Messages in this thread | | | From | Emil Renner Berthing <> | Date | Mon, 16 Oct 2023 01:17:02 -0700 | Subject | Re: [PATCH 2/2] riscv: kexec_file: Support loading Image binary file |
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Song Shuai wrote: > > > 在 2023/10/11 18:48, Emil Renner Berthing 写道: > > Song Shuai wrote: > >> > >> > >> 在 2023/9/14 16:37, Emil Renner Berthing 写道: > >>> Song Shuai wrote: > >>>> This patch creates image_kexec_ops to load Image binary file > >>>> for kexec_file_load() syscall. > >>>> > >>>> Signed-off-by: Song Shuai <songshuaishuai@tinylab.org> > >>>> --- > >>>> arch/riscv/include/asm/image.h | 2 + > >>>> arch/riscv/include/asm/kexec.h | 1 + > >>>> arch/riscv/kernel/Makefile | 2 +- > >>>> arch/riscv/kernel/kexec_image.c | 97 ++++++++++++++++++++++++++ > >>>> arch/riscv/kernel/machine_kexec_file.c | 1 + > >>>> 5 files changed, 102 insertions(+), 1 deletion(-) > >>>> create mode 100644 arch/riscv/kernel/kexec_image.c > >>>> > >>>> diff --git a/arch/riscv/include/asm/image.h b/arch/riscv/include/asm/image.h > >>>> index e0b319af3681..8927a6ea1127 100644 > >>>> --- a/arch/riscv/include/asm/image.h > >>>> +++ b/arch/riscv/include/asm/image.h > >>>> @@ -30,6 +30,8 @@ > >>>> RISCV_HEADER_VERSION_MINOR) > >>>> > >>>> #ifndef __ASSEMBLY__ > >>>> +#define riscv_image_flag_field(flags, field)\ > >>>> + (((flags) >> field##_SHIFT) & field##_MASK) > >>> > >>> Hi Song, > >>> > >>> This macro is almost FIELD_GET from linux/bitfield.h .. > >>> > >>>> /** > >>>> * struct riscv_image_header - riscv kernel image header > >>>> * @code0: Executable code > >>>> diff --git a/arch/riscv/include/asm/kexec.h b/arch/riscv/include/asm/kexec.h > >>>> index 518825fe4160..b9ee8346cc8c 100644 > >>>> --- a/arch/riscv/include/asm/kexec.h > >>>> +++ b/arch/riscv/include/asm/kexec.h > >>>> @@ -56,6 +56,7 @@ extern riscv_kexec_method riscv_kexec_norelocate; > >>>> > >>>> #ifdef CONFIG_KEXEC_FILE > >>>> extern const struct kexec_file_ops elf_kexec_ops; > >>>> +extern const struct kexec_file_ops image_kexec_ops; > >>>> > >>>> struct purgatory_info; > >>>> int arch_kexec_apply_relocations_add(struct purgatory_info *pi, > >>>> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > >>>> index 1c62c639e875..9ecba3231a36 100644 > >>>> --- a/arch/riscv/kernel/Makefile > >>>> +++ b/arch/riscv/kernel/Makefile > >>>> @@ -86,7 +86,7 @@ endif > >>>> obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o > >>>> obj-$(CONFIG_KGDB) += kgdb.o > >>>> obj-$(CONFIG_KEXEC_CORE) += kexec_relocate.o crash_save_regs.o machine_kexec.o > >>>> -obj-$(CONFIG_KEXEC_FILE) += kexec_elf.o machine_kexec_file.o > >>>> +obj-$(CONFIG_KEXEC_FILE) += kexec_elf.o kexec_image.o machine_kexec_file.o > >>>> obj-$(CONFIG_CRASH_DUMP) += crash_dump.o > >>>> obj-$(CONFIG_CRASH_CORE) += crash_core.o > >>>> > >>>> diff --git a/arch/riscv/kernel/kexec_image.c b/arch/riscv/kernel/kexec_image.c > >>>> new file mode 100644 > >>>> index 000000000000..b6aa7f59bd53 > >>>> --- /dev/null > >>>> +++ b/arch/riscv/kernel/kexec_image.c > >>>> @@ -0,0 +1,97 @@ > >>>> +// SPDX-License-Identifier: GPL-2.0 > >>>> +/* > >>>> + * RISC-V Kexec image loader > >>>> + * > >>>> + */ > >>>> + > >>>> +#define pr_fmt(fmt) "kexec_file(Image): " fmt > >>>> + > >>>> +#include <linux/err.h> > >>>> +#include <linux/errno.h> > >>>> +#include <linux/kernel.h> > >>>> +#include <linux/kexec.h> > >>>> +#include <linux/pe.h> > >>>> +#include <linux/string.h> > >>>> +#include <asm/byteorder.h> > >>>> +#include <asm/image.h> > >>>> + > >>>> +static int image_probe(const char *kernel_buf, unsigned long kernel_len) > >>>> +{ > >>>> + const struct riscv_image_header *h = > >>>> + (const struct riscv_image_header *)(kernel_buf); > >>>> + > >>>> + if (!h || (kernel_len < sizeof(*h))) > >>>> + return -EINVAL; > >>>> + > >>>> + /* According to Documentation/riscv/boot-image-header.rst, > >>>> + * use "magic2" field to check when version >= 0.2. > >>>> + */ > >>>> + > >>>> + if (h->version >= RISCV_HEADER_VERSION && > >>>> + memcmp(&h->magic2, RISCV_IMAGE_MAGIC2, sizeof(h->magic2))) > >>>> + return -EINVAL; > >>>> + > >>>> + return 0; > >>>> +} > >>>> + > >>>> +static void *image_load(struct kimage *image, > >>>> + char *kernel, unsigned long kernel_len, > >>>> + char *initrd, unsigned