* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
*
* Copyright (C) IBM Corporation, 2004. All rights reserved.
+ * Copyright (C) Red Hat Inc., 2014. All rights reserved.
+ * Authors:
+ * Vivek Goyal <vgoyal@redhat.com>
*
*/
+#define pr_fmt(fmt) "kexec: " fmt
+
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/module.h>
+#include <linux/slab.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
#include <asm/reboot.h>
#include <asm/virtext.h>
+/* Alignment required for elf header segment */
+#define ELF_CORE_HEADER_ALIGN 4096
+
+/* This primarily represents number of split ranges due to exclusion */
+#define CRASH_MAX_RANGES 16
+
+struct crash_mem_range {
+ u64 start, end;
+};
+
+struct crash_mem {
+ unsigned int nr_ranges;
+ struct crash_mem_range ranges[CRASH_MAX_RANGES];
+};
+
+/* Misc data about ram ranges needed to prepare elf headers */
+struct crash_elf_data {
+ struct kimage *image;
+ /*
+ * Total number of ram ranges we have after various adjustments for
+ * GART, crash reserved region etc.
+ */
+ unsigned int max_nr_ranges;
+ unsigned long gart_start, gart_end;
+
+ /* Pointer to elf header */
+ void *ehdr;
+ /* Pointer to next phdr */
+ void *bufp;
+ struct crash_mem mem;
+};
+
+/* Used while preparing memory map entries for second kernel */
+struct crash_memmap_data {
+ struct boot_params *params;
+ /* Type of memory */
+ unsigned int type;
+};
+
int in_crash_kexec;
/*
*/
crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
+unsigned long crash_zero_bytes;
static inline void cpu_crash_vmclear_loaded_vmcss(void)
{
#endif
crash_save_cpu(regs, safe_smp_processor_id());
}
+
+#ifdef CONFIG_X86_64
+
+static int get_nr_ram_ranges_callback(unsigned long start_pfn,
+ unsigned long nr_pfn, void *arg)
+{
+ int *nr_ranges = arg;
+
+ (*nr_ranges)++;
+ return 0;
+}
+
+static int get_gart_ranges_callback(u64 start, u64 end, void *arg)
+{
+ struct crash_elf_data *ced = arg;
+
+ ced->gart_start = start;
+ ced->gart_end = end;
+
+ /* Not expecting more than 1 gart aperture */
+ return 1;
+}
+
+
+/* Gather all the required information to prepare elf headers for ram regions */
+static void fill_up_crash_elf_data(struct crash_elf_data *ced,
+ struct kimage *image)
+{
+ unsigned int nr_ranges = 0;
+
+ ced->image = image;
+
+ walk_system_ram_range(0, -1, &nr_ranges,
+ get_nr_ram_ranges_callback);
+
+ ced->max_nr_ranges = nr_ranges;
+
+ /*
+ * We don't create ELF headers for GART aperture as an attempt
+ * to dump this memory in second kernel leads to hang/crash.
+ * If gart aperture is present, one needs to exclude that region
+ * and that could lead to need of extra phdr.
+ */
+ walk_iomem_res("GART", IORESOURCE_MEM, 0, -1,
+ ced, get_gart_ranges_callback);
+
+ /*
+ * If we have gart region, excluding that could potentially split
+ * a memory range, resulting in extra header. Account for that.
