From 180adfc532a83c1d74146449f7385f767d4b8059 Mon Sep 17 00:00:00 2001 From: Hari Bathini Date: Wed, 29 Jul 2020 17:10:00 +0530 Subject: powerpc/kexec_file: Add helper functions for getting memory ranges In kexec case, the kernel to be loaded uses the same memory layout as the running kernel. So, passing on the DT of the running kernel would be good enough. But in case of kdump, different memory ranges are needed to manage loading the kdump kernel, booting into it and exporting the elfcore of the crashing kernel. The ranges are exclude memory ranges, usable memory ranges, reserved memory ranges and crash memory ranges. Exclude memory ranges specify the list of memory ranges to avoid while loading kdump segments. Usable memory ranges list the memory ranges that could be used for booting kdump kernel. Reserved memory ranges list the memory regions for the loading kernel's reserve map. Crash memory ranges list the memory ranges to be exported as the crashing kernel's elfcore. Add helper functions for setting up the above mentioned memory ranges. This helpers facilitate in understanding the subsequent changes better and make it easy to setup the different memory ranges listed above, as and when appropriate. Signed-off-by: Hari Bathini Tested-by: Pingfan Liu Reviewed-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/159602279194.575379.8526552316948643550.stgit@hbathini --- arch/powerpc/kexec/Makefile | 2 +- arch/powerpc/kexec/ranges.c | 235 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 236 insertions(+), 1 deletion(-) create mode 100644 arch/powerpc/kexec/ranges.c (limited to 'arch/powerpc/kexec') diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile index 67c355329457..4aff6846c772 100644 --- a/arch/powerpc/kexec/Makefile +++ b/arch/powerpc/kexec/Makefile @@ -7,7 +7,7 @@ obj-y += core.o crash.o core_$(BITS).o obj-$(CONFIG_PPC32) += relocate_32.o -obj-$(CONFIG_KEXEC_FILE) += file_load.o file_load_$(BITS).o elf_$(BITS).o +obj-$(CONFIG_KEXEC_FILE) += file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o ifdef CONFIG_HAVE_IMA_KEXEC ifdef CONFIG_IMA diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c new file mode 100644 index 000000000000..dc3ce036f416 --- /dev/null +++ b/arch/powerpc/kexec/ranges.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * powerpc code to implement the kexec_file_load syscall + * + * Copyright (C) 2004 Adam Litke (agl@us.ibm.com) + * Copyright (C) 2004 IBM Corp. + * Copyright (C) 2004,2005 Milton D Miller II, IBM Corporation + * Copyright (C) 2005 R Sharada (sharada@in.ibm.com) + * Copyright (C) 2006 Mohan Kumar M (mohan@in.ibm.com) + * Copyright (C) 2020 IBM Corporation + * + * Based on kexec-tools' kexec-ppc64.c, fs2dt.c. + * Heavily modified for the kernel by + * Hari Bathini, IBM Corporation. + */ + +#define pr_fmt(fmt) "kexec ranges: " fmt + +#include +#include +#include +#include +#include +#include + +/** + * get_max_nr_ranges - Get the max no. of ranges crash_mem structure + * could hold, given the size allocated for it. + * @size: Allocation size of crash_mem structure. + * + * Returns the maximum no. of ranges. + */ +static inline unsigned int get_max_nr_ranges(size_t size) +{ + return ((size - sizeof(struct crash_mem)) / + sizeof(struct crash_mem_range)); +} + +/** + * get_mem_rngs_size - Get the allocated size of mem_rngs based on + * max_nr_ranges and chunk size. + * @mem_rngs: Memory ranges. + * + * Returns the maximum size of @mem_rngs. + */ +static inline size_t get_mem_rngs_size(struct crash_mem *mem_rngs) +{ + size_t size; + + if (!mem_rngs) + return 0; + + size = (sizeof(struct crash_mem) + + (mem_rngs->max_nr_ranges * sizeof(struct crash_mem_range))); + + /* + * Memory is allocated in size multiple of MEM_RANGE_CHUNK_SZ. + * So, align to get the actual length. + */ + return ALIGN(size, MEM_RANGE_CHUNK_SZ); +} + +/** + * __add_mem_range - add a memory range to memory ranges list. + * @mem_ranges: Range list to add the memory range to. + * @base: Base address of the range to add. + * @size: Size of the memory range to