It was <2020-06-01 pon 16:07>, when Russell King - ARM Linux admin wrote: > On Mon, Jun 01, 2020 at 04:27:54PM +0200, Łukasz Stelmach wrote: >> This is kexec_file_load implementation for ARM. It loads zImage and >> initrd from file descripters and resuses DTB. >> >> Most code is derived from arm64 kexec_file_load implementation >> and from kexec-tools. > > Please make the uImage loader able to be configured out of the > kernel; it's a legacy image format now, and some of us just don't > use it anymore. That way, those who wish to have it can, and > those who wish not to can have a smaller kernel.
The difference in size of arch/arm/boot/Image is 160 bytes, but OK. Done. >> Cc: AKASHI Takahiro <[email protected]> >> Signed-off-by: Łukasz Stelmach <[email protected]> >> --- >> arch/arm/Kconfig | 15 ++ >> arch/arm/include/asm/image.h | 26 ++++ >> arch/arm/include/asm/kexec.h | 14 ++ >> arch/arm/kernel/Makefile | 5 +- >> arch/arm/kernel/kexec_uimage.c | 80 ++++++++++ >> arch/arm/kernel/kexec_zimage.c | 199 +++++++++++++++++++++++++ >> arch/arm/kernel/machine_kexec.c | 11 +- >> arch/arm/kernel/machine_kexec_file.c | 209 +++++++++++++++++++++++++++ >> 8 files changed, 554 insertions(+), 5 deletions(-) >> create mode 100644 arch/arm/kernel/kexec_uimage.c >> create mode 100644 arch/arm/kernel/kexec_zimage.c >> create mode 100644 arch/arm/kernel/machine_kexec_file.c >> >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig >> index c77c93c485a0..6adb849cb304 100644 >> --- a/arch/arm/Kconfig >> +++ b/arch/arm/Kconfig >> @@ -1917,6 +1917,21 @@ config KEXEC >> is properly shutdown, so do not be surprised if this code does not >> initially work for you. >> >> +config KEXEC_FILE >> + bool "Kexec file based system call (EXPERIMENTAL)" >> + depends on (!SMP || PM_SLEEP_SMP) >> + depends on USE_OF >> + select KEXEC_CORE >> + select CRC32 >> + help >> + This is new version of kexec system call. This system call is >> + file based and takes file descriptors as system call argument >> + for kernel and initramfs as opposed to list of segments as >> + accepted by previous system call. >> + >> + The kernel to be loaded MUST support Flattened Device Tree >> + (selected with CONFIG_USE_OF). >> + >> config ATAGS_PROC >> bool "Export atags in procfs" >> depends on ATAGS && KEXEC >> diff --git a/arch/arm/include/asm/image.h b/arch/arm/include/asm/image.h >> index 624438740f23..95f23837b04f 100644 >> --- a/arch/arm/include/asm/image.h >> +++ b/arch/arm/include/asm/image.h >> @@ -8,8 +8,13 @@ >> (((x) >> 8) & 0x0000ff00) | \ >> (((x) << 8) & 0x00ff0000) | \ >> (((x) << 24) & 0xff000000)) >> +#define UIMAGE_MAGIC(x) (x) >> #else >> #define ZIMAGE_MAGIC(x) (x) >> +#define UIMAGE_MAGIC(x) ((((x) >> 24) & 0x000000ff) | \ >> + (((x) >> 8) & 0x0000ff00) | \ >> + (((x) << 8) & 0x00ff0000) | \ >> + (((x) << 24) & 0xff000000)) >> #endif >> >> #define ARM_ZIMAGE_MAGIC1 ZIMAGE_MAGIC(0x016f2818) >> @@ -17,6 +22,12 @@ >> #define ARM_ZIMAGE_MAGIC3 ZIMAGE_MAGIC(0x5a534c4b) >> #define ARM_ZIMAGE_MAGIC4 ZIMAGE_MAGIC(0x5a534344) >> >> +#define ARM_UIMAGE_MAGIC UIMAGE_MAGIC(0x27051956) >> +#define ARM_UIMAGE_NAME_LEN 32 >> +#define ARM_UIMAGE_TYPE_KERNEL 2 >> +#define ARM_UIMAGE_TYPE_KERNEL_NOLOAD 14 >> +#define ARM_UIMAGE_ARCH_ARM 2 >> + >> #ifndef __ASSEMBLY__ >> >> #include <linux/types.h> >> @@ -33,6 +44,21 @@ struct arm_zimage_header { >> __le32 extension_tag_offset; >> }; >> >> +struct arm_uimage_header { >> + __be32 magic; >> + __be32 hdr_crc; >> + __be32 time; >> + __be32 size; >> + __be32 