ARM: Add non-secure / virt Kconfig options and allow secure boot on non-secure configs

Hi Albert,

Here is the 4th version of my patch to allow secure-boot on u-boot builds build with non-secure boot support enabled. The first patch is new and it moves the enablement of ARMV7_NONSEC and ARMV7_VIRT to arch/arm/cpu/armv7/Kconfig.

This allows adding a Kconfig option in the second patch to select whether to boot in secure or non-secure mode by default for builds with non-secure boot mode support.

These patches depend on Tom's "Kconfig: Add EXPERT option" and Ian's "sunxi: kconfig: Add top-level ARCH_SUNXI" patches, as such I believe it is best to merge these through the sunxi tree. If I can get your Acked-by for these 2 patches then I'll take care of getting them merged.

Thanks & Regards,

Hans

Add arch/arm/cpu/armv7/Kconfig with non-secure and virt options, so that we can have CONFIG_ARMV7_SEC_BY_DEFAULT as a proper Kconfig option.

---
 arch/arm/Kconfig                    |  2 ++
 arch/arm/cpu/armv7/Kconfig          | 20 ++++++++++++++++++++
 include/configs/arndale.h           |  2 --
 include/configs/sun7i.h             |  2 --
 include/configs/vexpress_ca15_tc2.h |  2 --
 5 files changed, 22 insertions(+), 6 deletions(-)
 create mode 100644 arch/arm/cpu/armv7/Kconfig

index 0644917..d057dcc 100644
@@ -560,6 +560,8 @@ source "arch/arm/cpu/arm926ejs/versatile/Kconfig"
 
 source "arch/arm/cpu/armv7/zynq/Kconfig"
 
+source "arch/arm/cpu/armv7/Kconfig"
+
 source "board/aristainetos/Kconfig"
 source "board/BuR/kwb/Kconfig"
 source "board/BuR/tseries/Kconfig"

new file mode 100644
index 0000000..84e3edb
@@ -0,0 +1,20 @@
+# FIXME, Once overything in u-boot is properly Kconfig-ified
+# this entire file should be "if ARMV7"
+if ARCH_SUNXI || TARGET_ARNDALE || TARGET_VEXPRESS_CA15_TC2
+
+# FIXME, needs a "depends on ARMV7_HAS_NONSEC"
+config ARMV7_NONSEC
+	boolean "Enable support for booting in non-secure mode" if EXPERT
+	default y
+	---help---
+	Say Y here to enable support for booting in non-secure / SVC mode.
+
+# FIXME, needs a "depends on ARMV7_HAS_VIRT"
+config ARMV7_VIRT
+	boolean "Enable support for hardware virtualization" if EXPERT
+	depends on ARMV7_NONSEC
+	default y
+	---help---
+	Say Y here to boot in hypervisor (HYP) mode when booting non-secure.
+
+endif

index f9ee40f..aa6b631 100644
@@ -60,6 +60,4 @@
 /* The PERIPHBASE in the CBAR register is wrong on the Arndale, so override it */
 #define CONFIG_ARM_GIC_BASE_ADDRESS	0x10480000
 
-#define CONFIG_ARMV7_VIRT
-
 #endif	/* __CONFIG_H */

index 7f7369c..5531dfd 100644
@@ -30,8 +30,6 @@
 #endif
 #endif
 
-#define CONFIG_ARMV7_VIRT		1
-#define CONFIG_ARMV7_NONSEC		1
 #define CONFIG_ARMV7_PSCI		1
 #define CONFIG_ARMV7_SECURE_BASE	SUNXI_SRAM_B_BASE
 #define CONFIG_SYS_CLK_FREQ		24000000

index 982f4a7..b43afa2 100644
@@ -18,6 +18,4 @@
 #define CONFIG_SYSFLAGS_ADDR	0x1c010030
 #define CONFIG_SMP_PEN_ADDR	CONFIG_SYSFLAGS_ADDR
 
-#define CONFIG_ARMV7_VIRT
-
 #endif

2.1.0

The only problem I see is you aren't also updating the defconfigs for the boards in question, which results in a behavior change which we don't want.

Tom
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Hi,

The new Kconfig options have "default y", and the boards where using those settings before.

