powerpc: Move script to check relocations at compile time in scripts/

Relocating kernel at runtime is done very early in the boot process, so
it is not convenient to check for relocations there and react in case a
relocation was not expected.

Powerpc architecture has a script that allows to check at compile time
for such unexpected relocations: extract the common logic to scripts/
so that other architectures can take advantage of it.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Reviewed-by: Anup Patel <anup@brainfault.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lore.kernel.org/r/20230329045329.64565-5-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

powerpc/64: Add UADDR64 relocation support

When ld detects unaligned relocations, it emits R_PPC64_UADDR64
relocations instead of R_PPC64_RELATIVE. Currently R_PPC64_UADDR64 are
detected by arch/powerpc/tools/relocs_check.sh and expected not to work.
Below is a simple chunk to trigger this behaviour (this disables
optimization for the demonstration purposes only, this also happens with
-O1/-O2 when CONFIG_PRINTK_INDEX=y, for example):

\#pragma GCC push_options
\#pragma GCC optimize ("O0")
struct entry {
const char *file;
int line;
} __attribute__((packed));
static const struct entry e1 = { .file = __FILE__, .line = __LINE__ };
static const struct entry e2 = { .file = __FILE__, .line = __LINE__ };
...
prom_printf("e1=%s %lx %lx\n", e1.file, (unsigned long) e1.file, mfmsr());
prom_printf("e2=%s %lx\n", e2.file, (unsigned long) e2.file);
\#pragma GCC pop_options

This adds support for UADDR64 for 64bit. This reuses __dynamic_symtab
from the 32bit code which supports more relocation types already.

Because RELACOUNT includes only R_PPC64_RELATIVE, this replaces it with
RELASZ which is the size of all relocation records.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220309061822.168173-1-aik@ozlabs.ru

powerpc: Do not consider weak unresolved symbol relocations as bad

Commit 8580ac9404f6 ("bpf: Process in-kernel BTF") introduced two weak
symbols that may be unresolved at link time which result in an absolute
relocation to 0. relocs_check.sh emits the following warning:

"WARNING: 2 bad relocations
c000000001a41478 R_PPC64_ADDR64 _binary__btf_vmlinux_bin_start
c000000001a41480 R_PPC64_ADDR64 _binary__btf_vmlinux_bin_end"

whereas those relocations are legitimate even for a relocatable kernel
compiled with -pie option.

relocs_check.sh already excluded some weak unresolved symbols explicitly:
remove those hardcoded symbols and add some logic that parses the symbols
using nm, retrieves all the weak unresolved symbols and excludes those from
the list of the potential bad relocations.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200118170335.21440-1-alex@ghiti.fr

powerpc/tools: Don't quote $objdump in scripts

Some of our scripts are passed $objdump and then call it as
"$objdump". This doesn't work if it contains spaces because we're
using ccache, for example you get errors such as:

./arch/powerpc/tools/relocs_check.sh: line 48: ccache ppc64le-objdump: No such file or directory
./arch/powerpc/tools/unrel_branch_check.sh: line 26: ccache ppc64le-objdump: No such file or directory

Fix it by not quoting the string when we expand it, allowing the shell
to do the right thing for us.

Fixes: a71aa05e1416 ("powerpc: Convert relocs_check to a shell script using grep")
Fixes: 4ea80652dc75 ("powerpc/64s: Tool to flag direct branches from unrelocated interrupt vectors")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191024004730.32135-1-mpe@ellerman.id.au

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

powerpc: Add arch/powerpc/tools directory

Move a couple of existing scripts under there. Remove scripts directory:
a script is a tool, a tool is not a script.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>