Patch set updated for coreboot: soc/apollolake: Place new romstage stack in CAR instead of RAM
Alexandru Gagniuc (mr.nuke.me@gmail.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13357
-gerrit
commit adb2482a9ffbbd84700a1d30655a251079f8c5c0 Author: Alexandru Gagniuc alexandrux.gagniuc@intel.com Date: Fri Nov 13 17:15:03 2015 -0800
soc/apollolake: Place new romstage stack in CAR instead of RAM
We can allocate a new romstage stack in CAR because we don't tear down CAR in romstage. This simple change improves ramstage loading time by about 30%.
Change-Id: I5762c74cdc0ea8cb0aade3fdf8071cb86ec3fe0e Signed-off-by: Alexandru Gagniuc alexandrux.gagniuc@intel.com --- src/soc/intel/apollolake/Kconfig | 13 +------------ src/soc/intel/apollolake/romstage/entry.inc | 6 +++--- src/soc/intel/apollolake/romstage/romstage.c | 29 ++++++++++++---------------- 3 files changed, 16 insertions(+), 32 deletions(-)
diff --git a/src/soc/intel/apollolake/Kconfig b/src/soc/intel/apollolake/Kconfig index eb9bd79..1b60bcf 100644 --- a/src/soc/intel/apollolake/Kconfig +++ b/src/soc/intel/apollolake/Kconfig @@ -12,7 +12,6 @@ config CPU_SPECIFIC_OPTIONS select ARCH_ROMSTAGE_X86_32 select ARCH_VERSTAGE_X86_32 # CPU specific options - select CPU_INTEL_FIRMWARE_INTERFACE_TABLE select IOAPIC select SMP select SSE2 @@ -70,17 +69,7 @@ config DCACHE_RAM_BOOTBLOCK_STACK_SIZE default 0x800 help The amount of anticipated stack usage from the bootblock during - pre-romstage initialization. - -config ROMSTAGE_RAM_STACK_SIZE - hex - default 0x5000 - help - The size of the romstage stack after memory is available. Because CAR - space is very crowded, only a very limited part of CAR is available - for stack. More than that is needed to decompress ramstage. This - variable indicates how much RAM to reserve for the stack after - raminit. The stack is automatically switched after romstage_main(). + pre-romstage initialization..
config IFD_BIOS_START hex diff --git a/src/soc/intel/apollolake/romstage/entry.inc b/src/soc/intel/apollolake/romstage/entry.inc index 8c0670c..2c6dfd6 100644 --- a/src/soc/intel/apollolake/romstage/entry.inc +++ b/src/soc/intel/apollolake/romstage/entry.inc @@ -21,9 +21,9 @@ apollolake_entry: call romstage_entry
/* - * eax contains pointer to a region in RAM that we've been given the go - * ahead to use as stack. The old stack is empty at this point, so we - * don't have to relocate anything. + * eax contains pointer to a region that we've been given the go ahead + * to use as stack. The old stack is empty at this point, so we don't + * have to relocate anything. */ mov esp, eax
diff --git a/src/soc/intel/apollolake/romstage/romstage.c b/src/soc/intel/apollolake/romstage/romstage.c index b7ffd3a..24fad92 100644 --- a/src/soc/intel/apollolake/romstage/romstage.c +++ b/src/soc/intel/apollolake/romstage/romstage.c @@ -54,23 +54,18 @@ static void soc_early_romstage_init(void) pci_write_config32(PCI_DEV(0, 13, 0), 0x60, 1<<7); }
-static void *alloc_stack_in_ram(void) +/* + * Now that FSP is done consuming large amounts of CAR, we can use a much + * larger portion of CAR for the stack. The larger stack is needed for + * decompressing ramstage. It turns out that setting the stack pointer to top + * of CAR gives us the largest uninterrupted stack. + */ +static void *realloc_stack(void) { - uint8_t *ram_stack = cbmem_add(CBMEM_ID_ROMSTAGE_RAM_STACK, - CONFIG_ROMSTAGE_RAM_STACK_SIZE); - - /* - * If cbmem fails to give us a memory window, try to get a stack at - * 2 MiB, and hope we can go forward. The 2 MiB address is arbitrary. - */ - if (ram_stack == NULL) { - printk(BIOS_ALERT, "Could not find place for stack\n"); - return (void *)(2 * MiB); - } - - /* The initial stack pointer should point at the top of the region */ - ram_stack += CONFIG_ROMSTAGE_RAM_STACK_SIZE - sizeof(size_t); - return ram_stack; + uintptr_t new_stack = CONFIG_DCACHE_RAM_BASE + CONFIG_DCACHE_RAM_SIZE; + new_stack -= sizeof(size_t); + printk(BIOS_DEBUG, "Placing new stack at 0x%lx\n", new_stack); + return (void *)new_stack; }
asmlinkage void* romstage_entry(void) @@ -100,7 +95,7 @@ asmlinkage void* romstage_entry(void) if (fsp_mem.base != (uintptr_t)cbmem_find(CBMEM_ID_FSP_RESERVED_MEMORY)) die("Failed to accommodate FSP reserved memory request");
- return alloc_stack_in_ram(); + return realloc_stack(); }
asmlinkage void romstage_after_raminit(void)
-
Alexandru Gagniuc