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Tests can allocate from virtual memory using kunit_vm_mmap(), which transparently creates and attaches an mm_struct to the test runner if one is not already attached. This is suitable for most cases, except for when the code under test must access a task's mm before performing an mmap. Expose kunit_attach_mm() as part of the interface for those cases. This does not change the existing behavior. Cc: David Gow <davidgow@google.com> Signed-off-by: Tiffany Yang <ynaffit@google.com> Reviewed-by: Carlos Llamas <cmllamas@google.com> Link: https://lore.kernel.org/r/20250714185321.2417234-4-ynaffit@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
117 lines
2.4 KiB
C
117 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* KUnit userspace memory allocation resource management.
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*/
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#include <kunit/resource.h>
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#include <kunit/test.h>
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#include <linux/kthread.h>
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#include <linux/mm.h>
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struct kunit_vm_mmap_resource {
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unsigned long addr;
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size_t size;
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};
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/* vm_mmap() arguments */
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struct kunit_vm_mmap_params {
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struct file *file;
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unsigned long addr;
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unsigned long len;
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unsigned long prot;
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unsigned long flag;
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unsigned long offset;
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};
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int kunit_attach_mm(void)
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{
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struct mm_struct *mm;
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if (current->mm)
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return 0;
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/* arch_pick_mmap_layout() is only sane with MMU systems. */
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if (!IS_ENABLED(CONFIG_MMU))
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return -EINVAL;
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mm = mm_alloc();
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if (!mm)
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return -ENOMEM;
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/* Define the task size. */
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mm->task_size = TASK_SIZE;
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/* Make sure we can allocate new VMAs. */
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arch_pick_mmap_layout(mm, ¤t->signal->rlim[RLIMIT_STACK]);
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/* Attach the mm. It will be cleaned up when the process dies. */
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kthread_use_mm(mm);
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return 0;
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}
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EXPORT_SYMBOL_GPL(kunit_attach_mm);
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static int kunit_vm_mmap_init(struct kunit_resource *res, void *context)
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{
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struct kunit_vm_mmap_params *p = context;
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struct kunit_vm_mmap_resource vres;
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int ret;
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ret = kunit_attach_mm();
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if (ret)
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return ret;
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vres.size = p->len;
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vres.addr = vm_mmap(p->file, p->addr, p->len, p->prot, p->flag, p->offset);
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if (!vres.addr)
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return -ENOMEM;
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res->data = kmemdup(&vres, sizeof(vres), GFP_KERNEL);
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if (!res->data) {
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vm_munmap(vres.addr, vres.size);
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return -ENOMEM;
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}
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return 0;
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}
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static void kunit_vm_mmap_free(struct kunit_resource *res)
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{
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struct kunit_vm_mmap_resource *vres = res->data;
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/*
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* Since this is executed from the test monitoring process,
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* the test's mm has already been torn down. We don't need
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* to run vm_munmap(vres->addr, vres->size), only clean up
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* the vres.
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*/
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kfree(vres);
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res->data = NULL;
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}
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unsigned long kunit_vm_mmap(struct kunit *test, struct file *file,
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unsigned long addr, unsigned long len,
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unsigned long prot, unsigned long flag,
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unsigned long offset)
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{
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struct kunit_vm_mmap_params params = {
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.file = file,
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.addr = addr,
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.len = len,
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.prot = prot,
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.flag = flag,
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.offset = offset,
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};
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struct kunit_vm_mmap_resource *vres;
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vres = kunit_alloc_resource(test,
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kunit_vm_mmap_init,
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kunit_vm_mmap_free,
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GFP_KERNEL,
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¶ms);
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if (vres)
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return vres->addr;
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return 0;
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}
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EXPORT_SYMBOL_GPL(kunit_vm_mmap);
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MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
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