Or are you referring to the fact that CONFIG_ARMV7_NONSEC is getting set for arndale and vexpress_ca15_tc2 now too ? That is intentional ARMV7_VIRT depends on CONFIG_ARMV7_NONSEC.

So far this has been somewhat unelegantly solved by writing every #ifdef CONFIG_ARMV7_NONSEC as:

#if defined(CONFIG_ARMV7_NONSEC) || defined(CONFIG_ARMV7_VIRT)

So that setting CONFIG_ARMV7_VIRT automatically also includes all the NONSEC bits, note that after this patch we could simply these to just:

#ifdef CONFIG_ARMV7_NONSEC

Which would also more correctly reflect when the code should be enabled.

Regards,

Hans

Older Linux kernels will not properly boot in hyp mode, add support for a bootm_boot_mode environment variable, which can be set to "sec" or "nonsec" to force booting in secure or non-secure mode when build with non-sec support.

The default behavior can be selected through CONFIG_ARMV7_BOOT_SEC_DEFAULT, when this is set booting in secure mode is the default. The default setting for this Kconfig option is N, preserving the current behavior of booting in non-secure mode by default when non-secure mode is supported.

--
Changes in v2:
-Allow changing the default boot mode to secure through defining
CONFIG_ARMV7_BOOT_SEC_DEFAULT, this is useful for archs which have a Kconfig option for compatibility with older kernels
Changes in v3:
-Add an else at the end of the #ifdef NONSEC block so that if do_nonsec_entry
fails we do not end up re-trying in secure mode
Changes in v4:
-Add a Kconfig option to select to boot in secure or non-secure mode by default

---
 arch/arm/cpu/armv7/Kconfig | 11 +++++++++++
 arch/arm/lib/bootm.c       | 31 ++++++++++++++++++++++++++-----
 2 files changed, 37 insertions(+), 5 deletions(-)

index 84e3edb..18a4ff3 100644
@@ -9,6 +9,17 @@ config ARMV7_NONSEC
 	---help---
 	Say Y here to enable support for booting in non-secure / SVC mode.
 
+config ARMV7_BOOT_SEC_DEFAULT
+	boolean "Boot in secure mode by default" if EXPERT
+	depends on ARMV7_NONSEC
+	default n
+	---help---
+	Say Y here to boot in secure mode by default even if non-secure mode
+	is supported. This option is useful to boot kernels which do not
+	suppport booting in secure mode. Only set this if you need it.
+	This can be overriden at run-time by setting the bootm_boot_mode env.
+	variable to "sec" or "nonsec".
+
 # FIXME, needs a "depends on ARMV7_HAS_VIRT"
 config ARMV7_VIRT
 	boolean "Enable support for hardware virtualization" if EXPERT

index 39fe7a1..d2a956c 100644
@@ -235,6 +235,26 @@ static void boot_prep_linux(bootm_headers_t *images)
 	}
 }
 
+#if defined(CONFIG_ARMV7_NONSEC) || defined(CONFIG_ARMV7_VIRT)
+static bool boot_nonsec(void)
+{
+	char *s = getenv("bootm_boot_mode");
+#ifdef CONFIG_ARMV7_BOOT_SEC_DEFAULT
+	bool nonsec = false;
+#else
+	bool nonsec = true;
+#endif
+
+	if (s && !strcmp(s, "sec"))
+		nonsec = false;
+
+	if (s && !strcmp(s, "nonsec"))
+		nonsec = true;
+
+	return nonsec;
+}
+#endif
+
 /* Subcommand: GO */
 static void boot_jump_linux(bootm_headers_t *images, int flag)
 {

@@ -283,12 +303,13 @@ static void boot_jump_linux(bootm_headers_t *images, int flag)
 
 	if (!fake) {
 #if defined(CONFIG_ARMV7_NONSEC) || defined(CONFIG_ARMV7_VIRT)
-		armv7_init_nonsec();
-		secure_ram_addr(_do_nonsec_entry)(kernel_entry,
-						  0, machid, r2);
-#else
-		kernel_entry(0, machid, r2);
+		if (boot_nonsec()) {
+			armv7_init_nonsec();
+			secure_ram_addr(_do_nonsec_entry)(kernel_entry,
+							  0, machid, r2);
+		} else
 #endif
+			kernel_entry(0, machid, r2);
 	}
 #endif
 }

2.1.0