linux-kernel - [PATCH v3 0/7] powerpc/crash: use generic crashkernel reservation

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Message-ID: <20250131113830.925179-1-sourabhjain@linux.ibm.com>
Date: Fri, 31 Jan 2025 17:08:23 +0530
From: Sourabh Jain <sourabhjain@...ux.ibm.com>
To: linuxppc-dev@...ts.ozlabs.org
Cc: Sourabh Jain <sourabhjain@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>, Baoquan he <bhe@...hat.com>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 0/7] powerpc/crash: use generic crashkernel reservation

Commit 0ab97169aa05 ("crash_core: add generic function to do
reservation") added a generic function to reserve crashkernel memory.
So let's use the same function on powerpc and remove the
architecture-specific code that essentially does the same thing.

The generic crashkernel reservation also provides a way to split the
crashkernel reservation into high and low memory reservations, which can
be enabled for powerpc in the future.

Additionally move powerpc to use generic APIs to locate memory hole for
kexec segments while loading kdump kernel.

Patch series summary:
=====================
Patch 1-3: generic changes
Patch 4-7: powerpc changes

Changelog:

v1:
 https://lore.kernel.org/all/20241217064613.1042866-1-sourabhjain@linux.ibm.com/

v1 Resend:
 https://lore.kernel.org/all/20250108101458.406806-1-sourabhjain@linux.ibm.com/
 - Rebased on top of 6.13-rc6

v2:
 https://lore.kernel.org/all/20250121115442.1278458-1-sourabhjain@linux.ibm.com/
 - 01/06 new patch, fixes a bug with ELF load address
   It was posted in community as individual path but
   since it align with this patch series so include here:
   https://lore.kernel.org/all/20241210091314.185785-1-sourabhjain@linux.ibm.com/
 - Fixed a typo 06/06

 - Added Acked-by and Reviewed-by tags

 - Rebased it on 6.13

 - It was suggested to try HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY and
   see if 03/06 patch can be avoided:
   https://lore.kernel.org/all/Z35gnO2N%2FLFt1E7E@MiWiFi-R3L-srv/
   But after adding HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY the issue
   persisted and kernel prints below logs on boot:
   ...snip ...

v3:
 - Split the patch that adds the arch hook to handle special regions in
   crashkernel reserved: Now 03/07 and 04/07.

 - Dropped the patch that adds arch hooks to skip `Crash Kernel` from
   iomem_resource (/proc/iomem). Instead, a patch is added to include
   both `System RAM` and `Crash Kernel` memory ranges in iomem_resource: 06/07.

 - Rearranged the patches to ensure that generic patches come first,
   followed by PowerPC-specific patches.

 - Added Acked-by tags.

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Baoquan he <bhe@...hat.com>
Cc: Hari Bathini <hbathini@...ux.ibm.com>
CC: Madhavan Srinivasan <maddy@...ux.ibm.com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: kexec@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Cc: sourabhjain@...ux.ibm.com

Sourabh Jain (7):
  kexec: Initialize ELF lowest address to ULONG_MAX
  crash: remove an unused argument from reserve_crashkernel_generic()
  crash: Let arch decide usable memory range in reserved area
  powerpc/crash: Use generic APIs to locate memory hole for kdump
  powerpc/crash: preserve user-specified memory limit
  powerpc: insert System RAM resource to prevent crashkernel conflict
  powerpc/crash: use generic crashkernel reservation

 arch/arm64/mm/init.c                     |   6 +-
 arch/loongarch/kernel/setup.c            |   5 +-
 arch/powerpc/Kconfig                     |   3 +
 arch/powerpc/include/asm/crash_reserve.h |   8 +
 arch/powerpc/include/asm/kexec.h         |  10 +-
 arch/powerpc/kernel/prom.c               |   2 +-
 arch/powerpc/kexec/core.c                |  96 ++++-----
 arch/powerpc/kexec/file_load_64.c        | 259 +----------------------
 arch/powerpc/mm/mem.c                    |   2 +-
 arch/riscv/mm/init.c                     |   6 +-
 arch/x86/kernel/setup.c                  |   6 +-
 include/linux/crash_reserve.h            |  11 +-
 include/linux/kexec.h                    |   9 +
 kernel/crash_reserve.c                   |   9 +-
 kernel/kexec_elf.c                       |   2 +-
 kernel/kexec_file.c                      |  12 ++
 16 files changed, 105 insertions(+), 341 deletions(-)
 create mode 100644 arch/powerpc/include/asm/crash_reserve.h

-- 
2.48.1