diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-20 08:09:00 -1000 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-20 08:09:00 -1000 |
commit | a956f4e281fe548a541a4970a6e8a0ec283b0d6d (patch) | |
tree | 8d282eeba32305c2492dc8fba16b64cad6c87404 /arch/arm64/kernel/paravirt.c | |
parent | 3d7285a335edaf23b699e87c528cf0b0070e3293 (diff) | |
parent | 1d0cb4c8864addc362bae98e8ffa5500c87e1227 (diff) |
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
"Three arm64 fixes for -rc8/final.
The MTE and stolen time fixes have been doing the rounds for a little
while, but review and testing feedback was ongoing until earlier this
week. The kexec fix showed up on Monday and addresses a failure
observed under Qemu.
Summary:
- Add missing write barrier to publish MTE tags before a pte update
- Fix kexec relocation clobbering its own data structures
- Fix stolen time crash if a timer IRQ fires during CPU hotplug"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mte: Ensure the cleared tags are visible before setting the PTE
arm64: kexec: load from kimage prior to clobbering
arm64: paravirt: Use RCU read locks to guard stolen_time
Diffstat (limited to 'arch/arm64/kernel/paravirt.c')
-rw-r--r-- | arch/arm64/kernel/paravirt.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c index 75fed4460407..57c7c211f8c7 100644 --- a/arch/arm64/kernel/paravirt.c +++ b/arch/arm64/kernel/paravirt.c @@ -35,7 +35,7 @@ static u64 native_steal_clock(int cpu) DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); struct pv_time_stolen_time_region { - struct pvclock_vcpu_stolen_time *kaddr; + struct pvclock_vcpu_stolen_time __rcu *kaddr; }; static DEFINE_PER_CPU(struct pv_time_stolen_time_region, stolen_time_region); @@ -52,7 +52,9 @@ early_param("no-steal-acc", parse_no_stealacc); /* return stolen time in ns by asking the hypervisor */ static u64 para_steal_clock(int cpu) { + struct pvclock_vcpu_stolen_time *kaddr = NULL; struct pv_time_stolen_time_region *reg; + u64 ret = 0; reg = per_cpu_ptr(&stolen_time_region, cpu); @@ -61,28 +63,37 @@ static u64 para_steal_clock(int cpu) * online notification callback runs. Until the callback * has run we just return zero. */ - if (!reg->kaddr) + rcu_read_lock(); + kaddr = rcu_dereference(reg->kaddr); + if (!kaddr) { + rcu_read_unlock(); return 0; + } - return le64_to_cpu(READ_ONCE(reg->kaddr->stolen_time)); + ret = le64_to_cpu(READ_ONCE(kaddr->stolen_time)); + rcu_read_unlock(); + return ret; } static int stolen_time_cpu_down_prepare(unsigned int cpu) { + struct pvclock_vcpu_stolen_time *kaddr = NULL; struct pv_time_stolen_time_region *reg; reg = this_cpu_ptr(&stolen_time_region); if (!reg->kaddr) return 0; - memunmap(reg->kaddr); - memset(reg, 0, sizeof(*reg)); + kaddr = rcu_replace_pointer(reg->kaddr, NULL, true); + synchronize_rcu(); + memunmap(kaddr); return 0; } static int stolen_time_cpu_online(unsigned int cpu) { + struct pvclock_vcpu_stolen_time *kaddr = NULL; struct pv_time_stolen_time_region *reg; struct arm_smccc_res res; @@ -93,17 +104,19 @@ static int stolen_time_cpu_online(unsigned int cpu) if (res.a0 == SMCCC_RET_NOT_SUPPORTED) return -EINVAL; - reg->kaddr = memremap(res.a0, + kaddr = memremap(res.a0, sizeof(struct pvclock_vcpu_stolen_time), MEMREMAP_WB); + rcu_assign_pointer(reg->kaddr, kaddr); + if (!reg->kaddr) { pr_warn("Failed to map stolen time data structure\n"); return -ENOMEM; } - if (le32_to_cpu(reg->kaddr->revision) != 0 || - le32_to_cpu(reg->kaddr->attributes) != 0) { + if (le32_to_cpu(kaddr->revision) != 0 || + le32_to_cpu(kaddr->attributes) != 0) { pr_warn_once("Unexpected revision or attributes in stolen time data\n"); return -ENXIO; } |