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Revert "ANDROID: arm64: Handle AArch32 tasks running on non AArch32 cpu"

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This reverts commit cacae105ed.

Bug: 178507149
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I26369490f2f8b5c4eb47559cd1a8a197cdda1d75
This commit is contained in:
Will Deacon
2021-01-25 15:01:07 +00:00
parent fcecc7a35e
commit b6a3d75cd1
2 changed files with 10 additions and 29 deletions
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7
arch/arm64/Kconfig
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@@ -1934,9 +1934,10 @@ config ASYMMETRIC_AARCH32
Enable this option to allow support for asymmetric AArch32 EL0
CPU configurations. Once the AArch32 EL0 support is detected
on a CPU, the feature is made available to user space to allow
the execution of 32-bit (compat) applications by migrating
them to the capable CPUs. Offlining such CPUs leads to 32-bit
applications being killed.
the execution of 32-bit (compat) applications. If the affinity
of the 32-bit application contains a non-AArch32 capable CPU
or the last AArch32 capable CPU is offlined, the application
will be killed.
If unsure say N.

32
arch/arm64/kernel/signal.c
View File

@@ -912,34 +912,14 @@ static void do_signal(struct pt_regs *regs)
restore_saved_sigmask();
}
static void set_32bit_cpus_allowed(void)
static void check_aarch32_cpumask(void)
{
int ret;
/*
* Try to honour as best as possible whatever affinity request this
* task has. If it spans no compatible CPU, disregard it entirely.
* The task must be a subset of aarch32_el0_mask or it could end up
* migrating and running on the wrong CPU.
*/
if (cpumask_intersects(current->cpus_ptr, &aarch32_el0_mask)) {
cpumask_var_t cpus_allowed;
if (!alloc_cpumask_var(&cpus_allowed, GFP_ATOMIC)) {
ret = set_cpus_allowed_ptr(current, &aarch32_el0_mask);
} else {
cpumask_and(cpus_allowed, current->cpus_ptr, &aarch32_el0_mask);
ret = set_cpus_allowed_ptr(current, cpus_allowed);
free_cpumask_var(cpus_allowed);
}
} else {
ret = set_cpus_allowed_ptr(current, &aarch32_el0_mask);
}
if (ret) {
pr_warn_once("No CPUs capable of running 32-bit tasks\n");
if (!cpumask_subset(current->cpus_ptr, &aarch32_el0_mask)) {
pr_warn_once("CPU affinity contains CPUs that are not capable of running 32-bit tasks\n");
force_sig(SIGKILL);
}
}
@@ -962,7 +942,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
if (IS_ENABLED(CONFIG_ASYMMETRIC_AARCH32) &&
thread_flags & _TIF_CHECK_32BIT_AFFINITY) {
clear_thread_flag(TIF_CHECK_32BIT_AFFINITY);
set_32bit_cpus_allowed();
check_aarch32_cpumask();
}
if (thread_flags & _TIF_UPROBE)