6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kees Cook kees@kernel.org
commit ceca927c86e6f72f72d45487a34368bc9509431d upstream.
Seen during KPTI initialization:
CFI failure at create_kpti_ng_temp_pgd+0x124/0xce8 (target: kpti_ng_pgd_alloc+0x0/0x14; expected type: 0xd61b88b6)
The call site is alloc_init_pud() at arch/arm64/mm/mmu.c:
pud_phys = pgtable_alloc(TABLE_PUD);
alloc_init_pud() has the prototype:
static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, phys_addr_t phys, pgprot_t prot, phys_addr_t (*pgtable_alloc)(enum pgtable_type), int flags)
where the pgtable_alloc() prototype is declared.
The target (kpti_ng_pgd_alloc) is used in arch/arm64/kernel/cpufeature.c:
create_kpti_ng_temp_pgd(kpti_ng_temp_pgd, __pa(alloc), KPTI_NG_TEMP_VA, PAGE_SIZE, PAGE_KERNEL, kpti_ng_pgd_alloc, 0);
which is an alias for __create_pgd_mapping_locked() with prototype:
extern __alias(__create_pgd_mapping_locked) void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, phys_addr_t (*pgtable_alloc)(enum pgtable_type), int flags);
__create_pgd_mapping_locked() passes the function pointer down:
__create_pgd_mapping_locked() -> alloc_init_p4d() -> alloc_init_pud()
But the target function (kpti_ng_pgd_alloc) has the wrong signature:
static phys_addr_t __init kpti_ng_pgd_alloc(int shift);
The "int" should be "enum pgtable_type".
To make "enum pgtable_type" available to cpufeature.c, move enum pgtable_type definition from arch/arm64/mm/mmu.c to arch/arm64/include/asm/mmu.h.
Adjust kpti_ng_pgd_alloc to use "enum pgtable_type" instead of "int". The function behavior remains identical (parameter is unused).
Fixes: c64f46ee1377 ("arm64: mm: use enum to identify pgtable level instead of *_SHIFT") Cc: stable@vger.kernel.org # 6.16.x Signed-off-by: Kees Cook kees@kernel.org Acked-by: Ard Biesheuvel ardb@kernel.org Link: https://lore.kernel.org/r/20250829190721.it.373-kees@kernel.org Reviewed-by: Ryan Roberts ryan.roberts@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/include/asm/mmu.h | 7 +++++++ arch/arm64/kernel/cpufeature.c | 5 +++-- arch/arm64/mm/mmu.c | 7 ------- 3 files changed, 10 insertions(+), 9 deletions(-)
--- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -17,6 +17,13 @@ #include <linux/refcount.h> #include <asm/cpufeature.h>
+enum pgtable_type { + TABLE_PTE, + TABLE_PMD, + TABLE_PUD, + TABLE_P4D, +}; + typedef struct { atomic64_t id; #ifdef CONFIG_COMPAT --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -84,6 +84,7 @@ #include <asm/hwcap.h> #include <asm/insn.h> #include <asm/kvm_host.h> +#include <asm/mmu.h> #include <asm/mmu_context.h> #include <asm/mte.h> #include <asm/hypervisor.h> @@ -1941,11 +1942,11 @@ static bool has_pmuv3(const struct arm64 extern void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, - phys_addr_t (*pgtable_alloc)(int), int flags); + phys_addr_t (*pgtable_alloc)(enum pgtable_type), int flags);
static phys_addr_t __initdata kpti_ng_temp_alloc;
-static phys_addr_t __init kpti_ng_pgd_alloc(int shift) +static phys_addr_t __init kpti_ng_pgd_alloc(enum pgtable_type type) { kpti_ng_temp_alloc -= PAGE_SIZE; return kpti_ng_temp_alloc; --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -46,13 +46,6 @@ #define NO_CONT_MAPPINGS BIT(1) #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */
-enum pgtable_type { - TABLE_PTE, - TABLE_PMD, - TABLE_PUD, - TABLE_P4D, -}; - u64 kimage_voffset __ro_after_init; EXPORT_SYMBOL(kimage_voffset);