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2025-03-16kexec: initialize ELF lowest address to ULONG_MAXSourabh Jain
Patch series "powerpc/crash: use generic crashkernel reservation", v3. 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. This patch (of 7): kexec_elf_load() loads an ELF executable and sets the address of the lowest PT_LOAD section to the address held by the lowest_load_addr function argument. To determine the lowest PT_LOAD address, a local variable lowest_addr (type unsigned long) is initialized to UINT_MAX. After loading each PT_LOAD, its address is compared to lowest_addr. If a loaded PT_LOAD address is lower, lowest_addr is updated. However, setting lowest_addr to UINT_MAX won't work when the kernel image is loaded above 4G, as the returned lowest PT_LOAD address would be invalid. This is resolved by initializing lowest_addr to ULONG_MAX instead. This issue was discovered while implementing crashkernel high/low reservation on the PowerPC architecture. Link: https://lkml.kernel.org/r/20250131113830.925179-1-sourabhjain@linux.ibm.com Link: https://lkml.kernel.org/r/20250131113830.925179-2-sourabhjain@linux.ibm.com Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()") Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2019-09-06kexec_elf: support 32 bit ELF filesSven Schnelle
The powerpc version only supported 64 bit. Add some code to switch decoding of fields during runtime so we can kexec a 32 bit kernel from a 64 bit kernel and vice versa. Signed-off-by: Sven Schnelle <svens@stackframe.org> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Helge Deller <deller@gmx.de>
2019-09-06kexec_elf: remove unused variable in kexec_elf_load()Sven Schnelle
base was never assigned, so we can remove it. Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
2019-09-06kexec_elf: remove Elf_Rel macroSven Schnelle
It wasn't used anywhere, so lets drop it. Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
2019-09-06kexec_elf: remove PURGATORY_STACK_SIZESven Schnelle
It's not used anywhere so just drop it. Signed-off-by: Sven Schnelle <svens@stackframe.org> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Helge Deller <deller@gmx.de>
2019-09-06kexec_elf: remove parsing of section headersSven Schnelle
We're not using them, so we can drop the parsing. Signed-off-by: Sven Schnelle <svens@stackframe.org> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Helge Deller <deller@gmx.de>
2019-09-06kexec_elf: change order of elf_*_to_cpu() functionsSven Schnelle
Change the order to have a 64/32/16 order, no functional change. Signed-off-by: Sven Schnelle <svens@stackframe.org> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Helge Deller <deller@gmx.de>
2019-09-06kexec: add KEXEC_ELFSven Schnelle
Right now powerpc provides an implementation to read elf files with the kexec_file_load() syscall. Make that available as a public kexec interface so it can be re-used on other architectures. Signed-off-by: Sven Schnelle <svens@stackframe.org> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Helge Deller <deller@gmx.de>