[PATCH v3 2/3] arm64: Add arm64 kexec support

On Tue, 2016-08-09 at 12:05 +0900, AKASHI Takahiro wrote:

On Mon, Aug 08, 2016 at 10:19:33PM +0000, Geoff Levand wrote:

quoted

+/**
+ * struct arm64_image_header - arm64 kernel image header.
+ *
+ * @pe_sig: Optional PE format 'MZ' signature.
+ * @branch_code: Reserved for instructions to branch to stext.
+ * @text_offset: The image load offset in LSB byte order.
+ * @image_size: An estimated size of the memory image size in LSB byte order.
+ * @flags: Bit flags in LSB byte order:
+ *   Bit 0:   Image byte order: 1=MSB.
+ *   Bit 1-2: Kernel page size: 1=4K, 2=16K, 3=64K.
+ *   Bit 3:   Image placement: 0=low.
+ * @reserved_1: Reserved.
+ * @magic: Magic number, "ARM\x64".
+ * @pe_header: Optional offset to a PE format header.
+ **/
+
+struct arm64_image_header {
+> > 	> > uint8_t pe_sig[2];
+> > 	> > uint16_t branch_code[3];
+> > 	> > uint64_t text_offset;
+> > 	> > uint64_t image_size;
+> > 	> > uint64_t flags;
+> > 	> > uint64_t reserved_1[3];
+> > 	> > uint8_t magic[4];
+> > 	> > uint32_t pe_header;
+};
+
+static const uint8_t arm64_image_magic[4] = {'A', 'R', 'M', 0x64U};
+static const uint8_t arm64_image_pe_sig[2] = {'M', 'Z'};
+static const uint64_t arm64_image_flag_be = (1UL << 0);
+static const uint64_t arm64_image_flag_page_size = (3UL << 1);
+static const uint64_t arm64_image_flag_placement = (1UL << 3);

Why not define like:
#define ARM64_FLAG_PAGE_SIZE_4K  1
#define ARM64_FLAG_PAGE_SIZE_16K 2
#define ARM64_FLAG_PAGE_SIZE_64K 3
if you have arm64_header_page_size()?

To give them a type, I added these in as enum arm64_header_page_size.

quoted

+
+/**
+ * arm64_header_check_magic - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if header is OK.
+ */
+
+static inline int arm64_header_check_magic(const struct arm64_image_header *h)
+{
+> > 	> > if (!h)
+> > 	> > 	> > return 0;
+
+> > 	> > return (h->magic[0] == arm64_image_magic[0]
+> > 	> > 	> > && h->magic[1] == arm64_image_magic[1]
+> > 	> > 	> > && h->magic[2] == arm64_image_magic[2]
+> > 	> > 	> > && h->magic[3] == arm64_image_magic[3]);
+}
+
+/**
+ * arm64_header_check_pe_sig - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if 'MZ' signature is found.
+ */
+
+static inline int arm64_header_check_pe_sig(const struct arm64_image_header *h)
+{
+> > 	> > if (!h)
+> > 	> > 	> > return 0;

Why not add assert() here like get_phys_offset()?

The assert in get_phys_offset() is to check for incorrect usage.
arm64_header_check_pe_sig is a generic routine, and having a null
value may be OK.

quoted

+
+static inline uint64_t arm64_header_text_offset(
+> > 	> > const struct arm64_image_header *h)
+{

Why not check for !h?

ok.