load; >> + __be32 entry; >> + __be32 crc; >> + __u8 os; >> + __u8 arch; >> + __u8 type; >> + __u8 comp; >> + __u8 name[ARM_UIMAGE_NAME_LEN]; >> +}; >> + >> struct arm_zimage_tag { >> struct tag_header hdr; >> union { >> diff --git a/arch/arm/include/asm/kexec.h b/arch/arm/include/asm/kexec.h >> index 22751b5b5735..fda35afa7195 100644 >> --- a/arch/arm/include/asm/kexec.h >> +++ b/arch/arm/include/asm/kexec.h >> @@ -83,6 +83,20 @@ static inline struct page *boot_pfn_to_page(unsigned long >> boot_pfn) >> } >> #define boot_pfn_to_page boot_pfn_to_page >> >> +#ifdef CONFIG_KEXEC_FILE >> + >> +extern const struct kexec_file_ops kexec_zimage_ops; >> +extern const struct kexec_file_ops kexec_uimage_ops; >> + >> +struct kimage; >> + >> +extern int load_other_segments(struct kimage *image, >> + unsigned long kernel_load_addr, unsigned long kernel_size, >> + char *initrd, unsigned long initrd_len, >> + unsigned long initrd_offset, char *cmdline); >> + >> +#endif /* CONFIG_KEXEC_FILE */ >> + >> #endif /* __ASSEMBLY__ */ >> >> #endif /* CONFIG_KEXEC */ >> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile >> index 89e5d864e923..466c683bb551 100644 >> --- a/arch/arm/kernel/Makefile >> +++ b/arch/arm/kernel/Makefile >> @@ -3,6 +3,7 @@ >> # Makefile for the linux kernel. >> # >> >> +CFLAGS_kexec_zimage.o := -DTEXT_OFFSET=$(TEXT_OFFSET) >> CPPFLAGS_vmlinux.lds := -DTEXT_OFFSET=$(TEXT_OFFSET) >> AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET) >> >> @@ -56,7 +57,9 @@ obj-$(CONFIG_FUNCTION_TRACER) += entry-ftrace.o >> obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o patch.o >> obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o patch.o >> obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o >> -obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o >> +obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o >> +obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o kexec_zimage.o \ >> + kexec_uimage.o >> # Main staffs in KPROBES are in arch/arm/probes/ . >> obj-$(CONFIG_KPROBES) += patch.o insn.o >> obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o >> diff --git a/arch/arm/kernel/kexec_uimage.c b/arch/arm/kernel/kexec_uimage.c >> new file mode 100644 >> index 000000000000..47033574e24e >> --- /dev/null >> +++ b/arch/arm/kernel/kexec_uimage.c >> @@ -0,0 +1,80 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Kexec uImage loader >> + * >> + * Copyright (C) 2020 Samsung Electronics >> + * Author: Łukasz Stelmach <[email protected]> >> + */ >> + >> +#define pr_fmt(fmt) "kexec_file(uImage): " fmt >> + >> +#include <asm/image.h> >> +#include <linux/crc32.h> >> +#include <linux/err.h> >> +#include <linux/kexec.h> >> + >> +#define crc32_ones(crc, buf, len) \ >> + (crc32(crc ^ 0xffffffff, buf, len) ^ 0xffffffff) >> + >> +static int uimage_probe(const char *uimage_buf, unsigned long uimage_len) >> +{ >> + const struct arm_uimage_header *h = >> + (struct arm_uimage_header *) uimage_buf; >> + struct arm_uimage_header uhdr; >> + unsigned long zoff = sizeof(struct arm_uimage_header); >> + uint32_t crc; >> + >> + if (h->magic != ARM_UIMAGE_MAGIC) >> + return -EINVAL; >> + >> + if (h->type != ARM_UIMAGE_TYPE_KERNEL && >> + h->type != ARM_UIMAGE_TYPE_KERNEL_NOLOAD){ >> + pr_debug("Invalid image type: %d\n", h->type); >> + return -EINVAL; >> + } >> + >> + if (h->arch != ARM_UIMAGE_ARCH_ARM) { >> + pr_debug("Invalidy image arch: %d\n", h->arch); >> + return -EINVAL; >> + } >> + >> + memcpy((char *)&uhdr, h, sizeof(uhdr)); >> + crc = be32_to_cpu(uhdr.hdr_crc); >> + uhdr.hdr_crc = 0; >> + >> + if (crc32_ones(0, (char *)&uhdr, sizeof(uhdr)) != crc) { >> + pr_debug("Corrupt header, CRC do not match\n"); >> + return -EINVAL; >> + } >> + >> + crc = be32_to_cpu(uhdr.crc); >> + if (crc32_ones(0, uimage_buf + zoff, uimage_len - zoff) != crc) { >> + pr_debug("Corrupt zImage, CRC do not match\n"); >> + return -EINVAL; >> + } >> + >> + return kexec_zimage_ops.probe(uimage_buf + zoff, >> + uimage_len - zoff); >> +} >> + >> +static void *uimage_load(struct kimage *image, >> + char *uimage, unsigned long uimage_len, >> + char *initrd, unsigned long initrd_len, >> + char *cmdline, unsigned long cmdline_len) >> +{ >> + const struct arm_uimage_header *h = >> + (struct arm_uimage_header *) uimage; >> + unsigned long zimage_offset = sizeof(struct arm_uimage_header); >> + >> + pr_debug("Loading uImage"); >> + return kexec_zimage_ops.load(image, >> + uimage + zimage_offset, >> + uimage_len - zimage_offset, >> + initrd, initrd_len, >> + cmdline, cmdline_len); >> +} >> + >> +const struct kexec_file_ops kexec_uimage_ops = { >> + .probe = uimage_probe, >> + .load = uimage_load, >> +}; >> diff --git a/arch/arm/kernel/kexec_zimage.c b/arch/arm/kernel/kexec_zimage.c >> new file mode 100644 >> index 000000000000..d09795fc9072 >> --- /dev/null >> +++ b/arch/arm/kernel/kexec_zimage.c >> @@ -0,0 +1,199 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Kexec zImage loader >> + * >> + * Copyright (C) 2020 Samsung Electronics >> + * Author: Łukasz Stelmach <[email protected]> > > Please credit me as part author of this - you have taken some of my > code from the userspace kexec tool (such as the contents of > find_extension_tag()) and copied it in here, so this is not all your > own work. Done. >> + */ >> + >> +#define pr_fmt(fmt) "kexec_file(zImage): " fmt >> + >> +#include <asm/image.h> >> +#include <asm/unaligned.h> >> +#include <linux/err.h> >> +#include <linux/kexec.h> >> +#include <linux/memblock.h> >> + >> +#define byte_size(t) ((t)->hdr.size << 2) >> + >> +static const void *find_extension_tag(const char *buf, >> + unsigned long len, >> + uint32_t tag_id) >> +{ >> + const struct arm_zimage_header *h = (const struct arm_zimage_header >> *)buf; >> + const struct arm_zimage_tag *tag; >> + uint32_t offset, size; >> + uint32_t max = len - sizeof(struct tag_header); >> + >> + if (len < sizeof(*h) || >> + h->magic != ARM_ZIMAGE_MAGIC1 || >> + h->magic2 != ARM_ZIMAGE_MAGIC2) >> + return NULL; >> + >> + for (offset = h->extension_tag_offset; >> + (tag = (void *)(buf + offset)) != NULL && >> + offset < max && >> + (size = le32_to_cpu(byte_size(tag))) != 0 && >> + offset + size < len; >> + offset += size) { >> + pr_debug(" offset 0x%08x tag 0x%08x size %u\n", >> + offset, le32_to_cpu(tag->hdr.tag), size); >> + if (tag->hdr.tag == tag_id) >> + return tag; >> + } >> + >> + return NULL; >> +} >> + >> +static int zimage_probe(const char *kernel_buf, unsigned long kernel_len) >> +{ >> + const struct arm_zimage_header *h = >> + (struct arm_zimage_header *)(kernel_buf); >> + >> + if (!h || (kernel_len < sizeof(*h))) >> + return -EINVAL; >> + >> + if ((h->magic != ARM_ZIMAGE_MAGIC1) || >> + (h->magic2 != ARM_ZIMAGE_MAGIC2)) >> + return -EINVAL; >> + >> + return 0; >> +} >> + >> + >> +#if defined(DEBUG) >> +#define debug_offsets() ({ \ >> + pr_debug("Image offsets:\n"); \ >> + pr_debug(" kernel 0x%08lx 0x%08lx\n", kernel_offset, kernel_len); \ >> + pr_debug(" zimage 0x%08lx 0x%08lx\n", zimage_offset, zimage_len); \ >> + pr_debug(" initrd 0x%08lx 