Hari Bathini <hbathini@xxxxxxxxxxxxx> writes: > On 05/05/20 3:29 am, Eric W. Biederman wrote: >> >> Recently a patch was proposed to kimage_alloc_page to slightly alter >> the logic of how pages allocated with incompatible flags were >> detected. The logic was being altered because the semantics of the >> page alloctor were changing yet again. >> >> Looking at that case I realized that there is no reason for it to even >> exist. Either the indirect page allocations and the source page >> allocations could be separated out, or I could do as I am doing now >> and simply teach the indirect pages to live in high memory. >> >> This patch replaced pointers of type kimage_entry_t * with a new type >> kimage_entry_pos_t. This new type holds the physical address of the >> indirect page and the offset within that page of the next indirect >> entry to write. A special constant KIMAGE_ENTRY_POS_INVALID is added >> that kimage_image_pos_t variables that don't currently have a valid >> may be set to. >> >> Two new functions kimage_read_entry and kimage_write_entry have been >> provided to write entries in way that works if they live in high >> memory. >> >> The now unnecessary checks to see if a destination entry is non-zero >> and to increment it if so have been removed. For safety new indrect >> pages are now cleared so we have a guarantee everything that has not >> been used yet is zero. Along with this writing an extra trailing 0 >> entry has been removed, as it is known all trailing entries are now 0. >> >> With highmem support implemented for indirect pages >> kimage_image_alloc_page has been updated to always allocate >> GFP_HIGHUSER pages, and handling of pages with different >> gfp flags has been removed. >> >> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > Eric, the patch failed with data access exception on ppc64. Using the below patch on top > got me going... Doh! Somehow I thought I had put that logic or something equivalent into kimage_write_entry and it appears I did not. I will see if I can respin the patch. Thank you very much for testing. Eric > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index 45862fd..bef52f1 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -570,7 +570,12 @@ static int kimage_add_entry(struct kimage *image, kimage_entry_t entry) > return -ENOMEM; > > ind_addr = page_to_boot_pfn(page) << PAGE_SHIFT; > - kimage_write_entry(image->entry_pos, ind_addr | IND_INDIRECTION); > + > + /* If it is the first entry, handle it here */ > + if (!image->head) > + image->head = ind_addr | IND_INDIRECTION; > + else > + kimage_write_entry(image->entry_pos, ind_addr | IND_INDIRECTION); > > clear_highpage(page); > > @@ -623,7 +628,11 @@ int __weak machine_kexec_post_load(struct kimage *image) > > void kimage_terminate(struct kimage *image) > { > - kimage_write_entry(image->entry_pos, IND_DONE); > + /* This could be the only entry in case of kdump */ > + if (!image->head) > + image->head = IND_DONE; > + else > + kimage_write_entry(image->entry_pos, IND_DONE); > } > > #define for_each_kimage_entry(image, pos, entry) \ > > > Thanks > Hari _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec