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vdso/datastore: Map pages in terms of the faults pgoff

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To support mlockall() on the datapages the VMA can have no holes where
inner pages return VM_FAULT_SIGBUS. An upcoming change will avoid these
holes by mapping a zeroed pages into these holes. That logic will be
simpler when the mapping logic is based on vmf->pgoff instead of the
vdso_k_ symbols.

Switch to the equivalent vmf->pgoff logic.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Nam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/20260630-vdso-mlockall-v4-2-6c93708ce723@linutronix.de
This commit is contained in:
Thomas Weißschuh
2026-07-07 23:52:52 +02:00
committed by Thomas Gleixner
parent ff868f43eb
commit 7557273419
1 changed files with 4 additions and 5 deletions
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lib/vdso/datastore.c
+4 -5
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@@ -29,10 +29,11 @@ struct vdso_arch_data *vdso_k_arch_data __ro_after_init =
(void *)&vdso_initdata[VDSO_ARCH_PAGES_START * PAGE_SIZE];
#endif /* CONFIG_ARCH_HAS_VDSO_ARCH_DATA */
static struct page *vdso_data_pages __ro_after_init;
void __init vdso_setup_data_pages(void)
{
unsigned int order = get_order(VDSO_NR_PAGES * PAGE_SIZE);
struct page *vdso_data_pages;
/*
* Allocate the data pages dynamically. SPARC does not support mapping
@@ -67,13 +68,13 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
{
struct page *page, *timens_page;
page = vdso_data_pages + vmf->pgoff;
timens_page = find_timens_vvar_page(vma);
switch (vmf->pgoff) {
case VDSO_TIME_PAGE_OFFSET:
if (!IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY))
return VM_FAULT_SIGBUS;
page = virt_to_page(vdso_k_time_data);
if (timens_page) {
/*
* Fault in VVAR page too, since it will be accessed
@@ -99,17 +100,15 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
*/
if (!IS_ENABLED(CONFIG_TIME_NS) || !timens_page)
return VM_FAULT_SIGBUS;
page = virt_to_page(vdso_k_time_data);
page = vdso_data_pages + VDSO_TIME_PAGE_OFFSET;
break;
case VDSO_RNG_PAGE_OFFSET:
if (!IS_ENABLED(CONFIG_VDSO_GETRANDOM))
return VM_FAULT_SIGBUS;
page = virt_to_page(vdso_k_rng_data);
break;
case VDSO_ARCH_PAGES_START ... VDSO_ARCH_PAGES_END:
if (!IS_ENABLED(CONFIG_ARCH_HAS_VDSO_ARCH_DATA))
return VM_FAULT_SIGBUS;
page = virt_to_page(vdso_k_arch_data) + vmf->pgoff - VDSO_ARCH_PAGES_START;
break;
default:
return VM_FAULT_SIGBUS;