OXIESEC PANEL

Name	Size	Modified	Perms
📁 ..	-	05/09/2024 07:14:12 AM	rwxr-xr-x
📄 Kbuild	681 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 arcregs.h	8.59 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 asm-offsets.h	311 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 atomic.h	15.14 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 barrier.h	1.75 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 bitops.h	9.81 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 bug.h	938 bytes	06/16/2023 05:32:39 PM	rw-r--r--
📄 cache.h	3.77 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 cacheflush.h	3.88 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 checksum.h	2.45 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 cmpxchg.h	5.4 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 current.h	695 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 delay.h	1.99 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 disasm.h	3.87 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 dma-mapping.h	734 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 dma.h	459 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 dwarf.h	892 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 elf.h	2.15 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 entry-arcv2.h	4.85 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 entry-compact.h	9.29 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 entry.h	6.73 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 exec.h	410 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 fb.h	411 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 futex.h	3.67 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 highmem.h	1.46 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 hugepage.h	2.41 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 io.h	6.43 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 irq.h	825 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 irqflags-arcv2.h	3.45 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 irqflags-compact.h	4.25 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 irqflags.h	509 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 kdebug.h	400 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 kgdb.h	1.35 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 kmap_types.h	489 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 kprobes.h	1.37 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 linkage.h	1.42 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 mach_desc.h	2.06 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 mmu.h	2.44 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 mmu_context.h	5.67 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 mmzone.h	989 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 module.h	661 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 page.h	2.99 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 pci.h	705 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 perf_event.h	6.86 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 pgalloc.h	3.79 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 pgtable.h	14.2 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 processor.h	4.69 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 ptrace.h	3.87 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 sections.h	407 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 segment.h	612 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 serial.h	644 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 setup.h	1.18 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 shmparam.h	442 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 smp.h	4.25 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 spinlock.h	8.79 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 spinlock_types.h	1.03 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 stacktrace.h	1.29 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 string.h	1.15 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 switch_to.h	1.17 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 syscall.h	1.57 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 syscalls.h	653 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 thread_info.h	3.39 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 timex.h	508 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 tlb-mmu1.h	3.48 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 tlb.h	1.23 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 tlbflush.h	1.76 KB	01/28/2018 09:20:33 PM	rw-r--r--
📄 uaccess.h	18.45 KB	06/16/2023 05:32:39 PM	rw-r--r--
📄 unaligned.h	771 bytes	01/28/2018 09:20:33 PM	rw-r--r--
📄 unwind.h	3.51 KB	01/28/2018 09:20:33 PM	rw-r--r--

Editing: mmu_context.h

/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * vineetg: May 2011
 *  -Refactored get_new_mmu_context( ) to only handle live-mm.
 *   retiring-mm handled in other hooks
 *
 * Vineetg: March 25th, 2008: Bug #92690
 *  -Major rewrite of Core ASID allocation routine get_new_mmu_context
 *
 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
 */

#ifndef _ASM_ARC_MMU_CONTEXT_H
#define _ASM_ARC_MMU_CONTEXT_H

#include <asm/arcregs.h>
#include <asm/tlb.h>
#include <linux/sched/mm.h>

#include <asm-generic/mm_hooks.h>

/*		ARC700 ASID Management
 *
 * ARC MMU provides 8-bit ASID (0..255) to TAG TLB entries, allowing entries
 * with same vaddr (different tasks) to co-exit. This provides for
 * "Fast Context Switch" i.e. no TLB flush on ctxt-switch
 *
 * Linux assigns each task a unique ASID. A simple round-robin allocation
 * of H/w ASID is done using software tracker @asid_cpu.
 * When it reaches max 255, the allocation cycle starts afresh by flushing
 * the entire TLB and wrapping ASID back to zero.
 *
 * A new allocation cycle, post rollover, could potentially reassign an ASID
 * to a different task. Thus the rule is to refresh the ASID in a new cycle.
 * The 32 bit @asid_cpu (and mm->asid) have 8 bits MMU PID and rest 24 bits
 * serve as cycle/generation indicator and natural 32 bit unsigned math
 * automagically increments the generation when lower 8 bits rollover.
 */

#define MM_CTXT_ASID_MASK	0x000000ff /* MMU PID reg :8 bit PID */
#define MM_CTXT_CYCLE_MASK	(~MM_CTXT_ASID_MASK)

#define MM_CTXT_FIRST_CYCLE	(MM_CTXT_ASID_MASK + 1)
#define MM_CTXT_NO_ASID		0UL

#define asid_mm(mm, cpu)	mm->context.asid[cpu]
#define hw_pid(mm, cpu)		(asid_mm(mm, cpu) & MM_CTXT_ASID_MASK)

