Subject: linux-next: manual merge of the tip tree with the arm64 tree

From: Stephen Rothwell <[email-masked]>
Date: Fri, 27 Aug 2021 14:09:13 +1000

Hi all,

Today's linux-next merge of the tip tree got conflicts in:

  arch/arm64/kernel/process.c
  arch/arm64/kernel/signal.c

between commits:

  d2e0d8f9746d ("arm64: move preemption disablement to prctl handlers")
  4d1c2ee2709f ("arm64: entry: move bulk of ret_to_user to C")

from the arm64 tree and commit:

  94f9c00f6460 ("arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores")

from the tip tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

-- 
Cheers,
Stephen Rothwell

diff --cc arch/arm64/kernel/process.c
index 8334facd5356,e0e7f4e9b607..000000000000
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@@ -469,22 -469,7 +470,13 @@@ static void erratum_1418040_thread_swit
  	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)
 +/*
 + * __switch_to() checks current->thread.sctlr_user as an optimisation. Therefore
 + * this function must be called with preemption disabled and the update to
 + * sctlr_user must be made in the same preemption disabled block so that
 + * __switch_to() does not see the variable update before the SCTLR_EL1 one.
 + */
 +void update_sctlr_el1(u64 sctlr)
  {
  	/*
  	 * EnIA must not be cleared while in the kernel as this is necessary for
diff --cc arch/arm64/kernel/signal.c
index e42743134ae2,22899c86711a..000000000000
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@@ -917,20 -912,8 +917,7 @@@ static void do_signal(struct pt_regs *r
  	restore_saved_sigmask();
  }
  
- static bool cpu_affinity_invalid(struct pt_regs *regs)
- {
- 	if (!compat_user_mode(regs))
- 		return false;
- 
- 	/*
- 	 * We're preemptible, but a reschedule will cause us to check the
- 	 * affinity again.
- 	 */
- 	return !cpumask_test_cpu(raw_smp_processor_id(),
- 				 system_32bit_el0_cpumask());
- }
- 
 -asmlinkage void do_notify_resume(struct pt_regs *regs,
 -				 unsigned long thread_flags)
 +void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
  {
  	do {
  		if (thread_flags & _TIF_NEED_RESCHED) {