x86 boot: pass E820 memory map entries more than 128 via linked list of setup data

Because of the size limits of struct boot_params (zero page), the
maximum number of E820 memory map entries can be passed to kernel is
128. As pointed by Paul Jackson, there is some machine produced by SGI
with so many nodes that the number of E820 memory map entries is more
than 128. To enabling Linux kernel on these system, a new setup data
type named SETUP_E820_EXT is defined to pass additional memory map
entries to Linux kernel.

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

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index ed46b7a6bc1375e766b62f1fc45630d48a089286..544dd12c70f4e6bf191f499c9463584e1cc5c75c 100644 (file)
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -359,6 +359,26 @@ static struct e820entry new_bios[E820_X_MAX] __initdata;
        return 0;
 }
 
+static int __init __copy_e820_map(struct e820entry *biosmap, int nr_map)
+{
+       while (nr_map) {
+               u64 start = biosmap->addr;
+               u64 size = biosmap->size;
+               u64 end = start + size;
+               u32 type = biosmap->type;
+
+               /* Overflow in 64 bits? Ignore the memory map. */
+               if (start > end)
+                       return -1;
+
+               e820_add_region(start, size, type);
+
+               biosmap++;
+               nr_map--;
+       }
+       return 0;
+}
+
 /*
  * Copy the BIOS e820 map into a safe place.
  *
@@ -374,19 +394,7 @@ int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
        if (nr_map < 2)
                return -1;
 
-       do {
-               u64 start = biosmap->addr;
-               u64 size = biosmap->size;
-               u64 end = start + size;
-               u32 type = biosmap->type;
-
-               /* Overflow in 64 bits? Ignore the memory map. */
-               if (start > end)
-                       return -1;
-
-               e820_add_region(start, size, type);
-       } while (biosmap++, --nr_map);
-       return 0;
+       return __copy_e820_map(biosmap, nr_map);
 }
 
 u64 __init e820_update_range(u64 start, u64 size, unsigned old_type,
@@ -496,6 +504,31 @@ __init void e820_setup_gap(void)
               pci_mem_start, gapstart, gapsize);
 }
 
+/**
+ * Because of the size limitation of struct boot_params, only first
+ * 128 E820 memory entries are passed to kernel via
+ * boot_params.e820_map, others are passed via SETUP_E820_EXT node of
+ * linked list of struct setup_data, which is parsed here.
+ */
+void __init parse_e820_ext(struct setup_data *sdata, unsigned long pa_data)
+{
+       u32 map_len;
+       int entries;
+       struct e820entry *extmap;
+
+       entries = sdata->len / sizeof(struct e820entry);
+       map_len = sdata->len + sizeof(struct setup_data);
+       if (map_len > PAGE_SIZE)
+               sdata = early_ioremap(pa_data, map_len);
+       extmap = (struct e820entry *)(sdata->data);
+       __copy_e820_map(extmap, entries);
+       sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+       if (map_len > PAGE_SIZE)
+               early_iounmap(sdata, map_len);
+       printk(KERN_INFO "extended physical RAM map:\n");
+       e820_print_map("extended");
+}
+
 #if defined(CONFIG_X86_64) || \
        (defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))
 /**

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 45a5e247d45093af8db7305623e24d9f4a197ba5..5b0de38cde487570662dcc31ebe85fcab1cd5471 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -150,6 +150,9 @@ void __init parse_setup_data(void)
        while (pa_data) {
                data = early_ioremap(pa_data, PAGE_SIZE);
                switch (data->type) {
+               case SETUP_E820_EXT:
+                       parse_e820_ext(data, pa_data);
+                       break;
                default:
                        break;
                }

diff --git a/include/asm-x86/bootparam.h b/include/asm-x86/bootparam.h
index 0a073904168b48e18bf7613097dc0842cd6863fe..876f21136660e1c85cff44a5716460d9671baacd 100644 (file)
--- a/include/asm-x86/bootparam.h
+++ b/include/asm-x86/bootparam.h
@@ -11,6 +11,7 @@
 
 /* setup data types */
 #define SETUP_NONE                     0
+#define SETUP_E820_EXT                 1
 
 /* extensible setup data list node */
 struct setup_data {

diff --git a/include/asm-x86/e820.h b/include/asm-x86/e820.h
index 55d3105969079632ca454046780a203d14dc8a99..77fc24d8916302635878fdcf1a769aad50d0985a 100644 (file)
--- a/include/asm-x86/e820.h
+++ b/include/asm-x86/e820.h
@@ -69,6 +69,8 @@ extern u64 e820_update_range(u64 start, u64 size, unsigned old_type,
                               unsigned new_type);
 extern void update_e820(void);
 extern void e820_setup_gap(void);
+struct setup_data;
+extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data);
 
 #if defined(CONFIG_X86_64) || \
        (defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))