[PATCH] arm: kdump: Add DT properties to crash dump kernel's DTB
Geert Uytterhoeven
geert+renesas at glider.be
Wed Sep 2 11:41:29 EDT 2020
Pass the following properties to the crash dump kernel, to provide a
modern DT interface between kexec and the crash dump kernel:
- linux,elfcorehdr: ELF core header segment, similar to the
"elfcorehdr=" kernel parameter.
- linux,usable-memory-range: Usable memory reserved for the crash dump
kernel.
This makes the memory reservation explicit, so Linux no longer needs
to mask the program counter, and rely on the "mem=" kernel parameter
to obtain the start and size of usable memory.
For backwards compatibility, the "elfcorehdr=" and "mem=" kernel
parameters are still appended to the kernel command line.
Loosely based on the ARM64 version by Akashi Takahiro.
Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
---
kexec/arch/arm/crashdump-arm.c | 10 ++-
kexec/arch/arm/crashdump-arm.h | 2 +
kexec/arch/arm/kexec-zImage-arm.c | 137 ++++++++++++++++++++++++++++++
3 files changed, 147 insertions(+), 2 deletions(-)
diff --git a/kexec/arch/arm/crashdump-arm.c b/kexec/arch/arm/crashdump-arm.c
index daa478868b4976d7..1ec1826c24b52ed9 100644
--- a/kexec/arch/arm/crashdump-arm.c
+++ b/kexec/arch/arm/crashdump-arm.c
@@ -54,7 +54,7 @@ struct memory_ranges usablemem_rgns = {
};
/* The boot-time physical memory range reserved for crashkernel region */
-static struct memory_range crash_kernel_mem;
+struct memory_range crash_kernel_mem;
/* reserved regions */
#define CRASH_MAX_RESERVED_RANGES 2
@@ -64,6 +64,8 @@ static struct memory_ranges crash_reserved_rgns = {
.ranges = crash_reserved_ranges,
};
+struct memory_range elfcorehdr_mem;
+
static struct crash_elf_info elf_info = {
.class = ELFCLASS32,
.data = ELFDATANATIVE,
@@ -307,7 +309,11 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline)
crash_kernel_mem.start,
crash_kernel_mem.end, -1, 0);
- dbgprintf("elfcorehdr: %#lx\n", elfcorehdr);
+ elfcorehdr_mem.start = elfcorehdr;
+ elfcorehdr_mem.end = elfcorehdr + bufsz - 1;
+
+ dbgprintf("elfcorehdr 0x%llx-0x%llx\n", elfcorehdr_mem.start,
+ elfcorehdr_mem.end);
cmdline_add_elfcorehdr(mod_cmdline, elfcorehdr);
/*
diff --git a/kexec/arch/arm/crashdump-arm.h b/kexec/arch/arm/crashdump-arm.h
index 6e87b13c4b8c86fe..bbdf8bf9de58eb5d 100644
--- a/kexec/arch/arm/crashdump-arm.h
+++ b/kexec/arch/arm/crashdump-arm.h
@@ -13,6 +13,8 @@ extern "C" {
extern struct memory_ranges usablemem_rgns;
+extern struct memory_range crash_kernel_mem;
+extern struct memory_range elfcorehdr_mem;
struct kexec_info;
diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
index 925a9be120aa401a..e056f79124240e40 100644
--- a/kexec/arch/arm/kexec-zImage-arm.c
+++ b/kexec/arch/arm/kexec-zImage-arm.c
@@ -4,6 +4,7 @@
*/
#define _GNU_SOURCE
#define _XOPEN_SOURCE
+#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
@@ -374,6 +375,103 @@ static const struct zimage_tag *find_extension_tag(const char *buf, off_t len,
return NULL;
}
+static int get_cells_size(void *fdt, uint32_t *address_cells,
+ uint32_t *size_cells)
+{
+ int nodeoffset;
+ const uint32_t *prop = NULL;
+ int prop_len;
+
+ /* default values */
+ *address_cells = 1;
+ *size_cells = 1;
+
+ /* under root node */
+ nodeoffset = fdt_path_offset(fdt, "/");
+ if (nodeoffset < 0)
+ return -1;
+
+ prop = fdt_getprop(fdt, nodeoffset, "#address-cells", &prop_len);
+ if (prop) {
+ if (prop_len != sizeof(*prop))
+ return -1;
+
+ *address_cells = fdt32_to_cpu(*prop);
+ }
+
+ prop = fdt_getprop(fdt, nodeoffset, "#size-cells", &prop_len);
+ if (prop) {
