arm64: move kernel image to base of vmalloc area

This moves the module area to right before the vmalloc area, and moves
the kernel image to the base of the vmalloc area. This is an intermediate
step towards implementing KASLR, which allows the kernel image to be
located anywhere in the vmalloc area.

Since other subsystems such as hibernate may still need to refer to the
kernel text or data segments via their linears addresses, both are mapped
in the linear region as well. The linear alias of the text region is
mapped read-only/non-executable to prevent inadvertent modification or
execution.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 12 insertions, 11 deletions

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f3b061e67bfe..1d627cd8121c 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -36,6 +36,7 @@
 #include <linux/swiotlb.h>
 
 #include <asm/fixmap.h>
+#include <asm/kasan.h>
 #include <asm/memory.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -302,22 +303,26 @@ void __init mem_init(void)
 #ifdef CONFIG_KASAN
                   "    kasan   : 0x%16lx - 0x%16lx   (%6ld GB)\n"
 #endif
+                  "    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n"
                   "    vmalloc : 0x%16lx - 0x%16lx   (%6ld GB)\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"
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
                   "    vmemmap : 0x%16lx - 0x%16lx   (%6ld GB maximum)\n"
                   "              0x%16lx - 0x%16lx   (%6ld MB actual)\n"
 #endif
                   "    fixed   : 0x%16lx - 0x%16lx   (%6ld KB)\n"
                   "    PCI I/O : 0x%16lx - 0x%16lx   (%6ld MB)\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",
+                  "    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n",
 #ifdef CONFIG_KASAN
                   MLG(KASAN_SHADOW_START, KASAN_SHADOW_END),
 #endif
+                  MLM(MODULES_VADDR, MODULES_END),
                   MLG(VMALLOC_START, VMALLOC_END),
+                  MLK_ROUNDUP(__init_begin, __init_end),
+                  MLK_ROUNDUP(_text, _etext),
+                  MLK_ROUNDUP(_sdata, _edata),
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
                   MLG((unsigned long)vmemmap,
                       (unsigned long)vmemmap + VMEMMAP_SIZE),
@@ -326,11 +331,7 @@ void __init mem_init(void)
 #endif
                   MLK(FIXADDR_START, FIXADDR_TOP),
                   MLM(PCI_IO_START, PCI_IO_END),
-                  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));
+                  MLM(PAGE_OFFSET, (unsigned long)high_memory));
 
 #undef MLK
 #undef MLM
@@ -358,8 +359,8 @@ void __init mem_init(void)
 
 void free_initmem(void)
 {
-        fixup_init();
         free_initmem_default(0);
+        fixup_init();
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD