[PATCH AUTOSEL 4.14 01/37] ARC: u-boot args: check that magic number is correct

[PATCH AUTOSEL 4.14 01/37] ARC: u-boot args: check that magic number is correct

[Sasha Levin]

From: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>

[ Upstream commit edb64bca50cd736c6894cc6081d5263c007ce005 ]

In case of devboards we really often disable bootloader and load
Linux image in memory via JTAG. Even if kernel tries to verify
uboot_tag and uboot_arg there is sill a chance that we treat some
garbage in registers as valid u-boot arguments in JTAG case.
E.g. it is enough to have '1' in r0 to treat any value in r2 as
a boot command line.

So check that magic number passed from u-boot is correct and drop
u-boot arguments otherwise. That helps to reduce the possibility
of using garbage as u-boot arguments in JTAG case.

We can safely check U-boot magic value (0x0) in linux passed via
r1 register as U-boot pass it from the beginning. So there is no
backward-compatibility issues.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com>
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 arch/arc/kernel/head.S  | 1 +
 arch/arc/kernel/setup.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 1f945d0f40da..208bf2c9e7b0 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -107,6 +107,7 @@ ENTRY(stext)
 	;    r2 = pointer to uboot provided cmdline or external DTB in mem
 	; These are handled later in handle_uboot_args()
 	st	r0, [@uboot_tag]
+	st      r1, [@uboot_magic]
 	st	r2, [@uboot_arg]
 #endif
 
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 709649e5f9bc..6b8d106e0d53 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -35,6 +35,7 @@ unsigned int intr_to_DE_cnt;
 
 /* Part of U-boot ABI: see head.S */
 int __initdata uboot_tag;
+int __initdata uboot_magic;
 char __initdata *uboot_arg;
 
 const struct machine_desc *machine_desc;
@@ -433,6 +434,8 @@ static inline bool uboot_arg_invalid(unsigned long addr)
 #define UBOOT_TAG_NONE		0
 #define UBOOT_TAG_CMDLINE	1
 #define UBOOT_TAG_DTB		2
+/* We always pass 0 as magic from U-boot */
+#define UBOOT_MAGIC_VALUE	0
 
 void __init handle_uboot_args(void)
 {
@@ -448,6 +451,11 @@ void __init handle_uboot_args(void)
 		goto ignore_uboot_args;
 	}
 
+	if (uboot_magic != UBOOT_MAGIC_VALUE) {
+		pr_warn(IGNORE_ARGS "non zero uboot magic\n");
+		goto ignore_uboot_args;
+	}
+
 	if (uboot_tag != UBOOT_TAG_NONE &&
             uboot_arg_invalid((unsigned long)uboot_arg)) {
 		pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
-- 
2.19.1

[PATCH AUTOSEL 4.14 02/37] arc: hsdk_defconfig: Enable CONFIG_BLK_DEV_RAM

[Sasha Levin]

From: Corentin Labbe <clabbe@baylibre.com>

[ Upstream commit 0728aeb7ead99a9b0dac2f3c92b3752b4e02ff97 ]

We have now a HSDK device in our kernelci lab, but kernel builded via
the hsdk_defconfig lacks ramfs supports, so it cannot boot kernelci jobs
yet.

So this patch enable CONFIG_BLK_DEV_RAM in hsdk_defconfig.

Signed-off-by: Corentin Labbe <clabbe at baylibre.com>
Acked-by: Alexey Brodkin <abrodkin at synopsys.com>
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 arch/arc/configs/hsdk_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arc/configs/hsdk_defconfig b/arch/arc/configs/hsdk_defconfig
index 083560e9e571..4dac1169f528 100644
--- a/arch/arc/configs/hsdk_defconfig
+++ b/arch/arc/configs/hsdk_defconfig
@@ -9,6 +9,7 @@ CONFIG_NAMESPACES=y
 # CONFIG_UTS_NS is not set
 # CONFIG_PID_NS is not set
 CONFIG_BLK_DEV_INITRD=y
+CONFIG_BLK_DEV_RAM=y
 CONFIG_EMBEDDED=y
 CONFIG_PERF_EVENTS=y
 # CONFIG_VM_EVENT_COUNTERS is not set
-- 
2.19.1