On Wed, Nov 13, 2024 at 05:44:37PM +0200, Andy Shevchenko wrote: > When the kernel is built relocatable, the starting address can be > anything above 1Mb on x86. However, the startup_*() entries consider > that the minumum address for the kernel for the decompression has to > be at least LOAD_PHYSICAL_ADDR which is turn the value that is provided > as pref_address in boot protocol. The boot protocol itself says: > > This field, if nonzero, represents a preferred load address for the > kernel. A relocating bootloader should attempt to load at this > address if possible. > > Besides that the code in the kernel (arch/x86/kernel/kexec-bzimage64.c) > has these lines (in bzImage64_load() function): > > if (header->pref_address < MIN_KERNEL_LOAD_ADDR) > kbuf.buf_min = MIN_KERNEL_LOAD_ADDR; > else > kbuf.buf_min = header->pref_address; > > All that said, do the same in kexec tools. Without this patch > the relocatable kernel may end up in the memory hole that is > not enough for in-place decompression and Bad Things will happen > as it's proven on Intel Merrifield, that has a reserved memory > block starting at 64Mb. > > Note, it doesn't mean that kernel has no issues itself in this particular > stage, but at least we may work around some corner cases for kexec. > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Thanks Andy, applied.
