mirror of
https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
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| Filename | Latest commit message | Latest commit date |
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1bef5f25a6
[ Upstream commit cef397038167ac15d085914493d6c86385773709 ] 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: |
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| .. | ||
| bitops | ||
| vdso | ||
| 4level-fixup.h | ||
| 5level-fixup.h | ||
| asm-offsets.h | ||
| asm-prototypes.h | ||
| atomic-instrumented.h | ||
| atomic-long.h | ||
| atomic.h | ||
| atomic64.h | ||
| audit_change_attr.h | ||
| audit_dir_write.h | ||
| audit_read.h | ||
| audit_signal.h | ||
| audit_write.h | ||
| barrier.h | ||
| bitops-instrumented.h | ||
| bitops.h | ||
| bitsperlong.h | ||
| bug.h | ||
| bugs.h | ||
| cache.h | ||
| cacheflush.h | ||
| checksum.h | ||
| cmpxchg-local.h | ||
| cmpxchg.h | ||
| compat.h | ||
| current.h | ||
| delay.h | ||
| device.h | ||
| div64.h | ||
| dma-contiguous.h | ||
| dma-mapping.h | ||
| dma.h | ||
| early_ioremap.h | ||
| emergency-restart.h | ||
| error-injection.h | ||
| exec.h | ||
| export.h | ||
| extable.h | ||
| fb.h | ||
| fixmap.h | ||
| flat.h | ||
| ftrace.h | ||
| futex.h | ||
| getorder.h | ||
| gpio.h | ||
| hardirq.h | ||
| hugetlb.h | ||
| hw_irq.h | ||
| ide_iops.h | ||
| int-ll64.h | ||
| io.h | ||
| ioctl.h | ||
| iomap.h | ||
| irq.h | ||
| irq_regs.h | ||
| irq_work.h | ||
| irqflags.h | ||
| Kbuild | ||
| kdebug.h | ||
| kmap_types.h | ||
| kprobes.h | ||
| kvm_para.h | ||
| linkage.h | ||
| local.h | ||
| local64.h | ||
| mcs_spinlock.h | ||
| memory_model.h | ||
| mm-arch-hooks.h | ||
| mm_hooks.h | ||
| mmiowb.h | ||
| mmiowb_types.h | ||
| mmu.h | ||
| mmu_context.h | ||
| module.h | ||
| mshyperv.h | ||
| msi.h | ||
| page.h | ||
| param.h | ||
| parport.h | ||
| pci.h | ||
| pci_iomap.h | ||
| percpu.h | ||
| pgalloc.h | ||
| pgtable-nop4d-hack.h | ||
| pgtable-nop4d.h | ||
| pgtable-nopmd.h | ||
| pgtable-nopud.h | ||
| pgtable.h | ||
| preempt.h | ||
| qrwlock.h | ||
| qrwlock_types.h | ||
| qspinlock.h | ||
| qspinlock_types.h | ||
| resource.h | ||
| seccomp.h | ||
| sections.h | ||
| serial.h | ||
| set_memory.h | ||
| shmparam.h | ||
| signal.h | ||
| simd.h | ||
| spinlock.h | ||
| statfs.h | ||
| string.h | ||
| switch_to.h | ||
| syscall.h | ||
| syscalls.h | ||
| termios-base.h | ||
| termios.h | ||
| timex.h | ||
| tlb.h | ||
| tlbflush.h | ||
| topology.h | ||
| trace_clock.h | ||
| uaccess.h | ||
| unaligned.h | ||
| user.h | ||
| vga.h | ||
| vmlinux.lds.h | ||
| vtime.h | ||
| word-at-a-time.h | ||
| xor.h | ||