+ */
+ if (ced->gart_end)
+ ced->max_nr_ranges++;
+
+ /* Exclusion of crash region could split memory ranges */
+ ced->max_nr_ranges++;
+
+ /* If crashk_low_res is not 0, another range split possible */
+ if (crashk_low_res.end != 0)
+ ced->max_nr_ranges++;
+}
+
+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 == CRASH_MAX_RANGES - 1) {
+ pr_err("Too many crash ranges after split\n");
+ 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 ced->mem.ranges[] array
+ */
+static int elf_header_exclude_ranges(struct crash_elf_data *ced,
+ unsigned long long mstart, unsigned long long mend)
+{
+ struct crash_mem *cmem = &ced->mem;
+ int ret = 0;
+
+ memset(cmem->ranges, 0, sizeof(cmem->ranges));
+
+ cmem->ranges[0].start = mstart;
+ cmem->ranges[0].end = mend;
+ cmem->nr_ranges = 1;
+
+ /* Exclude crashkernel region */
+ ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+ if (ret)
+ return ret;
+
+ ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
+ if (ret)
+ return ret;
+
+ /* Exclude GART region */
+ if (ced->gart_end) {
+ ret = exclude_mem_range(cmem, ced->gart_start, ced->gart_end);
+ if (ret)
+ return ret;
+ }
+
+ return ret;
+}
+
+static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
+{
+ struct crash_elf_data *ced = arg;
+ Elf64_Ehdr *ehdr;
+ Elf64_Phdr *phdr;
+ unsigned long mstart, mend;
+ struct kimage *image = ced->image;
+ struct crash_mem *cmem;
+ int ret, i;
+
+ ehdr = ced->ehdr;
+
+ /* Exclude unwanted mem ranges */
+ ret = elf_header_exclude_ranges(ced, start, end);
+ if (ret)
+ return ret;
+
+ /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
+ cmem = &ced->mem;
+
+ for (i = 0; i < cmem->nr_ranges; i++) {
+ mstart = cmem->ranges[i].start;
+ mend = cmem->ranges[i].end;
+
+ phdr = ced->bufp;
+ ced->bufp += sizeof(Elf64_Phdr);
+
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R|PF_W|PF_X;
+ phdr->p_offset = mstart;
+
+ /*
+ * If a range matches backup region, adjust offset to backup
+ * segment.
+ */
+ if (mstart == image->arch.backup_src_start &&
+ (mend - mstart + 1) == image->arch.backup_src_sz)
+ phdr->p_offset = image->arch.backup_load_addr;
+
+ 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++;
+ 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);
+ }
+
+ return ret;
+}
+
+static int prepare_elf64_headers(struct crash_elf_data *ced,
+ 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, *bufp;
+ unsigned int cpu;
+ unsigned long long notes_addr;
+ int ret;
+
+ /* extra phdr for vmcoreinfo elf note */
+ nr_phdr = nr_cpus + 1;
+ nr_phdr += ced->max_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;
+
+ bufp = buf;
+ ehdr = (Elf64_Ehdr *)bufp;
+ bufp += sizeof(Elf64_Ehdr);
+ 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 = (Elf64_Phdr *)bufp;
+ bufp += sizeof(Elf64_Phdr);
+ 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)++;
+ }
+
+ /* Prepare one PT_NOTE header for vmcoreinfo */
+ phdr = (Elf64_Phdr *)bufp;
+ bufp += sizeof(Elf64_Phdr);
+ phdr->p_type = PT_NOTE;
+ phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
+ phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note);
+ (ehdr->e_phnum)++;
+
+#ifdef CONFIG_X86_64
+ /* Prepare PT_LOAD type program header for kernel text region */
+ phdr = (Elf64_Phdr *)bufp;
+ bufp += sizeof(Elf64_Phdr);
+ 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)++;
+#endif
+
+ /* Prepare PT_LOAD headers for system ram chunks. */
+ ced->ehdr = ehdr;
+ ced->bufp = bufp;
+ ret = walk_system_ram_res(0, -1, ced,
+ prepare_elf64_ram_headers_callback);
+ if (ret < 0)
+ return ret;
+
+ *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)
+{
+ struct crash_elf_data *ced;
+ int ret;
+
+ ced = kzalloc(sizeof(*ced), GFP_KERNEL);
+ if (!ced)
+ return -ENOMEM;
+
+ fill_up_crash_elf_data(ced, image);
