| From 6cf3d8e043cc4be7fc38171e8dc3b7be5ba74ccc Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 26 Nov 2021 12:11:53 +0800 |
| Subject: powerpc/85xx: Fix oops when CONFIG_FSL_PMC=n |
| |
| From: Xiaoming Ni <nixiaoming@huawei.com> |
| |
| [ Upstream commit 3dc709e518b47386e6af937eaec37bb36539edfd ] |
| |
| When CONFIG_FSL_PMC is set to n, no value is assigned to cpu_up_prepare |
| in the mpc85xx_pm_ops structure. As a result, oops is triggered in |
| smp_85xx_start_cpu(). |
| |
| smp: Bringing up secondary CPUs ... |
| kernel tried to execute user page (0) - exploit attempt? (uid: 0) |
| BUG: Unable to handle kernel instruction fetch (NULL pointer?) |
| Faulting instruction address: 0x00000000 |
| Oops: Kernel access of bad area, sig: 11 [#1] |
| ... |
| NIP [00000000] 0x0 |
| LR [c0021d2c] smp_85xx_kick_cpu+0xe8/0x568 |
| Call Trace: |
| [c1051da8] [c0021cb8] smp_85xx_kick_cpu+0x74/0x568 (unreliable) |
| [c1051de8] [c0011460] __cpu_up+0xc0/0x228 |
| [c1051e18] [c0031bbc] bringup_cpu+0x30/0x224 |
| [c1051e48] [c0031f3c] cpu_up.constprop.0+0x180/0x33c |
| [c1051e88] [c00322e8] bringup_nonboot_cpus+0x88/0xc8 |
| [c1051eb8] [c07e67bc] smp_init+0x30/0x78 |
| [c1051ed8] [c07d9e28] kernel_init_freeable+0x118/0x2a8 |
| [c1051f18] [c00032d8] kernel_init+0x14/0x124 |
| [c1051f38] [c0010278] ret_from_kernel_thread+0x14/0x1c |
| |
| Fixes: c45361abb918 ("powerpc/85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n") |
| Reported-by: Martin Kennedy <hurricos@gmail.com> |
| Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> |
| Tested-by: Martin Kennedy <hurricos@gmail.com> |
| Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
| Link: https://lore.kernel.org/r/20211126041153.16926-1-nixiaoming@huawei.com |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/powerpc/platforms/85xx/smp.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c |
| index 83f4a6389a282..d7081e9af65c7 100644 |
| --- a/arch/powerpc/platforms/85xx/smp.c |
| +++ b/arch/powerpc/platforms/85xx/smp.c |
| @@ -220,7 +220,7 @@ static int smp_85xx_start_cpu(int cpu) |
| local_irq_save(flags); |
| hard_irq_disable(); |
| |
| - if (qoriq_pm_ops) |
| + if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare) |
| qoriq_pm_ops->cpu_up_prepare(cpu); |
| |
| /* if cpu is not spinning, reset it */ |
| @@ -292,7 +292,7 @@ static int smp_85xx_kick_cpu(int nr) |
| booting_thread_hwid = cpu_thread_in_core(nr); |
| primary = cpu_first_thread_sibling(nr); |
| |
| - if (qoriq_pm_ops) |
| + if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare) |
| qoriq_pm_ops->cpu_up_prepare(nr); |
| |
| /* |
| -- |
| 2.34.1 |
| |