0dafcbe128
UML enables TRACE_IRQFLAGS_SUPPORT but doesn't actually implement
it. It seems to have been added for lockdep support, but that can't
actually really work well without IRQ flags tracing, as is also
very noisily reported when enabling CONFIG_DEBUG_LOCKDEP.
Implement it now.
Fixes: 711553efa5 ("[PATCH] uml: declare in Kconfig our partial LOCKDEP support")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
160 lines
3.3 KiB
C
160 lines
3.3 KiB
C
/*
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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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* Licensed under the GPL
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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 <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/sections.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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static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
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unsigned long kernel)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = pgd_offset(mm, proc);
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pud = pud_alloc(mm, pgd, proc);
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if (!pud)
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goto out;
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pmd = pmd_alloc(mm, pud, proc);
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if (!pmd)
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goto out_pmd;
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pte = pte_alloc_map(mm, pmd, proc);
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if (!pte)
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goto out_pte;
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*pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT));
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*pte = pte_mkread(*pte);
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return 0;
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out_pte:
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pmd_free(mm, pmd);
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out_pmd:
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pud_free(mm, pud);
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out:
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return -ENOMEM;
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}
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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_context *from_mm = NULL;
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struct mm_context *to_mm = &mm->context;
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unsigned long stack = 0;
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int ret = -ENOMEM;
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stack = get_zeroed_page(GFP_KERNEL);
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if (stack == 0)
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goto out;
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to_mm->id.stack = stack;
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if (current->mm != NULL && current->mm != &init_mm)
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from_mm = ¤t->mm->context;
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block_signals_trace();
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if (from_mm)
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to_mm->id.u.pid = copy_context_skas0(stack,
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from_mm->id.u.pid);
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else to_mm->id.u.pid = start_userspace(stack);
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unblock_signals_trace();
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if (to_mm->id.u.pid < 0) {
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ret = to_mm->id.u.pid;
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goto out_free;
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}
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ret = init_new_ldt(to_mm, from_mm);
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if (ret < 0) {
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printk(KERN_ERR "init_new_context_skas - init_ldt"
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" failed, errno = %d\n", ret);
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goto out_free;
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}
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return 0;
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out_free:
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if (to_mm->id.stack != 0)
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free_page(to_mm->id.stack);
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out:
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return ret;
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}
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void uml_setup_stubs(struct mm_struct *mm)
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{
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int err, ret;
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ret = init_stub_pte(mm, STUB_CODE,
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(unsigned long) __syscall_stub_start);
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if (ret)
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goto out;
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ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack);
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if (ret)
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goto out;
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mm->context.stub_pages[0] = virt_to_page(__syscall_stub_start);
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mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
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/* dup_mmap already holds mmap_sem */
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err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
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VM_READ | VM_MAYREAD | VM_EXEC |
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VM_MAYEXEC | VM_DONTCOPY | VM_PFNMAP,
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mm->context.stub_pages);
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if (err) {
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printk(KERN_ERR "install_special_mapping returned %d\n", err);
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goto out;
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}
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return;
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out:
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force_sigsegv(SIGSEGV);
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}
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void arch_exit_mmap(struct mm_struct *mm)
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{
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pte_t *pte;
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pte = virt_to_pte(mm, STUB_CODE);
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if (pte != NULL)
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pte_clear(mm, STUB_CODE, pte);
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pte = virt_to_pte(mm, STUB_DATA);
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if (pte == NULL)
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return;
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pte_clear(mm, STUB_DATA, pte);
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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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if (mmu->id.u.pid < 2) {
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printk(KERN_ERR "corrupt mm_context - pid = %d\n",
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mmu->id.u.pid);
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return;
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}
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os_kill_ptraced_process(mmu->id.u.pid, 1);
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free_page(mmu->id.stack);
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free_ldt(mmu);
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}
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