> >>+/* With 4K pages, we use section maps. */ > >>+#ifdef CONFIG_ARM64_4K_PAGES > >>+#define ARM64_SWAPPER_USES_SECTION_MAPS 1 > >>+#else > >>+#define ARM64_SWAPPER_USES_SECTION_MAPS 0 > >>+#endif > > > >The comment is somewhat redunant. It would be better to state why we do > >this for 4K and not 64K (or 16K). > > Something like : > > /* > * ARM64 kernel is guaranteed to be loaded at 2M aligned > * address (as per booting requirements). Hence we can use > * section mapping with 4K (section size = 2M) and not with > * 16K(section size = 32M) or 64K (section size = 512M). > */
That sounds much better. I hadn't figured out why myself, so thanks for the explanation :) However, there's one minor nit: the start of memory below the kernel is 2M aligned, but the offset means that the kernel itself is not loaded at a 2M aligned address. So how about: /* * The linear mapping and the start of memory are both 2M aligned (per * the arm64 booting.txt requirements). Hence we can use section mapping * with 4K (section size = 2M) but not with 16K (section size = 32M) or * 64K (section size = 512M). */ > >>+ * us PUD_SIZE (with SECTION maps, i.e, 4K) or PMD_SIZE (without > >>+ * SECTION maps, i.e, 64K pages) memory starting from PHYS_OFFSET > >>+ * (which must be aligned to 2MB as per > >>Documentation/arm64/booting.txt). > > > >This didn't seem to get updated for 16K later in the series, unless I > >missed something. > > > >Perhaps drop the mention of 4K / 64K entirely here? > > You are right, I missed it. We can drop the pagesize info entirely. Ok. Sounds good. > >>@@ -551,7 +552,7 @@ int kern_addr_valid(unsigned long addr) > >> return pfn_valid(pte_pfn(*pte)); > >> } > >> #ifdef CONFIG_SPARSEMEM_VMEMMAP > >>-#ifdef CONFIG_ARM64_64K_PAGES > >>+#if !ARM64_SWAPPER_USES_SECTION_MAPS > > > >This leaves the comments on the #else and #endif stale. Please update > >those too. > > Done. Great. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
