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authorDarren Stevens <darren@stevens-zone.net>2017-01-23 19:42:54 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2017-01-24 15:57:02 +1100
commitaf2b7fa17eb92e52b65f96604448ff7a2a89ee99 (patch)
treedeba86a57193fdc5facfaa8e73157a4bbef45820 /arch
parent178f358208ceb8b38e5cff3f815e0db4a6a70a07 (diff)
powerpc: Add missing error check to prom_find_boot_cpu()
prom_init.c calls 'instance-to-package' twice, but the return is not checked during prom_find_boot_cpu(). The result is then passed to prom_getprop(), which could be PROM_ERROR. Add a return check to prevent this. This was found on a pasemi system, where CFE doesn't have a working 'instance-to package' prom call. Before Commit 5c0484e25ec0 ('powerpc: Endian safe trampoline') the area around addr 0 was mostly 0's and this doesn't cause a problem. Once the macro 'FIXUP_ENDIAN' has been added to head_64.S, the low memory area now has non-zero values, which cause the prom_getprop() call to hang. mpe: Also confirmed that under SLOF if 'instance-to-package' did fail with PROM_ERROR we would crash in SLOF. So the bug is not specific to CFE, it's just that other open firmwares don't trigger it because they have a working 'instance-to-package'. Fixes: 5c0484e25ec0 ("powerpc: Endian safe trampoline") Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Darren Stevens <darren@stevens-zone.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/prom_init.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index ec47a939cbdd..ac83eb04a8b8 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -2834,6 +2834,9 @@ static void __init prom_find_boot_cpu(void)
cpu_pkg = call_prom("instance-to-package", 1, 1, prom_cpu);
+ if (!PHANDLE_VALID(cpu_pkg))
+ return;
+
prom_getprop(cpu_pkg, "reg", &rval, sizeof(rval));
prom.cpu = be32_to_cpu(rval);