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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Cc: uol@pengutronix.de, Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: [PATCH v2 09/10] ARM: early-mmu: don't cache/prefetch OPTEE_SIZE bytes from end of memory
Date: Wed, 17 Aug 2022 13:42:43 +0200	[thread overview]
Message-ID: <20220817114244.1810531-10-a.fatoum@pengutronix.de> (raw)
In-Reply-To: <20220817114244.1810531-1-a.fatoum@pengutronix.de>

OPTEE_SIZE is always defined in <asm-generic/memory_layout.h> either as
as CONFIG_OPTEE_SIZE or as 0 if the option is undefined.

There is never a reason to map the last OPTEE_SIZE bytes in the initial
memory as cached and executable:

 - OPTEE_SIZE == 0: no change
 - OPTEE_SIZE != 0 && CONFIG_PBL_OPTEE=y: cache must not be enabled for
   the region to avoid speculation
 - OPTEE_SIZE != 0 && CONFIG_BOOTM_OPTEE=y: we won't use this region
   for anything between MMU early init and normal init, so no harm
   in disabling caches.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/cpu/start.c      | 2 +-
 arch/arm/cpu/uncompress.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
index 5861c15d43df..672f26e0063c 100644
--- a/arch/arm/cpu/start.c
+++ b/arch/arm/cpu/start.c
@@ -171,7 +171,7 @@ __noreturn __no_sanitize_address void barebox_non_pbl_start(unsigned long membas
 		} else {
 			pr_debug("enabling MMU, ttb @ 0x%08lx\n", ttb);
 			arm_early_mmu_cache_invalidate();
-			mmu_early_enable(membase, memsize, ttb);
+			mmu_early_enable(membase, memsize - OPTEE_SIZE, ttb);
 		}
 	}
 
diff --git a/arch/arm/cpu/uncompress.c b/arch/arm/cpu/uncompress.c
index 2250b8ccd375..537ee63229d7 100644
--- a/arch/arm/cpu/uncompress.c
+++ b/arch/arm/cpu/uncompress.c
@@ -84,7 +84,7 @@ void __noreturn barebox_pbl_start(unsigned long membase, unsigned long memsize,
 	if (IS_ENABLED(CONFIG_MMU_EARLY)) {
 		unsigned long ttb = arm_mem_ttb(membase, endmem);
 		pr_debug("enabling MMU, ttb @ 0x%08lx\n", ttb);
-		mmu_early_enable(membase, memsize, ttb);
+		mmu_early_enable(membase, memsize - OPTEE_SIZE, ttb);
 	}
 
 	free_mem_ptr = arm_mem_early_malloc(membase, endmem);
-- 
2.30.2




  parent reply	other threads:[~2022-08-17 11:44 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-17 11:42 [PATCH v2 00/10] ARM: mmu: inhibit speculation into secure memory Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 01/10] resource: add flags parameter to __request_region Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 02/10] common: allow requesting SDRAM regions with custom flags Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 03/10] memory: define reserve_sdram_region helper Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 04/10] init: define new postmem_initcall() Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 05/10] of: reserved-mem: reserve regions prior to mmu_initcall() Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 06/10] ARM: mmu64: map reserved regions uncached Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 07/10] ARM: mmu: define attrs_uncached_mem() helper Ahmad Fatoum
2022-08-17 11:42 ` [PATCH v2 08/10] ARM: mmu: use reserve mem entries to modify maps Ahmad Fatoum
2022-09-12 12:01   ` Sascha Hauer
2022-09-12 15:15     ` Ahmad Fatoum
2022-09-12 16:36       ` Sascha Hauer
2022-08-17 11:42 ` Ahmad Fatoum [this message]
2022-08-17 11:42 ` [PATCH v2 10/10] commands: iomem: point out [R]eserved regions Ahmad Fatoum
2022-08-18 12:39 ` [PATCH v2 00/10] ARM: mmu: inhibit speculation into secure memory Sascha Hauer

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