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From: Fuad Tabba <tabba@google.com>
To: linux-arm-kernel@lists.infradead.org
Cc: will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com,
	 maz@kernel.org, ardb@kernel.org, james.morse@arm.com,
	 alexandru.elisei@arm.com, suzuki.poulose@arm.com,
	robin.murphy@arm.com,  tabba@google.com
Subject: [PATCH v3 07/18] arm64: Downgrade flush_icache_range to invalidate
Date: Thu, 20 May 2021 13:43:55 +0100	[thread overview]
Message-ID: <20210520124406.2731873-8-tabba@google.com> (raw)
In-Reply-To: <20210520124406.2731873-1-tabba@google.com>

Since __flush_dcache_area is called right before,
invalidate_icache_range is sufficient in this case.

Rewrite the comment to better explain the rationale behind the
cache maintenance operations used here.

No functional change intended.
Possible performance impact due to invalidating only the icache
rather than invalidating and cleaning both caches.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/linux-arch/20200511110014.lb9PEahJ4hVOYrbwIb_qUHXyNy9KQzNFdb_I3YlzY6A@z/
Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/kernel/machine_kexec.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 90a335c74442..a03944fd0cd4 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -68,10 +68,14 @@ int machine_kexec_post_load(struct kimage *kimage)
 	kimage->arch.kern_reloc = __pa(reloc_code);
 	kexec_image_info(kimage);
 
-	/* Flush the reloc_code in preparation for its execution. */
+	/*
+	 * For execution with the MMU off, reloc_code needs to be cleaned to the
+	 * PoC and invalidated from the I-cache.
+	 */
 	__flush_dcache_area(reloc_code, arm64_relocate_new_kernel_size);
-	flush_icache_range((uintptr_t)reloc_code, (uintptr_t)reloc_code +
-			   arm64_relocate_new_kernel_size);
+	invalidate_icache_range((uintptr_t)reloc_code,
+				(uintptr_t)reloc_code +
+					arm64_relocate_new_kernel_size);
 
 	return 0;
 }
-- 
2.31.1.751.gd2f1c929bd-goog


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  parent reply	other threads:[~2021-05-20 12:48 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-20 12:43 [PATCH v3 00/18] Tidy up cache.S Fuad Tabba
2021-05-20 12:43 ` [PATCH v3 01/18] arm64: assembler: replace `kaddr` with `addr` Fuad Tabba
2021-05-20 12:43 ` [PATCH v3 02/18] arm64: assembler: add conditional cache fixups Fuad Tabba
2021-05-20 12:43 ` [PATCH v3 03/18] arm64: Apply errata to swsusp_arch_suspend_exit Fuad Tabba
2021-05-20 12:46   ` Mark Rutland
2021-05-20 12:43 ` [PATCH v3 04/18] arm64: assembler: user_alt label optional Fuad Tabba
2021-05-20 12:57   ` Mark Rutland
2021-05-21 11:46     ` Fuad Tabba
2021-05-21 13:05       ` Mark Rutland
2021-05-20 12:43 ` [PATCH v3 05/18] arm64: Do not enable uaccess for flush_icache_range Fuad Tabba
2021-05-20 14:02   ` Mark Rutland
2021-05-20 15:37     ` Mark Rutland
2021-05-21 12:18       ` Mark Rutland
2021-05-25 11:18   ` Catalin Marinas
2021-05-20 12:43 ` [PATCH v3 06/18] arm64: Do not enable uaccess for invalidate_icache_range Fuad Tabba
2021-05-20 14:13   ` Mark Rutland
2021-05-25 11:18   ` Catalin Marinas
2021-05-20 12:43 ` Fuad Tabba [this message]
2021-05-20 14:15   ` [PATCH v3 07/18] arm64: Downgrade flush_icache_range to invalidate Mark Rutland
2021-05-25 11:18   ` Catalin Marinas
2021-05-20 12:43 ` [PATCH v3 08/18] arm64: Move documentation of dcache_by_line_op Fuad Tabba
2021-05-20 14:17   ` Mark Rutland
2021-05-20 12:43 ` [PATCH v3 09/18] arm64: Fix comments to refer to correct function __flush_icache_range Fuad Tabba
2021-05-20 14:18   ` Mark Rutland
2021-05-20 12:43 ` [PATCH v3 10/18] arm64: __inval_dcache_area to take end parameter instead of size Fuad Tabba
2021-05-20 15:46   ` Mark Rutland
2021-05-20 12:43 ` [PATCH v3 11/18] arm64: dcache_by_line_op " Fuad Tabba
2021-05-20 15:48   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 12/18] arm64: __flush_dcache_area " Fuad Tabba
2021-05-20 16:06   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 13/18] arm64: __clean_dcache_area_poc " Fuad Tabba
2021-05-20 16:16   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 14/18] arm64: __clean_dcache_area_pop " Fuad Tabba
2021-05-20 16:19   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 15/18] arm64: __clean_dcache_area_pou " Fuad Tabba
2021-05-20 16:24   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 16/18] arm64: sync_icache_aliases " Fuad Tabba
2021-05-20 16:34   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 17/18] arm64: Fix cache maintenance function comments Fuad Tabba
2021-05-20 16:48   ` Mark Rutland
2021-05-20 12:44 ` [PATCH v3 18/18] arm64: Rename arm64-internal cache maintenance functions Fuad Tabba
2021-05-20 17:01   ` Mark Rutland

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