forked from Minki/linux
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 Commit5c0484e25e
('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:5c0484e25e
("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>
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@ -2834,6 +2834,9 @@ static void __init prom_find_boot_cpu(void)
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cpu_pkg = call_prom("instance-to-package", 1, 1, prom_cpu);
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if (!PHANDLE_VALID(cpu_pkg))
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return;
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prom_getprop(cpu_pkg, "reg", &rval, sizeof(rval));
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prom.cpu = be32_to_cpu(rval);
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