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| author | Will Deacon <will@kernel.org> | 2021-06-08 19:02:57 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2021-06-11 13:25:41 +0100 |
| commit | 873c3e89777c8c56f936ae7aceca1a102aac6b9e (patch) | |
| tree | c84816eb04b65c9c89fe29e873fc311e108b532f /arch/arm64/kernel/process.c | |
| parent | 2f6a49bbc01da17867c26f6f650b1142e1d7c69d (diff) | |
| download | linux-873c3e89777c8c56f936ae7aceca1a102aac6b9e.tar.bz2 | |
arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs
Scheduling a 32-bit application on a 64-bit-only CPU is a bad idea.
Ensure that 32-bit applications always take the slow-path when returning
to userspace on a system with mismatched support at EL0, so that we can
avoid trying to run on a 64-bit-only CPU and force a SIGKILL instead.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210608180313.11502-5-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/process.c')
| -rw-r--r-- | arch/arm64/kernel/process.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index b4bb67f17a2c..f4a91bf1ce0c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -527,6 +527,15 @@ 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) { /* @@ -568,6 +577,7 @@ __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 @@ -633,8 +643,15 @@ unsigned long arch_align_stack(unsigned long sp) */ void arch_setup_new_exec(void) { - current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; + unsigned long mmflags = 0; + + if (is_compat_task()) { + mmflags = MMCF_AARCH32; + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } + current->mm->context.flags = mmflags; ptrauth_thread_init_user(); mte_thread_init_user(); |