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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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409a0c00c4
They are only used within mmu.c. Make them static. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20250708090403.1067440-3-tiwei.bie@linux.dev Signed-off-by: Johannes Berg <johannes.berg@intel.com>
146 lines
3.3 KiB
C
146 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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*/
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#include <linux/mm.h>
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#include <linux/sched/signal.h>
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#include <linux/slab.h>
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#include <shared/irq_kern.h>
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#include <asm/pgalloc.h>
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#include <asm/sections.h>
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#include <asm/mmu_context.h>
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#include <as-layout.h>
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#include <os.h>
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#include <skas.h>
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#include <stub-data.h>
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/* Ensure the stub_data struct covers the allocated area */
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static_assert(sizeof(struct stub_data) == STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);
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static spinlock_t mm_list_lock;
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static struct list_head mm_list;
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int init_new_context(struct task_struct *task, struct mm_struct *mm)
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{
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struct mm_id *new_id = &mm->context.id;
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unsigned long stack = 0;
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int ret = -ENOMEM;
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stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES));
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if (stack == 0)
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goto out;
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new_id->stack = stack;
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scoped_guard(spinlock_irqsave, &mm_list_lock) {
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/* Insert into list, used for lookups when the child dies */
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list_add(&mm->context.list, &mm_list);
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}
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ret = start_userspace(new_id);
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if (ret < 0)
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goto out_free;
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/* Ensure the new MM is clean and nothing unwanted is mapped */
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unmap(new_id, 0, STUB_START);
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return 0;
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out_free:
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free_pages(new_id->stack, ilog2(STUB_DATA_PAGES));
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out:
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return ret;
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}
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void destroy_context(struct mm_struct *mm)
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{
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struct mm_context *mmu = &mm->context;
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/*
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* If init_new_context wasn't called, this will be
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* zero, resulting in a kill(0), which will result in the
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* whole UML suddenly dying. Also, cover negative and
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* 1 cases, since they shouldn't happen either.
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*
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* Negative cases happen if the child died unexpectedly.
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*/
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if (mmu->id.pid >= 0 && mmu->id.pid < 2) {
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printk(KERN_ERR "corrupt mm_context - pid = %d\n",
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mmu->id.pid);
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return;
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}
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if (mmu->id.pid > 0) {
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os_kill_ptraced_process(mmu->id.pid, 1);
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mmu->id.pid = -1;
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}
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if (using_seccomp && mmu->id.sock)
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os_close_file(mmu->id.sock);
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free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));
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guard(spinlock_irqsave)(&mm_list_lock);
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list_del(&mm->context.list);
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}
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static irqreturn_t mm_sigchld_irq(int irq, void* dev)
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{
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struct mm_context *mm_context;
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pid_t pid;
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guard(spinlock)(&mm_list_lock);
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while ((pid = os_reap_child()) > 0) {
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/*
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* A child died, check if we have an MM with the PID. This is
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* only relevant in SECCOMP mode (as ptrace will fail anyway).
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*
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* See wait_stub_done_seccomp for more details.
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*/
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list_for_each_entry(mm_context, &mm_list, list) {
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if (mm_context->id.pid == pid) {
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struct stub_data *stub_data;
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printk("Unexpectedly lost MM child! Affected tasks will segfault.");
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/* Marks the MM as dead */
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mm_context->id.pid = -1;
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/*
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* NOTE: If SMP is implemented, a futex_wake
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* needs to be added here.
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*/
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stub_data = (void *)mm_context->id.stack;
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stub_data->futex = FUTEX_IN_KERN;
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/*
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* NOTE: Currently executing syscalls by
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* affected tasks may finish normally.
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*/
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break;
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}
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}
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}
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return IRQ_HANDLED;
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}
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static int __init init_child_tracking(void)
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{
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int err;
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spin_lock_init(&mm_list_lock);
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INIT_LIST_HEAD(&mm_list);
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err = request_irq(SIGCHLD_IRQ, mm_sigchld_irq, 0, "SIGCHLD", NULL);
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if (err < 0)
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panic("Failed to register SIGCHLD IRQ: %d", err);
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return 0;
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}
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early_initcall(init_child_tracking)
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