Handle U-boot arguments paranoidly:
* don't allow to pass unknown tag.
* try to use external device tree blob only if corresponding tag
(TAG_DTB) is set.
* don't check: uboot_tag if kernel build with no ARC_UBOOT_SUPPORT.
While I'm at it refactor U-boot arguments handling code.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
arch/arc/kernel/head.S | 2 +-
arch/arc/kernel/setup.c | 65 ++++++++++++++++++++++++++++++++-----------------
2 files changed, 44 insertions(+), 23 deletions(-)
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 8b90d25a15cc..7095055bb874 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -95,7 +95,7 @@ ENTRY(stext)
; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2
; r1 = magic number (board identity, unused as of now
; r2 = pointer to uboot provided cmdline or external DTB in mem
- ; These are handled later in setup_arch()
+ ; These are handled later in handle_uboot_args()
st r0, [@uboot_tag]
st r2, [@uboot_arg]
#endif
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index feb90093e6b1..7edb35c26322 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -462,43 +462,64 @@ void setup_processor(void)
arc_chk_core_config();
}
-static inline int is_kernel(unsigned long addr)
+static inline bool is_kernel(unsigned long addr)
{
- if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
- return 1;
- return 0;
+ return addr >= (unsigned long)_stext && addr <= (unsigned long)_end;
}
-void __init setup_arch(char **cmdline_p)
+/* uboot_tag values for U-boot - kernel ABI revisions 0+; see head.S */
+#define UBOOT_REV0P_TAG_NONE 0
+#define UBOOT_REV0P_TAG_CMDLINE 1
+#define UBOOT_REV0P_TAG_DTB 2
+
+void __init handle_uboot_args(void)
{
+ bool append_boot_cmdline = false;
+ bool use_embedded_dtb = true;
+
#ifdef CONFIG_ARC_UBOOT_SUPPORT
+ /* check that we know this tag */
+ if (uboot_tag != UBOOT_REV0P_TAG_NONE &&
+ uboot_tag != UBOOT_REV0P_TAG_CMDLINE &&
+ uboot_tag != UBOOT_REV0P_TAG_DTB)
+ panic("Invalid uboot tag: '%08x'\n", uboot_tag);
+
/* make sure that uboot passed pointer to cmdline/dtb is valid */
- if (uboot_tag && is_kernel((unsigned long)uboot_arg))
+ if (uboot_tag != UBOOT_REV0P_TAG_NONE && is_kernel((unsigned long)uboot_arg))
panic("Invalid uboot arg\n");
/* See if u-boot passed an external Device Tree blob */
- machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */
- if (!machine_desc)
+ if (uboot_tag == UBOOT_REV0P_TAG_DTB) {
+ machine_desc = setup_machine_fdt(uboot_arg);
+
+ /* external Device Tree blob is invalid - use embedded one */
+ use_embedded_dtb = !machine_desc;
+ }
+
+ if (uboot_tag == UBOOT_REV0P_TAG_CMDLINE)
+ append_boot_cmdline = true;
#endif
- {
- /* No, so try the embedded one */
+
+ if (use_embedded_dtb) {
machine_desc = setup_machine_fdt(__dtb_start);
if (!machine_desc)
panic("Embedded DT invalid\n");
+ }
- /*
- * If we are here, it is established that @uboot_arg didn't
- * point to DT blob. Instead if u-boot says it is cmdline,
- * append to embedded DT cmdline.
- * setup_machine_fdt() would have populated @boot_command_line
- */
- if (uboot_tag == 1) {
- /* Ensure a whitespace between the 2 cmdlines */
- strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
- strlcat(boot_command_line, uboot_arg,
- COMMAND_LINE_SIZE);
- }
+ /*
+ * If we are here, U-boot says that @uboot_arg is cmdline, so append it
+ * to embedded DT cmdline.
+ */
+ if (append_boot_cmdline) {
+ /* Ensure a whitespace between the 2 cmdlines */
+ strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+ strlcat(boot_command_line, uboot_arg, COMMAND_LINE_SIZE);
}
+}
+
+void __init setup_arch(char **cmdline_p)
+{
+ handle_uboot_args();
/* Save unparsed command line copy for /proc/cmdline */
*cmdline_p = boot_command_line;
--
2.14.5
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