x86: Make 64 bit use early_res instead of bootmem before slab

Finally we can use early_res to replace bootmem for x86_64 now.

Still can use CONFIG_NO_BOOTMEM to enable it or not.

-v2: fix 32bit compiling about MAX_DMA32_PFN
-v3: folded bug fix from LKML message below

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4B747239.4070907@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index eb4092568f9e..95439843cebc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -568,6 +568,19 @@ config PARAVIRT_DEBUG
           Enable to debug paravirt_ops internals.  Specifically, BUG if
           a paravirt_op is missing when it is called.
 
+config NO_BOOTMEM
+        default y
+        bool "Disable Bootmem code"
+        depends on X86_64
+        ---help---
+          Use early_res directly instead of bootmem before slab is ready.
+                - allocator (buddy) [generic]
+                - early allocator (bootmem) [generic]
+                - very early allocator (reserve_early*()) [x86]
+                - very very early allocator (early brk model) [x86]
+          So reduce one layer between early allocator to final allocator
+
+
 config MEMTEST
         bool "Memtest"
         ---help---