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A new mm doesn't have a PASID yet when it's created. Initialize the mm's PASID on fork() or for init_mm to INVALID_IOASID (-1). INIT_PASID (0) is reserved for kernel legacy DMA PASID. It cannot be allocated to a user process. Initializing the process's PASID to 0 may cause confusion that's why the process uses the reserved kernel legacy DMA PASID. Initializing the PASID to INVALID_IOASID (-1) explicitly tells the process doesn't have a valid PASID yet. Even though the only user of mm_pasid_init() is in fork.c, define it in <linux/sched/mm.h> as the first of three mm/pasid life cycle functions (init/set/drop) to keep these all together. Suggested-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20220207230254.3342514-5-fenghua.yu@intel.com
55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/mm_types.h>
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#include <linux/rbtree.h>
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#include <linux/rwsem.h>
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#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/cpumask.h>
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#include <linux/mman.h>
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#include <linux/pgtable.h>
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#include <linux/atomic.h>
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#include <linux/user_namespace.h>
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#include <linux/ioasid.h>
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#include <asm/mmu.h>
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#ifndef INIT_MM_CONTEXT
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#define INIT_MM_CONTEXT(name)
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#endif
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/*
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* For dynamically allocated mm_structs, there is a dynamically sized cpumask
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* at the end of the structure, the size of which depends on the maximum CPU
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* number the system can see. That way we allocate only as much memory for
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* mm_cpumask() as needed for the hundreds, or thousands of processes that
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* a system typically runs.
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*
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* Since there is only one init_mm in the entire system, keep it simple
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* and size this cpu_bitmask to NR_CPUS.
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*/
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struct mm_struct init_mm = {
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.mm_rb = RB_ROOT,
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.pgd = swapper_pg_dir,
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.mm_users = ATOMIC_INIT(2),
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.mm_count = ATOMIC_INIT(1),
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.write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
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MMAP_LOCK_INITIALIZER(init_mm)
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.page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
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.arg_lock = __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
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.mmlist = LIST_HEAD_INIT(init_mm.mmlist),
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.user_ns = &init_user_ns,
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.cpu_bitmap = CPU_BITS_NONE,
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#ifdef CONFIG_IOMMU_SVA
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.pasid = INVALID_IOASID,
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#endif
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INIT_MM_CONTEXT(init_mm)
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};
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void setup_initial_init_mm(void *start_code, void *end_code,
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void *end_data, void *brk)
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{
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init_mm.start_code = (unsigned long)start_code;
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init_mm.end_code = (unsigned long)end_code;
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init_mm.end_data = (unsigned long)end_data;
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init_mm.brk = (unsigned long)brk;
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}
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