linux-kernel - [RFC/RFT PATCH 5/6] arm64: mm: Remove arch_apei_flush_tlb

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Date:   Tue, 31 Oct 2017 15:38:31 +0000
From:   James Morse <james.morse@....com>
To:     linux-acpi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        x86@...nel.org, Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Tony Luck <tony.luck@...el.com>,
        Tyler Baicar <tbaicar@...eaurora.org>,
        Dongjiu Geng <gengdongjiu@...wei.com>,
        Xie XiuQi <xiexiuqi@...wei.com>, torvalds@...ux-foundation.org,
        James Morse <james.morse@....com>
Subject: [RFC/RFT PATCH 5/6] arm64: mm: Remove arch_apei_flush_tlb_one()

Nothing calls arch_apei_flush_tlb_one() anymore, instead relying on
__set_fixmap() to do the invalidation. Remove it.

Move the IPI-considered-harmful comment to __set_fixmap().

Signed-off-by: James Morse <james.morse@....com>
---
 arch/arm64/include/asm/acpi.h | 12 ------------
 arch/arm64/mm/mmu.c           |  4 ++++
 2 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 59cca1d6ec54..32f465a80e4e 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -126,18 +126,6 @@ static inline const char *acpi_get_enable_method(int cpu)
  */
 #define acpi_disable_cmcff 1
 pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr);
-
-/*
- * Despite its name, this function must still broadcast the TLB
- * invalidation in order to ensure other CPUs don't end up with junk
- * entries as a result of speculation. Unusually, its also called in
- * IRQ context (ghes_iounmap_irq) so if we ever need to use IPIs for
- * TLB broadcasting, then we're in trouble here.
- */
-static inline void arch_apei_flush_tlb_one(unsigned long addr)
-{
-	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
-}
 #endif /* CONFIG_ACPI_APEI */
 
 #ifdef CONFIG_ACPI_NUMA
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f1eb15e0e864..267d2b79d52d 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -778,6 +778,10 @@ void __init early_fixmap_init(void)
 	}
 }
 
+/*
+ * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
+ * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
+ */
 void __set_fixmap(enum fixed_addresses idx,
 			       phys_addr_t phys, pgprot_t flags)
 {
-- 
2.15.0.rc2