diff options
Diffstat (limited to 'sfi.c')
| -rw-r--r-- | sfi.c | 70 |
1 files changed, 59 insertions, 11 deletions
@@ -25,19 +25,67 @@ #define SFI_BASE_ADDR 0x000E0000 #define SFI_LENGTH 0x00020000 +#define SFI_TABLE_LENGTH 16 -static unsigned long sfi_search_mmap(unsigned long start, int len) +static int sfi_table_check(struct sfi_table_header *sbh) { - unsigned long i = 0; - char *pchar = (char *)start; - - for (i = 0; i < len; i++, pchar++) { - if (pchar[0] == 'M' - && pchar[1] == 'M' - && pchar[2] == 'A' - && pchar[3] == 'P') - return start + i; + char chksum = 0; + char *pos = (char *)sbh; + int i; + + if (sbh->length < SFI_TABLE_LENGTH) + return -1; + + if (sbh->length > SFI_LENGTH) + return -1; + + for (i = 0; i < sbh->length; i++) + chksum += *pos++; + + if (chksum) + bs_printk("sfi: Invalid checksum\n"); + + /* checksum is ok if zero */ + return chksum; +} + +static unsigned long sfi_search_mmap(void) +{ + u32 i = 0; + u32 *pos = (u32 *)SFI_BASE_ADDR; + u32 *end = (u32 *)(SFI_BASE_ADDR + SFI_LENGTH); + struct sfi_table_header *sbh; + struct sfi_table *sb; + u32 sys_entry_cnt = 0; + + /* Find SYST table */ + for (; pos < end; pos += 4) { + if (*pos == SFI_SYST_MAGIC) { + if (!sfi_table_check((struct sfi_table_header *)pos)) + break; + } + } + + if (pos >= end) { + bs_printk("Bootstub: failed to locate SFI SYST table\n"); + return 0; } + + /* map table pointers */ + sb = (struct sfi_table *)pos; + sbh = (struct sfi_table_header *)sb; + + sys_entry_cnt = (sbh->length - sizeof(struct sfi_table_header)) >> 3; + + /* Search through each SYST entry for MMAP table */ + for (i = 0; i < sys_entry_cnt; i++) { + sbh = (struct sfi_table_header *)sb->entry[i].low; + if (*(u32 *)sbh->signature == SFI_MMAP_MAGIC) { + if (!sfi_table_check((struct sfi_table_header *)sbh)) + return (unsigned long) sbh; + } + } + return 0; } @@ -52,7 +100,7 @@ void sfi_setup_e820(struct boot_params *bp) total = 0; /* search for sfi mmap table */ - sb = (struct sfi_table *)sfi_search_mmap(SFI_BASE_ADDR, SFI_LENGTH); + sb = (struct sfi_table *)sfi_search_mmap(); if (!sb) { bs_printk("Bootstub: failed to locate SFI MMAP table\n"); return; |