[PATCH 3/6] x86, boot: Rename "real_mode" to "boot_params"
From: Kees Cook
Date: Mon Apr 18 2016 - 12:43:40 EST
The non-compressed boot code uses the (much more obvious) name
"boot_params" for the global pointer to the x86 boot parameters. The
compressed kernel loader code, though, was using the legacy name
"real_mode". There is no need to have a different name, and changing it
improves readability.
Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
arch/x86/boot/compressed/cmdline.c | 4 ++--
arch/x86/boot/compressed/kaslr.c | 22 +++++++++++-----------
arch/x86/boot/compressed/misc.c | 27 ++++++++++++++-------------
arch/x86/boot/compressed/misc.h | 2 +-
4 files changed, 28 insertions(+), 27 deletions(-)
diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c
index b68e3033e6b9..73ccf63b0f48 100644
--- a/arch/x86/boot/compressed/cmdline.c
+++ b/arch/x86/boot/compressed/cmdline.c
@@ -15,9 +15,9 @@ static inline char rdfs8(addr_t addr)
#include "../cmdline.c"
static unsigned long get_cmd_line_ptr(void)
{
- unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr;
+ unsigned long cmd_line_ptr = boot_params->hdr.cmd_line_ptr;
- cmd_line_ptr |= (u64)real_mode->ext_cmd_line_ptr << 32;
+ cmd_line_ptr |= (u64)boot_params->ext_cmd_line_ptr << 32;
return cmd_line_ptr;
}
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 622aa881c6ab..a51ec841c9b9 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -55,7 +55,7 @@ static unsigned long get_random_boot(void)
unsigned long hash = 0;
hash = rotate_xor(hash, build_str, sizeof(build_str));
- hash = rotate_xor(hash, real_mode, sizeof(*real_mode));
+ hash = rotate_xor(hash, boot_params, sizeof(*boot_params));
return hash;
}
@@ -152,16 +152,16 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
mem_avoid[0].size = unsafe_len;
/* Avoid initrd. */
- initrd_start = (u64)real_mode->ext_ramdisk_image << 32;
- initrd_start |= real_mode->hdr.ramdisk_image;
- initrd_size = (u64)real_mode->ext_ramdisk_size << 32;
- initrd_size |= real_mode->hdr.ramdisk_size;
+ initrd_start = (u64)boot_params->ext_ramdisk_image << 32;
+ initrd_start |= boot_params->hdr.ramdisk_image;
+ initrd_size = (u64)boot_params->ext_ramdisk_size << 32;
+ initrd_size |= boot_params->hdr.ramdisk_size;
mem_avoid[1].start = initrd_start;
mem_avoid[1].size = initrd_size;
/* Avoid kernel command line. */
- cmd_line = (u64)real_mode->ext_cmd_line_ptr << 32;
- cmd_line |= real_mode->hdr.cmd_line_ptr;
+ cmd_line = (u64)boot_params->ext_cmd_line_ptr << 32;
+ cmd_line |= boot_params->hdr.cmd_line_ptr;
/* Calculate size of cmd_line. */
ptr = (char *)(unsigned long)cmd_line;
for (cmd_line_size = 0; ptr[cmd_line_size++]; )
@@ -190,7 +190,7 @@ static bool mem_avoid_overlap(struct mem_vector *img)
}
/* Avoid all entries in the setup_data linked list. */
- ptr = (struct setup_data *)(unsigned long)real_mode->hdr.setup_data;
+ ptr = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
while (ptr) {
struct mem_vector avoid;
@@ -288,8 +288,8 @@ static unsigned long find_random_addr(unsigned long minimum,
minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN);
/* Verify potential e820 positions, appending to slots list. */
- for (i = 0; i < real_mode->e820_entries; i++) {
- process_e820_entry(&real_mode->e820_map[i], minimum, size);
+ for (i = 0; i < boot_params->e820_entries; i++) {
+ process_e820_entry(&boot_params->e820_map[i], minimum, size);
}
return slots_fetch_random();
@@ -315,7 +315,7 @@ unsigned char *choose_kernel_location(unsigned char *input,
}
#endif
- real_mode->hdr.loadflags |= KASLR_FLAG;
+ boot_params->hdr.loadflags |= KASLR_FLAG;
/* Record the various known unsafe memory ranges. */
mem_avoid_init((unsigned long)input, input_size,
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index f35ad9eb1bf1..462dfbf7467b 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -114,7 +114,7 @@ static void error(char *m);
/*
* This is set up by the setup-routine at boot-time
*/
-struct boot_params *real_mode; /* Pointer to real-mode data */
+struct boot_params *boot_params;
memptr free_mem_ptr;
memptr free_mem_end_ptr;
@@ -184,12 +184,12 @@ void __putstr(const char *s)
}
}
- if (real_mode->screen_info.orig_video_mode == 0 &&
+ if (boot_params->screen_info.orig_video_mode == 0 &&
lines == 0 && cols == 0)
return;
- x = real_mode->screen_info.orig_x;
- y = real_mode->screen_info.orig_y;
+ x = boot_params->screen_info.orig_x;
+ y = boot_params->screen_info.orig_y;
while ((c = *s++) != '\0') {
if (c == '\n') {
@@ -210,8 +210,8 @@ void __putstr(const char *s)
}
}
- real_mode->screen_info.orig_x = x;
- real_mode->screen_info.orig_y = y;
+ boot_params->screen_info.orig_x = x;
+ boot_params->screen_info.orig_y = y;
pos = (x + cols * y) * 2; /* Update cursor position */
outb(14, vidport);
@@ -392,14 +392,15 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
{
unsigned char *output_orig = output;
- real_mode = rmode;
+ /* Retain x86 boot parameters pointer passed from startup_32/64. */
+ boot_params = rmode;
- /* Clear it for solely in-kernel use */
- real_mode->hdr.loadflags &= ~KASLR_FLAG;
+ /* Clear flags intended for solely in-kernel use. */
+ boot_params->hdr.loadflags &= ~KASLR_FLAG;
- sanitize_boot_params(real_mode);
+ sanitize_boot_params(boot_params);
- if (real_mode->screen_info.orig_video_mode == 7) {
+ if (boot_params->screen_info.orig_video_mode == 7) {
vidmem = (char *) 0xb0000;
vidport = 0x3b4;
} else {
@@ -407,8 +408,8 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
vidport = 0x3d4;
}
- lines = real_mode->screen_info.orig_video_lines;
- cols = real_mode->screen_info.orig_video_cols;
+ lines = boot_params->screen_info.orig_video_lines;
+ cols = boot_params->screen_info.orig_video_cols;
console_init();
debug_putstr("early console in decompress_kernel\n");
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 22346d5a2fa0..1f750a516580 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -32,7 +32,7 @@
/* misc.c */
extern memptr free_mem_ptr;
extern memptr free_mem_end_ptr;
-extern struct boot_params *real_mode; /* Pointer to real-mode data */
+extern struct boot_params *boot_params;
void __putstr(const char *s);
void __puthex(unsigned long value);
#define error_putstr(__x) __putstr(__x)
--
2.6.3