string: add strdup_const and kstrdup_const

Extend Linux compat by adding kstrdup_const(), backed by lib/string.c.
This leverages U-Boots .rodata section on ARM64 to avoid pointlessly
duplicating const strings.

This is used by the Linux CCF_FULL port and may be useful elsewhere
in U-Boot.

Signed-off-by: Casey Connolly <[email protected]>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d59787948fd..48bd4fa8604 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -9,6 +9,7 @@
 #define _ASM_GENERIC_SECTIONS_H_
 
 #include <linux/types.h>
+#include <stdbool.h>
 
 /* References to section boundaries */
 
@@ -62,6 +63,24 @@ static inline int arch_is_kernel_data(unsigned long addr)
 }
 #endif
 
+/**
+ * is_kernel_rodata - checks if the pointer address is located in the
+ *                    .rodata section
+ *
+ * @addr: address to check
+ *
+ * Returns: true if the address is located in .rodata, false otherwise.
+ */
+static inline bool is_kernel_rodata(unsigned long addr)
+{
+#ifdef CONFIG_ARM64
+	return addr >= (unsigned long)__start_rodata &&
+	       addr < (unsigned long)__end_rodata;
+#else
+	return false;
+#endif
+}
+
 /* U-Boot-specific things begin here */
 
 /* Start of U-Boot text region */