On 07/26/2018 04:50 PM, Kirill A. Shutemov wrote:
2. reading from memory which may be reserved in case of EFI systems:
ebda_start = *(unsigned short *)0x40e << 4;
bios_start = *(unsigned short *)0x413 << 10;
Also, on EFI system without CSM it will results in all zeros. Which will
place trampoline_start to 0x9d000. And it also may be reserved memory. In
fact I have such system and it is causes instant reboot (when code starts
copying to "trampoline_start").
Could you show dmesg from such system?
Sure, here it is (please note than not both pages are reserved but only
second one: 0x9e000-0x9ffff):
Well. That's bad.
I don't see much options but parse e820 in decompression code. I hoped to
avoid this.
Let me see what I can do there.
Just in case of UEFI (I don't know much about BIOS and kexec):
register RSI (right before call paging_prepare) will contains pointer to
"struct boot_params" (returned by function efi_main() in eboot.c).
There are fields e820_table and e820_entries.
