Hi On 14.04.2020 17:34, Mike Rapoport wrote: > From: Mike Rapoport <rppt****@linux*****> > > Implement primitives necessary for the 4th level folding, add walks of p4d > level where appropriate, and remove __ARCH_USE_5LEVEL_HACK. > > Signed-off-by: Mike Rapoport <rppt****@linux*****> Today I've noticed that kexec is broken on ARM 32bit. Bisecting between current linux-next and v5.7-rc1 pointed to this commit. I've tested this on Odroid XU4 and Raspberry Pi4 boards. Here is the relevant log: # kexec --kexec-syscall -l zImage --append "$(cat /proc/cmdline)" memory_range[0]:0x40000000..0xbe9fffff memory_range[0]:0x40000000..0xbe9fffff # kexec -e kexec_core: Starting new kernel 8<--- cut here --- Unable to handle kernel paging request at virtual address c010f1f4 pgd = c6817793 [c010f1f4] *pgd=4000041e(bad) Internal error: Oops: 80d [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 1329 Comm: kexec Tainted: G W 5.7.0-rc3-00127-g6cba81ed0f62 #611 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at machine_kexec+0x40/0xfc LR is at 0xffffffff pc : [<c010f0b4>] lr : [<ffffffff>] psr: 60000013 sp : ebc13e60 ip : 40008000 fp : 00000001 r10: 00000058 r9 : fee1dead r8 : 00000001 r7 : c121387c r6 : 6c224000 r5 : ece40c00 r4 : ec222000 r3 : c010f1f4 r2 : c1100000 r1 : c1100000 r0 : 418d0000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: 6bc14059 DAC: 00000051 Process kexec (pid: 1329, stack limit = 0x366bb4dc) Stack: (0xebc13e60 to 0xebc14000) ... [<c010f0b4>] (machine_kexec) from [<c01c0d84>] (kernel_kexec+0x74/0x7c) [<c01c0d84>] (kernel_kexec) from [<c014b1bc>] (__do_sys_reboot+0x1f8/0x210) [<c014b1bc>] (__do_sys_reboot) from [<c0100060>] (ret_fast_syscall+0x0/0x28) Exception stack(0xebc13fa8 to 0xebc13ff0) ... ---[ end trace 3e8d6c81723c778d ]--- 1329 Segmentation fault ./kexec -e > --- > arch/arm/include/asm/pgtable.h | 1 - > arch/arm/lib/uaccess_with_memcpy.c | 7 +++++- > arch/arm/mach-sa1100/assabet.c | 2 +- > arch/arm/mm/dump.c | 29 +++++++++++++++++----- > arch/arm/mm/fault-armv.c | 7 +++++- > arch/arm/mm/fault.c | 22 ++++++++++------ > arch/arm/mm/idmap.c | 3 ++- > arch/arm/mm/init.c | 2 +- > arch/arm/mm/ioremap.c | 12 ++++++--- > arch/arm/mm/mm.h | 2 +- > arch/arm/mm/mmu.c | 35 +++++++++++++++++++++----- > arch/arm/mm/pgd.c | 40 ++++++++++++++++++++++++------ > 12 files changed, 125 insertions(+), 37 deletions(-) > > ... Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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