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a051216427
The four cpumasks cpu_{possible,online,present,active}_bits are exposed
readonly via the corresponding const variables cpu_xyz_mask. But they are
also accessible for arbitrary writing via the exposed functions
set_cpu_xyz. There's quite a bit of code throughout the kernel which
iterates over or otherwise accesses these bitmaps, and having the access
go via the cpu_xyz_mask variables is nowadays [1] simply a useless
indirection.
It may be that any problem in CS can be solved by an extra level of
indirection, but that doesn't mean every extra indirection solves a
problem. In this case, it even necessitates some minor ugliness (see
4/6).
Patch 1/6 is new in v2, and fixes a build failure on ppc by renaming a
struct member, to avoid problems when the identifier cpu_online_mask
becomes a macro later in the series. The next four patches eliminate the
cpu_xyz_mask variables by simply exposing the actual bitmaps, after
renaming them to discourage direct access - that still happens through
cpu_xyz_mask, which are now simply macros with the same type and value as
they used to have.
After that, there's no longer any reason to have the setter functions be
out-of-line: The boolean parameter is almost always a literal true or
false, so by making them static inlines they will usually compile to one
or two instructions.
For a defconfig build on x86_64, bloat-o-meter says we save ~3000 bytes.
We also save a little stack (stackdelta says 127 functions have a 16 byte
smaller stack frame, while two grow by that amount). Mostly because, when
iterating over the mask, gcc typically loads the value of cpu_xyz_mask
into a callee-saved register and from there into %rdi before each
find_next_bit call - now it can just load the appropriate immediate
address into %rdi before each call.
[1] See Rusty's kind explanation
http://thread.gmane.org/gmane.linux.kernel/2047078/focus=2047722 for
some historic context.
This patch (of 6):
As preparation for eliminating the indirect access to the various global
cpu_*_bits bitmaps via the pointer variables cpu_*_mask, rename the
cpu_online_mask member of struct fadump_crash_info_header to simply
online_mask, thus allowing cpu_online_mask to become a macro.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
217 lines
6 KiB
C
217 lines
6 KiB
C
/*
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* Firmware Assisted dump header file.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright 2011 IBM Corporation
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* Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
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*/
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#ifndef __PPC64_FA_DUMP_H__
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#define __PPC64_FA_DUMP_H__
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#ifdef CONFIG_FA_DUMP
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/*
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* The RMA region will be saved for later dumping when kernel crashes.
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* RMA is Real Mode Area, the first block of logical memory address owned
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* by logical partition, containing the storage that may be accessed with
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* translate off.
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*/
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#define RMA_START 0x0
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#define RMA_END (ppc64_rma_size)
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/*
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* On some Power systems where RMO is 128MB, it still requires minimum of
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* 256MB for kernel to boot successfully. When kdump infrastructure is
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* configured to save vmcore over network, we run into OOM issue while
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* loading modules related to network setup. Hence we need aditional 64M
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* of memory to avoid OOM issue.
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*/
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#define MIN_BOOT_MEM (((RMA_END < (0x1UL << 28)) ? (0x1UL << 28) : RMA_END) \
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+ (0x1UL << 26))
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#define memblock_num_regions(memblock_type) (memblock.memblock_type.cnt)
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#ifndef ELF_CORE_EFLAGS
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#define ELF_CORE_EFLAGS 0
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#endif
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/* Firmware provided dump sections */
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#define FADUMP_CPU_STATE_DATA 0x0001
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#define FADUMP_HPTE_REGION 0x0002
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#define FADUMP_REAL_MODE_REGION 0x0011
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/* Dump request flag */
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#define FADUMP_REQUEST_FLAG 0x00000001
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/* FAD commands */
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#define FADUMP_REGISTER 1
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#define FADUMP_UNREGISTER 2
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#define FADUMP_INVALIDATE 3
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/* Dump status flag */
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#define FADUMP_ERROR_FLAG 0x2000
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#define FADUMP_CPU_ID_MASK ((1UL << 32) - 1)
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#define CPU_UNKNOWN (~((u32)0))
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/* Utility macros */
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#define SKIP_TO_NEXT_CPU(reg_entry) \
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({ \
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while (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUEND")) \
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reg_entry++; \
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reg_entry++; \
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})
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/* Kernel Dump section info */
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struct fadump_section {
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__be32 request_flag;
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__be16 source_data_type;
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__be16 error_flags;
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__be64 source_address;
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__be64 source_len;
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__be64 bytes_dumped;
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__be64 destination_address;
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};
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/* ibm,configure-kernel-dump header. */
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struct fadump_section_header {
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__be32 dump_format_version;
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__be16 dump_num_sections;
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__be16 dump_status_flag;
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__be32 offset_first_dump_section;
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/* Fields for disk dump option. */
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__be32 dd_block_size;
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__be64 dd_block_offset;
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__be64 dd_num_blocks;
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__be32 dd_offset_disk_path;
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/* Maximum time allowed to prevent an automatic dump-reboot. */
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__be32 max_time_auto;
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};
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/*
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* Firmware Assisted dump memory structure. This structure is required for
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* registering future kernel dump with power firmware through rtas call.
