[ Upstream commit 4d8e3e951a856777720272ce27f2c738a3eeef8c ]
During early system resume on Exynos5422 with performance counters enabled the following kernel oops happens:
Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 1433 Comm: bash Tainted: G W 5.0.0-rc5-next-20190208-00023-gd5fb5a8a13e6-dirty #5480 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) ... Flags: nZCv IRQs off FIQs off Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: 4451006a DAC: 00000051 Process bash (pid: 1433, stack limit = 0xb7e0e22f) ... (reset_ctrl_regs) from [<c0112ad0>] (dbg_cpu_pm_notify+0x1c/0x24) (dbg_cpu_pm_notify) from [<c014c840>] (notifier_call_chain+0x44/0x84) (notifier_call_chain) from [<c014cbc0>] (__atomic_notifier_call_chain+0x7c/0x128) (__atomic_notifier_call_chain) from [<c01ffaac>] (cpu_pm_notify+0x30/0x54) (cpu_pm_notify) from [<c055116c>] (syscore_resume+0x98/0x3f4) (syscore_resume) from [<c0189350>] (suspend_devices_and_enter+0x97c/0xe74) (suspend_devices_and_enter) from [<c0189fb8>] (pm_suspend+0x770/0xc04) (pm_suspend) from [<c0187740>] (state_store+0x6c/0xcc) (state_store) from [<c09fa698>] (kobj_attr_store+0x14/0x20) (kobj_attr_store) from [<c030159c>] (sysfs_kf_write+0x4c/0x50) (sysfs_kf_write) from [<c0300620>] (kernfs_fop_write+0xfc/0x1e0) (kernfs_fop_write) from [<c0282be8>] (__vfs_write+0x2c/0x160) (__vfs_write) from [<c0282ea4>] (vfs_write+0xa4/0x16c) (vfs_write) from [<c0283080>] (ksys_write+0x40/0x8c) (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x28)
Undefined instruction is triggered during CP14 reset, because bits: #16 (Secure privileged invasive debug disabled) and #17 (Secure privileged noninvasive debug disable) are set in DSCR. Those bits depend on SPNIDEN and SPIDEN lines, which are provided by Secure JTAG hardware block. That block in turn is powered from cluster 0 (big/Eagle), but the Exynos5422 boots on cluster 1 (LITTLE/KFC).
To fix this issue it is enough to turn on the power on the cluster 0 for a while. This lets the Secure JTAG block to propagate the needed signals to LITTLE/KFC cores and change their DSCR.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Signed-off-by: Krzysztof Kozlowski krzk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/mach-exynos/suspend.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/arch/arm/mach-exynos/suspend.c b/arch/arm/mach-exynos/suspend.c index 81c935ce089b..b406c12077b9 100644 --- a/arch/arm/mach-exynos/suspend.c +++ b/arch/arm/mach-exynos/suspend.c @@ -500,8 +500,27 @@ early_wakeup:
static void exynos5420_prepare_pm_resume(void) { + unsigned int mpidr, cluster; + + mpidr = read_cpuid_mpidr(); + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + if (IS_ENABLED(CONFIG_EXYNOS5420_MCPM)) WARN_ON(mcpm_cpu_powered_up()); + + if (IS_ENABLED(CONFIG_HW_PERF_EVENTS) && cluster != 0) { + /* + * When system is resumed on the LITTLE/KFC core (cluster 1), + * the DSCR is not properly updated until the power is turned + * on also for the cluster 0. Enable it for a while to + * propagate the SPNIDEN and SPIDEN signals from Secure JTAG + * block and avoid undefined instruction issue on CP14 reset. + */ + pmu_raw_writel(S5P_CORE_LOCAL_PWR_EN, + EXYNOS_COMMON_CONFIGURATION(0)); + pmu_raw_writel(0, + EXYNOS_COMMON_CONFIGURATION(0)); + } }
static void exynos5420_pm_resume(void)