diff options
Diffstat (limited to 'include/asm-x86')
| -rw-r--r-- | include/asm-x86/e820.h | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/include/asm-x86/e820.h b/include/asm-x86/e820.h index 65c891d..ab18457 100644 --- a/include/asm-x86/e820.h +++ b/include/asm-x86/e820.h @@ -2,6 +2,41 @@ #define __ASM_E820_H #define E820MAP 0x2d0 /* our map */ #define E820MAX 128 /* number of entries in E820MAP */ + +/* + * Legacy E820 BIOS limits us to 128 (E820MAX) nodes due to the + * constrained space in the zeropage. If we have more nodes than + * that, and if we've booted off EFI firmware, then the EFI tables + * passed us from the EFI firmware can list more nodes. Size our + * internal memory map tables to have room for these additional + * nodes, based on up to three entries per node for which the + * kernel was built: MAX_NUMNODES == (1 << CONFIG_NODES_SHIFT), + * plus E820MAX, allowing space for the possible duplicate E820 + * entries that might need room in the same arrays, prior to the + * call to sanitize_e820_map() to remove duplicates. The allowance + * of three memory map entries per node is "enough" entries for + * the initial hardware platform motivating this mechanism to make + * use of additional EFI map entries. Future platforms may want + * to allow more than three entries per node or otherwise refine + * this size. + */ + +/* + * Odd: 'make headers_check' complains about numa.h if I try + * to collapse the next two #ifdef lines to a single line: + * #if defined(__KERNEL__) && defined(CONFIG_EFI) + */ +#ifdef __KERNEL__ +#ifdef CONFIG_EFI +#include <linux/numa.h> +#define E820_X_MAX (E820MAX + 3 * MAX_NUMNODES) +#else /* ! CONFIG_EFI */ +#define E820_X_MAX E820MAX +#endif +#else /* ! __KERNEL__ */ +#define E820_X_MAX E820MAX +#endif + #define E820NR 0x1e8 /* # entries in E820MAP */ #define E820_RAM 1 @@ -18,7 +53,7 @@ struct e820entry { struct e820map { __u32 nr_map; - struct e820entry map[E820MAX]; + struct e820entry map[E820_X_MAX]; }; extern struct e820map e820; |