[S] Change in coreboot[main]: src/cpu/intel/car/romstage.c: Refactor stack guard code in romstage.

[Name of user not set (Code Review)]

Name of user not set #1005756 has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/86562?usp=email )

Change subject: src/cpu/intel/car/romstage.c: Refactor stack guard code in romstage.
......................................................................

src/cpu/intel/car/romstage.c: Refactor stack guard code in romstage.

Refactor stack guard code in romstage.
It's just for improving readability. :)

Change-Id: I754e422c0023cd7824dd6109f031239756acff4b
Signed-off-by: melongmelong 
---
M src/cpu/intel/car/romstage.c
1 file changed, 31 insertions(+), 12 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/62/86562/1

diff --git a/src/cpu/intel/car/romstage.c b/src/cpu/intel/car/romstage.c
index 63a83ab..a2dec35 100644
--- a/src/cpu/intel/car/romstage.c
+++ b/src/cpu/intel/car/romstage.c
@@ -15,14 +15,14 @@
 /* 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
+#define NUM_STACK_GUARDS 64
+#define STACK_GUARD 0xdeadbeef

-void __noreturn romstage_main(void)
+static u32 *stack_guard_set(void)
 {
    int i;
-	const int num_guards = 64;
-	const u32 stack_guard = 0xdeadbeef;
-	u32 *stack_base;
    u32 size;
+	u32 *stack_base;
    const size_t stack_size = MAX(CONFIG_DCACHE_BSP_STACK_SIZE,
    			      DCACHE_RAM_ROMSTAGE_STACK_SIZE);

@@ -34,8 +34,33 @@
    	printk(BIOS_DEBUG, "Romstage stack size limited to 0x%x!\n",
    		size);

+	/* Set stack guard */
    stack_base = (u32 *)(_ecar_stack - size);

+	for (i = 0; i < NUM_STACK_GUARDS; i++)
+		stack_base[i] = STACK_GUARD;
+
+	return stack_base;
+}
+
+static void stack_guard_check(u32 *stack_base)
+{
+	int i;
+
+	if (stack_base == NULL) {
+		die("Cannot check stack guard because NULL stack base.\n");
+	}
+
+	/* Check the stack. */
+	for (i = 0; i < NUM_STACK_GUARDS; i++) {
+		if (stack_base[i] == STACK_GUARD)
+			continue;
+		printk(BIOS_DEBUG, "Smashed stack detected in romstage!\n");
+	}
+}
+
+void __noreturn romstage_main(void)
+{
    /* Disable breakpoint since stack is intentionally corrupted */
    stack_canary_breakpoint_remove();

@@ -51,8 +76,7 @@
     * report the instruction pointer immediately, which can hint at which function
     * may be using too much stack. FSP might disable HW breakpoints, though.
     */
-	for (i = 0; i < num_guards; i++)
-		stack_base[i] = stack_guard;
+	u32 *stack_base = stack_guard_set();

stack_canary_breakpoint_init();

@@ -73,12 +97,7 @@

mainboard_romstage_entry();

-	/* Check the stack. */
-	for (i = 0; i < num_guards; i++) {
-		if (stack_base[i] == stack_guard)
-			continue;
-		printk(BIOS_DEBUG, "Smashed stack detected in romstage!\n");
-	}
+	stack_guard_check(stack_base);

if (CONFIG(SMM_TSEG))
    	smm_list_regions();