From 4c095fc9e91e68ab15d2ff256260acc9fd65dd91 Mon Sep 17 00:00:00 2001 From: Arthur Heymans Date: Sun, 18 Aug 2019 08:40:56 +0200 Subject: [PATCH] cpu/intel/car: Make stack guards more useful on C_ENV_BOOTBLOCK MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With C_ENVIRONMENT_BOOTBLOCK, CONFIG_DCACHE_BSP_STACK_SIZE needs to be set to define a stack region that can be shared over all stages using CAR. It makes sense to use that Kconfig option's value instead of a hardcoded value. This will result in less false positives when the stack size is big, for instance with FSP using the coreboot stack. In many configurations with C_ENVIRONMENT_BOOTBLOCK the stack_base is at the base of CAR. If the stack grows too large it operates out of CAR, typically resulting in a hang. Therefore the stack guards are extended to cover 256 bytes at the base to at least provide a warning when the romstage is dangerously close of running out of stack. Change-Id: I2ce1dda4d1f254e6c36de4d3fea26e12c34195ff Signed-off-by: Arthur Heymans Signed-off-by: Kyösti Mälkki Reviewed-on: https://review.coreboot.org/c/coreboot/+/34976 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin --- src/cpu/intel/car/romstage.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/src/cpu/intel/car/romstage.c b/src/cpu/intel/car/romstage.c index 28801458cd..e24225e71e 100644 --- a/src/cpu/intel/car/romstage.c +++ b/src/cpu/intel/car/romstage.c @@ -21,6 +21,8 @@ #include #include +/* If we do not have a constrained _car_stack region size, use the + following as a guideline for acceptable stack usage. */ #define DCACHE_RAM_ROMSTAGE_STACK_SIZE 0x2000 static struct postcar_frame early_mtrrs; @@ -43,16 +45,18 @@ static void prepare_and_run_postcar(struct postcar_frame *pcf) static void romstage_main(unsigned long bist) { int i; - const int num_guards = 4; + const int num_guards = 64; const u32 stack_guard = 0xdeadbeef; u32 *stack_base; u32 size; + const size_t stack_size = MAX(CONFIG_DCACHE_BSP_STACK_SIZE, + DCACHE_RAM_ROMSTAGE_STACK_SIZE); /* Size of unallocated CAR. */ size = ALIGN_DOWN(_car_stack_size, 16); - size = MIN(size, DCACHE_RAM_ROMSTAGE_STACK_SIZE); - if (size < DCACHE_RAM_ROMSTAGE_STACK_SIZE) + size = MIN(size, stack_size); + if (size < stack_size) printk(BIOS_DEBUG, "Romstage stack size limited to 0x%x!\n", size);