmap(struct mm_struct *mm,
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unsigned long start, unsigned long end)
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{
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unsigned long vdso_base = (unsigned long)mm->context.vdso;
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if (start <= vdso_base && vdso_base < end)
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mm->context.vdso = NULL;
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}
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#ifdef CONFIG_PPC_MEM_KEYS
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bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
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bool execute, bool foreign);
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void arch_dup_pkeys(struct mm_struct *oldmm, struct mm_struct *mm);
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#else /* CONFIG_PPC_MEM_KEYS */
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static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
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bool write, bool execute, bool foreign)
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{
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/* by default, allow everything */
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return true;
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}
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#define pkey_mm_init(mm)
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#define arch_dup_pkeys(oldmm, mm)
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static inline u64 pte_to_hpte_pkey_bits(u64 pteflags, unsigned long flags)
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{
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return 0x0UL;
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}
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#endif /* CONFIG_PPC_MEM_KEYS */
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static inline int arch_dup_mmap(struct mm_struct *oldmm,
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struct mm_struct *mm)
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{
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arch_dup_pkeys(oldmm, mm);
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return 0;
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}
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#include <asm-generic/mmu_context.h>
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#endif /* __KERNEL__ */
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#endif /* __ASM_POWERPC_MMU_CONTEXT_H */
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