New patch to review for coreboot: HACK/RFC: Make cbmem_find() fail cleanly before cbmem_initialize()

[Julius Werner]

Julius Werner ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/16273

-gerrit

commit ad3eadf18968d409c87717c9aab54f9c12650168
Author: Julius Werner 
Date:   Fri Aug 19 16:20:40 2016 -0700

HACK/RFC: Make cbmem_find() fail cleanly before cbmem_initialize()

Right now, calling cbmem_find() on my ARM64 system in romstage before
    DRAM has been initialized will cause the IMD/CBMEM code to immediately
    initialize CBMEM (which hangs the system). The code from
    vb2_selected_region() suggests that this is not intended and it's
    supposed to cleanly return NULL instead.

There is probably a more appropriate way to do this than just adding a
    global (and it would need to be a CAR_GLOBAL, at least), but I'm not
    really familiar enough with this code. Can somebody point me in the
    right direction?

Alternatively, we can declare that cbmem_find() is not allowed before
    cbmem_initialize() and instead add an extra CAR_GLOBAL to the vboot code
    to keep track of whether the CBMEM handoff has been initialized.

Change-Id: Ia6c1db00ae01dee485d5e96e4315cb399dc63696
    Signed-off-by: Julius Werner 
---
 src/lib/imd_cbmem.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/lib/imd_cbmem.c b/src/lib/imd_cbmem.c
index 3e3e2b0..538756b 100644
--- a/src/lib/imd_cbmem.c
+++ b/src/lib/imd_cbmem.c
@@ -26,6 +26,8 @@
 #include <arch/acpi.h>
 #endif

+static int haxxor = 0;
+
 static inline struct imd *cbmem_get_imd(void)
 {
    /* Only supply a backing store for imd in ramstage. */
@@ -75,6 +77,7 @@ static struct imd *imd_init_backing(struct imd *backing)
 static struct imd *imd_init_backing_with_recover(struct imd *backing)
 {
    struct imd *imd;
+	haxxor = 1;

imd = imd_init_backing(backing);
    if (!ENV_RAMSTAGE) {
@@ -221,6 +224,9 @@ void *cbmem_find(u32 id)
    struct imd imd_backing;
    const struct imd_entry *e;

+	if (!haxxor)
+		return NULL;
+
    imd = imd_init_backing_with_recover(&imd_backing);

e = imd_entry_find(imd, id);