[XS] Change in coreboot[main]: security/memory_clear: fix wrong size of reserved memory range

[Felix Held (Code Review)]

Felix Held has submitted this change. ( https://review.coreboot.org/c/coreboot/+/82397?usp=email )

Change subject: security/memory_clear: fix wrong size of reserved memory range
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security/memory_clear: fix wrong size of reserved memory range

The code used to reserve MEMSET_PAE_PGTL_SIZE (20 KiB) for page used
for clearing the memory above 4 GiB that was assumed to be 2 MiB page.
memset_pae() checks only the alignment and not the size of this region,
so no error was reported by it.

In most cases this reserved memory in 2-4 MiB range, and because this
range isn't usually used by coreboot (architectural stuff is located in
lower 1 MiB, coreboot tables and ramstage are close to TOLUM and payload
isn't yet loaded when the broken code is executed), it never caused any
problems.

Change MEMSET_PAE_PGTL_SIZE to MEMSET_PAE_VMEM_SIZE and fix wrong macro
definition to reserve properly sized region.

Change-Id: I0df15b0d1767196fe70be14d94428ccdf8dbd5d3
Signed-off-by: Krystian Hebel 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82397
Tested-by: build bot (Jenkins) 
Reviewed-by: Sergii Dmytruk 
Reviewed-by: Paul Menzel 
---
M src/security/memory/memory_clear.c
1 file changed, 2 insertions(+), 2 deletions(-)

Approvals:
  Paul Menzel: Looks good to me, but someone else must approve
  Sergii Dmytruk: Looks good to me, approved
  build bot (Jenkins): Verified

diff --git a/src/security/memory/memory_clear.c b/src/security/memory/memory_clear.c
index 03c6f8b..996b1d3 100644
--- a/src/security/memory/memory_clear.c
+++ b/src/security/memory/memory_clear.c
@@ -6,8 +6,8 @@
 #define memset_pae(a, b, c, d, e) 0
 #define MEMSET_PAE_PGTL_ALIGN 0
 #define MEMSET_PAE_PGTL_SIZE 0
-#define MEMSET_PAE_PGTL_SIZE 0
 #define MEMSET_PAE_VMEM_ALIGN 0
+#define MEMSET_PAE_VMEM_SIZE 0
 #endif

#include <memrange.h>
@@ -92,7 +92,7 @@
    				BM_MEM_TABLE);

vmem_addr = get_free_memory_range(&mem, MEMSET_PAE_VMEM_ALIGN,
-						MEMSET_PAE_PGTL_SIZE);
+						MEMSET_PAE_VMEM_SIZE);

printk(BIOS_SPEW, "%s: pgtbl at %p, virt memory at %p\n",
    	__func__, (void *)pgtbl, (void *)vmem_addr);