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23fefe119c
The system control vm.alloc_pgste is used to control the size of the page tables, either 2K or 4K. The idea is that a KVM host sets the vm.alloc_pgste control to 1 which causes *all* new processes to run with 4K page tables. For a non-kvm system the control should stay off to save on memory used for page tables. Trouble is that distributions choose to set the control globally to be able to run KVM guests. This wastes memory on non-KVM systems. Introduce the PT_S390_PGSTE ELF segment type to "mark" the qemu executable with it. All executables with this (empty) segment in its ELF phdr array will be started with 4K page tables. Any executable without PT_S390_PGSTE will run with the default 2K page tables. This removes the need to set vm.alloc_pgste=1 for a KVM host and minimizes the waste of memory for page tables. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
92 lines
2.9 KiB
C
92 lines
2.9 KiB
C
/*
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* S390 version
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* Copyright IBM Corp. 2002, 2006
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*/
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#ifndef _ASM_THREAD_INFO_H
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#define _ASM_THREAD_INFO_H
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#include <linux/const.h>
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/*
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* Size of kernel stack for each process
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*/
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#define THREAD_SIZE_ORDER 2
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#define ASYNC_ORDER 2
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#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
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#define ASYNC_SIZE (PAGE_SIZE << ASYNC_ORDER)
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#ifndef __ASSEMBLY__
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#include <asm/lowcore.h>
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#include <asm/page.h>
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#include <asm/processor.h>
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/*
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* low level task data that entry.S needs immediate access to
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* - this struct should fit entirely inside of one cache line
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* - this struct shares the supervisor stack pages
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* - if the contents of this structure are changed, the assembly constants must also be changed
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*/
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struct thread_info {
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unsigned long flags; /* low level flags */
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};
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/*
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* macros/functions for gaining access to the thread information structure
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*/
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.flags = 0, \
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}
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#define init_stack (init_thread_union.stack)
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void arch_release_task_struct(struct task_struct *tsk);
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int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
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#endif
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/*
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* thread information flags bit numbers
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*/
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/* _TIF_WORK bits */
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#define TIF_NOTIFY_RESUME 0 /* callback before returning to user */
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#define TIF_SIGPENDING 1 /* signal pending */
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#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
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#define TIF_UPROBE 3 /* breakpointed or single-stepping */
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#define TIF_GUARDED_STORAGE 4 /* load guarded storage control block */
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#define TIF_PATCH_PENDING 5 /* pending live patching update */
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#define TIF_PGSTE 6 /* New mm's will use 4K page tables */
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#define TIF_31BIT 16 /* 32bit process */
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#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
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#define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal() */
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#define TIF_SINGLE_STEP 19 /* This task is single stepped */
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#define TIF_BLOCK_STEP 20 /* This task is block stepped */
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#define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */
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/* _TIF_TRACE bits */
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#define TIF_SYSCALL_TRACE 24 /* syscall trace active */
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#define TIF_SYSCALL_AUDIT 25 /* syscall auditing active */
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#define TIF_SECCOMP 26 /* secure computing */
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#define TIF_SYSCALL_TRACEPOINT 27 /* syscall tracepoint instrumentation */
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#define _TIF_NOTIFY_RESUME _BITUL(TIF_NOTIFY_RESUME)
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#define _TIF_SIGPENDING _BITUL(TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED _BITUL(TIF_NEED_RESCHED)
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#define _TIF_UPROBE _BITUL(TIF_UPROBE)
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#define _TIF_GUARDED_STORAGE _BITUL(TIF_GUARDED_STORAGE)
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#define _TIF_PATCH_PENDING _BITUL(TIF_PATCH_PENDING)
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#define _TIF_31BIT _BITUL(TIF_31BIT)
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#define _TIF_SINGLE_STEP _BITUL(TIF_SINGLE_STEP)
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#define _TIF_SYSCALL_TRACE _BITUL(TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT _BITUL(TIF_SYSCALL_AUDIT)
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#define _TIF_SECCOMP _BITUL(TIF_SECCOMP)
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#define _TIF_SYSCALL_TRACEPOINT _BITUL(TIF_SYSCALL_TRACEPOINT)
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#endif /* _ASM_THREAD_INFO_H */
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