diff options
Diffstat (limited to 'arch/um/kernel/skas/mmu.c')
| -rw-r--r-- | arch/um/kernel/skas/mmu.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c new file mode 100644 index 0000000000..656fe16c9b --- /dev/null +++ b/arch/um/kernel/skas/mmu.c @@ -0,0 +1,79 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) + * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + */ + +#include <linux/mm.h> +#include <linux/sched/signal.h> +#include <linux/slab.h> + +#include <asm/pgalloc.h> +#include <asm/sections.h> +#include <as-layout.h> +#include <os.h> +#include <skas.h> + +int init_new_context(struct task_struct *task, struct mm_struct *mm) +{ + struct mm_context *from_mm = NULL; + struct mm_context *to_mm = &mm->context; + unsigned long stack = 0; + int ret = -ENOMEM; + + stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES)); + if (stack == 0) + goto out; + + to_mm->id.stack = stack; + if (current->mm != NULL && current->mm != &init_mm) + from_mm = ¤t->mm->context; + + block_signals_trace(); + if (from_mm) + to_mm->id.u.pid = copy_context_skas0(stack, + from_mm->id.u.pid); + else to_mm->id.u.pid = start_userspace(stack); + unblock_signals_trace(); + + if (to_mm->id.u.pid < 0) { + ret = to_mm->id.u.pid; + goto out_free; + } + + ret = init_new_ldt(to_mm, from_mm); + if (ret < 0) { + printk(KERN_ERR "init_new_context_skas - init_ldt" + " failed, errno = %d\n", ret); + goto out_free; + } + + return 0; + + out_free: + if (to_mm->id.stack != 0) + free_pages(to_mm->id.stack, ilog2(STUB_DATA_PAGES)); + out: + return ret; +} + +void destroy_context(struct mm_struct *mm) +{ + struct mm_context *mmu = &mm->context; + + /* + * If init_new_context wasn't called, this will be + * zero, resulting in a kill(0), which will result in the + * whole UML suddenly dying. Also, cover negative and + * 1 cases, since they shouldn't happen either. + */ + if (mmu->id.u.pid < 2) { + printk(KERN_ERR "corrupt mm_context - pid = %d\n", + mmu->id.u.pid); + return; + } + os_kill_ptraced_process(mmu->id.u.pid, 1); + + free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES)); + free_ldt(mmu); +} |