[coreboot-gerrit] [XS] Change in coreboot[main]: cpu/intel/car/romstage: Fix false-positive stack corruption

[Patrick Rudolph (Code Review)]

Patrick Rudolph has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/85568?usp=email )

Change subject: cpu/intel/car/romstage: Fix false-positive stack corruption
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cpu/intel/car/romstage: Fix false-positive stack corruption

Fix regression introduced in commit 03518727313119a8c7a273eb745663c99f8e4d22
("arch/x86: Add breakpoint to stack canary").

romstage_main writes to the stack-canary, but since that's expected
temporarily disable the breakpoint. This only caused a warning on
platforms that do select IDT_IN_EVERY_STAGE, since those install the
stack canary breakpoint.

TEST: No more exceptions are printed in romstage when IDT_IN_EVERY_STAGE
      is enabled.

Change-Id: I7ebf0a5e8eaad49af77ab4d5f6b58fc849013b14
Signed-off-by: Patrick Rudolph 
---
M src/cpu/intel/car/romstage.c
1 file changed, 6 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/68/85568/1

diff --git a/src/cpu/intel/car/romstage.c b/src/cpu/intel/car/romstage.c
index 7df512d..9607a3a 100644
--- a/src/cpu/intel/car/romstage.c
+++ b/src/cpu/intel/car/romstage.c
@@ -3,6 +3,7 @@
 #include <adainit.h>
 #include <arch/romstage.h>
 #include <arch/symbols.h>
+#include <arch/stack_canary_breakpoint.h>
 #include <commonlib/helpers.h>
 #include <console/console.h>
 #include <cpu/x86/smm.h>
@@ -35,9 +36,14 @@

stack_base = (u32 *)(_ecar_stack - size);

+	/* Disable breakpoint since stack is intentionally corrupted */
+	stack_canary_breakpoint_remove();
+
    for (i = 0; i < num_guards; i++)
    	stack_base[i] = stack_guard;

+	stack_canary_breakpoint_init();
+
    if (CONFIG(VBOOT_EARLY_EC_SYNC))
    	vboot_sync_ec();