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From: Ard Biesheuvel <ardb@google.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH v2 2/3] arm64: mm: Only map KPTI trampoline if it is going to be used
Date: Mon, 27 Nov 2023 13:00:52 +0100	[thread overview]
Message-ID: <20231127120049.2258650-7-ardb@google.com> (raw)
In-Reply-To: <20231127120049.2258650-5-ardb@google.com>

From: Ard Biesheuvel <ardb@kernel.org>

Avoid creating the fixmap entries for the KPTI trampoline if KPTI is not
in use.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/mm/mmu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 15f6347d23b6..6c8078916f5e 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -674,6 +674,9 @@ static int __init map_entry_trampoline(void)
 {
 	int i;
 
+	if (!arm64_kernel_unmapped_at_el0())
+		return 0;
+
 	pgprot_t prot = kernel_exec_prot();
 	phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
 
-- 
2.43.0.rc1.413.gea7ed67945-goog


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  parent reply	other threads:[~2023-11-27 12:01 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-27 12:00 [PATCH v2 0/3] arm64 kpti fixes Ard Biesheuvel
2023-11-27 12:00 ` [PATCH v2 1/3] arm64: Avoid enabling KPTI unnecessarily Ard Biesheuvel
2023-11-27 15:48   ` Will Deacon
2023-11-27 15:52     ` Ard Biesheuvel
2023-11-27 16:31       ` Will Deacon
2023-11-27 16:39         ` Ard Biesheuvel
2023-11-27 16:41         ` Will Deacon
2023-11-27 17:49           ` Mark Rutland
2023-11-28 11:03             ` Will Deacon
2023-11-28 14:13               ` Mark Rutland
2023-12-11 11:39                 ` Will Deacon
2023-12-12 17:16                   ` Mark Rutland
2023-11-28 11:06   ` Will Deacon
2023-11-27 12:00 ` Ard Biesheuvel [this message]
2023-11-27 12:00 ` [PATCH v2 3/3] arm64: Kconfig: drop KAISER reference from KPTI option description Ard Biesheuvel
2023-11-27 12:47 ` [PATCH v2 0/3] arm64 kpti fixes Mark Rutland
2023-11-30 19:14 ` (subset) " Catalin Marinas
2023-12-11 20:27 ` Will Deacon

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