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Commit babac4a8 authored by AKASHI Takahiro's avatar AKASHI Takahiro Committed by Linus Torvalds
Browse files

kexec_file, x86: move re-factored code to generic side 

In the previous patches, commonly-used routines, exclude_mem_range() and
prepare_elf64_headers(), were carved out.  Now place them in kexec
common code.  A prefix "crash_" is given to each of their names to avoid
possible name collisions.

Link: http://lkml.kernel.org/r/20180306102303.9063-8-takahiro.akashi@linaro.org


Signed-off-by: default avatarAKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: default avatarDave Young <dyoung@redhat.com>
Tested-by: default avatarDave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent eb7dae94

arch/x86/kernel/crash.c

+7 −188
Original line number Diff line number Diff line
@@ -38,19 +38,6 @@ 
#include <asm/virtext.h>

#include <asm/intel_pt.h>



/* Alignment required for elf header segment */

#define ELF_CORE_HEADER_ALIGN   4096



struct crash_mem_range {

	u64 start, end;

};



struct crash_mem {

	unsigned int max_nr_ranges;

	unsigned int nr_ranges;

	struct crash_mem_range ranges[0];

};



/* Used while preparing memory map entries for second kernel */

struct crash_memmap_data {

	struct boot_params *params;
@@ -227,77 +214,6 @@ static struct crash_mem *fill_up_crash_elf_data(void) 
	return cmem;

}



static int exclude_mem_range(struct crash_mem *mem,

		unsigned long long mstart, unsigned long long mend)

{

	int i, j;

	unsigned long long start, end;

	struct crash_mem_range temp_range = {0, 0};



	for (i = 0; i < mem->nr_ranges; i++) {

		start = mem->ranges[i].start;

		end = mem->ranges[i].end;



		if (mstart > end || mend < start)

			continue;



		/* Truncate any area outside of range */

		if (mstart < start)

			mstart = start;

		if (mend > end)

			mend = end;



		/* Found completely overlapping range */

		if (mstart == start && mend == end) {

			mem->ranges[i].start = 0;

			mem->ranges[i].end = 0;

			if (i < mem->nr_ranges - 1) {

				/* Shift rest of the ranges to left */

				for (j = i; j < mem->nr_ranges - 1; j++) {

					mem->ranges[j].start =

						mem->ranges[j+1].start;

					mem->ranges[j].end =

							mem->ranges[j+1].end;

				}

			}

			mem->nr_ranges--;

			return 0;

		}



		if (mstart > start && mend < end) {

			/* Split original range */

			mem->ranges[i].end = mstart - 1;

			temp_range.start = mend + 1;

			temp_range.end = end;

		} else if (mstart != start)

			mem->ranges[i].end = mstart - 1;

		else

			mem->ranges[i].start = mend + 1;

		break;

	}



	/* If a split happend, add the split to array */

	if (!temp_range.end)

		return 0;



	/* Split happened */

	if (i == mem->max_nr_ranges - 1)

		return -ENOMEM;



	/* Location where new range should go */

	j = i + 1;

	if (j < mem->nr_ranges) {

		/* Move over all ranges one slot towards the end */

		for (i = mem->nr_ranges - 1; i >= j; i--)

			mem->ranges[i + 1] = mem->ranges[i];

	}



	mem->ranges[j].start = temp_range.start;

	mem->ranges[j].end = temp_range.end;

	mem->nr_ranges++;

	return 0;

}



/*

 * Look for any unwanted ranges between mstart, mend and remove them. This

 * might lead to split and split ranges are put in cmem->ranges[] array
@@ -307,12 +223,13 @@ static int elf_header_exclude_ranges(struct crash_mem *cmem) 
	int ret = 0;



	/* Exclude crashkernel region */

	ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

	if (ret)

		return ret;



	if (crashk_low_res.end) {

		ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);

		ret = crash_exclude_mem_range(cmem, crashk_low_res.start,

							crashk_low_res.end);

		if (ret)

			return ret;

	}
@@ -331,105 +248,6 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) 
	return 0;

}



static int prepare_elf64_headers(struct crash_mem *cmem, bool kernel_map,

		void **addr, unsigned long *sz)

{

	Elf64_Ehdr *ehdr;

	Elf64_Phdr *phdr;

	unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;

	unsigned char *buf;

	unsigned int cpu, i;

	unsigned long long notes_addr;

	unsigned long mstart, mend;



	/* extra phdr for vmcoreinfo elf note */

	nr_phdr = nr_cpus + 1;

	nr_phdr += cmem->nr_ranges;



	/*

	 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping

	 * area on x86_64 (ffffffff80000000 - ffffffffa0000000).

	 * I think this is required by tools like gdb. So same physical

	 * memory will be mapped in two elf headers. One will contain kernel

	 * text virtual addresses and other will have __va(physical) addresses.

