kexec: Fix kexec_file_load for llvm16 with PGO

When upreving llvm I realised that kexec stopped working on my test
platform.

The reason seems to be that due to PGO there are multiple .text sections
on the purgatory, and kexec does not supports that.

To: Eric Biederman <ebiederm@xmission.com>
To: Philipp Rudo <prudo@linux.vnet.ibm.com>
To: Dave Young <dyoung@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
To: Thomas Gleixner <tglx@linutronix.de>
To: Ingo Molnar <mingo@redhat.com>
To: Borislav Petkov <bp@alien8.de>
To: Dave Hansen <dave.hansen@linux.intel.com>
To: x86@kernel.org
To: "H. Peter Anvin" <hpa@zytor.com>
To: Nathan Chancellor <nathan@kernel.org>
To: Tom Rix <trix@redhat.com>
To: Michael Ellerman <mpe@ellerman.id.au>
To: Nicholas Piggin <npiggin@gmail.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Paul Walmsley <paul.walmsley@sifive.com>
To: Palmer Dabbelt <palmer@dabbelt.com>
To: Albert Ou <aou@eecs.berkeley.edu>
Cc: Baoquan He <bhe@redhat.com>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: kexec@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Ross Zwisler <zwisler@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: llvm@lists.linux.dev
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
Changes in v7:
- Fix $SUBJECT of riscv patch
- Rename PGO as Profile-guided optimization
- Link to v6: https://lore.kernel.org/r/20230321-kexec_clang16-v6-0-a2255e81ab45@chromium.org

Changes in v6:
- Replace linker script with Makefile rule. Thanks Nick
- Link to v5: https://lore.kernel.org/r/20230321-kexec_clang16-v5-0-5563bf7c4173@chromium.org

Changes in v5:
- Add warning when multiple text sections are found. Thanks Simon!
- Add Fixes tag.
- Link to v4: https://lore.kernel.org/r/20230321-kexec_clang16-v4-0-1340518f98e9@chromium.org

Changes in v4:
- Add Cc: stable
- Add linker script for x86
- Add a warning when the kernel image has overlapping sections.
- Link to v3: https://lore.kernel.org/r/20230321-kexec_clang16-v3-0-5f016c8d0e87@chromium.org

Changes in v3:
- Fix initial value. Thanks Ross!
- Link to v2: https://lore.kernel.org/r/20230321-kexec_clang16-v2-0-d10e5d517869@chromium.org

Changes in v2:
- Fix if condition. Thanks Steven!.
- Update Philipp email. Thanks Baoquan.
- Link to v1: https://lore.kernel.org/r/20230321-kexec_clang16-v1-0-a768fc2c7c4d@chromium.org

---
Ricardo Ribalda (4):
      kexec: Support purgatories with .text.hot sections
      x86/purgatory: Remove PGO flags
      powerpc/purgatory: Remove PGO flags
      riscv/purgatory: Remove PGO flags

 arch/powerpc/purgatory/Makefile |  5 +++++
 arch/riscv/purgatory/Makefile   |  5 +++++
 arch/x86/purgatory/Makefile     |  5 +++++
 kernel/kexec_file.c             | 14 +++++++++++++-
 4 files changed, 28 insertions(+), 1 deletion(-)
---
base-commit: 58390c8ce1bddb6c623f62e7ed36383e7fa5c02f
change-id: 20230321-kexec_clang16-4510c23d129c

Best regards,