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Arnd Bergmann 1bef5f25a6 arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed 
[ Upstream commit cef3970381 ]

Stefan Agner reported a bug when using zsram on 32-bit Arm machines
with RAM above the 4GB address boundary:

  Unable to handle kernel NULL pointer dereference at virtual address 00000000
  pgd = a27bd01c
  [00000000] *pgd=236a0003, *pmd=1ffa64003
  Internal error: Oops: 207 [#1] SMP ARM
  Modules linked in: mdio_bcm_unimac(+) brcmfmac cfg80211 brcmutil raspberrypi_hwmon hci_uart crc32_arm_ce bcm2711_thermal phy_generic genet
  CPU: 0 PID: 123 Comm: mkfs.ext4 Not tainted 5.9.6 #1
  Hardware name: BCM2711
  PC is at zs_map_object+0x94/0x338
  LR is at zram_bvec_rw.constprop.0+0x330/0xa64
  pc : [<c0602b38>]    lr : [<c0bda6a0>]    psr: 60000013
  sp : e376bbe0  ip : 00000000  fp : c1e2921c
  r10: 00000002  r9 : c1dda730  r8 : 00000000
  r7 : e8ff7a00  r6 : 00000000  r5 : 02f9ffa0  r4 : e3710000
  r3 : 000fdffe  r2 : c1e0ce80  r1 : ebf979a0  r0 : 00000000
  Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
  Control: 30c5383d  Table: 235c2a80  DAC: fffffffd
  Process mkfs.ext4 (pid: 123, stack limit = 0x495a22e6)
  Stack: (0xe376bbe0 to 0xe376c000)

As it turns out, zsram needs to know the maximum memory size, which
is defined in MAX_PHYSMEM_BITS when CONFIG_SPARSEMEM is set, or in
MAX_POSSIBLE_PHYSMEM_BITS on the x86 architecture.

The same problem will be hit on all 32-bit architectures that have a
physical address space larger than 4GB and happen to not enable sparsemem
and include asm/sparsemem.h from asm/pgtable.h.

After the initial discussion, I suggested just always defining
MAX_POSSIBLE_PHYSMEM_BITS whenever CONFIG_PHYS_ADDR_T_64BIT is
set, or provoking a build error otherwise. This addresses all
configurations that can currently have this runtime bug, but
leaves all other configurations unchanged.

I looked up the possible number of bits in source code and
datasheets, here is what I found:

 - on ARC, CONFIG_ARC_HAS_PAE40 controls whether 32 or 40 bits are used
 - on ARM, CONFIG_LPAE enables 40 bit addressing, without it we never
   support more than 32 bits, even though supersections in theory allow
   up to 40 bits as well.
 - on MIPS, some MIPS32r1 or later chips support 36 bits, and MIPS32r5
   XPA supports up to 60 bits in theory, but 40 bits are more than
   anyone will ever ship
 - On PowerPC, there are three different implementations of 36 bit
   addressing, but 32-bit is used without CONFIG_PTE_64BIT
 - On RISC-V, the normal page table format can support 34 bit
   addressing. There is no highmem support on RISC-V, so anything
   above 2GB is unused, but it might be useful to eventually support
   CONFIG_ZRAM for high pages.

