arm64: Determine the vmalloc/vmemmap space at build time based on VA_BITS

Rather than guessing what the maximum vmmemap space should be, this
patch allows the calculation based on the VA_BITS and sizeof(struct
page). The vmalloc space extends to the beginning of the vmemmap space.

Since the virtual kernel memory layout now depends on the build
configuration, this patch removes the detailed description in
Documentation/arm64/memory.txt in favour of information printed during
kernel booting.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Jungseok Lee <jungseoklee85@gmail.com>

2 files changed, 23 insertions, 12 deletions

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 9f862e6e9286..ec82789d03c3 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -33,13 +33,16 @@
 
 /*
  * VMALLOC and SPARSEMEM_VMEMMAP ranges.
+ *
+ * VMEMAP_SIZE: allows the whole VA space to be covered by a struct page array
+ *	(rounded up to PUD_SIZE).
+ * VMALLOC_START: beginning of the kernel VA space
+ * VMALLOC_END: extends to the available space below vmmemmap, PCI I/O space,
+ *	fixed mappings and modules
  */
+#define VMEMMAP_SIZE		ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
 #define VMALLOC_START		(UL(0xffffffffffffffff) << VA_BITS)
-#if CONFIG_ARM64_PGTABLE_LEVELS != 4
-#define VMALLOC_END		(PAGE_OFFSET - UL(0x400000000) - SZ_64K)
-#else
-#define VMALLOC_END		(PAGE_OFFSET - UL(0x40000000000) - SZ_64K)
-#endif
+#define VMALLOC_END		(PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
 
 #define vmemmap			((struct page *)(VMALLOC_END + SZ_64K))
 
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 7f68804814a1..0b32504e280f 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -33,6 +33,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
 
+#include <asm/fixmap.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/sizes.h>
@@ -256,26 +257,33 @@ void __init mem_init(void)
 
 #define MLK(b, t) b, t, ((t) - (b)) >> 10
 #define MLM(b, t) b, t, ((t) - (b)) >> 20
+#define MLG(b, t) b, t, ((t) - (b)) >> 30
 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
 
 	pr_notice("Virtual kernel memory layout:\n"
-		  "    vmalloc : 0x%16lx - 0x%16lx   (%6ld MB)\n"
+		  "    vmalloc : 0x%16lx - 0x%16lx   (%6ld GB)\n"
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-		  "    vmemmap : 0x%16lx - 0x%16lx   (%6ld MB)\n"
+		  "    vmemmap : 0x%16lx - 0x%16lx   (%6ld GB maximum)\n"
+		  "              0x%16lx - 0x%16lx   (%6ld MB actual)\n"
 #endif
+		  "    PCI I/O : 0x%16lx - 0x%16lx   (%6ld MB)\n"
+		  "    fixed   : 0x%16lx - 0x%16lx   (%6ld KB)\n"
 		  "    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n"
 		  "    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n"
-		  "      .init : 0x%p" " - 0x%p" "   (%6ld kB)\n"
-		  "      .text : 0x%p" " - 0x%p" "   (%6ld kB)\n"
-		  "      .data : 0x%p" " - 0x%p" "   (%6ld kB)\n",
-		  MLM(VMALLOC_START, VMALLOC_END),
+		  "      .init : 0x%p" " - 0x%p" "   (%6ld KB)\n"
+		  "      .text : 0x%p" " - 0x%p" "   (%6ld KB)\n"
+		  "      .data : 0x%p" " - 0x%p" "   (%6ld KB)\n",
+		  MLG(VMALLOC_START, VMALLOC_END),
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
+		  MLG((unsigned long)vmemmap,
+		      (unsigned long)vmemmap + VMEMMAP_SIZE),
 		  MLM((unsigned long)virt_to_page(PAGE_OFFSET),
 		      (unsigned long)virt_to_page(high_memory)),
 #endif
+		  MLM((unsigned long)PCI_IOBASE, (unsigned long)PCI_IOBASE + SZ_16M),
+		  MLK(FIXADDR_START, FIXADDR_TOP),
 		  MLM(MODULES_VADDR, MODULES_END),
 		  MLM(PAGE_OFFSET, (unsigned long)high_memory),
-
 		  MLK_ROUNDUP(__init_begin, __init_end),
 		  MLK_ROUNDUP(_text, _etext),
 		  MLK_ROUNDUP(_sdata, _edata));