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authorWill Deacon <will@kernel.org>2021-07-30 14:24:42 +0300
committerPeter Zijlstra <peterz@infradead.org>2021-08-20 13:33:07 +0300
commit94f9c00f6460c0b175226c8fe6fd137547b239bd (patch)
treebc8be003ad95d2127507ed38ee96c20c90dac654 /arch/arm64/kernel/process.c
parentead7de462ae56b2d2e56fb5a414f6e916dddc4c9 (diff)
downloadlinux-94f9c00f6460c0b175226c8fe6fd137547b239bd.tar.xz
arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores
The scheduler now knows enough about these braindead systems to place 32-bit tasks accordingly, so throw out the safety checks and allow the ret-to-user path to avoid do_notify_resume() if there is nothing to do. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20210730112443.23245-16-will@kernel.org
Diffstat (limited to 'arch/arm64/kernel/process.c')
-rw-r--r--arch/arm64/kernel/process.c14
1 files changed, 1 insertions, 13 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 583ee58f8c9c..e0e7f4e9b607 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -469,15 +469,6 @@ static void erratum_1418040_thread_switch(struct task_struct *prev,
write_sysreg(val, cntkctl_el1);
}
-static void compat_thread_switch(struct task_struct *next)
-{
- if (!is_compat_thread(task_thread_info(next)))
- return;
-
- if (static_branch_unlikely(&arm64_mismatched_32bit_el0))
- set_tsk_thread_flag(next, TIF_NOTIFY_RESUME);
-}
-
static void update_sctlr_el1(u64 sctlr)
{
/*
@@ -519,7 +510,6 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
ssbs_thread_switch(next);
erratum_1418040_thread_switch(prev, next);
ptrauth_thread_switch_user(next);
- compat_thread_switch(next);
/*
* Complete any pending TLB or cache maintenance on this CPU in case
@@ -621,10 +611,8 @@ void arch_setup_new_exec(void)
* at the point of execve(), although we try a bit harder to
* honour the cpuset hierarchy.
*/
- if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) {
+ if (static_branch_unlikely(&arm64_mismatched_32bit_el0))
force_compatible_cpus_allowed_ptr(current);
- set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
- }
} else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) {
relax_compatible_cpus_allowed_ptr(current);
}