From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>,
lst@pengutronix.de, rcz@pengutronix.de
Subject: [PATCH 11/11] ARM: mmuinfo: add options for enabling/disabling zero page trapping
Date: Mon, 22 May 2023 07:28:35 +0200 [thread overview]
Message-ID: <20230522052835.1039143-12-a.fatoum@pengutronix.de> (raw)
In-Reply-To: <20230522052835.1039143-1-a.fatoum@pengutronix.de>
mmuinfo 0 will most likely trigger a translation fault. To allow
decoding the zero page or to allow reading BootROM code at address 0,
teach mmuinfo -z to disable trapping of the zero page and mmuinfo -Z to
reinstate the faulting zero page.
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
arch/arm/cpu/mmuinfo.c | 47 ++++++++++++++++++++++++++++++++++++++++--
include/zero_page.h | 12 +++++++++++
2 files changed, 57 insertions(+), 2 deletions(-)
diff --git a/arch/arm/cpu/mmuinfo.c b/arch/arm/cpu/mmuinfo.c
index 413f2f337e95..44d6980a7569 100644
--- a/arch/arm/cpu/mmuinfo.c
+++ b/arch/arm/cpu/mmuinfo.c
@@ -6,8 +6,10 @@
#include <common.h>
#include <command.h>
+#include <getopt.h>
#include <asm/mmuinfo.h>
#include <asm/system_info.h>
+#include <zero_page.h>
#include <mmu.h>
int mmuinfo(void *addr)
@@ -23,8 +25,40 @@ int mmuinfo(void *addr)
static __maybe_unused int do_mmuinfo(int argc, char *argv[])
{
unsigned long addr;
+ int access_zero_page = -1;
+ int opt;
- if (argc < 2)
+ while ((opt = getopt(argc, argv, "zZ")) > 0) {
+ switch (opt) {
+ case 'z':
+ access_zero_page = true;
+ break;
+ case 'Z':
+ access_zero_page = false;
+ break;
+ default:
+ return COMMAND_ERROR_USAGE;
+ }
+ }
+
+ if (access_zero_page >= 0) {
+ if (argc - optind != 0)
+ return COMMAND_ERROR_USAGE;
+
+ if (!zero_page_remappable()) {
+ pr_warn("No architecture support for zero page remap\n");
+ return -ENOSYS;
+ }
+
+ if (access_zero_page)
+ zero_page_access();
+ else
+ zero_page_faulting();
+
+ return 0;
+ }
+
+ if (argc - optind != 1)
return COMMAND_ERROR_USAGE;
addr = strtoul_suffix(argv[1], NULL, 0);
@@ -32,11 +66,20 @@ static __maybe_unused int do_mmuinfo(int argc, char *argv[])
return mmuinfo((void *)addr);
}
+BAREBOX_CMD_HELP_START(mmuinfo)
+BAREBOX_CMD_HELP_TEXT("Show MMU/cache information using the cp15/model-specific registers.")
+BAREBOX_CMD_HELP_TEXT("")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-z", "enable access to zero page")
+BAREBOX_CMD_HELP_OPT ("-Z", "disable access to zero page")
+BAREBOX_CMD_HELP_END
+
#ifdef CONFIG_COMMAND_SUPPORT
BAREBOX_CMD_START(mmuinfo)
.cmd = do_mmuinfo,
BAREBOX_CMD_DESC("show MMU/cache information of an address")
- BAREBOX_CMD_OPTS("ADDRESS")
+ BAREBOX_CMD_OPTS("[-zZ | ADDRESS]")
BAREBOX_CMD_GROUP(CMD_GRP_INFO)
+ BAREBOX_CMD_HELP(cmd_mmuinfo_help)
BAREBOX_CMD_END
#endif
diff --git a/include/zero_page.h b/include/zero_page.h
index a71c0e0b8733..79e0f22c7b5b 100644
--- a/include/zero_page.h
+++ b/include/zero_page.h
@@ -20,6 +20,13 @@ void zero_page_faulting(void);
*/
void zero_page_access(void);
+void zero_page_access(void);
+
+static inline bool zero_page_remappable(void)
+{
+ return true;
+}
+
#else
static inline void zero_page_faulting(void)
@@ -30,6 +37,11 @@ static inline void zero_page_access(void)
{
}
+static inline bool zero_page_remappable(void)
+{
+ return false;
+}
+
#endif
static inline bool zero_page_contains(unsigned long addr)
--
2.39.2
next prev parent reply other threads:[~2023-05-22 5:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 5:28 [PATCH 00/11] ARM: qemu-virt: remap cfi-flash from 0 to 0x1000 Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 01/11] treewide: use remap_range instead of arch_remap_range Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 02/11] mmu: add physical address parameter to arch_remap_range Ahmad Fatoum
2023-05-23 7:17 ` Sascha Hauer
2023-05-23 7:21 ` Ahmad Fatoum
2023-05-23 7:27 ` Sascha Hauer
2023-05-22 5:28 ` [PATCH 03/11] ARM: mmu32: support non-1:1 mappings in arch_remap_range Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 04/11] ARM: mmu64: " Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 05/11] of: platform: remap memory when encountering virtual-reg property Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 06/11] common: boards: qemu-virt: remap cfi-flash from 0 to 0x1000 Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 07/11] ARM: prepare extending mmuinfo beyond ARMv7 Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 08/11] ARM64: mmu: implement ARMv8 mmuinfo command Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 09/11] common: memtest: prepare for reuse in self test Ahmad Fatoum
2023-05-22 5:28 ` [PATCH 10/11] test: self: add MMU remapping " Ahmad Fatoum
2023-05-22 5:28 ` Ahmad Fatoum [this message]
2023-05-23 7:21 ` [PATCH 00/11] ARM: qemu-virt: remap cfi-flash from 0 to 0x1000 Sascha Hauer
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