402b08622d
The SIE instruction on s390 uses the 2nd half of the page table page to virtualize the storage keys of a guest. This patch offers the s390_enable_sie function, which reorganizes the page tables of a single-threaded process to reserve space in the page table: s390_enable_sie makes sure that the process is single threaded and then uses dup_mm to create a new mm with reorganized page tables. The old mm is freed and the process has now a page status extended field after every page table. Code that wants to exploit pgstes should SELECT CONFIG_PGSTE. This patch has a small common code hit, namely making dup_mm non-static. Edit (Carsten): I've modified Martin's patch, following Jeremy Fitzhardinge's review feedback. Now we do have the prototype for dup_mm in include/linux/sched.h. Following Martin's suggestion, s390_enable_sie() does now call task_lock() to prevent race against ptrace modification of mm_users. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Avi Kivity <avi@qumranet.com>
77 lines
2 KiB
C
77 lines
2 KiB
C
/*
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* include/asm-s390/mmu_context.h
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*
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* S390 version
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*
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* Derived from "include/asm-i386/mmu_context.h"
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*/
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#ifndef __S390_MMU_CONTEXT_H
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#define __S390_MMU_CONTEXT_H
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#include <asm/pgalloc.h>
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#include <asm/uaccess.h>
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#include <asm-generic/mm_hooks.h>
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static inline int init_new_context(struct task_struct *tsk,
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struct mm_struct *mm)
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{
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mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
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#ifdef CONFIG_64BIT
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mm->context.asce_bits |= _ASCE_TYPE_REGION3;
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#endif
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if (current->mm->context.pgstes) {
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mm->context.noexec = 0;
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mm->context.pgstes = 1;
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} else {
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mm->context.noexec = s390_noexec;
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mm->context.pgstes = 0;
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}
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mm->context.asce_limit = STACK_TOP_MAX;
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crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
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return 0;
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}
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#define destroy_context(mm) do { } while (0)
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#ifndef __s390x__
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#define LCTL_OPCODE "lctl"
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#else
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#define LCTL_OPCODE "lctlg"
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#endif
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static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
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{
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pgd_t *pgd = mm->pgd;
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S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
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if (switch_amode) {
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/* Load primary space page table origin. */
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pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
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S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
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asm volatile(LCTL_OPCODE" 1,1,%0\n"
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: : "m" (S390_lowcore.user_exec_asce) );
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} else
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/* Load home space page table origin. */
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asm volatile(LCTL_OPCODE" 13,13,%0"
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: : "m" (S390_lowcore.user_asce) );
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set_fs(current->thread.mm_segment);
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}
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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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cpu_set(smp_processor_id(), next->cpu_vm_mask);
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update_mm(next, tsk);
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}
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#define enter_lazy_tlb(mm,tsk) do { } while (0)
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#define deactivate_mm(tsk,mm) do { } while (0)
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static inline void activate_mm(struct mm_struct *prev,
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struct mm_struct *next)
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{
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switch_mm(prev, next, current);
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}
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#endif /* __S390_MMU_CONTEXT_H */
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