Messages in this thread | | | Subject | Re: [PATCH v10 08/14] arm64: kexec_file: load initrd and device-tree | From | James Morse <> | Date | Tue, 3 Jul 2018 17:32:09 +0100 |
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Hi Akashi,
On 23/06/18 03:20, AKASHI Takahiro wrote: > load_other_segments() is expected to allocate and place all the necessary > memory segments other than kernel, including initrd and device-tree > blob (and elf core header for crash). > While most of the code was borrowed from kexec-tools' counterpart, > users may not be allowed to specify dtb explicitly, instead, the dtb > presented by the original boot loader is reused. > > arch_kimage_kernel_post_load_cleanup() is responsible for freeing arm64- > specific data allocated in load_other_segments().
> diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c > index c38a8048ed00..7115c4f915dc 100644 > --- a/arch/arm64/kernel/machine_kexec_file.c > +++ b/arch/arm64/kernel/machine_kexec_file.c
> +static int setup_dtb(struct kimage *image, > + unsigned long initrd_load_addr, unsigned long initrd_len, > + char *cmdline, unsigned long cmdline_len, > + char **dtb_buf, size_t *dtb_buf_len) > +{ > + char *buf = NULL; > + size_t buf_size; > + int nodeoffset; > + u64 value; > + int ret; > + > + /* duplicate dt blob */ > + buf_size = fdt_totalsize(initial_boot_params); > + > + if (initrd_load_addr) { > + buf_size += fdt_prop_len("linux,initrd-start", sizeof(u64)); > + buf_size += fdt_prop_len("linux,initrd-end", sizeof(u64)); > + } > + > + if (cmdline) > + buf_size += fdt_prop_len("bootargs", cmdline_len + 1);
(a comment here about the possibility of an embedded NULL may avoid surprises later)
> + buf = vmalloc(buf_size); > + if (!buf) { > + ret = -ENOMEM; > + goto out_err; > + } > + > + ret = fdt_open_into(initial_boot_params, buf, buf_size); > + if (ret) > + goto out_err; > + > + nodeoffset = fdt_path_offset(buf, "/chosen"); > + if (nodeoffset < 0) > + goto out_err;
This doesn't update 'ret', so we return the 0/success from above...
> + > + /* add bootargs */ > + if (cmdline) { > + ret = fdt_setprop(buf, nodeoffset, "bootargs", > + cmdline, cmdline_len + 1); > + if (ret) > + goto out_err; > + }
So (cmdline_len == 0) from user-space means keep the old cmdline. Sounds sensible. Is this documented anywhere?
powerpc does the opposite, it deletes the bootargs in this case. Are we happy making his a per-arch thing?
> + /* add initrd-* */ > + if (initrd_load_addr) { > + value = cpu_to_fdt64(initrd_load_addr); > + ret = fdt_setprop_u64(buf, nodeoffset, "linux,initrd-start", > + value); > + if (ret) > + goto out_err; > + > + value = cpu_to_fdt64(initrd_load_addr + initrd_len); > + ret = fdt_setprop_u64(buf, nodeoffset, "linux,initrd-end", > + value); > + if (ret) > + goto out_err; > + }
Won't this do the same with the initrd? Re-use the old values if no new one was provided? I can't find anything that deletes the property by the time we come to kexec, and the old physical addresses may have been re-used by who-knows-what.
(powerpc has some code to: /* If there's no new initrd, delete the old initrd's info. */)
Thanks,
James
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