On Tue, Aug 12, 2025 at 10:38 AM Youling Tang <youling.t...@linux.dev> wrote:
>
> Hi, Huacai
> On 2025/8/11 22:12, Huacai Chen wrote:
> > Hi, Youling,
> >
> > On Mon, Aug 11, 2025 at 5:28 PM Youling Tang <youling.t...@linux.dev> wrote:
> >> From: Youling Tang <tangyoul...@kylinos.cn>
> >>
> >> Add inird loading support and pass it to the second kernel via the
> >> cmdline 'initrd=start,size'.
> > I think Patch-3 and Patch-5 should be merged into Patch-2.
> Not all cases require loading initrd, so Patch-2 is a runnable basic patch.
> Separating it into different patches makes it easier to understand and
> review the code.
Unnecessary, without separating the code is clear enough.
>
> Patch-5 coming out separately can better illustrate the role of "mem"
> parameters in capturing the kernel.
Emm, Patch-5 should be squashed to Patch-4, not Patch-2.
Huacai
>
> Youling.
> >
> > Huacai
> >
> >> Signed-off-by: Youling Tang <tangyoul...@kylinos.cn>
> >> ---
> >> arch/loongarch/kernel/machine_kexec_file.c | 71 ++++++++++++++++++++++
> >> 1 file changed, 71 insertions(+)
> >>
> >> diff --git a/arch/loongarch/kernel/machine_kexec_file.c
> >> b/arch/loongarch/kernel/machine_kexec_file.c
> >> index bc91ae0afa4c..e1240644f529 100644
> >> --- a/arch/loongarch/kernel/machine_kexec_file.c
> >> +++ b/arch/loongarch/kernel/machine_kexec_file.c
> >> @@ -34,13 +34,84 @@ int arch_kimage_file_post_load_cleanup(struct kimage
> >> *image)
> >> return kexec_image_post_load_cleanup_default(image);
> >> }
> >>
> >> +/* Adds the "initrd=start,size" command line parameter to command line. */
> >> +static void cmdline_add_initrd(struct kimage *image, unsigned long
> >> *cmdline_tmplen,
> >> + char *modified_cmdline, unsigned long
> >> initrd)
> >> +{
> >> + int initrd_strlen;
> >> +
> >> + initrd_strlen = sprintf(modified_cmdline + (*cmdline_tmplen),
> >> "initrd=0x%lx,0x%lx ",
> >> + initrd, image->initrd_buf_len);
> >> + *cmdline_tmplen += initrd_strlen;
> >> +}
> >> +
> >> +/*
> >> + * Tries to add the initrd to the image. If it is not possible to find
> >> + * valid locations, this function will undo changes to the image and
> >> return non
> >> + * zero.
> >> + */
> >> int load_other_segments(struct kimage *image,
> >> unsigned long kernel_load_addr,
> >> unsigned long kernel_size,
> >> char *initrd, unsigned long initrd_len,
> >> char *cmdline, unsigned long cmdline_len)
> >> {
> >> + struct kexec_buf kbuf;
> >> + unsigned long orig_segments = image->nr_segments;
> >> + char *modified_cmdline = NULL;
> >> + unsigned long cmdline_tmplen = 0;
> >> + unsigned long initrd_load_addr = 0;
> >> + int ret = 0;
> >> +
> >> +
> >> + kbuf.image = image;
> >> + /* not allocate anything below the kernel */
> >> + kbuf.buf_min = kernel_load_addr + kernel_size;
> >> +
> >> + modified_cmdline = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
> >> + if (!modified_cmdline)
> >> + return -EINVAL;
> >> +
> >> + /* Ensure it's nul terminated */
> >> + modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
> >> +
> >> + /* load initrd */
> >> + if (initrd) {
> >> + kbuf.buffer = initrd;
> >> + kbuf.bufsz = initrd_len;
> >> + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
> >> + kbuf.memsz = initrd_len;
> >> + kbuf.buf_align = 0;
> >> + /* within 1GB-aligned window of up to 32GB in size */
> >> + kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
> >> + + (unsigned long)SZ_1G *
> >> 32;
> >> + kbuf.top_down = false;
> >> +
> >> + ret = kexec_add_buffer(&kbuf);
> >> + if (ret)
> >> + goto out_err;
> >> + initrd_load_addr = kbuf.mem;
> >> +
> >> + kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx
> >> memsz=0x%lx\n",
> >> + initrd_load_addr, kbuf.bufsz, kbuf.memsz);
> >> +
> >> + /* Add the initrd=start,size parameter to the command line
> >> */
> >> + cmdline_add_initrd(image, &cmdline_tmplen,
> >> modified_cmdline, initrd_load_addr);
> >> + }
> >> +
> >> + if (cmdline_len + cmdline_tmplen > COMMAND_LINE_SIZE) {
> >> + pr_err("Appending kdump cmdline exceeds cmdline size\n");
> >> + ret = -EINVAL;
> >> + goto out_err;
> >> + }
> >> + memcpy(modified_cmdline + cmdline_tmplen, cmdline, cmdline_len);
> >> + cmdline = modified_cmdline;
> >> image->arch.cmdline_ptr = (unsigned long)cmdline;
> >>
> >> return 0;
> >> +
> >> +out_err:
> >> + image->nr_segments = orig_segments;
> >> + kfree(modified_cmdline);
> >> + return ret;
> >> }
> >> --
> >> 2.34.1
> >>