Fixes: 61989a80fb ("staging: zsmalloc: zsmalloc memory allocation library")
Fixes: 02390b87a9 ("mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS")
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/linux-mm/bdfa44bf1c570b05d6c70898e2bbb0acf234ecdf.1604762181.git.stefan@agner.ch/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2020-12-02 08:49:50 +01:00
..
bitops fls: change parameter to unsigned int 2019-01-04 13:13:46 -08:00
vdso lib/vdso: Make __arch_update_vdso_data() logic understandable 2020-03-05 16:43:49 +01:00
4level-fixup.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-11-02 08:31:52 +01:00
5level-fixup.h include/asm-generic/5level-fixup.h: fix variable 'p4d' set but not used 2019-08-13 16:06:52 -07:00
Kbuild asm-generic: make simd.h a mandatory include/asm header 2019-07-31 21:29:24 +10:00
asm-offsets.h asm-generic: Add common asm-offsets.h 2015-06-23 13:35:49 +09:00
asm-prototypes.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
atomic-instrumented.h locking/atomics: Check atomic headers with sha1sum 2019-02-13 08:07:31 +01:00
atomic-long.h locking/atomics: Check atomic headers with sha1sum 2019-02-13 08:07:31 +01:00
atomic.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
atomic64.h locking/atomic: Use s64 for atomic64 2019-06-03 12:32:56 +02:00
audit_change_attr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_dir_write.h audit: Avoid build failures on systems without renameat 2018-01-30 19:07:54 -08:00
audit_read.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_signal.h
…
audit_write.h audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
barrier.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
bitops-instrumented.h asm-generic, x86: add bitops instrumentation for KASAN 2019-07-12 11:05:42 -07:00
bitops.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bitsperlong.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bug.h bug: move WARN_ON() "cut here" into exception handler 2019-09-25 17:51:41 -07:00
bugs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cache.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cacheflush.h asm-generic/nds32: don't redefine cacheflush primitives 2020-01-17 19:48:43 +01:00
checksum.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cmpxchg-local.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cmpxchg.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat.h asm-generic: Move common compat types to asm-generic/compat.h 2018-08-29 15:42:20 +02:00
current.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
delay.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
device.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
div64.h asm-generic changes for v5.4 2019-09-17 14:30:30 -07:00
dma-contiguous.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dma-mapping.h dma-mapping: bypass indirect calls for dma-direct 2018-12-13 21:06:18 +01:00
dma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
early_ioremap.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
emergency-restart.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
error-injection.h error-injection: Consolidate override function definition 2019-08-07 13:52:43 +01:00
exec.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
export.h module: Remove leftover '#undef' from export header 2019-09-12 15:29:46 +02:00
extable.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fb.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fixmap.h mm: introduce common STRUCT_PAGE_MAX_SHIFT define 2018-12-14 15:05:45 -08:00
flat.h binfmt_flat: remove the persistent argument from flat_get_addr_from_rp 2019-06-24 09:16:47 +10:00
ftrace.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
futex.h futex: Cleanup generic SMP variant of arch_futex_atomic_op_inuser() 2019-07-22 11:20:10 +02:00
getorder.h asm-generic: fix -Wtype-limits compiler warnings 2019-08-03 07:02:01 -07:00
gpio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hardirq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hugetlb.h hugetlb: allow to free gigantic pages regardless of the configuration 2019-05-14 09:47:47 -07:00
hw_irq.h
…
ide_iops.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
int-ll64.h int-ll64.h: define u{8,16,32,64} and s{8,16,32,64} based on uapi header 2018-06-07 17:34:38 -07:00
io.h asm-generic: don't provide __ioremap 2019-08-30 21:46:27 +02:00
ioctl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap.h iomap: introduce io{read|write}64_{lo_hi|hi_lo} 2019-01-22 13:39:59 +01:00
irq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq_regs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
irq_work.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irqflags.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kdebug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kmap_types.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kprobes.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kvm_para.h KVM: Introduce paravirtualization hints and KVM_HINTS_DEDICATED 2018-03-06 18:40:44 +01:00
linkage.h
…
local.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
local64.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mcs_spinlock.h locking/mcs: Allow architecture specific asm files to be used for contended case 2014-02-09 21:18:52 +01:00
memory_model.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm-arch-hooks.h mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
mm_hooks.h x86/mpx, mm/core: Fix recursive munmap() corruption 2019-05-09 10:37:17 +02:00
mmiowb.h asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible() 2020-07-29 10:18:40 +02:00
mmiowb_types.h asm-generic/mmiowb: Add generic implementation of mmiowb() tracking 2019-04-08 11:59:39 +01:00
mmu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mmu_context.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
module.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mshyperv.h x86/Hyper-V: Report crash data in die() when panic_on_oops is set 2020-04-23 10:36:24 +02:00
msi.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page.h asm-generic/page.h: fix typo in #error text requiring a real asm/page.h 2019-02-22 21:53:25 +01:00
param.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
parport.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci.h PCI: remove PCI_DMA_BUS_IS_PHYS 2018-05-07 07:15:41 +02:00
pci_iomap.h mn10300: Remove the architecture 2018-03-09 23:19:56 +01:00
percpu.h percpu: remove PER_CPU_DEF_ATTRIBUTES macro 2018-10-31 08:54:14 -07:00
pgalloc.h mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
pgtable-nop4d-hack.h x86/mm: Validate kernel_physical_mapping_init() PTE population 2018-12-05 09:03:06 +01:00
pgtable-nop4d.h x86/mm: Validate kernel_physical_mapping_init() PTE population 2018-12-05 09:03:06 +01:00
pgtable-nopmd.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-11-02 08:31:52 +01:00
pgtable-nopud.h x86/mm: Validate kernel_physical_mapping_init() PTE population 2018-12-05 09:03:06 +01:00
pgtable.h arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed 2020-12-02 08:49:50 +01:00
preempt.h sched/preempt: Use CONFIG_PREEMPTION where appropriate 2019-07-31 19:03:34 +02:00
qrwlock.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qrwlock_types.h locking/qrwlock: include asm/byteorder.h as needed 2018-02-06 10:28:58 +01:00
qspinlock.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qspinlock_types.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
resource.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
seccomp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sections.h locking/lockdep: check for freed initmem in static_obj() 2019-04-29 10:47:10 +02:00
serial.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
set_memory.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
shmparam.h treewide: remove SPDX "WITH Linux-syscall-note" from kernel-space headers 2019-05-14 19:52:48 -07:00
signal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
simd.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
spinlock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
statfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
string.h
…
switch_to.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
syscall.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193 2019-05-30 11:29:21 -07:00
syscalls.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
termios-base.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
termios.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
timex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tlb.h mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush 2020-02-11 04:35:42 -08:00
tlbflush.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
topology.h include/asm-generic/topology.h: guard cpumask_of_node() macro argument 2020-06-03 08:21:27 +02:00
trace_clock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
uaccess.h asm-generic: optimize generic uaccess for 8-byte loads and stores 2019-04-23 21:51:41 +02:00
unaligned.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
user.h asm-generic/user.h: Fix spelling in comment 2011-03-01 15:49:39 +01:00
vga.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmlinux.lds.h bpf: Prevent .BTF section elimination 2020-10-14 10:32:58 +02:00
vtime.h include/asm-generic/vtime.h: avoid zero-length file 2013-09-30 14:31:02 -07:00
word-at-a-time.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xor.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00