diff options
| author | Kees Cook <keescook@chromium.org> | 2013-10-10 17:18:14 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-10-13 03:12:07 -0700 |
| commit | 8ab3820fd5b2896d66da7bb2a906bc382e63e7bc (patch) | |
| tree | 50f6f4458f86eb66552c13bef81169e44d27dc28 /arch/x86/boot/compressed/head_64.S | |
| parent | dd78b97367bd575918204cc89107c1479d3fc1a7 (diff) | |
x86, kaslr: Return location from decompress_kernel
This allows decompress_kernel to return a new location for the kernel to
be relocated to. Additionally, enforces CONFIG_PHYSICAL_START as the
minimum relocation position when building with CONFIG_RELOCATABLE.
With CONFIG_RANDOMIZE_BASE set, the choose_kernel_location routine
will select a new location to decompress the kernel, though here it is
presently a no-op. The kernel command line option "nokaslr" is introduced
to bypass these routines.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1381450698-28710-3-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index c337422b575d..c5c1ae0997e7 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -94,9 +94,11 @@ ENTRY(startup_32) addl %eax, %ebx notl %eax andl %eax, %ebx -#else - movl $LOAD_PHYSICAL_ADDR, %ebx + cmpl $LOAD_PHYSICAL_ADDR, %ebx + jge 1f #endif + movl $LOAD_PHYSICAL_ADDR, %ebx +1: /* Target address to relocate to for decompression */ addl $z_extract_offset, %ebx @@ -269,9 +271,11 @@ preferred_addr: addq %rax, %rbp notq %rax andq %rax, %rbp -#else - movq $LOAD_PHYSICAL_ADDR, %rbp + cmpq $LOAD_PHYSICAL_ADDR, %rbp + jge 1f #endif + movq $LOAD_PHYSICAL_ADDR, %rbp +1: /* Target address to relocate to for decompression */ leaq z_extract_offset(%rbp), %rbx @@ -339,13 +343,13 @@ relocated: movl $z_input_len, %ecx /* input_len */ movq %rbp, %r8 /* output target address */ movq $z_output_len, %r9 /* decompressed length */ - call decompress_kernel + call decompress_kernel /* returns kernel location in %rax */ popq %rsi /* * Jump to the decompressed kernel. */ - jmp *%rbp + jmp *%rax .code32 no_longmode: |