i386-pc (normal and PXE): the core image size (compressed) is limited by 458240 bytes.
kernel.img (.text + .data + .bss, uncompressed) is limited by 392704 bytes.
module size (uncompressed) + kernel.img (.text + .data, uncompressed) is limited by the size of contiguous chunk at 1M address.
sparc64-ieee1275: kernel.img (.text + .data + .bss) + modules + 256K (stack) + 2M (heap) is limited by space available at 0x4400. On most platforms it’s just 3 or 4M since ieee1275 maps only so much.
i386-ieee1275: kernel.img (.text + .data + .bss) + modules is limited by memory available at 0x10000, at most 596K
Lightly limited platforms:
*-xen: limited only by address space and RAM size.
i386-qemu: kernel.img (.text + .data + .bss) is limited by 392704 bytes.
(core.img would be limited by ROM size but it’s unlimited on qemu
All EFI platforms: limited by contiguous RAM size and possibly firmware bugs
Coreboot and multiboot. kernel.img (.text + .data + .bss) is limited by 392704 bytes.
module size is limited by the size of contiguous chunk at 1M address.
mipsel-loongson (ELF), mips(el)-qemu_mips (ELF): if uncompressed:
kernel.img (.text + .data) + modules is limited by the space from 80200000 forward
if compressed:
kernel.img (.text + .data, uncompressed) + modules (uncompressed)
+ (modules + kernel.img (.text + .data)) (compressed)
+ decompressor is limited by the space from 80200000 forward
mipsel-loongson (Flash), mips(el)-qemu_mips (Flash): kernel.img (.text + .data) + modules is limited by the space from 80200000 forward
core.img (final) is limited by flash size (512K on yeeloong and fulooong)
mips-arc: if uncompressed:
kernel.img (.text + .data) is limited by the space from 8bd00000 forward
modules + dummy decompressor is limited by the space from 8bd00000 backward
if compressed:
kernel.img (.text + .data, uncompressed) is limited by the space from 8bd00000 forward
modules (uncompressed) + (modules + kernel.img (.text + .data)) (compressed, aligned to 1M)
+ 1M (decompressor + scratch space) is limited by the space from 8bd00000 backward
powerpc-ieee1275: kernel.img (.text + .data + .bss) + modules is limited by space available at 0x200000