From: "Aneesh Kumar K.V" aneesh.kumar@linux.ibm.com
[ Upstream commit 7dd3a7b90bca2c12e2146a47d63cf69a2f5d7e89 ]
Powerpc architecture supports 16GB hugetlb pages with hash translation. For 4K page size, this is implemented as a hugepage directory entry at PGD level and for 64K it is implemented as a huge page pte at PUD level
With 16GB hugetlb size, offset within a page is greater than 32 bits. Hence switch to use unsigned long type when using hugepd_shift.
In order to keep things simpler, we make sure we always use unsigned long type when using hugepd_shift() even though all the hugetlb page size won't require that.
The hugetlb_free_p*d_range changes are all related to nohash usage where we can have multiple pgd entries pointing to the same hugepd entries. Hence on book3s64 where we can have > 4GB hugetlb page size we will always find more < next even if we compute the value of more correctly.
Hence there is no functional change in this patch except that it fixes the below warning.
UBSAN: shift-out-of-bounds in arch/powerpc/mm/hugetlbpage.c:499:21 shift exponent 34 is too large for 32-bit type 'int' CPU: 39 PID: 1673 Comm: a.out Not tainted 6.0.0-rc2-00327-gee88a56e8517-dirty #1 Call Trace: dump_stack_lvl+0x98/0xe0 (unreliable) ubsan_epilogue+0x18/0x70 __ubsan_handle_shift_out_of_bounds+0x1bc/0x390 hugetlb_free_pgd_range+0x5d8/0x600 free_pgtables+0x114/0x290 exit_mmap+0x150/0x550 mmput+0xcc/0x210 do_exit+0x420/0xdd0 do_group_exit+0x4c/0xd0 sys_exit_group+0x24/0x30 system_call_exception+0x250/0x600 system_call_common+0xec/0x250
Signed-off-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com [mpe: Drop generic change to be sent separately, change 1ULL to 1UL] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220908072440.258301-1-aneesh.kumar@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/mm/hugetlbpage.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index b282af39fcf6..089ad890ee36 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -391,7 +391,7 @@ static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud, * single hugepage, but all of them point to * the same kmem cache that holds the hugepte. */ - more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd)); + more = addr + (1UL << hugepd_shift(*(hugepd_t *)pmd)); if (more > next) next = more;
@@ -433,7 +433,7 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, * single hugepage, but all of them point to * the same kmem cache that holds the hugepte. */ - more = addr + (1 << hugepd_shift(*(hugepd_t *)pud)); + more = addr + (1UL << hugepd_shift(*(hugepd_t *)pud)); if (more > next) next = more;
@@ -495,7 +495,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb, * for a single hugepage, but all of them point to the * same kmem cache that holds the hugepte. */ - more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd)); + more = addr + (1UL << hugepd_shift(*(hugepd_t *)pgd)); if (more > next) next = more;