From e8f3010f7326c00368dbc057bd052bec80dfc072 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 8 Oct 2015 20:02:04 +0100 Subject: arm64/efi: isolate EFI stub from the kernel proper Since arm64 does not use a builtin decompressor, the EFI stub is built into the kernel proper. So far, this has been working fine, but actually, since the stub is in fact a PE/COFF relocatable binary that is executed at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we should not be seamlessly sharing code with the kernel proper, which is a position dependent executable linked at a high virtual offset. So instead, separate the contents of libstub and its dependencies, by putting them into their own namespace by prefixing all of its symbols with __efistub. This way, we have tight control over what parts of the kernel proper are referenced by the stub. Signed-off-by: Ard Biesheuvel Reviewed-by: Matt Fleming Signed-off-by: Catalin Marinas --- drivers/firmware/efi/libstub/string.c | 57 +++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 drivers/firmware/efi/libstub/string.c (limited to 'drivers/firmware/efi/libstub/string.c') diff --git a/drivers/firmware/efi/libstub/string.c b/drivers/firmware/efi/libstub/string.c new file mode 100644 index 000000000000..09d5a0894343 --- /dev/null +++ b/drivers/firmware/efi/libstub/string.c @@ -0,0 +1,57 @@ +/* + * Taken from: + * linux/lib/string.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include +#include + +#ifndef __HAVE_ARCH_STRSTR +/** + * strstr - Find the first substring in a %NUL terminated string + * @s1: The string to be searched + * @s2: The string to search for + */ +char *strstr(const char *s1, const char *s2) +{ + size_t l1, l2; + + l2 = strlen(s2); + if (!l2) + return (char *)s1; + l1 = strlen(s1); + while (l1 >= l2) { + l1--; + if (!memcmp(s1, s2, l2)) + return (char *)s1; + s1++; + } + return NULL; +} +#endif + +#ifndef __HAVE_ARCH_STRNCMP +/** + * strncmp - Compare two length-limited strings + * @cs: One string + * @ct: Another string + * @count: The maximum number of bytes to compare + */ +int strncmp(const char *cs, const char *ct, size_t count) +{ + unsigned char c1, c2; + + while (count) { + c1 = *cs++; + c2 = *ct++; + if (c1 != c2) + return c1 < c2 ? -1 : 1; + if (!c1) + break; + count--; + } + return 0; +} +#endif -- cgit v1.2.3