quoted

--- /dev/null
+++ b/kexec/arch/arm64/kexec-arm64.c
+static int get_memory_ranges_dt(struct memory_range *array, unsigned int *count)
+{
+> > 	> > struct region {uint64_t base; uint64_t size;};
+> > 	> > struct dtb dtb = {.name = "range_dtb"};
+> > 	> > int offset;
+> > 	> > int result;
+
+> > 	> > *count = 0;
+
+> > 	> > result = read_1st_dtb(&dtb);
+
+> > 	> > if (result) {
+> > 	> > 	> > goto on_error;
+> > 	> > }
+
+> > 	> > result = fdt_check_header(dtb.buf);
+
+> > 	> > if (result) {
+> > 	> > 	> > dbgprintf("%s:%d: %s: fdt_check_header failed:%s\n", __func__,
+> > 	> > 	> > 	> > __LINE__, dtb.path, fdt_strerror(result));
+> > 	> > 	> > goto on_error;
+> > 	> > }
+
+> > 	> > for (offset = 0; ; ) {
+> > 	> > 	> > const struct region *region;
+> > 	> > 	> > const struct region *end;
+> > 	> > 	> > int len;
+
+> > 	> > 	> > offset = fdt_subnode_offset(dtb.buf, offset, "memory");
+
+> > 	> > 	> > if (offset == -FDT_ERR_NOTFOUND)
+> > 	> > 	> > 	> > break;
+
+> > 	> > 	> > if (offset <= 0) {
+> > 	> > 	> > 	> > dbgprintf("%s:%d: fdt_subnode_offset failed: %d %s\n",
+> > 	> > 	> > 	> > 	> > __func__, __LINE__, offset,
+> > 	> > 	> > 	> > 	> > fdt_strerror(offset));
+> > 	> > 	> > 	> > goto on_error;
+> > 	> > 	> > }
+
+> > 	> > 	> > dbgprintf("%s:%d: node_%d %s\n", __func__, __LINE__, offset,
+> > 	> > 	> > 	> > fdt_get_name(dtb.buf, offset, NULL));
+
+> > 	> > 	> > region = fdt_getprop(dtb.buf, offset, "reg", &len);
+
+> > 	> > 	> > if (region <= 0) {
+> > 	> > 	> > 	> > dbgprintf("%s:%d: fdt_getprop failed: %d %s\n",
+> > 	> > 	> > 	> > 	> > __func__, __LINE__, offset,
+> > 	> > 	> > 	> > 	> > fdt_strerror(offset));
+> > 	> > 	> > 	> > goto on_error;
+> > 	> > 	> > }
+
+> > 	> > 	> > for (end = region + len / sizeof(*region);
+> > 	> > 	> > 	> > region < end && *count < KEXEC_SEGMENT_MAX;
+> > 	> > 	> > 	> > region++) {
+> > 	> > 	> > 	> > struct memory_range r;
+
+> > 	> > 	> > 	> > r.type = RANGE_RAM;
+> > 	> > 	> > 	> > r.start = fdt64_to_cpu(region->base);
+> > 	> > 	> > 	> > r.end = r.start + fdt64_to_cpu(region->size) - 1;
+
+> > 	> > 	> > 	> > if (!region->size) {
+> > 	> > 	> > 	> > 	> > dbgprintf("%s:%d: SKIP: %016llx - %016llx\n",
+> > 	> > 	> > 	> > 	> > 	> > __func__, __LINE__, r.start, r.end);
+> > 	> > 	> > 	> > 	> > continue;
+> > 	> > 	> > 	> > }
+
+> > 	> > 	> > 	> > dbgprintf("%s:%d:  RAM: %016llx - %016llx\n", __func__,
+> > 	> > 	> > 	> > 	> > __LINE__, r.start, r.end);
+
+> > 	> > 	> > 	> > array[(*count)++] = r;
+
+> > 	> > 	> > 	> > set_phys_offset(r.start);
+> > 	> > 	> > }
+> > 	> > }
+
+> > 	> > if (!*count) {
+> > 	> > 	> > dbgprintf("%s:%d: %s: No RAM found.\n", __func__, __LINE__,
+> > 	> > 	> > 	> > dtb.path);
+> > 	> > 	> > goto on_error;
+> > 	> > }
+
+> > 	> > dbgprintf("%s:%d: %s: Success\n", __func__, __LINE__, dtb.path);
+> > 	> > result = 0;
+> > 	> > goto on_exit;
+
+on_error:
+> > 	> > fprintf(stderr, "%s:%d: %s: Unusable device-tree file\n", __func__,
+> > 	> > 	> > __LINE__, dtb.path);
+> > 	> > result = -1;

EFAILED?

quoted

+
+on_exit:
+> > 	> > free(dtb.buf);
+> > 	> > return -EFAILED;

return result?

