On 2/19/25 22:41, Gwan-gyeong Mun wrote:
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 01ea7c6df303..7935859bcc21 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1498,6 +1498,54 @@ static long __meminitdata addr_start, addr_end; static void __meminitdata *p_start, *p_end; static int __meminitdata node_start; +static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) +{
- void *p = vmemmap_alloc_block(size, node);
- if (!p)
return NULL;- memset(p, 0, size);
- return p;
+}
This is a pure copy and paste of the generic function. I assume this is because the mm/sparse-vmemmap.c is static. But this kind of copying is really unfortunate.
...
+pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) +{
- pgd_t *pgd = pgd_offset_k(addr);
- if (pgd_none(*pgd)) {
void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);if (!p)return NULL;pgd_populate(&init_mm, pgd, p);sync_global_pgds(addr, addr);- }
- return pgd;
+}
I'd _really_ like to find another way to do this. We really don't want to add copy-and-paste versions of generic functions that we now need to maintain on the x86 side.
The _best_ way is probably to create some p*d_populate_kernel() helpers:
void pgd_populate_kernel(unsigned long addr, pgd_t *pgd, p4d_t *p4d) { pgd_populate(&init_mm, pgd, p4d); arch_sync_global_pgds(addr, addr+something); }
and move over most of the callers of:
p*d_populate(&init_mm, ...);
Because I suspect that'll fix your issue _and_ solve the generic class of issues where folks populate a kernel page table entry but forget to call sync_global_pgds().