Commit da8dd0c7 authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

efi: libstub: Provide local implementations of strrchr() and memchr() 



Clone the implementations of strrchr() and memchr() in lib/string.c so
we can use them in the standalone zboot decompressor app. These routines
are used by the FDT handling code.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 732ea9db

arch/arm64/kernel/image-vars.h

+0 −3
Original line number Diff line number Diff line
@@ -21,9 +21,6 @@ PROVIDE(__efistub_primary_entry_offset = primary_entry - _text); 
 * linked at. The routines below are all implemented in assembler in a

 * position independent manner

 */

PROVIDE(__efistub_memchr		= __pi_memchr);

PROVIDE(__efistub_strcmp		= __pi_strcmp);

PROVIDE(__efistub_strrchr		= __pi_strrchr);

PROVIDE(__efistub_dcache_clean_poc	= __pi_dcache_clean_poc);



PROVIDE(__efistub__text			= _text);

arch/riscv/kernel/image-vars.h

+0 −2
Original line number Diff line number Diff line
@@ -23,9 +23,7 @@ 
 * linked at. The routines below are all implemented in assembler in a

 * position independent manner

 */

__efistub_memchr		= memchr;

__efistub_strcmp		= strcmp;

__efistub_strrchr		= strrchr;



__efistub__start		= _start;

__efistub__start_kernel		= _start_kernel;

drivers/firmware/efi/libstub/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -25,7 +25,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ 
cflags-$(CONFIG_ARM64)		+= -fpie $(DISABLE_STACKLEAK_PLUGIN) \

				   $(call cc-option,-mbranch-protection=none)

cflags-$(CONFIG_ARM)		+= -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \

				   -fno-builtin -fpic \

				   -DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \

				   -DEFI_HAVE_STRCMP -fno-builtin -fpic \

				   $(call cc-option,-mno-single-pic-base)

cflags-$(CONFIG_RISCV)		+= -fpic

cflags-$(CONFIG_LOONGARCH)	+= -fpie

drivers/firmware/efi/libstub/string.c

+62 −0
Original line number Diff line number Diff line
@@ -64,6 +64,28 @@ char *strstr(const char *s1, const char *s2) 
	return NULL;

}



#ifndef EFI_HAVE_STRCMP

/**

 * strcmp - Compare two strings

 * @cs: One string

 * @ct: Another string

 */

int strcmp(const char *cs, const char *ct)

{

	unsigned char c1, c2;



	while (1) {

		c1 = *cs++;

		c2 = *ct++;

		if (c1 != c2)

			return c1 < c2 ? -1 : 1;

		if (!c1)

			break;

	}

	return 0;

}

#endif



/**

 * strncmp - Compare two length-limited strings

 * @cs: One string
@@ -140,3 +162,43 @@ long simple_strtol(const char *cp, char **endp, unsigned int base) 


	return simple_strtoull(cp, endp, base);

}



#ifdef CONFIG_EFI_PARAMS_FROM_FDT

#ifndef EFI_HAVE_STRRCHR

/**

 * strrchr - Find the last occurrence of a character in a string

 * @s: The string to be searched

 * @c: The character to search for

 */

char *strrchr(const char *s, int c)

{

	const char *last = NULL;

	do {

		if (*s == (char)c)

			last = s;

	} while (*s++);

	return (char *)last;

}

#endif

#ifndef EFI_HAVE_MEMCHR

/**

 * memchr - Find a character in an area of memory.

 * @s: The memory area

 * @c: The byte to search for

 * @n: The size of the area.

 *

 * returns the address of the first occurrence of @c, or %NULL

 * if @c is not found

 */

void *memchr(const void *s, int c, size_t n)

{

	const unsigned char *p = s;

	while (n-- != 0) {

		if ((unsigned char)c == *p++) {

			return (void *)(p - 1);

		}

	}

	return NULL;

}

#endif

#endif