[Skiboot] [PATCH v2] phb4: Enforce root complex config space size of 2048

[Michael Neuling]

The root complex config space size on PHB4 is 2048. This patch sets
that size and enforces it when trying to read/write the config space
in the root complex.

Without this someone reading the config space via /sysfs in linux will
cause an EEH on the PHB.

If too high, reads returns 1s and writes are silently dropped.

Signed-off-by: Michael Neuling <mikey at neuling.org>
---
 hw/phb4.c           | 9 +++++++--
 include/phb4-regs.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/hw/phb4.c b/hw/phb4.c
index 41468c98c1..9019c6bf9b 100644
--- a/hw/phb4.c
+++ b/hw/phb4.c
@@ -229,8 +229,10 @@ static int64_t phb4_rc_read(struct phb4 *p, uint32_t offset, uint8_t sz,
 		oval = p->rc_cache[(reg - 0x20) >> 2];
 		break;
 	default:
-		/* XXX Add ASB support ? */
-		oval = in_le32(p->regs + PHB_RC_CONFIG_BASE + reg);
+		oval = 0xffffffff; /* default if offset too big */
+		if (reg < PHB_RC_CONFIG_SIZE)
+			/* XXX Add ASB support ? */
+			oval = in_le32(p->regs + PHB_RC_CONFIG_BASE + reg);
 	}
 	switch (sz) {
 	case 1:
@@ -257,6 +259,9 @@ static int64_t phb4_rc_write(struct phb4 *p, uint32_t offset, uint8_t sz,
 	uint32_t old, mask, shift;
 	int64_t rc;
 
+	if (reg > PHB_RC_CONFIG_SIZE)
+		return OPAL_SUCCESS;
+
 	/* If size isn't 4-bytes, do a RMW cycle
 	 *
 	 * XXX TODO: Filter out registers that do write-1-to-clear !!!
diff --git a/include/phb4-regs.h b/include/phb4-regs.h
index 548094907a..92bee88f6b 100644
--- a/include/phb4-regs.h
+++ b/include/phb4-regs.h
@@ -235,6 +235,7 @@
 
 // FIXME add more here
 #define PHB_RC_CONFIG_BASE			0x1000
+#define   PHB_RC_CONFIG_SIZE			0x800
 
 /* PHB4 REGB registers */
 #define PHB_PBL_CONTROL				0x1800
-- 
2.11.0