On ARM, [vtop -C task] doesn't work correctly for kernel addresses: it
always uses swapper_pg_dir when it should be using the task's mm->pgd.
The patch below fixes this, and also makes ARM handle kernel threads
like the other arches.
Rabin
diff --git a/arm.c b/arm.c
index 4be224e..cac9a9a 100644
--- a/arm.c
+++ b/arm.c
@@ -1020,22 +1020,37 @@ static int
arm_uvtop(struct task_context *tc, ulong uvaddr, physaddr_t *paddr, int verbose)
{
ulong *pgd;
- ulong mm;
if (!tc)
error(FATAL, "current context invalid\n");
*paddr = 0;
- if (IS_KVADDR(uvaddr))
- return arm_kvtop(tc, uvaddr, paddr, verbose);
+ if (is_kernel_thread(tc->task) && IS_KVADDR(uvaddr)) {
+ ulong active_mm;
- mm = task_mm(tc->task, TRUE);
- if (mm)
- pgd = ULONG_PTR(tt->mm_struct + OFFSET(mm_struct_pgd));
- else
- readmem(tc->mm_struct + OFFSET(mm_struct_pgd), KVADDR, &pgd,
- sizeof(long), "mm_struct pgd", FAULT_ON_ERROR);
+ readmem(tc->task + OFFSET(task_struct_active_mm),
+ KVADDR, &active_mm, sizeof(void *),
+ "task active_mm contents", FAULT_ON_ERROR);
+
+ if (!active_mm)
+ error(FATAL,
+ "no active_mm for this kernel thread\n");
+
+ readmem(active_mm + OFFSET(mm_struct_pgd),
+ KVADDR, &pgd, sizeof(long),
+ "mm_struct pgd", FAULT_ON_ERROR);
+ } else {
+ ulong mm;
+
+ mm = task_mm(tc->task, TRUE);
+ if (mm)
+ pgd = ULONG_PTR(tt->mm_struct + OFFSET(mm_struct_pgd));
+ else
+ readmem(tc->mm_struct + OFFSET(mm_struct_pgd),
+ KVADDR, &pgd, sizeof(long), "mm_struct pgd",
+ FAULT_ON_ERROR);
+ }
return arm_vtop(uvaddr, pgd, paddr, verbose);
}
--
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