x86: replace hard coded reservations in 64-bit early boot code with dynamic table
On x86-64 there are several memory allocations before bootmem. To avoid
them stomping on each other they used to be all hard coded in bad_area().
Replace this with an array that is filled as needed.
This cleans up the code considerably and allows to expand its use.
Cc: peterz@infradead.org
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 87e031d..58438ba 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -21,6 +21,7 @@
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/kdebug.h>
+#include <asm/e820.h>
static void __init zap_identity_mappings(void)
{
@@ -48,6 +49,35 @@
}
}
+#define EBDA_ADDR_POINTER 0x40E
+
+static __init void reserve_ebda(void)
+{
+ unsigned ebda_addr, ebda_size;
+
+ /*
+ * there is a real-mode segmented pointer pointing to the
+ * 4K EBDA area at 0x40E
+ */
+ ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
+ ebda_addr <<= 4;
+
+ if (!ebda_addr)
+ return;
+
+ ebda_size = *(unsigned short *)__va(ebda_addr);
+
+ /* Round EBDA up to pages */
+ if (ebda_size == 0)
+ ebda_size = 1;
+ ebda_size <<= 10;
+ ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
+ if (ebda_size > 64*1024)
+ ebda_size = 64*1024;
+
+ reserve_early(ebda_addr, ebda_addr + ebda_size);
+}
+
void __init x86_64_start_kernel(char * real_mode_data)
{
int i;
@@ -75,5 +105,23 @@
pda_init(0);
copy_bootdata(__va(real_mode_data));
+ reserve_early(__pa_symbol(&_text), __pa_symbol(&_end));
+
+ /* Reserve INITRD */
+ if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
+ unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
+ unsigned long ramdisk_size = boot_params.hdr.ramdisk_size;
+ unsigned long ramdisk_end = ramdisk_image + ramdisk_size;
+ reserve_early(ramdisk_image, ramdisk_end);
+ }
+
+ reserve_ebda();
+
+ /*
+ * At this point everything still needed from the boot loader
+ * or BIOS or kernel text should be early reserved or marked not
+ * RAM in e820. All other memory is free game.
+ */
+
start_kernel();
}