	 */



	nr_phdr++;

	elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);

	elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);



	buf = vzalloc(elf_sz);

	if (!buf)

		return -ENOMEM;



	ehdr = (Elf64_Ehdr *)buf;

	phdr = (Elf64_Phdr *)(ehdr + 1);

	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);

	ehdr->e_ident[EI_CLASS] = ELFCLASS64;

	ehdr->e_ident[EI_DATA] = ELFDATA2LSB;

	ehdr->e_ident[EI_VERSION] = EV_CURRENT;

	ehdr->e_ident[EI_OSABI] = ELF_OSABI;

	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);

	ehdr->e_type = ET_CORE;

	ehdr->e_machine = ELF_ARCH;

	ehdr->e_version = EV_CURRENT;

	ehdr->e_phoff = sizeof(Elf64_Ehdr);

	ehdr->e_ehsize = sizeof(Elf64_Ehdr);

	ehdr->e_phentsize = sizeof(Elf64_Phdr);



	/* Prepare one phdr of type PT_NOTE for each present cpu */

	for_each_present_cpu(cpu) {

		phdr->p_type = PT_NOTE;

		notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));

		phdr->p_offset = phdr->p_paddr = notes_addr;

		phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);

		(ehdr->e_phnum)++;

		phdr++;

	}



	/* Prepare one PT_NOTE header for vmcoreinfo */

	phdr->p_type = PT_NOTE;

	phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();

	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;

	(ehdr->e_phnum)++;

	phdr++;



	/* Prepare PT_LOAD type program header for kernel text region */

	if (kernel_map) {

		phdr->p_type = PT_LOAD;

		phdr->p_flags = PF_R|PF_W|PF_X;

		phdr->p_vaddr = (Elf64_Addr)_text;

		phdr->p_filesz = phdr->p_memsz = _end - _text;

		phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);

		ehdr->e_phnum++;

		phdr++;

	}



	/* Go through all the ranges in cmem->ranges[] and prepare phdr */

	for (i = 0; i < cmem->nr_ranges; i++) {

		mstart = cmem->ranges[i].start;

		mend = cmem->ranges[i].end;



		phdr->p_type = PT_LOAD;

		phdr->p_flags = PF_R|PF_W|PF_X;

		phdr->p_offset  = mstart;



		phdr->p_paddr = mstart;

		phdr->p_vaddr = (unsigned long long) __va(mstart);

		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;

		phdr->p_align = 0;

		ehdr->e_phnum++;

		phdr++;

		pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",

			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,

			ehdr->e_phnum, phdr->p_offset);

	}



	*addr = buf;

	*sz = elf_sz;

	return 0;

}



/* Prepare elf headers. Return addr and size */

static int prepare_elf_headers(struct kimage *image, void **addr,

					unsigned long *sz)
@@ -454,7 +272,8 @@ static int prepare_elf_headers(struct kimage *image, void **addr, 
		goto out;



	/* By default prepare 64bit headers */

	ret =  prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);

	ret =  crash_prepare_elf64_headers(cmem,

				IS_ENABLED(CONFIG_X86_64), addr, sz);

	if (ret)

		goto out;
@@ -518,14 +337,14 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem, 
	/* Exclude Backup region */

	start = image->arch.backup_load_addr;

	end = start + image->arch.backup_src_sz - 1;

	ret = exclude_mem_range(cmem, start, end);

	ret = crash_exclude_mem_range(cmem, start, end);

	if (ret)

		return ret;



	/* Exclude elf header region */

	start = image->arch.elf_load_addr;

	end = start + image->arch.elf_headers_sz - 1;

	return exclude_mem_range(cmem, start, end);

	return crash_exclude_mem_range(cmem, start, end);

}



/* Prepare memory map for crash dump kernel */

include/linux/kexec.h

+19 −0
Original line number Diff line number Diff line
@@ -168,6 +168,25 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf, 
			       int (*func)(struct resource *, void *));

extern int kexec_add_buffer(struct kexec_buf *kbuf);

int kexec_locate_mem_hole(struct kexec_buf *kbuf);



/* Alignment required for elf header segment */

#define ELF_CORE_HEADER_ALIGN   4096



struct crash_mem_range {

	u64 start, end;

};



struct crash_mem {

	unsigned int max_nr_ranges;

	unsigned int nr_ranges;

	struct crash_mem_range ranges[0];

};



extern int crash_exclude_mem_range(struct crash_mem *mem,

				   unsigned long long mstart,

				   unsigned long long mend);

extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,

				       void **addr, unsigned long *sz);

#endif /* CONFIG_KEXEC_FILE */



struct kimage {

kernel/kexec_file.c

+175 −0
Original line number Diff line number Diff line
@@ -22,6 +22,11 @@ 
#include <linux/ima.h>

#include <crypto/hash.h>

#include <crypto/sha.h>

#include <linux/elf.h>

#include <linux/elfcore.h>

#include <linux/kernel.h>

#include <linux/kexec.h>

#include <linux/slab.h>

#include <linux/syscalls.h>

#include <linux/vmalloc.h>

#include "kexec_internal.h"
@@ -1079,3 +1084,173 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 
	return 0;

}

#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */



int crash_exclude_mem_range(struct crash_mem *mem,

			    unsigned long long mstart, unsigned long long mend)

