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um: embed ->stub_pages[] into mmu_context

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seriously, kmalloc() for two-element array of pointers?

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-02-23 01:33:19 -05:00
parent 104bb37d3e
commit ea6fb41752
2 changed files with 6 additions and 19 deletions
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2
arch/um/include/asm/mmu.h
View file

@ -12,7 +12,7 @@
typedef struct mm_context { typedef struct mm_context {
struct mm_id id; struct mm_id id;
struct uml_arch_mm_context arch; struct uml_arch_mm_context arch;
struct page **stub_pages; struct page *stub_pages[2];
} mm_context_t; } mm_context_t;
extern void __switch_mm(struct mm_id * mm_idp); extern void __switch_mm(struct mm_id * mm_idp);

23
arch/um/kernel/skas/mmu.c
View file

@ -92,8 +92,6 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
goto out_free; goto out_free;
} }
to_mm->stub_pages = NULL;
return 0; return 0;
out_free: out_free:
@ -120,29 +118,20 @@ void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
if (ret) if (ret)
goto out; goto out;
pages = kmalloc(2 * sizeof(struct page *), GFP_KERNEL); mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
if (pages == NULL) { mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
printk(KERN_ERR "arch_dup_mmap failed to allocate 2 page "
"pointers\n");
goto out;
}
pages[0] = virt_to_page(&__syscall_stub_start);
pages[1] = virt_to_page(mm->context.id.stack);
mm->context.stub_pages = pages;
/* dup_mmap already holds mmap_sem */ /* dup_mmap already holds mmap_sem */
err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START, err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
VM_READ | VM_MAYREAD | VM_EXEC | VM_READ | VM_MAYREAD | VM_EXEC |
VM_MAYEXEC | VM_DONTCOPY, pages); VM_MAYEXEC | VM_DONTCOPY,
mm->context.stub_pages);
if (err) { if (err) {
printk(KERN_ERR "install_special_mapping returned %d\n", err); printk(KERN_ERR "install_special_mapping returned %d\n", err);
goto out_free; goto out;
} }
return; return;
out_free:
kfree(pages);
out: out:
force_sigsegv(SIGSEGV, current); force_sigsegv(SIGSEGV, current);
} }
@ -151,8 +140,6 @@ void arch_exit_mmap(struct mm_struct *mm)
{ {
pte_t *pte; pte_t *pte;
if (mm->context.stub_pages != NULL)
kfree(mm->context.stub_pages);
pte = virt_to_pte(mm, STUB_CODE); pte = virt_to_pte(mm, STUB_CODE);
if (pte != NULL) if (pte != NULL)
pte_clear(mm, STUB_CODE, pte); pte_clear(mm, STUB_CODE, pte);