OK.

quoted

+}
+
+/**
+ * get_memory_ranges - Try to get the memory ranges some how.
+ */
+
+int get_memory_ranges(struct memory_range **range, int *ranges,
+> > 	> > unsigned long kexec_flags)
+{
+> > 	> > static struct memory_range array[KEXEC_SEGMENT_MAX];
+> > 	> > unsigned int count;
+> > 	> > int result;
+
+> > 	> > result = get_memory_ranges_iomem(array, &count);
+
+> > 	> > if (result)
+> > 	> > 	> > result = get_memory_ranges_dt(array, &count);
+
+> > 	> > *range = result ? NULL : array;
+> > 	> > *ranges = result ? 0 : count;
+
+> > 	> > return -EFAILED;

return result?

OK.

quoted

+}
+
+int arch_compat_trampoline(struct kexec_info *info)
+{
+> > 	> > return 0;
+}
+
+int machine_verify_elf_rel(struct mem_ehdr *ehdr)
+{
+> > 	> > return (ehdr->e_machine == EM_AARCH64);
+}
+
+void machine_apply_elf_rel(struct mem_ehdr *ehdr, struct mem_sym *UNUSED(sym),
+> > 	> > unsigned long r_type, void *ptr, unsigned long address,
+> > 	> > unsigned long value)
+{
+#if !defined(R_AARCH64_ABS64)
+# define R_AARCH64_ABS64 257
+#endif
+
+#if !defined(R_AARCH64_LD_PREL_LO19)
+# define R_AARCH64_LD_PREL_LO19 273
+#endif
+
+#if !defined(R_AARCH64_ADR_PREL_LO21)
+# define R_AARCH64_ADR_PREL_LO21 274
+#endif
+
+#if !defined(R_AARCH64_JUMP26)
+# define R_AARCH64_JUMP26 282
+#endif
+
+#if !defined(R_AARCH64_CALL26)
+# define R_AARCH64_CALL26 283
+#endif

I still believe those definitons should go into elf.h.

They should be comming from the c library headers.  When
toolchains catch up these can be removed.

quoted

--- /dev/null
+++ b/kexec/arch/arm64/kexec-arm64.h

@@ -0,0 +1,70 @@
+/*
+ * ARM64 kexec.
+ */
+
+#if !defined(KEXEC_ARM64_H)
+#define KEXEC_ARM64_H
+
+#include 
+#include 
+
+#include "image-header.h"
+#include "kexec.h"
+
+#define KEXEC_SEGMENT_MAX 16
+
+#define BOOT_BLOCK_VERSION 17
+#define BOOT_BLOCK_LAST_COMP_VERSION 16
+#define COMMAND_LINE_SIZE 512
+
+#define KiB(x) ((x) * 1024UL)
+#define MiB(x) (KiB(x) * 1024UL)
+#define GiB(x) (MiB(x) * 1024UL)
+
+int elf_arm64_probe(const char *kernel_buf, off_t kernel_size);
+int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
+> > 	> > off_t kernel_size, struct kexec_info *info);
+void elf_arm64_usage(void);
+
+int image_arm64_probe(const char *kernel_buf, off_t kernel_size);
+int image_arm64_load(int argc, char **argv, const char *kernel_buf,
+> > 	> > off_t kernel_size, struct kexec_info *info);
+void image_arm64_usage(void);
+
+off_t initrd_base;
+off_t initrd_size;
+
+/**
+ * struct arm64_mem - Memory layout info.
+ */
+
+struct arm64_mem {
+> > 	> > uint64_t phys_offset;
+> > 	> > uint64_t text_offset;
+> > 	> > uint64_t image_size;
+> > 	> > uint64_t page_offset;
+};
+
+#define arm64_mem_ngv UINT64_MAX

In image_header.h, you define "const" variables,
here you define a macro.

