From: Rouven Czerwinski <r.czerwinski@pengutronix.de>
To: barebox@lists.infradead.org
Cc: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Subject: [PATCH 3/8] ARM: mmu: use reserve mem entries to modify maps
Date: Tue, 20 Apr 2021 09:56:56 +0200 [thread overview]
Message-ID: <20210420075700.246124-3-r.czerwinski@pengutronix.de> (raw)
In-Reply-To: <20210420075700.246124-1-r.czerwinski@pengutronix.de>
Use the information from the reserved memory entries to modify the
mapping of memory regions to mark them as uncachable and not-executable.
This also prevents the processor from speculating into these regions,
preventing hard to debug scenarios where boots fail for unknown reasons.
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
arch/arm/cpu/mmu.c | 60 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 58 insertions(+), 2 deletions(-)
diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
index 6af228505d..71d6cad1ef 100644
--- a/arch/arm/cpu/mmu.c
+++ b/arch/arm/cpu/mmu.c
@@ -17,6 +17,7 @@
#include <memory.h>
#include <asm/system_info.h>
#include <asm/sections.h>
+#include <of.h>
#include "mmu.h"
@@ -387,6 +388,57 @@ static void vectors_init(void)
create_vector_table(ARM_LOW_VECTORS);
}
+static void create_sections_with_intersect(struct memory_bank *bank)
+{
+ int i;
+ unsigned flag;
+ struct of_reserve_map *res_map = of_get_reserve_map();
+ unsigned long j_end;
+ unsigned long end;
+ unsigned long j;
+
+ res_map = of_get_reserve_map();
+ if (!res_map)
+ return;
+
+ end = bank->start + bank->size - 1;
+ j = bank->start;
+
+ while(j < end) {
+ flag = PMD_SECT_DEF_CACHED;
+ j_end = j + PGDIR_SIZE - 1;
+
+ for (i = 0; i < res_map->num_entries; i++) {
+ if(BIT(i) & res_map->xn && (j_end >= res_map->start[i] &&
+ j_end <= res_map->end[i]))
+ flag = PMD_SECT_DEF_UNCACHED | PMD_SECT_XN;
+ }
+
+ create_sections(ttb, j, j_end, flag);
+ j += PGDIR_SIZE;
+ }
+}
+
+static bool intersects_reserved_map_xn(struct memory_bank *bank)
+{
+ struct of_reserve_map *res_map;
+ unsigned long bank_end;
+ int i;
+
+ res_map = of_get_reserve_map();
+
+ if (!res_map)
+ return false;
+
+ bank_end = bank->start + bank->size;
+ for (i = 0; i < res_map->num_entries; i++) {
+ if(res_map->start[i] >= bank->start || res_map->end[i] <= bank_end)
+ return true;
+ }
+ return false;
+}
+
+
/*
* Prepare MMU for usage enable it.
*/
@@ -448,8 +500,12 @@ void __mmu_init(bool mmu_on)
vectors_init();
for_each_memory_bank(bank) {
- create_sections(ttb, bank->start, bank->start + bank->size - 1,
- PMD_SECT_DEF_CACHED);
+ if (intersects_reserved_map_xn(bank)) {
+ create_sections_with_intersect(bank);
+ } else {
+ create_sections(ttb, bank->start, bank->start + bank->size - 1,
+ PMD_SECT_DEF_CACHED);
+ }
__mmu_cache_flush();
}
--
2.31.1
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next prev parent reply other threads:[~2021-04-20 8:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 7:56 [PATCH 1/8] of: reserve: add xn flag mem entries Rouven Czerwinski
2021-04-20 7:56 ` [PATCH 2/8] of: export of_get_reserve_map Rouven Czerwinski
2021-04-20 8:47 ` Ahmad Fatoum
2021-04-20 7:56 ` Rouven Czerwinski [this message]
2021-04-20 9:09 ` [PATCH 3/8] ARM: mmu: use reserve mem entries to modify maps Ahmad Fatoum
2021-04-20 7:56 ` [PATCH 4/8] of: add flag to not create resmem DT entries Rouven Czerwinski
2021-04-20 9:22 ` Ahmad Fatoum
2021-04-20 7:56 ` [PATCH 5/8] of: add reserved_mem_read initcall Rouven Czerwinski
2021-04-20 9:23 ` Ahmad Fatoum
2021-04-20 10:36 ` Ahmad Fatoum
2021-04-20 7:56 ` [PATCH 6/8] pbl: fdt: add support to parse reserved mem Rouven Czerwinski
2021-04-20 10:29 ` Ahmad Fatoum
2021-04-20 7:57 ` [PATCH 7/8] ARM: mmu-early: map no-map entries XN & uncached Rouven Czerwinski
2021-04-20 9:00 ` Lucas Stach
2021-04-20 7:57 ` [PATCH 8/8] PBL: enable LIBFDT for OP-TEE early loading Rouven Czerwinski
2021-04-20 10:33 ` Ahmad Fatoum
2021-04-20 8:45 ` [PATCH 1/8] of: reserve: add xn flag mem entries Ahmad Fatoum
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