[PATCH 1/7] x86/mm: Add mm argument to unuse_temporary_mm()

From: Peter Zijlstra
Date: Tue Nov 19 2024 - 11:37:04 EST


In commit 209954cbc7d0 ("x86/mm/tlb: Update mm_cpumask lazily")
unuse_temporary_mm() grew the assumption that it gets used on
poking_nn exclusively. While this is currently true, lets not hard
code this assumption.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/kernel/alternative.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1828,14 +1828,14 @@ static inline temp_mm_state_t use_tempor
__ro_after_init struct mm_struct *poking_mm;
__ro_after_init unsigned long poking_addr;

-static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
+static inline void unuse_temporary_mm(struct mm_struct *mm, temp_mm_state_t prev_state)
{
lockdep_assert_irqs_disabled();

switch_mm_irqs_off(NULL, prev_state.mm, current);

/* Clear the cpumask, to indicate no TLB flushing is needed anywhere */
- cpumask_clear_cpu(raw_smp_processor_id(), mm_cpumask(poking_mm));
+ cpumask_clear_cpu(raw_smp_processor_id(), mm_cpumask(mm));

/*
* Restore the breakpoints if they were disabled before the temporary mm
@@ -1942,7 +1942,7 @@ static void *__text_poke(text_poke_f fun
* instruction that already allows the core to see the updated version.
* Xen-PV is assumed to serialize execution in a similar manner.
*/
- unuse_temporary_mm(prev);
+ unuse_temporary_mm(poking_mm, prev);

/*
* Flushing the TLB might involve IPIs, which would require enabled