Yes, because arm64_mem_ngv is used as a static
initializer of arm64_mem.

quoted

+struct arm64_mem arm64_mem;
+
+uint64_t get_phys_offset(void);
+uint64_t get_page_offset(void);
+
+static inline void reset_page_offset(void)
+{
+> > 	> > arm64_mem.page_offset = arm64_mem_ngv;
+}
+
+static inline void set_phys_offset(uint64_t v)
+{
+> > 	> > if (arm64_mem.phys_offset == arm64_mem_ngv
+> > 	> > 	> > || v < arm64_mem.phys_offset)
+> > 	> > 	> > arm64_mem.phys_offset = v;
+}
+
+int arm64_process_image_header(const struct arm64_image_header *h);
+int arm64_load_other_segments(struct kexec_info *info,
+> > 	> > uint64_t kernel_entry);
+
+#endif

diff --git a/kexec/arch/arm64/kexec-elf-arm64.c b/kexec/arch/arm64/kexec-elf-arm64.c
new file mode 100644
index 0000000..fcac9bb
--- /dev/null
+++ b/kexec/arch/arm64/kexec-elf-arm64.c

@@ -0,0 +1,130 @@
+/*
+ * ARM64 kexec elf support.
+ */
+
+#define _GNU_SOURCE
+
+#include 
+#include 
+#include 
+
+#include "kexec-arm64.h"
+#include "kexec-elf.h"
+#include "kexec-syscall.h"
+
+int elf_arm64_probe(const char *kernel_buf, off_t kernel_size)
+{
+> > 	> > struct mem_ehdr ehdr;
+> > 	> > int result;
+
+> > 	> > result = build_elf_exec_info(kernel_buf, kernel_size, &ehdr, 0);
+
+> > 	> > if (result < 0) {
+> > 	> > 	> > dbgprintf("%s: Not an ELF executable.\n", __func__);
+> > 	> > 	> > goto on_exit;
+> > 	> > }
+
+> > 	> > if (ehdr.e_machine != EM_AARCH64) {
+> > 	> > 	> > dbgprintf("%s: Not an AARCH64 ELF executable.\n", __func__);
+> > 	> > 	> > result = -1;
+> > 	> > 	> > goto on_exit;
+> > 	> > }
+
+> > 	> > result = 0;
+on_exit:
+> > 	> > free_elf_info(&ehdr);
+> > 	> > return result;
+}
+
+int elf_arm64_load(int argc, char **argv, const char *kernel_buf,
+> > 	> > off_t kernel_size, struct kexec_info *info)
+{
+> > 	> > struct mem_ehdr ehdr;
+> > 	> > int result;
+> > 	> > int i;
+
+> > 	> > if (info->kexec_flags & KEXEC_ON_CRASH) {
+> > 	> > 	> > fprintf(stderr, "kexec: kdump not yet supported on arm64\n");
+> > 	> > 	> > return -EFAILED;
+> > 	> > }
+
+> > 	> > result = build_elf_exec_info(kernel_buf, kernel_size, &ehdr, 0);
+
+> > 	> > if (result < 0) {
+> > 	> > 	> > dbgprintf("%s: build_elf_exec_info failed\n", __func__);
+> > 	> > 	> > goto exit;
+> > 	> > }
+
+> > 	> > /* Find and process the arm64 image header. */
+
+> > 	> > for (i = 0; i < ehdr.e_phnum; i++) {
+> > 	> > 	> > struct mem_phdr *phdr = &ehdr.e_phdr[i];
+> > 	> > 	> > const struct arm64_image_header *h;
+> > 	> > 	> > unsigned long header_offset;
+
+> > 	> > 	> > if (phdr->p_type != PT_LOAD)
+> > 	> > 	> > 	> > continue;
