riscv: module: move find_section to module.h

Move find_section() to module.h so that the implementation can be shared
by the alternatives code. This will allow us to use alternatives in
the vdso.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/r/20230128172856.3814-8-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h>

As the bug report [1] pointed out, <linux/vermagic.h> must be included
after <linux/module.h>.

I believe we should not impose any include order restriction. We often
sort include directives alphabetically, but it is just coding style
convention. Technically, we can include header files in any order by
making every header self-contained.

Currently, arch-specific MODULE_ARCH_VERMAGIC is defined in
<asm/module.h>, which is not included from <linux/vermagic.h>.

Hence, the straight-forward fix-up would be as follows:

|--- a/include/linux/vermagic.h
|+++ b/include/linux/vermagic.h
|@@ -1,5 +1,6 @@
| /* SPDX-License-Identifier: GPL-2.0 */
| #include <generated/utsrelease.h>
|+#include <linux/module.h>
|
| /* Simply sanity version stamp for modules. */
| #ifdef CONFIG_SMP

This works enough, but for further cleanups, I split MODULE_ARCH_VERMAGIC
definitions into <asm/vermagic.h>.

With this, <linux/module.h> and <linux/vermagic.h> will be orthogonal,
and the location of MODULE_ARCH_VERMAGIC definitions will be consistent.

For arc and ia64, MODULE_PROC_FAMILY is only used for defining
MODULE_ARCH_VERMAGIC. I squashed it.

For hexagon, nds32, and xtensa, I removed <asm/modules.h> entirely
because they contained nothing but MODULE_ARCH_VERMAGIC definition.
Kbuild will automatically generate <asm/modules.h> at build-time,
wrapping <asm-generic/module.h>.

[1] https://lore.kernel.org/lkml/20200411155623.GA22175@zn.tnic

Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>

RISC-V: Support MODULE_SECTIONS mechanism on RV32

This patch supports dynamic generate got and plt sections mechanism on
rv32. It contains the modification as follows:
- Always enable MODULE_SECTIONS (both rv64 and rv32)
- Change the fixed size type.

This patch had been tested by following modules:

btrfs 6795991 0 - Live 0xa544b000
test_static_keys 17304 0 - Live 0xa28be000
zstd_compress 1198986 1 btrfs, Live 0xa2a25000
zstd_decompress 608112 1 btrfs, Live 0xa24e7000
lzo 8787 0 - Live 0xa2049000
xor 27461 1 btrfs, Live 0xa2041000
zram 78849 0 - Live 0xa2276000
netdevsim 55909 0 - Live 0xa202d000
tun 211534 0 - Live 0xa21b5000
fuse 566049 0 - Live 0xa25fb000
nfs_layout_flexfiles 192597 0 - Live 0xa229b000
ramoops 74895 0 - Live 0xa2019000
xfs 3973221 0 - Live 0xa507f000
libcrc32c 3053 2 btrfs,xfs, Live 0xa34af000
lzo_compress 17302 2 btrfs,lzo, Live 0xa347d000
lzo_decompress 7178 2 btrfs,lzo, Live 0xa3451000
raid6_pq 142086 1 btrfs, Live 0xa33a4000
reed_solomon 31022 1 ramoops, Live 0xa31eb000
test_bitmap 3734 0 - Live 0xa31af000
test_bpf 1588736 0 - Live 0xa2c11000
test_kmod 41161 0 - Live 0xa29f8000
test_module 1356 0 - Live 0xa299e000
test_printf 6024 0 [permanent], Live 0xa2971000
test_static_key_base 5797 1 test_static_keys, Live 0xa2931000
test_user_copy 4382 0 - Live 0xa28c9000
xxhash 70501 2 zstd_compress,zstd_decompress, Live 0xa2055000

Signed-off-by: Zong Li <zong@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

riscv: fix warning in arch/riscv/include/asm/module.h

Fixes warning: 'struct module' declared inside parameter list will not be
visible outside of this definition or declaration

Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

RISC-V: Add section of GOT.PLT for kernel module

Separate the function symbol address from .plt to .got.plt section.

The original plt entry has trampoline code with symbol address,
there is a 32-bit padding bwtween jar instruction and symbol address.

Extract the symbol address to .got.plt to reduce the module size.

Signed-off-by: Zong Li <zong@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

RISC-V: Add sections of PLT and GOT for kernel module

The address of external symbols will locate more than 32-bit offset
in 64-bit kernel with sv39 or sv48 virtual addressing.

Module loader emits the GOT and PLT entries for data symbols and
function symbols respectively.

The PLT entry is a trampoline code for jumping to the 64-bit
real address. The GOT entry is just the data symbol address.

Signed-off-by: Zong Li <zong@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>