[PATCH 2/6] x86, KASLR: Remove unneeded boot_params argument

From: Kees Cook
Date: Mon Apr 18 2016 - 12:42:57 EST


From: Yinghai Lu <yinghai@xxxxxxxxxx>

Since the boot_params can be found using the real_mode global variable,
there is no need to pass around a pointer to it. This slightly simplifies
the choose_kernel_location function and its callers.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
[kees: rewrote changelog, tracked file rename]
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
arch/x86/boot/compressed/kaslr.c | 5 ++---
arch/x86/boot/compressed/misc.c | 2 +-
arch/x86/boot/compressed/misc.h | 6 ++----
3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 6a9b96b4624d..622aa881c6ab 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -295,8 +295,7 @@ static unsigned long find_random_addr(unsigned long minimum,
return slots_fetch_random();
}

-unsigned char *choose_kernel_location(struct boot_params *boot_params,
- unsigned char *input,
+unsigned char *choose_kernel_location(unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size)
@@ -316,7 +315,7 @@ unsigned char *choose_kernel_location(struct boot_params *boot_params,
}
#endif

- boot_params->hdr.loadflags |= KASLR_FLAG;
+ real_mode->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 79dac1758e7c..f35ad9eb1bf1 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -428,7 +428,7 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
* the entire decompressed kernel plus relocation table, or the
* entire decompressed kernel plus .bss and .brk sections.
*/
- output = choose_kernel_location(real_mode, input_data, input_len, output,
+ output = choose_kernel_location(input_data, input_len, output,
output_len > run_size ? output_len
: run_size);

diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index a8c4e087e14d..22346d5a2fa0 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -67,8 +67,7 @@ int cmdline_find_option_bool(const char *option);

#if CONFIG_RANDOMIZE_BASE
/* kaslr.c */
-unsigned char *choose_kernel_location(struct boot_params *boot_params,
- unsigned char *input,
+unsigned char *choose_kernel_location(unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size);
@@ -76,8 +75,7 @@ unsigned char *choose_kernel_location(struct boot_params *boot_params,
bool has_cpuflag(int flag);
#else
static inline
-unsigned char *choose_kernel_location(struct boot_params *boot_params,
- unsigned char *input,
+unsigned char *choose_kernel_location(unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size)
--
2.6.3