Geert Uytterhoeven <geert at linux-m68k.org> writes:
> Print a list of pages to be copied if debugging is enabled.
> Consecutive entries are merged to reduce screen clutter.
Why is this desirable?
I can understand this as debugging code to understand what is happening,
but why would we want to maintain this print statement long term?
> Signed-off-by: Geert Uytterhoeven <geert at linux-m68k.org>
> Cc: Eric Biederman <ebiederm at xmission.com>
> ---
> kernel/kexec.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 76 insertions(+)
>
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 490afc03627e..e25022ac229e 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -1073,6 +1073,80 @@ asmlinkage long compat_sys_kexec_load(unsigned long entry,
> }
> #endif
>
> +#ifdef DEBUG
> +struct kimage_block {
> + unsigned long dst, src, len;
> +};
> +
> +static void kimage_print_block(const struct kimage_block *block)
> +{
> + pr_info("Copy from 0x%lx-0x%lx to 0x%lx-0x%lx (0x%lx bytes)\n",
> + block->src, block->src + block->len - 1, block->dst,
> + block->dst + block->len - 1, block->len);
> +}
> +
> +static void kimage_print(const struct kimage *image)
> +{
> + void *control_code_page;
> + const kimage_entry_t *ptr;
> + kimage_entry_t entry;
> + struct kimage_block block;
> + unsigned long dnext = KIMAGE_NO_DEST, snext = KIMAGE_NO_DEST;
> + unsigned long total = 0;
> +
> + control_code_page = page_address(image->control_code_page);
> + pr_info("Control code page 0x%p (phys 0x%lx)\n",
> + control_code_page, virt_to_phys(control_code_page));
> +
> + ptr = &image->head;
> + block.dst = KIMAGE_NO_DEST;
> + block.src = KIMAGE_NO_DEST;
> + block.len = 0;
> + while ((entry = *ptr)) {
> + if (entry & IND_DONE)
> + break;
> +
> + if (entry & IND_DESTINATION) {
> + if (block.len > 0) {
> + kimage_print_block(&block);
> + total += block.len;
> + }
> + dnext = block.dst = entry & PAGE_MASK;
> + block.src = KIMAGE_NO_DEST;
> + block.len = 0;
> + }
> +
> + if (entry & IND_SOURCE) {
> + if (!block.len) {
> + snext = block.src = entry & PAGE_MASK;
> + } else if ((entry & PAGE_MASK) != snext) {
> + kimage_print_block(&block);
> + total += block.len;
> + block.dst = dnext;
> + snext = block.src = entry & PAGE_MASK;
> + block.len = 0;
> + }
> + dnext += PAGE_SIZE;
> + snext += PAGE_SIZE;
> + block.len += PAGE_SIZE;
> + }
> +
> + if (entry & IND_INDIRECTION) {
> + pr_info("Indirection page 0x%lx\n", entry & PAGE_MASK);
> + ptr = phys_to_virt(entry & PAGE_MASK);
> + } else
> + ptr++;
> + }
> + if (block.len) {
> + kimage_print_block(&block);
> + total += block.len;
> + }
> + pr_info("Total: 0x%lx/%ld bytes\n", total, total);
> +}
> +#else
> +static inline void kimage_print(const struct kimage *image) {}
> +#endif
> +
> void crash_kexec(struct pt_regs *regs)
> {
> /* Take the kexec_mutex here to prevent sys_kexec_load
> @@ -1090,6 +1164,7 @@ void crash_kexec(struct pt_regs *regs)
> crash_setup_regs(&fixed_regs, regs);
> crash_save_vmcoreinfo();
> machine_crash_shutdown(&fixed_regs);
> + kimage_print(kexec_crash_image);
> machine_kexec(kexec_crash_image);
> }
> mutex_unlock(&kexec_mutex);
> @@ -1680,6 +1755,7 @@ int kernel_kexec(void)
> machine_shutdown();
> }
>
> + kimage_print(kexec_image);
> machine_kexec(kexec_image);
>
> #ifdef CONFIG_KEXEC_JUMP
