From: Gabe Black gabeblack@chromium.org
Because calculate_relocation_address now uses the e820 map, it will be able to avoid addresses over 32 bits and regions that are at high addresses but not big enough for U-Boot. It also means we can remove the hack which limitted U-Boot's idea of the size of memory to less than 4GB.
Also take into account the space needed for the heap and stack, so we avoid picking a very small region those areas might overlap with something it shouldn't.
Signed-off-by: Gabe Black gabeblack@google.com Signed-off-by: Gabe Black gabeblack@google.com Signed-off-by: Simon Glass sjg@chromium.org --- arch/x86/cpu/coreboot/sdram.c | 53 +++++++++++++++++++++++++++++++++++++--- 1 files changed, 49 insertions(+), 4 deletions(-)
diff --git a/arch/x86/cpu/coreboot/sdram.c b/arch/x86/cpu/coreboot/sdram.c index 5d3da99..611f554 100644 --- a/arch/x86/cpu/coreboot/sdram.c +++ b/arch/x86/cpu/coreboot/sdram.c @@ -51,6 +51,55 @@ unsigned install_e820_map(unsigned max_entries, struct e820entry *entries) return num_entries; }
+/* + * This function looks for the highest region of memory lower than 4GB which + * has enough space for U-Boot where U-Boot is aligned on a page boundary. It + * overrides the default implementation found elsewhere which simply picks the + * end of ram, wherever that may be. The location of the stack, the relocation + * address, and how far U-Boot is moved by relocation are set in the global + * data structure. + */ +int calculate_relocation_address(void) +{ + const uint64_t uboot_size = &__bss_end - &__text_start; + const uint64_t total_size = uboot_size + CONFIG_SYS_MALLOC_LEN + + CONFIG_SYS_STACK_SIZE; + uintptr_t dest_addr = 0; + int i; + + for (i = 0; i < lib_sysinfo.n_memranges; i++) { + struct memrange *memrange = &lib_sysinfo.memrange[i]; + /* Force U-Boot to relocate to a page aligned address. */ + uint64_t start = roundup(memrange->base, 1 << 12); + uint64_t end = memrange->base + memrange->size; + + /* Ignore non-memory regions. */ + if (memrange->type != CB_MEM_RAM) + continue; + + /* Filter memory over 4GB. */ + if (end > 0xffffffffULL) + end = 0x100000000ULL; + /* Skip this region if it's too small. */ + if (end - start < total_size) + continue; + + /* Use this address if it's the largest so far. */ + if (end - uboot_size > dest_addr) + dest_addr = (end - uboot_size) & ~((1 << 12) - 1); + } + + /* If no suitable area was found, return an error. */ + if (!dest_addr) + return 1; + + gd->start_addr_sp = dest_addr - CONFIG_SYS_MALLOC_LEN; + gd->relocaddr = dest_addr; + gd->reloc_off = dest_addr - (uintptr_t)&__text_start; + + return 0; +} + int dram_init_f(void) { int i; @@ -60,10 +109,6 @@ int dram_init_f(void) struct memrange *memrange = &lib_sysinfo.memrange[i]; unsigned long long end = memrange->base + memrange->size;
- /* Ignore memory over 4GB, we can't use it. */ - if (memrange->base > 0xffffffff) - continue; - if (memrange->type == CB_MEM_RAM && end > ram_size) ram_size = end; }