[PATCH 01/12] efi_loader: add runtime memset helper

[Harsimran Singh Tungal]

Add efi_memset_runtime() for EFI runtime paths

This keeps buffer initialization in runtime-resident code after
ExitBootServices() and avoids relying on non-runtime helpers.

Signed-off-by: Harsimran Singh Tungal <harsimransingh.tungal at arm.com>
---
 include/efi_loader.h         |  3 +++
 lib/efi_loader/efi_runtime.c | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 3a4d502631c..63944192aeb 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -1151,6 +1151,9 @@ void efi_memcpy_runtime(void *dest, const void *src, size_t n);
 /* runtime implementation of memcmp() */
 int efi_memcmp_runtime(const void *s1, const void *s2, size_t n);
 
+/* runtime implementation of memset */
+__efi_runtime void *efi_memset_runtime(void *dest, int c, size_t n);
+
 /* commonly used helper functions */
 u16 *efi_create_indexed_name(u16 *buffer, size_t buffer_size, const char *name,
 			     unsigned int index);
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index 73d4097464c..d9604399209 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -233,6 +233,27 @@ int __efi_runtime efi_memcmp_runtime(const void *s1, const void *s2, size_t n)
 	return 0;
 }
 
+/**
+ * efi_memset_runtime() - fill a memory region with a byte value
+ *
+ * At runtime memset() is not available.
+ *
+ * @dest:   pointer to the block of memory to fill.
+ * @c:      value to be set. The value is passed as an int, but the
+ *          function fills the block of memory using the u8 conversion of this value.
+ * @n:      number of bytes to be set to the value.
+ * Return:  dest is returned
+ */
+__efi_runtime void *efi_memset_runtime(void *dest, int c, size_t n)
+{
+	u8 *d = dest;
+
+	for (; n; --n)
+		*d++ = c;
+
+	return dest;
+}
+
 /**
  * efi_update_table_header_crc32() - Update crc32 in table header
  *
-- 
2.34.1