add. + * + * (Re)allocates memory, if needed. + * + * Returns 0 on success, negative errno on error. + */ +static int __add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size) +{ + struct crash_mem *mem_rngs = *mem_ranges; + + if (!mem_rngs || (mem_rngs->nr_ranges == mem_rngs->max_nr_ranges)) { + mem_rngs = realloc_mem_ranges(mem_ranges); + if (!mem_rngs) + return -ENOMEM; + } + + mem_rngs->ranges[mem_rngs->nr_ranges].start = base; + mem_rngs->ranges[mem_rngs->nr_ranges].end = base + size - 1; + pr_debug("Added memory range [%#016llx - %#016llx] at index %d\n", + base, base + size - 1, mem_rngs->nr_ranges); + mem_rngs->nr_ranges++; + return 0; +} + +/** + * __merge_memory_ranges - Merges the given memory ranges list. + * @mem_rngs: Range list to merge. + * + * Assumes a sorted range list. + * + * Returns nothing. + */ +static void __merge_memory_ranges(struct crash_mem *mem_rngs) +{ + struct crash_mem_range *ranges; + int i, idx; + + if (!mem_rngs) + return; + + idx = 0; + ranges = &(mem_rngs->ranges[0]); + for (i = 1; i < mem_rngs->nr_ranges; i++) { + if (ranges[i].start <= (ranges[i-1].end + 1)) + ranges[idx].end = ranges[i].end; + else { + idx++; + if (i == idx) + continue; + + ranges[idx] = ranges[i]; + } + } + mem_rngs->nr_ranges = idx + 1; +} + +/* cmp_func_t callback to sort ranges with sort() */ +static int rngcmp(const void *_x, const void *_y) +{ + const struct crash_mem_range *x = _x, *y = _y; + + if (x->start > y->start) + return 1; + if (x->start < y->start) + return -1; + return 0; +} + +/** + * sort_memory_ranges - Sorts the given memory ranges list. + * @mem_rngs: Range list to sort. + * @merge: If true, merge the list after sorting. + * + * Returns nothing. + */ +void sort_memory_ranges(struct crash_mem *mem_rngs, bool merge) +{ + int i; + + if (!mem_rngs) + return; + + /* Sort the ranges in-place */ + sort(&(mem_rngs->ranges[0]), mem_rngs->nr_ranges, + sizeof(mem_rngs->ranges[0]), rngcmp, NULL); + + if (merge) + __merge_memory_ranges(mem_rngs); + + /* For debugging purpose */ + pr_debug("Memory ranges:\n"); + for (i = 0; i < mem_rngs->nr_ranges; i++) { + pr_debug("\t[%03d][%#016llx - %#016llx]\n", i, + mem_rngs->ranges[i].start, + mem_rngs->ranges[i].end); + } +} + +/** + * realloc_mem_ranges - reallocate mem_ranges with size incremented + * by MEM_RANGE_CHUNK_SZ. Frees up the old memory, + * if memory allocation fails. + * @mem_ranges: Memory ranges to reallocate. + * + * Returns pointer to reallocated memory on success, NULL otherwise. + */ +struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges) +{ + struct crash_mem *mem_rngs = *mem_ranges; + unsigned int nr_ranges; + size_t size; + + size = get_mem_rngs_size(mem_rngs); + nr_ranges = mem_rngs ? mem_rngs->nr_ranges : 0; + + size += MEM_RANGE_CHUNK_SZ; + mem_rngs = krealloc(*mem_ranges, size, GFP_KERNEL); + if (!mem_rngs) { + kfree(*mem_ranges); + *mem_ranges = NULL; + return NULL; + } + + mem_rngs->nr_ranges = nr_ranges; + mem_rngs->max_nr_ranges = get_max_nr_ranges(size); + *mem_ranges = mem_rngs; + + return mem_rngs; +} + +/** + * add_mem_range - Updates existing memory range, if there is an overlap. + * Else, adds a new memory range. + * @mem_ranges: Range list to add the memory range to. + * @base: Base address of the range to add. + * @size: Size of the memory range to add. + * + * (Re)allocates memory, if needed. + * + * Returns 0 on success, negative errno on error. + */ +int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size) +{ + struct crash_mem *mem_rngs = *mem_ranges; + u64 mstart, mend, end; + unsigned int i; + + if (!size) + return 0; + + end = base + size - 1; + + if (!mem_rngs || !(mem_rngs->nr_ranges)) + return __add_mem_range(mem_ranges, base, size); + + for (i = 0; i < mem_rngs->nr_ranges; i++) { + mstart = mem_rngs->ranges[i].start; + mend = mem_rngs->ranges[i].end; + if (base < mend && end > mstart) { + if (base < mstart) + mem_rngs->ranges[i].start = base; + if (end > mend) + mem_rngs->ranges[i].end = end; + return 0; + } + } + + return __add_mem_range(mem_ranges, base, size); +} -- cgit v1.2.3