diff mbox

[23/41] powerpc: Ensure that ppc_md is empty before probing for machine type

Message ID 1467695057-12431-24-git-send-email-benh@kernel.crashing.org (mailing list archive)
State Accepted
Headers show

Commit Message

Benjamin Herrenschmidt July 5, 2016, 5:03 a.m. UTC 
Anything in there will be overwritten, so it helps catching nasty
bugs if we check that it's indeed full of NULL's before we do so.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 arch/powerpc/kernel/setup-common.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Michael Ellerman July 21, 2016, 11:09 a.m. UTC | #1 
On Tue, 2016-05-07 at 05:03:59 UTC, Benjamin Herrenschmidt wrote:
> Anything in there will be overwritten, so it helps catching nasty
> bugs if we check that it's indeed full of NULL's before we do so.
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/84b62c72faa197a5c9b75ee935

cheers
diff mbox

Patch

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 2a3564c..7e85fac 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -575,6 +575,7 @@  void probe_machine(void)
 {
 	extern struct machdep_calls __machine_desc_start;
 	extern struct machdep_calls __machine_desc_end;
+	unsigned int i;
 
 	/*
 	 * Iterate all ppc_md structures until we find the proper
@@ -582,6 +583,16 @@  void probe_machine(void)
 	 */
 	DBG("Probing machine type ...\n");
 
+	/* Check ppc_md is empty, if not we have a bug, ie, we setup an
+	 * entry before probe_machine() which will be overwritten
+	 */
+	for (i = 0; i < (sizeof(ppc_md) / sizeof(void *)); i++) {
+		if (((void **)&ppc_md)[i]) {
+			printk(KERN_ERR "Entry %d in ppc_md non empty before"
+			       " machine probe !\n", i);
+		}
+	}
+
 	for (machine_id = &__machine_desc_start;
 	     machine_id < &__machine_desc_end;
 	     machine_id++) {