[PATCH 2/2] x86 boot: early_res_to_e820

["Huang, Ying" <ying.huang@intel.com>]

This patch reserves some memory areas of early_res in E820 as
E820_RESVD_KERN. This is used mainly on i386, for some memory area
from boot-loader and in highmem, such as linked list of setup_data,
EFI memory map, etc.

This patch is based on latest x86/master branch of git-x86 tree and
has been tested on i386 and x86_64 platform.

Signed-off-by: Huang Ying <ying.huang@intel.com>

---
 arch/x86/kernel/e820.c     |   22 ++++++++++++++++++++++
 arch/x86/kernel/setup_32.c |    2 ++
 include/asm-x86/e820.h     |    1 +
 3 files changed, 25 insertions(+)

--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -844,6 +844,28 @@ void __init early_res_to_bootmem(u64 sta
 	}
 }
 
+void __init early_res_to_e820(u64 start, u64 end)
+{
+	int i, changed = 0;
+	u64 final_start, final_end;
+	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
+		struct early_res *r = &early_res[i];
+		final_start = max(start, r->start);
+		final_end = min(end, r->end);
+		if (final_start >= final_end)
+			continue;
+		printk(KERN_INFO "  early res: %d [%llx-%llx] %s\n", i,
+			final_start, final_end - 1, r->name);
+		e820_update_range(final_start, final_end - final_start,
+				  E820_RAM, E820_RESVD_KERN);
+		changed = 1;
+	}
+	if (changed) {
+		printk(KERN_INFO "update e820 for early_res\n");
+		update_e820();
+	}
+}
+
 /* Check for already reserved areas */
 static inline int __init bad_addr(u64 *addrp, u64 size, u64 align)
 {
--- a/include/asm-x86/e820.h
+++ b/include/asm-x86/e820.h
@@ -96,6 +96,7 @@ extern void reserve_early(u64 start, u64
 extern void reserve_early_overlap_ok(u64 start, u64 end, char *name);
 extern void free_early(u64 start, u64 end);
 extern void early_res_to_bootmem(u64 start, u64 end);
+extern void early_res_to_e820(u64 start, u64 end);
 extern u64 early_reserve_e820(u64 startt, u64 sizet, u64 align);
 
 extern unsigned long e820_end_of_ram(void);
--- a/arch/x86/kernel/setup_32.c
+++ b/arch/x86/kernel/setup_32.c
@@ -447,6 +447,8 @@ void __init setup_arch(char **cmdline_p)
         acpi_numa_init();
 #endif
 
+	early_res_to_e820(max_low_pfn<<PAGE_SHIFT, -1);
+
 	initmem_init(0, max_pfn);
 
 #ifdef CONFIG_ACPI_SLEEP