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charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Aug 12, 2025 at 1:09=E2=80=AFAM Yao Zi wrote: > > On Mon, Aug 11, 2025 at 05:26:55PM +0800, Youling Tang wrote: > > From: Youling Tang > > > > This patch adds support for kexec_file on LoongArch. > > > > The image_load() as two parts: > > - the first part loads the kernel image (vmlinuz.efi or vmlinux.efi) > > - the second part loads other segments (eg: initrd, cmdline) > > > > Currently, pez(vmlinuz.efi) and pei(vmlinux.efi) format images are supp= orted, > > but ELF format is not supported. > > > > Signed-off-by: Youling Tang > > --- > > arch/loongarch/Kconfig | 8 ++ > > arch/loongarch/include/asm/image.h | 18 ++++ > > arch/loongarch/include/asm/kexec.h | 12 +++ > > arch/loongarch/kernel/Makefile | 1 + > > arch/loongarch/kernel/kexec_image.c | 112 +++++++++++++++++++++ > > arch/loongarch/kernel/machine_kexec.c | 33 ++++-- > > arch/loongarch/kernel/machine_kexec_file.c | 46 +++++++++ > > 7 files changed, 219 insertions(+), 11 deletions(-) > > create mode 100644 arch/loongarch/kernel/kexec_image.c > > create mode 100644 arch/loongarch/kernel/machine_kexec_file.c > > ... > > > diff --git a/arch/loongarch/include/asm/image.h b/arch/loongarch/includ= e/asm/image.h > > index 1f090736e71d..829e1ecb1f5d 100644 > > --- a/arch/loongarch/include/asm/image.h > > +++ b/arch/loongarch/include/asm/image.h > > @@ -36,5 +36,23 @@ struct loongarch_image_header { > > uint32_t pe_header; > > }; > > > > +static const uint8_t loongarch_image_pe_sig[2] =3D {'M', 'Z'}; > > +static const uint8_t loongarch_pe_machtype[6] =3D {'P', 'E', 0x0, 0x0,= 0x64, 0x62}; > > loongarch_pe_machtype isn't used at all. > > > + > > +/** > > + * loongarch_header_check_pe_sig - Helper to check the loongarch image= header. > > + * > > + * Returns non-zero if 'MZ' signature is found. > > + */ > > + > > +static inline int loongarch_header_check_pe_sig(const struct loongarch= _image_header *h) > > +{ > > + if (!h) > > + return 0; > > + > > + return (h->pe_sig[0] =3D=3D loongarch_image_pe_sig[0] > > + && h->pe_sig[1] =3D=3D loongarch_image_pe_sig[1]); > > This could be simplified with a memcmp(). Also, this check isn't strict > enough: PE files for any architectures, and even legacy MS-DOS COM > executables all start with "MZ". > > > +} > > + > > #endif /* __ASSEMBLY__ */ > > #endif /* __ASM_IMAGE_H */ > > ... > > > diff --git a/arch/loongarch/kernel/kexec_image.c b/arch/loongarch/kerne= l/kexec_image.c > > new file mode 100644 > > index 000000000000..fdd1845b4e2e > > --- /dev/null > > +++ b/arch/loongarch/kernel/kexec_image.c > > @@ -0,0 +1,112 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Kexec image loader for LoongArch > > + > > + * Author: Youling Tang > > + * Copyright (C) 2025 KylinSoft Corporation. > > + */ > > + > > +#define pr_fmt(fmt) "kexec_file(Image): " fmt > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +static int image_probe(const char *kernel_buf, unsigned long kernel_le= n) > > +{ > > + const struct loongarch_image_header *h =3D > > + (const struct loongarch_image_header *)(kernel_buf); > > Parentheses around "kernel_buf" are unnecessary. > > > + if (!h || (kernel_len < sizeof(*h))) { > > Comparisons have higher priority than logic operations, so this pair of > parentheses is redundant, too. But the kernel coding style suggest to use parentheses in this case. > > > + pr_err("No loongarch image header.\n"); > > + return -EINVAL; > > + } > > + > > + if (!loongarch_header_check_pe_sig(h)) { > > + pr_err("Bad loongarch PE image header.