Re: [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel

Chao Fan
2019-03-29T09:21:02Z

On Fri, Mar 29, 2019 at 05:16:55PM +0800, bhe@redhat.com wrote:
>On 03/29/19 at 04:29pm, Chao Fan wrote:
>> On Fri, Mar 29, 2019 at 07:20:38AM +0000, Junichi Nomura wrote:
>> >Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
>> >boot_params") broke kexec boot on EFI systems. efi_get_rsdp_addr()
>> >in the early parsing code tries to search RSDP from EFI table but
>> >that will crash because the table address is virtual when the kernel
>> >was booted by kexec.
>> [...]
>> >- guid = tbl->guid;
>> >- table = tbl->table;
>> >- }
>> >-
>> >- if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
>> >- rsdp_addr = table;
>> >- else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
>> >- return table;
>> >- }
>> >+ return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
>> >+#else
>> >+ return 0;
>> > #endif
>> >- return rsdp_addr;
>>
>> I remeber the rsdp_addr is defined before #ifdef CONFIG_EFI
>> If so, you don't need
>> #else
>> return 0;
>
>it doesn't change the old logic. Junichi moved rsdp_addr definition inside
>the CONFIG_EFI iedeffery block.

Yes, got it. Thanks for your explain.

Thanks,
Chao Fan
>>
>> BY the way, what's your patch based on? I like add patch on my local
>> branch and then review code, but failed.
>> I try to use 'patch -p1 <' your patch to the latest tip master branch,
>> but failed.
>>
>> Thanks,
>> Chao Fan
>>
>> > }
>> >
>> > static u8 compute_checksum(u8 *buffer, u32 length)
>> >@@ -221,6 +284,9 @@ acpi_physical_address get_rsdp_addr(void)
>> > pa = boot_params->acpi_rsdp_addr;
>> >
>> > if (!pa)
>> >+ pa = kexec_get_rsdp_addr();
>> >+
>> >+ if (!pa)
>> > pa = efi_get_rsdp_addr();
>> >
>> > if (!pa)
>> >
>> >
>>
>>
>
>