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: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Dave Young <dyoung@redhat.com>
Tested-by: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 175 insertions, 0 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 332c4fd12cb1..b06b1fac5252 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -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;
+}