x86/boot: Simplify pointer casting in choose_random_location()

Pass them down as 'unsigned long' directly and get rid of more casting and
assignments.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: bhe@redhat.com
Cc: dyoung@redhat.com
Cc: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org
Cc: vgoyal@redhat.com
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20160506115015.GI24044@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 6392f00..ff12277 100644 (file)
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -350,20 +350,15 @@ static unsigned long find_random_addr(unsigned long minimum,
        return slots_fetch_random();
 }
 
-unsigned char *choose_random_location(unsigned char *input_ptr,
+/*
+ * Since this function examines addresses much more numerically,
+ * it takes the input and output pointers as 'unsigned long'.
+ */
+unsigned char *choose_random_location(unsigned long input,
                                      unsigned long input_size,
-                                     unsigned char *output_ptr,
+                                     unsigned long output,
                                      unsigned long output_size)
 {
-       /*
-        * The caller of choose_random_location() uses unsigned char * for
-        * buffer pointers since it performs decompression, elf parsing, etc.
-        * Since this code examines addresses much more numerically,
-        * unsigned long is used internally here. Instead of sprinkling
-        * more casts into extract_kernel, do them here and at return.
-        */
-       unsigned long input = (unsigned long)input_ptr;
-       unsigned long output = (unsigned long)output_ptr;
        unsigned long choice = output;
        unsigned long random_addr;
 

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 9536d77..f14db4e 100644 (file)
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -366,7 +366,8 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
         * the entire decompressed kernel plus relocation table, or the
         * entire decompressed kernel plus .bss and .brk sections.
         */
-       output = choose_random_location(input_data, input_len, output,
+       output = choose_random_location((unsigned long)input_data, input_len,
+                                       (unsigned long)output,
                                        max(output_len, kernel_total_size));
 
        /* Validate memory location choices. */

diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 1f23d02..0112005 100644 (file)
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -67,20 +67,20 @@ int cmdline_find_option_bool(const char *option);
 
 #if CONFIG_RANDOMIZE_BASE
 /* kaslr.c */
-unsigned char *choose_random_location(unsigned char *input_ptr,
+unsigned char *choose_random_location(unsigned long input_ptr,
                                      unsigned long input_size,
-                                     unsigned char *output_ptr,
+                                     unsigned long output_ptr,
                                      unsigned long output_size);
 /* cpuflags.c */
 bool has_cpuflag(int flag);
 #else
 static inline
-unsigned char *choose_random_location(unsigned char *input_ptr,
+unsigned char *choose_random_location(unsigned long input_ptr,
                                      unsigned long input_size,
-                                     unsigned char *output_ptr,
+                                     unsigned long output_ptr,
                                      unsigned long output_size)
 {
-       return output_ptr;
+       return (unsigned char *)output_ptr;
 }
 #endif