Turning on -Wvla found a new VLA usage:
In file included from include/linux/kernel.h:15,
from include/asm-generic/bug.h:18,
from arch/x86/include/asm/bug.h:83,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from include/linux/mm.h:9,
from arch/x86/mm/pgtable.c:2:
arch/x86/mm/pgtable.c: In function 'pgd_alloc':
include/linux/build_bug.h:29:45: error: ISO C90 forbids variable length array
'u_pmds' [-Werror=vla]
arch/x86/mm/pgtable.c:190:34: note: in expansion of macro 'static_cpu_has'
#define PREALLOCATED_USER_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \
^~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:431:16: note: in expansion of macro
'PREALLOCATED_USER_PMDS'
pmd_t *u_pmds[PREALLOCATED_USER_PMDS];
^~~~~~~~~~~~~~~~~~~~~~
Use the actual size of the array that is used for X86_FEATURE_PTI
instead of the variable size.
Fixes: f59dbe9ca670 ("x86/pgtable/pae: Use separate kernel PMDs for user
page-table")
Fixes: 68664695ae57 ("Makefile: Globally enable VLA warning")
Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/x86/mm/pgtable.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 089e78c4effd..386b43e3e0ac 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -189,6 +189,7 @@ static void pgd_dtor(pgd_t *pgd)
*/
#define PREALLOCATED_USER_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \
KERNEL_PGD_PTRS : 0)
+#define MAX_PREALLOCATED_USER_PMDS KERNEL_PGD_PTRS
void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
{
@@ -211,6 +212,7 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t
*pmd)
/* No need to prepopulate any pagetable entries in non-PAE modes. */
#define PREALLOCATED_PMDS 0
#define PREALLOCATED_USER_PMDS 0
+#define MAX_PREALLOCATED_USER_PMDS 0
#endif /* CONFIG_X86_PAE */
static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
@@ -428,8 +430,8 @@ static inline void _pgd_free(pgd_t *pgd)
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd;
- pmd_t *u_pmds[PREALLOCATED_USER_PMDS];
- pmd_t *pmds[PREALLOCATED_PMDS];
+ pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
+ pmd_t *pmds[MAX_PREALLOCATED_USER_PMDS];
pgd = _pgd_alloc();
--
2.18.0
