Re: [PATCH stable 5.10 0/3] ARM FDT relocation backports

[Ard Biesheuvel]

On Sun, 9 May 2021 at 19:30, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
>
> Hi Greg, Sasha,
>
> These patches were not marked with a Fixes: tag but they do fix booting
> ARM 32-bit platforms that have specific FDT placement and would cause
> boot failures like these:
>

I don't have any objections to backporting these changes, but it would
be helpful if you could explain why this is a regression. Also, you'll
need to pull in the following patch as well

10fce53c0ef8 ARM: 9027/1: head.S: explicitly map DT even if it lives
in the first physical section


> [    0.000000] 8<--- cut here ---
> [    0.000000] Unable to handle kernel paging request at virtual address
> ffa14000
> [    0.000000] pgd = (ptrval)
> [    0.000000] [ffa14000] *pgd=80000040007003, *pmd=00000000
> [    0.000000] Internal error: Oops: 206 [#1] SMP ARM
> [    0.000000] Modules linked in:
> [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.85-1.0 #1
> [    0.000000] Hardware name: Broadcom STB (Flattened Device Tree)
> [    0.000000] PC is at fdt_check_header+0xc/0x21c
> [    0.000000] LR is at __unflatten_device_tree+0x7c/0x2f8
> [    0.000000] pc : [<c0d30e44>]    lr : [<c0a6c0fc>]    psr: 600000d3
> [    0.000000] sp : c1401eac  ip : c1401ec8  fp : c1401ec4
> [    0.000000] r10: 00000000  r9 : c150523c  r8 : 00000000
> [    0.000000] r7 : c124eab4  r6 : ffa14000  r5 : 00000000  r4 :
> c14ba920
> [    0.000000] r3 : 00000000  r2 : c150523c  r1 : 00000000  r0 :
> ffa14000
> [    0.000000] Flags: nZCv  IRQs off  FIQs off  Mode SVC_32  ISA ARM
> Segment user
> [    0.000000] Control: 30c5383d  Table: 40003000  DAC: fffffffd
> [    0.000000] Process swapper (pid: 0, stack limit = 0x(ptrval))
> [    0.000000] Stack: (0xc1401eac to 0xc1402000)
> [    0.000000] 1ea0:                            c14ba920 00000000
> ffa14000 c1401ef4 c1401ec8
> [    0.000000] 1ec0: c0a6c0fc c0d30e44 c124eab4 c124eab4 00000000
> c14ebfc0 c140e5b8 00000000
> [    0.000000] 1ee0: 00000001 c126f5a0 c1401f14 c1401ef8 c1250064
> c0a6c08c 00000000 c1401f08
> [    0.000000] 1f00: c022ddac c140ce80 c1401f9c c1401f18 c120506c
> c125002c 00000000 00000000
> [    0.000000] 1f20: 00000000 00000000 ffffffff c1401f94 c1401f6c
> c1406308 3fffffff 00000001
> [    0.000000] 1f40: 00000000 00000001 c1432b58 c14ca180 c1213ca4
> c1406308 c1406300 30c0387d
> [    0.000000] 1f60: c1401f8c c1401f70 c028e0ec 00000000 c1401f94
> c1406308 c1406300 30c0387d
> [    0.000000] 1f80: 00000000 7fa14000 420f1000 30c5387d c1401ff4
> c1401fa0 c1200c98 c120467c
> [    0.000000] 1fa0: 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 c127fa44
> [    0.000000] 1fc0: 00000000 00000000 00000000 c1200330 00000000
> 30c0387d ffffffff 7fa14000
> [    0.000000] 1fe0: 420f1000 30c5387d 00000000 c1401ff8 00000000
> c1200c28 00000000 00000000
> [    0.000000] Backtrace:
> [    0.000000] [<c0d30e38>] (fdt_check_header) from [<c0a6c0fc>]
> (__unflatten_device_tree+0x7c/0x2f8)
> [    0.000000]  r6:ffa14000 r5:00000000 r4:c14ba920
> [    0.000000] [<c0a6c080>] (__unflatten_device_tree) from [<c1250064>]
> (unflatten_device_tree+0x44/0x54)
> [    0.000000]  r10:c126f5a0 r9:00000001 r8:00000000 r7:c140e5b8
> r6:c14ebfc0 r5:00000000
> [    0.000000]  r4:c124eab4 r3:c124eab4
> [    0.000000] [<c1250020>] (unflatten_device_tree) from [<c120506c>]
> (setup_arch+0x9fc/0xc84)
> [    0.000000]  r4:c140ce80
> [    0.000000] [<c1204670>] (setup_arch) from [<c1200c98>]
> (start_kernel+0x7c/0x540)
> [    0.000000]  r10:30c5387d r9:420f1000 r8:7fa14000 r7:00000000
> r6:30c0387d r5:c1406300
> [    0.000000]  r4:c1406308
> [    0.000000] [<c1200c1c>] (start_kernel) from [<00000000>] (0x0)
> [    0.000000]  r10:30c5387d r9:420f1000 r8:7fa14000 r7:ffffffff
> r6:30c0387d r5:00000000
> [    0.000000]  r4:c1200330
> [    0.000000] Code: e89da800 e1a0c00d e92dd870 e24cb004 (e5d03000)
> [    0.000000] random: get_random_bytes called from
> print_oops_end_marker+0x50/0x58 with crng_init=0
> [    0.000000] ---[ end trace f34b4929828506c1 ]---
> [    0.000000] Kernel panic - not syncing: Attempted to kill the idle
> task!
> [    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill
> the idle task! ]---
>
>
> Ard Biesheuvel (3):
>   ARM: 9011/1: centralize phys-to-virt conversion of DT/ATAGS address
>   ARM: 9012/1: move device tree mapping out of linear region
>   ARM: 9020/1: mm: use correct section size macro to describe the FDT
>     virtual address
>
>  Documentation/arm/memory.rst  |  7 ++++++-
>  arch/arm/include/asm/fixmap.h |  2 +-
>  arch/arm/include/asm/memory.h |  5 +++++
>  arch/arm/include/asm/prom.h   |  4 ++--
>  arch/arm/kernel/atags.h       |  4 ++--
>  arch/arm/kernel/atags_parse.c |  6 +++---
>  arch/arm/kernel/devtree.c     |  6 +++---
>  arch/arm/kernel/head.S        |  5 ++---
>  arch/arm/kernel/setup.c       | 19 ++++++++++++++-----
>  arch/arm/mm/init.c            |  1 -
>  arch/arm/mm/mmu.c             | 20 ++++++++++++++------
>  arch/arm/mm/pv-fixup-asm.S    |  4 ++--
>  12 files changed, 54 insertions(+), 29 deletions(-)
>
> --
> 2.25.1
>