Clone the implementations of strrchr() and memchr() in lib/string.c so
we can use them in the standalone zboot decompressor app. These routines
are used by the FDT handling code.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Split the efi_printk() routine into its own source file, and provide
local implementations of strlen() and strnlen() so that the standalone
zboot app can efi_err and efi_info etc.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
We will no longer be able to call into the kernel image once we merge
the decompressor with the EFI stub, so we need our own implementation of
memcmp(). Let's add the one from lib/string.c and simplify it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
In preparation for moving the EFI stub functionality into the zboot
decompressor, switch to the stub's implementation of strncmp()
unconditionally.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The stub is used in different execution environments, but on arm64,
RISC-V and LoongArch, we still use the core kernel's implementation of
memcpy and memset, as they are just a branch instruction away, and can
generally be reused even from code such as the EFI stub that runs in a
completely different address space.
KAsan complicates this slightly, resulting in the need for some hacks to
expose the uninstrumented, __ prefixed versions as the normal ones, as
the latter are instrumented to include the KAsan checks, which only work
in the core kernel.
Unfortunately, #define'ing memcpy to __memcpy when building C code does
not guarantee that no explicit memcpy() calls will be emitted. And with
the upcoming zboot support, which consists of a separate binary which
therefore needs its own implementation of memcpy/memset anyway, it's
better to provide one explicitly instead of linking to the existing one.
Given that EFI exposes implementations of memmove() and memset() via the
boot services table, let's wire those up in the appropriate way, and
drop the references to the core kernel ones.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Linux kernel Image can appear as an EFI application With appropriate
PE/COFF header fields in the beginning of the Image header. An EFI
application loader can directly load a Linux kernel Image and an EFI
stub residing in kernel can boot Linux kernel directly.
Add the necessary PE/COFF header.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20200421033336.9663-3-atish.patra@wdc.com
[ardb: - use C prefix for c.li to ensure the expected opcode is emitted
- align all image sections according to PE/COFF section alignment ]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Ard Biesheuvel