On 2/8/2019 5:39 AM, Thomas Gleixner wrote:
On Thu, 31 Jan 2019, Liang, Kan wrote:
+u64 perf_get_page_size(u64 virt)
+{
+ unsigned long flags;
+ unsigned int level;
+ pte_t *pte;
+
+ if (!virt)
+ return 0;
+
+ /*
+ * Interrupts are disabled, so it prevents any tear down
+ * of the page tables.
+ * See the comment near struct mmu_table_batch.
+ */
+ local_irq_save(flags);
+ if (virt >= TASK_SIZE)
+ pte = lookup_address(virt, &level);
+ else {
+ if (current->mm)
+ pte = lookup_address_in_pgd(pgd_offset(current->mm,
virt),
+ virt, &level);
Aside from all the missin {}, I'm fairly sure this is broken since this
happens from NMI context. This can interrupt switch_mm() and things like
use_temporary_mm().
Also; why does this live in the x86 code and not in the generic code?
This is x86 implementation.
In generic code, there is a __weak function. I'll make it clear in the change
log in v4.
No, instead of hiding it in the changelog, split the patch into two:
#1 Adding the core stuff including the weak function
#2 Adding the x86 implementation.
Thanks for the comments. I will do it in V5.
Thanks,
Kan
