From 4afc01a8d44d49617eab567b4bcc6c8d00bdd385 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Thu, 6 Dec 2018 22:50:40 +0000 Subject: arm64: mm: Prevent mismatched 52-bit VA support [ Upstream commit a96a33b1ca57dbea4285893dedf290aeb8eb090b ] For cases where there is a mismatch in ARMv8.2-LVA support between CPUs we have to be careful in allowing secondary CPUs to boot if 52-bit virtual addresses have already been enabled on the boot CPU. This patch adds code to the secondary startup path. If the boot CPU has enabled 52-bit VAs then ID_AA64MMFR2_EL1 is checked to see if the secondary can also enable 52-bit support. If not, the secondary is prevented from booting and an error message is displayed indicating why. Technically this patch could be implemented using the cpufeature code when considering 52-bit userspace support. However, we employ low level checks here as the cpufeature code won't be able to run if we have mismatched 52-bit kernel va support. Signed-off-by: Steve Capper Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/smp.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/arm64/kernel/smp.c') diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index cfd33f18f437..f0c41524b052 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -136,6 +136,7 @@ static int boot_secondary(unsigned int cpu, struct task_struct *idle) } static DECLARE_COMPLETION(cpu_running); +bool va52mismatch __ro_after_init; int __cpu_up(unsigned int cpu, struct task_struct *idle) { @@ -164,6 +165,10 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) if (!cpu_online(cpu)) { pr_crit("CPU%u: failed to come online\n", cpu); + + if (IS_ENABLED(CONFIG_ARM64_52BIT_VA) && va52mismatch) + pr_crit("CPU%u: does not support 52-bit VAs\n", cpu); + ret = -EIO; } } else { -- cgit v1.2.3 From 42c9c872d7da3d8c75785d8c67b10cef542f23a8 Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Mon, 10 Dec 2018 18:07:33 +0000 Subject: arm64: smp: Handle errors reported by the firmware [ Upstream commit f357b3a7e17af7736d67d8267edc1ed3d1dd9391 ] The __cpu_up() routine ignores the errors reported by the firmware for a CPU bringup operation and looks for the error status set by the booting CPU. If the CPU never entered the kernel, we could end up in assuming stale error status, which otherwise would have been set/cleared appropriately by the booting CPU. Reported-by: Steve Capper Cc: Will Deacon Signed-off-by: Suzuki K Poulose Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/smp.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm64/kernel/smp.c') diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index f0c41524b052..b2d6de9f6f4f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -173,6 +173,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) } } else { pr_err("CPU%u: failed to boot: %d\n", cpu, ret); + return ret; } secondary_data.stack = NULL; -- cgit v1.2.3 From 35989bb9eddedf7dda8dbadefc7dc95ccb552f4a Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Wed, 11 Mar 2020 17:12:44 +0000 Subject: arm64: smp: fix smp_send_stop() behaviour commit d0bab0c39e32d39a8c5cddca72e5b4a3059fe050 upstream. On a system with only one CPU online, when another one CPU panics while starting-up, smp_send_stop() will fail to send any STOP message to the other already online core, resulting in a system still responsive and alive at the end of the panic procedure. [ 186.700083] CPU3: shutdown [ 187.075462] CPU2: shutdown [ 187.162869] CPU1: shutdown [ 188.689998] ------------[ cut here ]------------ [ 188.691645] kernel BUG at arch/arm64/kernel/cpufeature.c:886! [ 188.692079] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 188.692444] Modules linked in: [ 188.693031] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.6.0-rc4-00001-g338d25c35a98 #104 [ 188.693175] Hardware name: Foundation-v8A (DT) [ 188.693492] pstate: 200001c5 (nzCv dAIF -PAN -UAO) [ 188.694183] pc : has_cpuid_feature+0xf0/0x348 [ 188.694311] lr : verify_local_elf_hwcaps+0x84/0xe8 [ 188.694410] sp : ffff800011b1bf60 [ 188.694536] x29: ffff800011b1bf60 x28: 0000000000000000 [ 188.694707] x27: 0000000000000000 x26: 0000000000000000 [ 188.694801] x25: 0000000000000000 x24: ffff80001189a25c [ 188.694905] x23: 0000000000000000 x22: 0000000000000000 [ 188.694996] x21: ffff8000114aa018 x20: ffff800011156a38 [ 188.695089] x19: ffff800010c944a0 x18: 0000000000000004 [ 188.695187] x17: 0000000000000000 x16: 0000000000000000 [ 188.695280] x15: 0000249dbde5431e x14: 0262cbe497efa1fa [ 188.695371] x13: 0000000000000002 x12: 0000000000002592 [ 188.695472] x11: 0000000000000080 x10: 00400032b5503510 [ 188.695572] x9 : 0000000000000000 x8 : ffff800010c80204 [ 188.695659] x7 : 00000000410fd0f0 x6 : 0000000000000001 [ 188.695750] x5 : 00000000410fd0f0 x4 : 0000000000000000 [ 188.695836] x3 : 0000000000000000 x2 : ffff8000100939d8 [ 188.695919] x1 : 0000000000180420 x0 : 0000000000180480 [ 188.696253] Call trace: [ 188.696410] has_cpuid_feature+0xf0/0x348 [ 188.696504] verify_local_elf_hwcaps+0x84/0xe8 [ 188.696591] check_local_cpu_capabilities+0x44/0x128 [ 188.696666] secondary_start_kernel+0xf4/0x188 [ 188.697150] Code: 52805001 72a00301 6b01001f 54000ec0 (d4210000) [ 188.698639] ---[ end trace 3f12ca47652f7b72 ]--- [ 188.699160] Kernel panic - not syncing: Attempted to kill the idle task! [ 188.699546] Kernel Offset: disabled [ 188.699828] CPU features: 0x00004,20c02008 [ 188.700012] Memory Limit: none [ 188.700538] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- [root@arch ~]# echo Helo Helo [root@arch ~]# cat /proc/cpuinfo | grep proce processor : 0 Make smp_send_stop() account also for the online status of the calling CPU while evaluating how many CPUs are effectively online: this way, the right number of STOPs is sent, so enforcing a proper freeze of the system at the end of panic even under the above conditions. Fixes: 08e875c16a16c ("arm64: SMP support") Reported-by: Dave Martin Acked-by: Mark Rutland Signed-off-by: Cristian Marussi Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/smp.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'arch/arm64/kernel/smp.c') diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index b2d6de9f6f4f..13b9c20a84b5 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -901,11 +901,22 @@ void tick_broadcast(const struct cpumask *mask) } #endif +/* + * The number of CPUs online, not counting this CPU (which may not be + * fully online and so not counted in num_online_cpus()). + */ +static inline unsigned int num_other_online_cpus(void) +{ + unsigned int this_cpu_online = cpu_online(smp_processor_id()); + + return num_online_cpus() - this_cpu_online; +} + void smp_send_stop(void) { unsigned long timeout; - if (num_online_cpus() > 1) { + if (num_other_online_cpus()) { cpumask_t mask; cpumask_copy(&mask, cpu_online_mask); @@ -919,10 +930,10 @@ void smp_send_stop(void) /* Wait up to one second for other CPUs to stop */ timeout = USEC_PER_SEC; - while (num_online_cpus() > 1 && timeout--) + while (num_other_online_cpus() && timeout--) udelay(1); - if (num_online_cpus() > 1) + if (num_other_online_cpus()) pr_warning("SMP: failed to stop secondary CPUs %*pbl\n", cpumask_pr_args(cpu_online_mask)); } -- cgit v1.2.3