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.
Patch-5 coming out separately can better illustrate the role of "mem"
parameters in capturing the kernel.
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