long initrd_len, > >>>> + char *cmdline, unsigned long cmdline_len) > >>>> +{ > >>>> + struct riscv_image_header *h; > >>>> + u64 flags; > >>>> + bool be_image, be_kernel; > >>>> + struct kexec_buf kbuf; > >>>> + int ret; > >>>> + > >>>> + /* Check Image header */ > >>>> + h = (struct riscv_image_header *)kernel; > >>>> + if (!h->image_size) { > >>>> + ret = -EINVAL; > >>>> + goto out; > >>>> + } > >>>> + > >>>> + /* Check endianness */ > >>>> + flags = le64_to_cpu(h->flags); > >>>> + be_image = riscv_image_flag_field(flags, RISCV_IMAGE_FLAG_BE); > >>> > >>> ..but here you're just testing a single bit, so since be_image is a bool it > >>> could just be > >>> be_image = flags & RISCV_IMAGE_FLAG_BE_MASK; > >>> > >>> /Emil > >> Hi Emil, > >> > >> Sorry for the delayed response, > >> > >> The `flags` field currently only has bit-0 to indicate the kenrel > >> endianness, your comment looks good in this case. > >> > >> While considering the future extension of the `flags` feild, the > >> riscv_image_flag_field() is neccessiry to make callers to require the > >> bits they want. > > > > Right, but please don't invent your own FIELD_GET then. > > Hi Emil, > > I tried to use FIELD_PREP/FIELD_GET to set/get the RISCV_IMAGE_FLAG_BE, > but using FIELD_PREP to define the __HEAD_FLAGS (used in head.S) emitted > AS build error and the final .s file looked like: > > 883 .dword _end - _start > 884 .dword (({ ({ do { } while (0); do { } while (0); do { } while > (0); do { } while (0); do { } while (0); }); ((typeof((((1)) << > (0))))(0) << (__builtin_ffsll((((1)) << (0))) - 1)) & ((((1)) << (0))); })) > > IIUC the FIELD_PREP can't work well in this asm context, and using > FILED_GET without FIELD_PREP paired looks not good to me. > > The original riscv/*/image.h and the riscv_image_flag_filed() of this > patch just do what arm64 does, so I still like to keep them.
Hi Song,
Your riscv_image_flag_field macro is already guarded by a #ifndef __ASSEMBLY__ and your patches above doesn't touch any __HEAD_FLAGS macro, so I don't know what you're trying to do with FIELD_PREP.
What I'm saying is that instead of defining the riscv_image_flag_field macro you can just do
-be_image = riscv_image_flag_field(flags, RISCV_IMAGE_FLAG_BE); +be_image = FIELD_GET(RISCV_IMAGE_FLAG_BE, flags);
/Emil
> I also found that Patch1 has a build issue due to my previous uncareful > cherry-picking, > V2 will be sent to fix it if you're ok this patch without bitfield armed. > > I would like to listen to your advice. > > > > >> > >> So I prefer to keep this snippet. > >>> > >>>> + be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN); > >>>> + if (be_image != be_kernel) { > >>>> + ret = -EINVAL; > >>>> + goto out; > >>>> + } > >>>> + > >>>> + /* Load the kernel image */ > >>>> + kbuf.image = image; > >>>> + kbuf.buf_min = 0; > >>>> + kbuf.buf_max = ULONG_MAX; > >>>> + kbuf.top_down = false; > >>>> + > >>>> + kbuf.buffer = kernel; > >>>> + kbuf.bufsz = kernel_len; > >>>> + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; > >>>> + kbuf.memsz = le64_to_cpu(h->image_size); > >>>> + kbuf.buf_align = le64_to_cpu(h->text_offset); > >>>> + > >>>> + ret = kexec_add_buffer(&kbuf); > >>>> + if (ret) { > >>>> + pr_err("Error add kernel image ret=%d\n", ret); > >>>> + goto out; > >>>> + } > >>>> + > >>>> + image->start = kbuf.mem; > >>>> + > >>>> + pr_info("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n", > >>>> + kbuf.mem, kbuf.bufsz, kbuf.memsz); > >>>> + > >>>> + ret = load_extra_segments(image, kbuf.mem, kbuf.memsz, > >>>> + initrd, initrd_len, cmdline, cmdline_len); > >>>> + > >>>> +out: > >>>> + return ret ? ERR_PTR(ret) : NULL; > >>>> +} > >>>> + > >>>> +const struct kexec_file_ops image_kexec_ops = { > >>>> + .probe = image_probe, > >>>> + .load = image_load, > >>>> +}; > >>>> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c > >>>> index aedb8c16a283..5dc700834f1e 100644 > >>>> --- a/arch/riscv/kernel/machine_kexec_file.c > >>>> +++ b/arch/riscv/kernel/machine_kexec_file.c > >>>> @@ -17,6 +17,7 @@ > >>>> > >>>> const struct kexec_file_ops * const kexec_file_loaders[] = { > >>>> &elf_kexec_ops, > >>>> + &image_kexec_ops, > >>>> NULL > >>>> }; > >>>> > >>>> -- > >>>> 2.20.1
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