+
+ /* By default prepare 64bit headers */
+ ret = prepare_elf64_headers(ced, addr, sz);
+ kfree(ced);
+ return ret;
+}
+
+static int add_e820_entry(struct boot_params *params, struct e820entry *entry)
+{
+ unsigned int nr_e820_entries;
+
+ nr_e820_entries = params->e820_entries;
+ if (nr_e820_entries >= E820MAX)
+ return 1;
+
+ memcpy(¶ms->e820_map[nr_e820_entries], entry,
+ sizeof(struct e820entry));
+ params->e820_entries++;
+ return 0;
+}
+
+static int memmap_entry_callback(u64 start, u64 end, void *arg)
+{
+ struct crash_memmap_data *cmd = arg;
+ struct boot_params *params = cmd->params;
+ struct e820entry ei;
+
+ ei.addr = start;
+ ei.size = end - start + 1;
+ ei.type = cmd->type;
+ add_e820_entry(params, &ei);
+
+ return 0;
+}
+
+static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
+ unsigned long long mstart,
+ unsigned long long mend)
+{
+ unsigned long start, end;
+ int ret = 0;
+
+ cmem->ranges[0].start = mstart;
+ cmem->ranges[0].end = mend;
+ cmem->nr_ranges = 1;
+
+ /* Exclude Backup region */
+ start = image->arch.backup_load_addr;
+ end = start + image->arch.backup_src_sz - 1;
+ ret = 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);
+}
+
+/* Prepare memory map for crash dump kernel */
+int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
+{
+ int i, ret = 0;
+ unsigned long flags;
+ struct e820entry ei;
+ struct crash_memmap_data cmd;
+ struct crash_mem *cmem;
+
+ cmem = vzalloc(sizeof(struct crash_mem));
+ if (!cmem)
+ return -ENOMEM;
+
+ memset(&cmd, 0, sizeof(struct crash_memmap_data));
+ cmd.params = params;
+
+ /* Add first 640K segment */
+ ei.addr = image->arch.backup_src_start;
+ ei.size = image->arch.backup_src_sz;
+ ei.type = E820_RAM;
+ add_e820_entry(params, &ei);
+
+ /* Add ACPI tables */
+ cmd.type = E820_ACPI;
+ flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ walk_iomem_res("ACPI Tables", flags, 0, -1, &cmd,
+ memmap_entry_callback);
+
+ /* Add ACPI Non-volatile Storage */
+ cmd.type = E820_NVS;
+ walk_iomem_res("ACPI Non-volatile Storage", flags, 0, -1, &cmd,
+ memmap_entry_callback);
+
+ /* Add crashk_low_res region */
+ if (crashk_low_res.end) {
+ ei.addr = crashk_low_res.start;
+ ei.size = crashk_low_res.end - crashk_low_res.start + 1;
+ ei.type = E820_RAM;
+ add_e820_entry(params, &ei);
+ }
+
+ /* Exclude some ranges from crashk_res and add rest to memmap */
+ ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
+ crashk_res.end);
+ if (ret)
+ goto out;
+
+ for (i = 0; i < cmem->nr_ranges; i++) {
+ ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
+
+ /* If entry is less than a page, skip it */
+ if (ei.size < PAGE_SIZE)
+ continue;
+ ei.addr = cmem->ranges[i].start;
+ ei.type = E820_RAM;
+ add_e820_entry(params, &ei);
+ }
+
+out:
+ vfree(cmem);
+ return ret;
+}
+
+static int determine_backup_region(u64 start, u64 end, void *arg)
+{
+ struct kimage *image = arg;
+
+ image->arch.backup_src_start = start;
+ image->arch.backup_src_sz = end - start + 1;
+
+ /* Expecting only one range for backup region */
+ return 1;
+}
+
+int crash_load_segments(struct kimage *image)
+{
+ unsigned long src_start, src_sz, elf_sz;
+ void *elf_addr;
+ int ret;
+
+ /*
+ * Determine and load a segment for backup area. First 640K RAM
+ * region is backup source
+ */
+
+ ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
+ image, determine_backup_region);
+
+ /* Zero or postive return values are ok */
+ if (ret < 0)
+ return ret;
+
+ src_start = image->arch.backup_src_start;
+ src_sz = image->arch.backup_src_sz;
+
+ /* Add backup segment. */
+ if (src_sz) {
+ /*
+ * Ideally there is no source for backup segment. This is
+ * copied in purgatory after crash. Just add a zero filled
+ * segment for now to make sure checksum logic works fine.