+
+> > 	> > 	> > /*
+> > 	> > 	> >  * When CONFIG_ARM64_RANDOMIZE_TEXT_OFFSET=y the image header
+> > 	> > 	> >  * could be offset in the elf segment.  The linker script sets
+> > 	> > 	> >  * ehdr.e_entry to the start of text.
+> > 	> > 	> >  */
+
+> > 	> > 	> > header_offset = ehdr.e_entry - phdr->p_vaddr;
+
+> > 	> > 	> > h = (const struct arm64_image_header *)(
+> > 	> > 	> > 	> > kernel_buf + phdr->p_offset + header_offset);
+
+> > 	> > 	> > if (arm64_process_image_header(h))
+> > 	> > 	> > 	> > continue;
+
+> > 	> > 	> > arm64_mem.page_offset = ehdr.e_entry - arm64_mem.text_offset;
+
+> > 	> > 	> > dbgprintf("%s: e_entry:       %016llx -> %016lx\n", __func__,
+> > 	> > 	> > 	> > ehdr.e_entry,
+> > 	> > 	> > 	> > virt_to_phys(ehdr.e_entry));
+> > 	> > 	> > dbgprintf("%s: p_vaddr:       %016llx -> %016lx\n", __func__,
+> > 	> > 	> > 	> > phdr->p_vaddr,
+> > 	> > 	> > 	> > virt_to_phys(phdr->p_vaddr));
+> > 	> > 	> > dbgprintf("%s: header_offset: %016lx\n", __func__,
+> > 	> > 	> > 	> > header_offset);
+> > 	> > 	> > dbgprintf("%s: text_offset:   %016lx\n", __func__,
+> > 	> > 	> > 	> > arm64_mem.text_offset);
+> > 	> > 	> > dbgprintf("%s: image_size:    %016lx\n", __func__,
+> > 	> > 	> > 	> > arm64_mem.image_size);
+> > 	> > 	> > dbgprintf("%s: phys_offset:   %016lx\n", __func__,
+> > 	> > 	> > 	> > arm64_mem.phys_offset);
+> > 	> > 	> > dbgprintf("%s: page_offset:   %016lx\n", __func__,
+> > 	> > 	> > 	> > arm64_mem.page_offset);
+> > 	> > 	> > dbgprintf("%s: PE format:     %s\n", __func__,
+> > 	> > 	> > 	> > (arm64_header_check_pe_sig(h) ? "yes" : "no"));
+
+> > 	> > 	> > result = elf_exec_load(&ehdr, info);
+
+> > 	> > 	> > if (result) {
+> > 	> > 	> > 	> > fprintf(stderr, "kexec: Elf load failed.\n");

dbgprintf?
You use this for build_elf_exec_info() above.

quoted

+> > 	> > 	> > 	> > goto exit;
+> > 	> > 	> > }
+
+> > 	> > 	> > result = arm64_load_other_segments(info,
+> > 	> > 	> > 	> > virt_to_phys(ehdr.e_entry));
+> > 	> > 	> > goto exit;
+> > 	> > }
+
+> > 	> > fprintf(stderr, "kexec: Bad arm64 image header.\n");

Is this an appropriate message?

I changed elf_arm64_load to output dbgprintf during its operation, then
a final message to stderr on exit.

quoted

+> > 	> > result = -EFAILED;
+> > 	> > goto exit;
+
+exit:
+> > 	> > reset_page_offset();
+> > 	> > free_elf_info(&ehdr);
+> > 	> > return result;
+}
+

--- /dev/null
+++ b/kexec/arch/arm64/kexec-image-arm64.c

@@ -0,0 +1,44 @@
+/*
+ * ARM64 kexec binary image support.
+ */
+
+#define _GNU_SOURCE
+
+#include 

Not used.

OK.

Thanks for the review.

-Geoff