0x%08lx\n", initrd_offset, initrd_len); \ >> +}) >> +#else >> +#define debug_offsets() >> +#endif >> + >> +static void *zimage_load(struct kimage *image, >> + char *zimage, unsigned long zimage_len, >> + char *initrd, unsigned long initrd_len, >> + char *cmdline, unsigned long cmdline_len) >> +{ >> + struct arm_zimage_header *h; >> + struct kexec_buf kbuf; >> + struct kexec_segment *zimage_segment; >> + const struct arm_zimage_tag *klsz_tag; >> + const struct arm_zimage_tag_dc *dcsz_tag; >> + int ret = -EINVAL; >> + >> + unsigned long zimage_mem = 0x20000; /* malloc 64kB + stack 4 kB + some >> bss */ >> + unsigned long kernel_len = zimage_len * 4; /* 4:1 compression */ > > This has been proven wrong. 5:1? The comment and the code in kexec-tools are inconsisten in this regard. The comment says 4:1, but the code multiplies by 5. Your recommendation? This value is used as a fallback anyway in a very unlikely case, when tags are missing (see below). >> + unsigned long kernel_offset = memblock_start_of_DRAM() + >> + ALIGN(TEXT_OFFSET, PAGE_SIZE); > > TEXT_OFFSET is actually a property of the loaded kernel, not of the > currently running kernel. Indeed. > I have a patch to add that into the zImage tag. I am afraid, I haven't seen it before. Where can I find it? >> + unsigned long zimage_offset = kernel_offset + >> + ALIGN(kernel_len, PAGE_SIZE); >> + unsigned long initrd_offset = zimage_offset + >> + ALIGN(zimage_len + zimage_mem, PAGE_SIZE); > > Since kernel_len is wrong, these will be wrong... please only fall > back to this if you don't find the extension tag - in other words, > declare the variables here, but don't initialise them, set them > lower down in the file if we fail to find the extension tag. That is how it works now. This is the structure I have taken from kexec-tools: initialize and change if additional information is available. If the tags are not available use these values as a fallback. >> + >> + if (image->type == KEXEC_TYPE_CRASH) { >> + kernel_offset += crashk_res.start; >> + zimage_offset += crashk_res.start; >> + initrd_offset += crashk_res.start; >> + } >> + debug_offsets(); >> + >> + h = (struct arm_zimage_header *)zimage; >> + >> + klsz_tag = find_extension_tag(zimage, zimage_len, ZIMAGE_TAG_KRNL_SIZE); >> + if (klsz_tag) { >> + uint32_t *p = (void *)zimage + >> + le32_to_cpu(klsz_tag->u.krnl_size.size_ptr); >> + uint32_t edata_size = le32_to_cpu(get_unaligned(p)); >> + uint32_t bss_size = le32_to_cpu(klsz_tag->u.krnl_size.bss_size); >> + >> + kernel_len = edata_size + bss_size; >> + >> + pr_debug("Decompressed kernel sizes:\n"); >> + pr_debug(" text+data 0x%08lx bss 0x%08lx total 0x%08lx\n", >> + (unsigned long)edata_size, >> + (unsigned long)bss_size, >> + (unsigned long)kernel_len); >> + >> + zimage_offset = kernel_offset + ALIGN(edata_size, PAGE_SIZE); >> + initrd_offset = zimage_offset + >> + max(ALIGN(zimage_len + 0x20000, PAGE_SIZE), >> + ALIGN((unsigned long)bss_size, PAGE_SIZE)); >> + debug_offsets(); > > This looks incorrect to me. Please see the kexec tool - what its doing > in its corresponding section that you copied some of this code from is > carefully thought out and can't be simplified. Ergo, I think this is > wrong. As I explained in <dleftjwo4qsqqf.fsf%[email protected]> my approach is slightly different. I am trying to avoid copying zImage by putting it hight enough in the first place. Kind regards, -- Łukasz Stelmach Samsung R&D Institute Poland Samsung Electronics
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