x86/boot: Clarify purpose of functions in misc.c

The function "decompress_kernel" now performs many more duties, so this
patch renames it to "extract_kernel" and updates callers and comments.
Additionally the file header comment for misc.c is improved to actually
describe what is contained.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1460997735-24785-5-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 0256064..26dd9df 100644 (file)
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -233,9 +233,9 @@ relocated:
 2:
 
 /*
- * Do the decompression, and jump to the new kernel..
+ * Do the extraction, and jump to the new kernel..
  */
-                               /* push arguments for decompress_kernel: */
+                               /* push arguments for extract_kernel: */
        pushl   $z_run_size     /* size of kernel with .bss and .brk */
        pushl   $z_output_len   /* decompressed length, end of relocs */
        leal    z_extract_offset_negative(%ebx), %ebp
@@ -246,11 +246,11 @@ relocated:
        leal    boot_heap(%ebx), %eax
        pushl   %eax            /* heap area */
        pushl   %esi            /* real mode pointer */
-       call    decompress_kernel /* returns kernel location in %eax */
+       call    extract_kernel  /* returns kernel location in %eax */
        addl    $28, %esp
 
 /*
- * Jump to the decompressed kernel.
+ * Jump to the extracted kernel.
  */
        xorl    %ebx, %ebx
        jmp     *%eax

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 86558a1..d43c30e 100644 (file)
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -408,7 +408,7 @@ relocated:
 2:
        
 /*
- * Do the decompression, and jump to the new kernel..
+ * Do the extraction, and jump to the new kernel..
  */
        pushq   %rsi                    /* Save the real mode argument */
        movq    $z_run_size, %r9        /* size of kernel with .bss and .brk */
@@ -419,7 +419,7 @@ relocated:
        movl    $z_input_len, %ecx      /* input_len */
        movq    %rbp, %r8               /* output target address */
        movq    $z_output_len, %r9      /* decompressed length, end of relocs */
-       call    decompress_kernel       /* returns kernel location in %rax */
+       call    extract_kernel          /* returns kernel location in %rax */
        popq    %r9
        popq    %rsi
 

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 462dfbf..0d69e80 100644 (file)
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -1,8 +1,10 @@
 /*
  * misc.c
  *
- * This is a collection of several routines from gzip-1.0.3
- * adapted for Linux.
+ * This is a collection of several routines used to extract the kernel
+ * which includes KASLR relocation, decompression, ELF parsing, and
+ * relocation processing. Additionally included are the screen and serial
+ * output functions and related debugging support functions.
  *
  * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
  * puts by Nick Holloway 1993, better puts by Martin Mares 1995
@@ -383,7 +385,7 @@ static void parse_elf(void *output)
        free(phdrs);
 }
 
-asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
+asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
                                  unsigned char *input_data,
                                  unsigned long input_len,
                                  unsigned char *output,
@@ -412,7 +414,7 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
        cols = boot_params->screen_info.orig_video_cols;
 
        console_init();
-       debug_putstr("early console in decompress_kernel\n");
+       debug_putstr("early console in extract_kernel\n");
 
        free_mem_ptr     = heap;        /* Heap */
        free_mem_end_ptr = heap + BOOT_HEAP_SIZE;