+ if (prop_len != sizeof(*prop))
+ return -1;
+
+ *size_cells = fdt32_to_cpu(*prop);
+ }
+
+ dbgprintf("%s: #address-cells:%d #size-cells:%d\n", __func__,
+ *address_cells, *size_cells);
+ return 0;
+}
+
+static bool cells_size_fitted(uint32_t address_cells, uint32_t size_cells,
+ struct memory_range *range)
+{
+ dbgprintf("%s: %llx-%llx\n", __func__, range->start, range->end);
+
+ /* if *_cells >= 2, cells can hold 64-bit values anyway */
+ if ((address_cells == 1) && (range->start >= (1ULL << 32)))
+ return false;
+
+ if ((size_cells == 1) &&
+ ((range->end - range->start + 1) >= (1ULL << 32)))
+ return false;
+
+ return true;
+}
+
+static void fill_property(void *buf, uint64_t val, uint32_t cells)
+{
+ uint32_t val32;
+ int i;
+
+ if (cells == 1) {
+ val32 = cpu_to_fdt32((uint32_t)val);
+ memcpy(buf, &val32, sizeof(uint32_t));
+ } else {
+ for (i = 0;
+ i < (cells * sizeof(uint32_t) - sizeof(uint64_t)); i++)
+ *(char *)buf++ = 0;
+
+ val = cpu_to_fdt64(val);
+ memcpy(buf, &val, sizeof(uint64_t));
+ }
+}
+
+static int setup_dtb_prop_range(char **bufp, off_t *sizep, int parentoffset,
+ const char *node_name, const char *prop_name,
+ struct memory_range *range,
+ uint32_t address_cells, uint32_t size_cells)
+{
+ void *buf, *prop;
+ size_t buf_size;
+ int result;
+
+ buf_size = (address_cells + size_cells) * sizeof(uint32_t);
+ prop = buf = xmalloc(buf_size);
+
+ fill_property(prop, range->start, address_cells);
+ prop += address_cells * sizeof(uint32_t);
+
+ fill_property(prop, range->end - range->start + 1, size_cells);
+ prop += size_cells * sizeof(uint32_t);
+
+ result = setup_dtb_prop(bufp, sizep, parentoffset, node_name,
+ prop_name, buf, buf_size);
+
+ free(buf);
+
+ return result;
+}
+
int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
struct kexec_info *info)
{
@@ -381,6 +479,7 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
unsigned long base, kernel_base;
unsigned int atag_offset = 0x1000; /* 4k offset from memory start */
unsigned int extra_size = 0x8000; /* TEXT_OFFSET */
+ uint32_t address_cells, size_cells;
const struct zimage_tag *tag;
size_t kernel_mem_size;
const char *command_line;
@@ -390,6 +489,7 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
const char *ramdisk_buf;
int opt;
int use_atags;
+ int result;
char *dtb_buf;
off_t dtb_length;
char *dtb_file;
@@ -733,6 +833,43 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
return -1;
}
+ if (info->kexec_flags & KEXEC_ON_CRASH) {
+ /* Determine #address-cells and #size-cells */
+ result = get_cells_size(dtb_buf, &address_cells,
+ &size_cells);
+ if (result) {
+ fprintf(stderr, "Cannot determine cells-size.\n");
+ return -1;
+ }
+
+ if (!cells_size_fitted(address_cells, size_cells,
+ &elfcorehdr_mem)) {
+ fprintf(stderr, "elfcorehdr doesn't fit cells-size.\n");
+ return -1;
+ }
+
+ if (!cells_size_fitted(address_cells, size_cells,
+ &crash_kernel_mem)) {
+ fprintf(stderr, "kexec: usable memory range doesn't fit cells-size.\n");
+ return -1;
+ }
+
+ /* Add linux,elfcorehdr */
+ if (setup_dtb_prop_range(&dtb_buf, &dtb_length, 0,
+ "chosen", "linux,elfcorehdr",
+ &elfcorehdr_mem,
+ address_cells, size_cells))
+ return -1;
+
+ /* Add linux,usable-memory-range */
+ if (setup_dtb_prop_range(&dtb_buf, &dtb_length, 0,
+ "chosen",
+ "linux,usable-memory-range",
+ &crash_kernel_mem,
+ address_cells, size_cells))
+ return -1;
+ }
+
/*
* The dtb must also be placed above the memory used by
* the zImage. We don't care about its position wrt the
--
2.17.1
More information about the linux-arm-kernel
mailing list