+ */
+ ret = kexec_add_buffer(image, (char *)&crash_zero_bytes,
+ sizeof(crash_zero_bytes), src_sz,
+ PAGE_SIZE, 0, -1, 0,
+ &image->arch.backup_load_addr);
+ if (ret)
+ return ret;
+ pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
+ image->arch.backup_load_addr, src_start, src_sz);
+ }
+
+ /* Prepare elf headers and add a segment */
+ ret = prepare_elf_headers(image, &elf_addr, &elf_sz);
+ if (ret)
+ return ret;
+
+ image->arch.elf_headers = elf_addr;
+ image->arch.elf_headers_sz = elf_sz;
+
+ ret = kexec_add_buffer(image, (char *)elf_addr, elf_sz, elf_sz,
+ ELF_CORE_HEADER_ALIGN, 0, -1, 0,
+ &image->arch.elf_load_addr);
+ if (ret) {
+ vfree((void *)image->arch.elf_headers);
+ return ret;
+ }
+ pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ image->arch.elf_load_addr, elf_sz, elf_sz);
+
+ return ret;
+}
+
+#endif /* CONFIG_X86_64 */
#include <asm/bootparam.h>
#include <asm/setup.h>
+#include <asm/crash.h>
+
+#define MAX_ELFCOREHDR_STR_LEN 30 /* elfcorehdr=0x<64bit-value> */
/*
* Defines lowest physical address for various segments. Not sure where
return 0;
}
-static int setup_cmdline(struct boot_params *params,
+static int setup_cmdline(struct kimage *image, struct boot_params *params,
unsigned long bootparams_load_addr,
unsigned long cmdline_offset, char *cmdline,
unsigned long cmdline_len)
{
char *cmdline_ptr = ((char *)params) + cmdline_offset;
- unsigned long cmdline_ptr_phys;
+ unsigned long cmdline_ptr_phys, len;
uint32_t cmdline_low_32, cmdline_ext_32;
memcpy(cmdline_ptr, cmdline, cmdline_len);
+ if (image->type == KEXEC_TYPE_CRASH) {
+ len = sprintf(cmdline_ptr + cmdline_len - 1,
+ " elfcorehdr=0x%lx", image->arch.elf_load_addr);
+ cmdline_len += len;
+ }
cmdline_ptr[cmdline_len - 1] = '\0';
+ pr_debug("Final command line is: %s\n", cmdline_ptr);
cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
cmdline_ext_32 = cmdline_ptr_phys >> 32;
return 0;
}
-static int setup_boot_parameters(struct boot_params *params)
+static int setup_boot_parameters(struct kimage *image,
+ struct boot_params *params)
{
unsigned int nr_e820_entries;
unsigned long long mem_k, start, end;
- int i;
+ int i, ret = 0;
/* Get subarch from existing bootparams */
params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
/* Default sysdesc table */
params->sys_desc_table.length = 0;
- setup_memory_map_entries(params);
+ if (image->type == KEXEC_TYPE_CRASH) {
+ ret = crash_setup_memmap_entries(image, params);
+ if (ret)
+ return ret;
+ } else
+ setup_memory_map_entries(params);
+
nr_e820_entries = params->e820_entries;
for (i = 0; i < nr_e820_entries; i++) {
memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
EDD_MBR_SIG_MAX * sizeof(unsigned int));
- return 0;
+ return ret;
}
int bzImage64_probe(const char *buf, unsigned long len)
}
/*
+ * In case of crash dump, we will append elfcorehdr=<addr> to
+ * command line. Make sure it does not overflow
+ */
+ if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
+ pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ /* Allocate and load backup region */
+ if (image->type == KEXEC_TYPE_CRASH) {
+ ret = crash_load_segments(image);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+
+ /*
* Load purgatory. For 64bit entry point, purgatory code can be
* anywhere.
*/
pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
/* Load Bootparams and cmdline */
- params_cmdline_sz = sizeof(struct boot_params) + cmdline_len;
+ params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
+ MAX_ELFCOREHDR_STR_LEN;
params = kzalloc(params_cmdline_sz, GFP_KERNEL);
if (!params)
return ERR_PTR(-ENOMEM);
setup_initrd(params, initrd_load_addr, initrd_len);
}
- setup_cmdline(params, bootparam_load_addr, sizeof(struct boot_params),
- cmdline, cmdline_len);
+ setup_cmdline(image, params, bootparam_load_addr,
+ sizeof(struct boot_params), cmdline, cmdline_len);
/* bootloader info. Do we need a separate ID for kexec kernel loader? */
params->hdr.type_of_loader = 0x0D << 4;
if (ret)
goto out_free_params;
- setup_boot_parameters(params);
+ ret = setup_boot_parameters(image, params);
+ if (ret)
+ goto out_free_params;
/* Allocate loader specific data */
ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
projects / platform / kernel / linux-exynos.git / commitdiff