On Mon, 2024-07-01 at 15:43 +0300, Kirill A. Shutemov wrote:
> init_transition_pgtable() setups transitional page tables. Rewrite it
> using kernel_ident_mapping_init() to avoid code duplication.
setups -> sets up
>
> struct kimage_arch changed to track allocated page tables as a list, not
> linking them to specific page table levels.
This doesn't look like imperative mode. Perhaps change to:
Change struct kimage_arch to track ...
[...]
> static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
> {
> - pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
> - unsigned long vaddr, paddr;
> - int result = -ENOMEM;
> - p4d_t *p4d;
> - pud_t *pud;
> - pmd_t *pmd;
> - pte_t *pte;
> + struct x86_mapping_info info = {
> + .alloc_pgt_page = alloc_transition_pgt_page,
> + .context = image,
> + .page_flag = __PAGE_KERNEL_LARGE_EXEC,
> + .kernpg_flag = _KERNPG_TABLE_NOENC,
> + .offset = __START_KERNEL_map - phys_base,
> + };
> + unsigned long mstart = PAGE_ALIGN_DOWN(__pa(relocate_kernel));
> + unsigned long mend = mstart + PAGE_SIZE;
>
> - vaddr = (unsigned long)relocate_kernel;
> - paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
Perhaps I am missing something, but this seems a functional change to me.
IIUC the page after image->control_code_page is allocated when loading the
kexec kernel image. It is a different page from the page where the
relocate_kernel code resides in.
The old code maps relocate_kernel kernel VA to the page after the
control_code_page. Later in machine_kexec(), the relocate_kernel code is
copied to that page so the mapping can work for that:
control_page = page_address(image->control_code_page) + PAGE_SIZE;
__memcpy(control_page, relocate_kernel,
KEXEC_CONTROL_CODE_MAX_SIZE);
The new code in this patch, however, seems just maps the relocate_kernel VA
to the PA of the relocate_kernel, which should be different from the old
mapping.
