linux-kernel - [PATCH 4/7] x86/mm: Remove 'mm' argument from unuse_temporary

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Message-ID: <20250402094540.3586683-5-mingo@kernel.org>
Date: Wed,  2 Apr 2025 11:45:37 +0200
From: Ingo Molnar <mingo@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Andy Lutomirski <luto@...nel.org>,
	Rik van Riel <riel@...riel.com>,
	"H . Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 4/7] x86/mm: Remove 'mm' argument from unuse_temporary_mm() again

From: Peter Zijlstra <peterz@...radead.org>

Now that unuse_temporary_mm() lives in tlb.c it can access
cpu_tlbstate.loaded_mm.

[ mingo: Merged it on top of x86/alternatives ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Rik van Riel <riel@...riel.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Link: https://lore.kernel.org/r/20241119163035.648739178@infradead.org
---
 arch/x86/include/asm/mmu_context.h | 2 +-
 arch/x86/kernel/alternative.c      | 2 +-
 arch/x86/mm/tlb.c                  | 8 ++++----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index b103e1709a67..988c11792634 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -273,6 +273,6 @@ unsigned long __get_current_cr3_fast(void);
 #include <asm-generic/mmu_context.h>
 
 extern struct mm_struct *use_temporary_mm(struct mm_struct *temp_mm);
-extern void unuse_temporary_mm(struct mm_struct *mm, struct mm_struct *prev_mm);
+extern void unuse_temporary_mm(struct mm_struct *prev_mm);
 
 #endif /* _ASM_X86_MMU_CONTEXT_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 25abadaf8751..964a2eb0071a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2211,7 +2211,7 @@ static void *__text_poke(text_poke_f func, void *addr, const void *src, size_t l
 	 * 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(text_poke_mm, prev_mm);
+	unuse_temporary_mm(prev_mm);
 
 	/*
 	 * Flushing the TLB might involve IPIs, which would require enabled
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 06a1ad39be74..e672508ca158 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -1019,14 +1019,14 @@ struct mm_struct *use_temporary_mm(struct mm_struct *temp_mm)
 	return prev_mm;
 }
 
-void unuse_temporary_mm(struct mm_struct *mm, struct mm_struct *prev_mm)
+void unuse_temporary_mm(struct mm_struct *prev_mm)
 {
 	lockdep_assert_irqs_disabled();
 
-	switch_mm_irqs_off(NULL, prev_mm, current);
-
 	/* Clear the cpumask, to indicate no TLB flushing is needed anywhere */
-	cpumask_clear_cpu(raw_smp_processor_id(), mm_cpumask(mm));
+	cpumask_clear_cpu(smp_processor_id(), mm_cpumask(this_cpu_read(cpu_tlbstate.loaded_mm)));
+
+	switch_mm_irqs_off(NULL, prev_mm, current);
 
 	/*
 	 * Restore the breakpoints if they were disabled before the temporary mm
-- 
2.45.2