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: Ard Biesheuvel <ardb@kernel.org>

diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index ace584e..f31130b 100644 (file)
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -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);

diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h
index 4913abd..7e2962e 100644 (file)
--- a/arch/riscv/kernel/image-vars.h
+++ b/arch/riscv/kernel/image-vars.h
@@ -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;

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 3f44e27..4964d31 100644 (file)
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -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

diff --git a/drivers/firmware/efi/libstub/string.c b/drivers/firmware/efi/libstub/string.c
index 5a1519d..168fe8e 100644 (file)
--- a/drivers/firmware/efi/libstub/string.c
+++ b/drivers/firmware/efi/libstub/string.c
@@ -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