Hi Mike,
On 08.05.2020 19:42, Mike Rapoport wrote:
> On Fri, May 08, 2020 at 08:53:27AM +0200, Marek Szyprowski wrote:
>> On 07.05.2020 18:11, Mike Rapoport wrote:
>>> On Thu, May 07, 2020 at 02:16:56PM +0200, Marek Szyprowski wrote:
>>>> On 14.04.2020 17:34, Mike Rapoport wrote:
>>>>> From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
>>>>>
>>>>> 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@xxxxxxxxxxxxx>
>>>> 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
>>> Any chance you have the debug info in this kernel?
>>> scripts/faddr2line would come handy here.
>> # ./scripts/faddr2line --list vmlinux machine_kexec+0x40
>> machine_kexec+0x40/0xf8:
>>
>> machine_kexec at arch/arm/kernel/machine_kexec.c:182
>> 177 reboot_code_buffer =
>> page_address(image->control_code_page);
>> 178
>> 179 /* Prepare parameters for reboot_code_buffer*/
>> 180 set_kernel_text_rw();
>> 181 kexec_start_address = image->start;
>> >182< kexec_indirection_page = page_list;
>> 183 kexec_mach_type = machine_arch_type;
>> 184 kexec_boot_atags = image->arch.kernel_r2;
>> 185
>> 186 /* copy our kernel relocation code to the control code
>> page */
>> 187 reboot_entry = fncpy(reboot_code_buffer,
> Can you please try the patch below:
>
> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> index 963b5284d284..f86b3d17928e 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -571,7 +571,7 @@ static inline void section_update(unsigned long addr, pmdval_t mask,
> {
> pmd_t *pmd;
>
> - pmd = pmd_off_k(addr);
> + pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
>
> #ifdef CONFIG_ARM_LPAE
> pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
This fixes kexec issue! Thanks!
Feel free to add:
Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Fixes: 218f1c390557 ("arm: add support for folded p4d page tables")
Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