\n"); > > + 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 loongarch_image_header *h; > > + struct kexec_buf kbuf; > > + unsigned long text_offset, kernel_segment_number; > > + struct kexec_segment *kernel_segment; > > + int ret; > > + > > + h =3D (struct loongarch_image_header *)kernel; > > + if (!h->image_size) > > + return ERR_PTR(-EINVAL); > > + > > + /* Load the kernel */ > > + kbuf.image =3D image; > > + kbuf.buf_min =3D 0; > > + kbuf.buf_max =3D ULONG_MAX; > > + kbuf.top_down =3D false; > > + > > + kbuf.buffer =3D kernel; > > + kbuf.bufsz =3D kernel_len; > > + kbuf.mem =3D KEXEC_BUF_MEM_UNKNOWN; > > + kbuf.memsz =3D le64_to_cpu(h->image_size); > > + text_offset =3D le64_to_cpu(h->text_offset); > > + kbuf.buf_align =3D SZ_2M; > > I think this aligment is unnecessary for relocatable LoongArch kernels: > it should be enough to align to the page size. See also my comments > below. > > > + kernel_segment_number =3D image->nr_segments; > > + > > + /* > > + * The location of the kernel segment may make it impossible to s= atisfy > > + * the other segment requirements, so we try repeatedly to find a > > + * location that will work. > > + */ > > + while ((ret =3D kexec_add_buffer(&kbuf)) =3D=3D 0) { > > + /* Try to load additional data */ > > + kernel_segment =3D &image->segment[kernel_segment_number]= ; > > + ret =3D load_other_segments(image, kernel_segment->mem, > > + kernel_segment->memsz, initrd, > > + initrd_len, cmdline, cmdline_le= n); > > + if (!ret) > > + break; > > + > > + /* > > + * We couldn't find space for the other segments; erase t= he > > + * kernel segment and try the next available hole. > > + */ > > + image->nr_segments -=3D 1; > > + kbuf.buf_min =3D kernel_segment->mem + kernel_segment->me= msz; > > + kbuf.mem =3D KEXEC_BUF_MEM_UNKNOWN; > > + } > > + > > + if (ret) { > > + pr_err("Could not find any suitable kernel location!"); > > + return ERR_PTR(ret); > > + } > > + > > + kernel_segment =3D &image->segment[kernel_segment_number]; > > + > > + /* Make sure the second kernel jumps to the correct "kernel_entry= ". */ > > + image->start =3D kernel_segment->mem + h->kernel_entry - text_off= set; > > A non-relocatable loongarch kernel cannot be loaded to arbitrary > address. Thus this loading function seems to only work for relocatable > kernels, maybe it's better to leave a comment indicating the limitation. > > For now, we don't seem to have a way to find out whether the kernel is > relocatable (for example, a flag in kernel image header), so it's > impossible to point out whether the loaded kernel boots fine with > arbitrary loading address... > > > + kexec_dprintk("Loaded kernel at 0x%lx bufsz=3D0x%lx memsz=3D0x%lx= \n", > > + kernel_segment->mem, kbuf.bufsz, > > + kernel_segment->memsz); > > + > > + return NULL; > > +} > > + > > +const struct kexec_file_ops kexec_image_ops =3D { > > + .probe =3D image_probe, > > + .load =3D image_load, > > +}; > > diff --git a/arch/loongarch/kernel/machine_kexec.c b/arch/loongarch/ker= nel/machine_kexec.c > > index f9381800e291..008f43e26120 100644 > > --- a/arch/loongarch/kernel/machine_kexec.c > > +++ b/arch/loongarch/kernel/machine_kexec.c > > @@ -70,18 +70,28 @@ int machine_kexec_prepare(struct kimage *kimage) > > ... > > > - if (!kimage->arch.cmdline_ptr) { > > - pr_err("Command line not included in the provided image\n= "); > > - return -EINVAL; > > + if (!kimage->arch.cmdline_ptr) { > > + pr_err("Command line not included in the provided= image\n"); > > + return -EINVAL; > > + } > > } > > > > /* kexec/kdump need a safe page to save reboot_code_buffer */ > > @@ -288,7 +298,8 @@ void machine_kexec(struct kimage *image) > > local_irq_disable(); > > > > pr_notice("EFI boot flag 0x%lx\n", efi_boot); > > - pr_notice("Command line at 0x%lx\n", cmdline_ptr); > > + pr_notice("Command line addr at 0x%lx\n", cmdline_ptr); > > + pr_notice("Command line at %s\n", (char *)cmdline_ptr); > > The printed message doesn't match meaning of the pointer: you're > printing the content of cmdline_ptr, instead of its address, thus > "Command line at" sounds confusing to me. > > Furthermore, this chunk isn't related to "support for kexec_file", I > think it's better to separate it into another patch (or even another > series). Separating is not necessary from my point of view, indeed I suggest to squash patches in this series. Huacai > > > pr_notice("System table at 0x%lx\n", systable_ptr); > > pr_notice("We will call new kernel at 0x%lx\n", start_addr); > > pr_notice("Bye ...\n"); > > Best regards, > Yao Zi