[coreboot-gerrit] Change in coreboot[master]: arch/x86: Include stack_top region into postcar_frame

[Subrata Banik (Code Review)]

Hello Aaron Durbin,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/coreboot/+/34991

to review the following change.

Change subject: arch/x86: Include stack_top region into postcar_frame
......................................................................

arch/x86: Include stack_top region into postcar_frame

This patch signals to the system that stack region also needs to be
accounted for as it holds MTRR related values.

Change-Id: I9279bbd66be0ad309bdabbbb90bf59c6f5967c47
Signed-off-by: Aaron Durbin 
Signed-off-by: Subrata Banik 
---
M src/arch/x86/include/arch/cpu.h
M src/arch/x86/postcar_loader.c
2 files changed, 12 insertions(+), 5 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/91/34991/1

diff --git a/src/arch/x86/include/arch/cpu.h b/src/arch/x86/include/arch/cpu.h
index 9aa446e..075e890 100644
--- a/src/arch/x86/include/arch/cpu.h
+++ b/src/arch/x86/include/arch/cpu.h
@@ -298,6 +298,7 @@
  */

struct postcar_frame {
+	uintptr_t stack_top;
    uintptr_t stack;
    uint32_t upper_mask;
    int max_var_mtrrs;
diff --git a/src/arch/x86/postcar_loader.c b/src/arch/x86/postcar_loader.c
index b1b2da0..d017260 100644
--- a/src/arch/x86/postcar_loader.c
+++ b/src/arch/x86/postcar_loader.c
@@ -66,7 +66,10 @@

postcar_frame_prepare(pcf);
    pcf->stack = (uintptr_t)stack;
-	pcf->stack += stack_size;
+	/* Keep track of stack top to calculate size used */
+	pcf->stack_top = pcf->stack;
+	pcf->stack_top += stack_size;
+
    return 0;
 }

@@ -143,15 +146,18 @@
    return (void *) pcf->stack;
 }

-static void finalize_load(uintptr_t *stack_top_ptr, uintptr_t stack_top)
+static void finalize_load(uintptr_t *stack_top_ptr,
+			const struct postcar_frame *pcf)
 {
-	*stack_top_ptr = stack_top;
+	*stack_top_ptr = pcf->stack;
    /*
     * Signal to rest of system that another update was made to the
     * postcar program prior to running it.
     */
    prog_segment_loaded((uintptr_t)stack_top_ptr, sizeof(uintptr_t),
    	SEG_FINAL);
+	 /* Also signal the stack region that was written as well */
+	prog_segment_loaded(pcf->stack, pcf->stack_top - pcf->stack, SEG_FINAL);
 }

static void load_postcar_cbfs(struct prog *prog, struct postcar_frame *pcf)
@@ -173,7 +179,7 @@
    	die_with_post_code(POST_INVALID_ROM,
    			   "No parameters found in after CAR program.\n");

-	finalize_load(rsl.params, pcf->stack);
+	finalize_load(rsl.params, pcf);

stage_cache_add(STAGE_POSTCAR, prog);
 }
@@ -191,7 +197,7 @@
    	/* This is here to allow platforms to pass different stack
    	   parameters between S3 resume and normal boot. On the
    	   platforms where the values are the same it's a nop. */
-		finalize_load(prog.arg, pcf->stack);
+		finalize_load(prog.arg, pcf);
    } else
    	load_postcar_cbfs(&prog, pcf);