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*
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* No disk dump option. Hence disk dump path string section is not included.
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*/
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struct fadump_mem_struct {
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struct fadump_section_header header;
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/* Kernel dump sections */
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struct fadump_section cpu_state_data;
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struct fadump_section hpte_region;
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struct fadump_section rmr_region;
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};
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/* Firmware-assisted dump configuration details. */
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struct fw_dump {
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unsigned long cpu_state_data_size;
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unsigned long hpte_region_size;
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unsigned long boot_memory_size;
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unsigned long reserve_dump_area_start;
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unsigned long reserve_dump_area_size;
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/* cmd line option during boot */
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unsigned long reserve_bootvar;
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unsigned long fadumphdr_addr;
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unsigned long cpu_notes_buf;
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unsigned long cpu_notes_buf_size;
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int ibm_configure_kernel_dump;
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unsigned long fadump_enabled:1;
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unsigned long fadump_supported:1;
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unsigned long dump_active:1;
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unsigned long dump_registered:1;
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};
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/*
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* Copy the ascii values for first 8 characters from a string into u64
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* variable at their respective indexes.
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* e.g.
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* The string "FADMPINF" will be converted into 0x4641444d50494e46
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*/
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static inline u64 str_to_u64(const char *str)
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{
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u64 val = 0;
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int i;
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for (i = 0; i < sizeof(val); i++)
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val = (*str) ? (val << 8) | *str++ : val << 8;
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return val;
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}
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#define STR_TO_HEX(x) str_to_u64(x)
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#define REG_ID(x) str_to_u64(x)
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#define FADUMP_CRASH_INFO_MAGIC STR_TO_HEX("FADMPINF")
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#define REGSAVE_AREA_MAGIC STR_TO_HEX("REGSAVE")
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/* The firmware-assisted dump format.
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*
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* The register save area is an area in the partition's memory used to preserve
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* the register contents (CPU state data) for the active CPUs during a firmware
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* assisted dump. The dump format contains register save area header followed
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* by register entries. Each list of registers for a CPU starts with
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* "CPUSTRT" and ends with "CPUEND".
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*/
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/* Register save area header. */
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struct fadump_reg_save_area_header {
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__be64 magic_number;
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__be32 version;
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__be32 num_cpu_offset;
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};
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/* Register entry. */
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struct fadump_reg_entry {
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__be64 reg_id;
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__be64 reg_value;
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};
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/* fadump crash info structure */
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struct fadump_crash_info_header {
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u64 magic_number;
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u64 elfcorehdr_addr;
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u32 crashing_cpu;
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struct pt_regs regs;
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struct cpumask online_mask;
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};
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/* Crash memory ranges */
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#define INIT_CRASHMEM_RANGES (INIT_MEMBLOCK_REGIONS + 2)
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struct fad_crash_memory_ranges {
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unsigned long long base;
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unsigned long long size;
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};
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extern int early_init_dt_scan_fw_dump(unsigned long node,
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const char *uname, int depth, void *data);
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extern int fadump_reserve_mem(void);
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extern int setup_fadump(void);
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extern int is_fadump_active(void);
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extern void crash_fadump(struct pt_regs *, const char *);
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extern void fadump_cleanup(void);
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#else /* CONFIG_FA_DUMP */
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static inline int is_fadump_active(void) { return 0; }
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static inline void crash_fadump(struct pt_regs *regs, const char *str) { }
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#endif
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#endif
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