DECLARE_PER_CPU(unsigned int, asid_cache);
#define asid_cpu(cpu)		per_cpu(asid_cache, cpu)

/*
 * Get a new ASID if task doesn't have a valid one (unalloc or from prev cycle)
 * Also set the MMU PID register to existing/updated ASID
 */
static inline void get_new_mmu_context(struct mm_struct *mm)
{
	const unsigned int cpu = smp_processor_id();
	unsigned long flags;

local_irq_save(flags);

/*
	 * Move to new ASID if it was not from current alloc-cycle/generation.
	 * This is done by ensuring that the generation bits in both mm->ASID
	 * and cpu's ASID counter are exactly same.
	 *
	 * Note: Callers needing new ASID unconditionally, independent of
	 * 	 generation, e.g. local_flush_tlb_mm() for forking  parent,
	 * 	 first need to destroy the context, setting it to invalid
	 * 	 value.
	 */
	if (!((asid_mm(mm, cpu) ^ asid_cpu(cpu)) & MM_CTXT_CYCLE_MASK))
		goto set_hw;

/* move to new ASID and handle rollover */
	if (unlikely(!(++asid_cpu(cpu) & MM_CTXT_ASID_MASK))) {

local_flush_tlb_all();

/*
		 * Above check for rollover of 8 bit ASID in 32 bit container.
		 * If the container itself wrapped around, set it to a non zero
		 * "generation" to distinguish from no context
		 */
		if (!asid_cpu(cpu))
			asid_cpu(cpu) = MM_CTXT_FIRST_CYCLE;
	}

/* Assign new ASID to tsk */
	asid_mm(mm, cpu) = asid_cpu(cpu);

set_hw:
	write_aux_reg(ARC_REG_PID, hw_pid(mm, cpu) | MMU_ENABLE);

local_irq_restore(flags);
}

/*
 * Initialize the context related info for a new mm_struct
 * instance.
 */
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
	int i;

for_each_possible_cpu(i)
		asid_mm(mm, i) = MM_CTXT_NO_ASID;

return 0;
}

static inline void destroy_context(struct mm_struct *mm)
{
	unsigned long flags;

/* Needed to elide CONFIG_DEBUG_PREEMPT warning */
	local_irq_save(flags);
	asid_mm(mm, smp_processor_id()) = MM_CTXT_NO_ASID;
	local_irq_restore(flags);
}

/* Prepare the MMU for task: setup PID reg with allocated ASID
    If task doesn't have an ASID (never alloc or stolen, get a new ASID)
*/
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
			     struct task_struct *tsk)
{
	const int cpu = smp_processor_id();

/*
	 * Note that the mm_cpumask is "aggregating" only, we don't clear it
	 * for the switched-out task, unlike some other arches.
	 * It is used to enlist cpus for sending TLB flush IPIs and not sending
	 * it to CPUs where a task once ran-on, could cause stale TLB entry
	 * re-use, specially for a multi-threaded task.
	 * e.g. T1 runs on C1, migrates to C3. T2 running on C2 munmaps.
	 *      For a non-aggregating mm_cpumask, IPI not sent C1, and if T1
	 *      were to re-migrate to C1, it could access the unmapped region
	 *      via any existing stale TLB entries.
	 */
	cpumask_set_cpu(cpu, mm_cpumask(next));

#ifndef CONFIG_SMP
	/* PGD cached in MMU reg to avoid 3 mem lookups: task->mm->pgd */
	write_aux_reg(ARC_REG_SCRATCH_DATA0, next->pgd);
#endif

get_new_mmu_context(next);
}

/*
 * Called at the time of execve() to get a new ASID
 * Note the subtlety here: get_new_mmu_context() behaves differently here
 * vs. in switch_mm(). Here it always returns a new ASID, because mm has
 * an unallocated "initial" value, while in latter, it moves to a new ASID,
 * only if it was unallocated
 */
#define activate_mm(prev, next)		switch_mm(prev, next, NULL)

/* it seemed that deactivate_mm( ) is a reasonable place to do book-keeping
 * for retiring-mm. However destroy_context( ) still needs to do that because
 * between mm_release( ) = >deactive_mm( ) and
 * mmput => .. => __mmdrop( ) => destroy_context( )
 * there is a good chance that task gets sched-out/in, making it's ASID valid
 * again (this teased me for a whole day).
 */
#define deactivate_mm(tsk, mm)   do { } while (0)

#define enter_lazy_tlb(mm, tsk)

#endif /* __ASM_ARC_MMU_CONTEXT_H */