{

	int i, j;

	unsigned long long start, end;

	struct crash_mem_range temp_range = {0, 0};



	for (i = 0; i < mem->nr_ranges; i++) {

		start = mem->ranges[i].start;

		end = mem->ranges[i].end;



		if (mstart > end || mend < start)

			continue;



		/* Truncate any area outside of range */

		if (mstart < start)

			mstart = start;

		if (mend > end)

			mend = end;



		/* Found completely overlapping range */

		if (mstart == start && mend == end) {

			mem->ranges[i].start = 0;

			mem->ranges[i].end = 0;

			if (i < mem->nr_ranges - 1) {

				/* Shift rest of the ranges to left */

				for (j = i; j < mem->nr_ranges - 1; j++) {

					mem->ranges[j].start =

						mem->ranges[j+1].start;

					mem->ranges[j].end =

							mem->ranges[j+1].end;

				}

			}

			mem->nr_ranges--;

			return 0;

		}



		if (mstart > start && mend < end) {

			/* Split original range */

			mem->ranges[i].end = mstart - 1;

			temp_range.start = mend + 1;

			temp_range.end = end;

		} else if (mstart != start)

			mem->ranges[i].end = mstart - 1;

		else

			mem->ranges[i].start = mend + 1;

		break;

	}



	/* If a split happened, add the split to array */

	if (!temp_range.end)

		return 0;



	/* Split happened */

	if (i == mem->max_nr_ranges - 1)

		return -ENOMEM;



	/* Location where new range should go */

	j = i + 1;

	if (j < mem->nr_ranges) {

		/* Move over all ranges one slot towards the end */

		for (i = mem->nr_ranges - 1; i >= j; i--)

			mem->ranges[i + 1] = mem->ranges[i];

	}



	mem->ranges[j].start = temp_range.start;

	mem->ranges[j].end = temp_range.end;

	mem->nr_ranges++;

	return 0;

}



int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,

			  void **addr, unsigned long *sz)

{

	Elf64_Ehdr *ehdr;

	Elf64_Phdr *phdr;

	unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;

	unsigned char *buf;

	unsigned int cpu, i;

	unsigned long long notes_addr;

	unsigned long mstart, mend;



	/* extra phdr for vmcoreinfo elf note */

	nr_phdr = nr_cpus + 1;

	nr_phdr += mem->nr_ranges;



	/*

	 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping

	 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).

	 * I think this is required by tools like gdb. So same physical

	 * memory will be mapped in two elf headers. One will contain kernel

	 * text virtual addresses and other will have __va(physical) addresses.

	 */



	nr_phdr++;

	elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);

	elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);



	buf = vzalloc(elf_sz);

	if (!buf)

		return -ENOMEM;



	ehdr = (Elf64_Ehdr *)buf;

	phdr = (Elf64_Phdr *)(ehdr + 1);

	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);

	ehdr->e_ident[EI_CLASS] = ELFCLASS64;

	ehdr->e_ident[EI_DATA] = ELFDATA2LSB;

	ehdr->e_ident[EI_VERSION] = EV_CURRENT;

	ehdr->e_ident[EI_OSABI] = ELF_OSABI;

	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);

	ehdr->e_type = ET_CORE;

	ehdr->e_machine = ELF_ARCH;

	ehdr->e_version = EV_CURRENT;

	ehdr->e_phoff = sizeof(Elf64_Ehdr);

	ehdr->e_ehsize = sizeof(Elf64_Ehdr);

	ehdr->e_phentsize = sizeof(Elf64_Phdr);



	/* Prepare one phdr of type PT_NOTE for each present cpu */

	for_each_present_cpu(cpu) {

		phdr->p_type = PT_NOTE;

		notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));

		phdr->p_offset = phdr->p_paddr = notes_addr;

		phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);

		(ehdr->e_phnum)++;

		phdr++;

	}



	/* Prepare one PT_NOTE header for vmcoreinfo */

	phdr->p_type = PT_NOTE;

	phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();

	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;

	(ehdr->e_phnum)++;

	phdr++;



	/* Prepare PT_LOAD type program header for kernel text region */

	if (kernel_map) {

		phdr->p_type = PT_LOAD;

		phdr->p_flags = PF_R|PF_W|PF_X;

		phdr->p_vaddr = (Elf64_Addr)_text;

		phdr->p_filesz = phdr->p_memsz = _end - _text;

		phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);

		ehdr->e_phnum++;

		phdr++;

	}



	/* Go through all the ranges in mem->ranges[] and prepare phdr */

	for (i = 0; i < mem->nr_ranges; i++) {

		mstart = mem->ranges[i].start;

		mend = mem->ranges[i].end;



		phdr->p_type = PT_LOAD;

		phdr->p_flags = PF_R|PF_W|PF_X;

		phdr->p_offset  = mstart;



		phdr->p_paddr = mstart;

		phdr->p_vaddr = (unsigned long long) __va(mstart);

		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;

		phdr->p_align = 0;

		ehdr->e_phnum++;

		phdr++;

		pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",

			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,

			ehdr->e_phnum, phdr->p_offset);

	}



	*addr = buf;

	*sz = elf_sz;

	return 0;

}