ARM: early traps initialisation

stable inclusion
from stable-v5.10.105
commit 46deb224680bb33c8e87440a7b909d16e5a7d7c5
category: bugfix
bugzilla: 186460 https://gitee.com/src-openeuler/kernel/issues/I53MHA
CVE: CVE-2022-23960

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=46deb224680b

--------------------------------

commit 04e91b73 upstream.

Provide a couple of helpers to copy the vectors and stubs, and also
to flush the copied vectors and stubs.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jiahao <chenjiahao16@huawei.com>
Reviewed-by: NLiao Chang <liaochang1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm/kernel/traps.c

@@ -806,10 +806,22 @@ static inline void __init kuser_init(void *vectors)
 }
 #endif
 
+#ifndef CONFIG_CPU_V7M
+static void copy_from_lma(void *vma, void *lma_start, void *lma_end)
+{
+	memcpy(vma, lma_start, lma_end - lma_start);
+}
+
+static void flush_vectors(void *vma, size_t offset, size_t size)
+{
+	unsigned long start = (unsigned long)vma + offset;
+	unsigned long end = start + size;
+
+	flush_icache_range(start, end);
+}
+
 void __init early_trap_init(void *vectors_base)
 {
-#ifndef CONFIG_CPU_V7M
-	unsigned long vectors = (unsigned long)vectors_base;
 	extern char __stubs_start[], __stubs_end[];
 	extern char __vectors_start[], __vectors_end[];
 	unsigned i;
@@ -830,17 +842,20 @@ void __init early_trap_init(void *vectors_base)
 	 * into the vector page, mapped at 0xffff0000, and ensure these
 	 * are visible to the instruction stream.
 	 */
-	memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
-	memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
+	copy_from_lma(vectors_base, __vectors_start, __vectors_end);
+	copy_from_lma(vectors_base + 0x1000, __stubs_start, __stubs_end);
 
 	kuser_init(vectors_base);
 
-	flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
+	flush_vectors(vectors_base, 0, PAGE_SIZE * 2);
+}
 #else /* ifndef CONFIG_CPU_V7M */
+void __init early_trap_init(void *vectors_base)
+{
 	/*
 	 * on V7-M there is no need to copy the vector table to a dedicated
 	 * memory area. The address is configurable and so a table in the kernel
 	 * image can be used.
 	 */
-#endif
 }
+#endif