[PATCH v3 08/14] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0
From: Will Deacon <will@kernel.org>
Date: 2020-11-13 09:38:50
Also in:
linux-arch, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
When exec'ing a 32-bit task on a system with mismatched support for 32-bit EL0, try to ensure that it starts life on a CPU that can actually run it. Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/kernel/process.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 1540ab0fbf23..17b94007fed4 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c@@ -625,6 +625,16 @@ unsigned long arch_align_stack(unsigned long sp) return sp & ~0xf; } +static void adjust_compat_task_affinity(struct task_struct *p) +{ + const struct cpumask *mask = system_32bit_el0_cpumask(); + + if (restrict_cpus_allowed_ptr(p, mask)) + set_cpus_allowed_ptr(p, mask); + + set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); +} + /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */
@@ -635,7 +645,7 @@ void arch_setup_new_exec(void) if (is_compat_task()) { mmflags = MMCF_AARCH32; if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) - set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + adjust_compat_task_affinity(current); } current->mm->context.flags = mmflags;
--
2.29.2.299.gdc1121823c-goog
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