kernel.git/arch/x86/boot/Makefile, branch linux-3.17.y

x86, build: Don't get confused by local symbols

2014-05-05T22:23:35Z

arch/x86/crypto/sha1_avx2_x86_64_asm.S introduced _end as a local symbol, which broke the build under certain circumstances. Although the wisdom of _end as a local symbol can definitely be questioned, the build should not break for that reason. Thus, filter the output of nm to only get global symbols of appropriate type. Reported-by: Andy Lutomirski Cc: Chandramouli Narayanan Cc: Herbert Xu Signed-off-by: H. Peter Anvin Link: http://lkml.kernel.org/n/tip-uxm3j3w3odglcwhafwq5tjqu@git.kernel.org

x86/efi: Firmware agnostic handover entry points

2014-03-04T21:25:06Z

The EFI handover code only works if the "bitness" of the firmware and the kernel match, i.e. 64-bit firmware and 64-bit kernel - it is not possible to mix the two. This goes against the tradition that a 32-bit kernel can be loaded on a 64-bit BIOS platform without having to do anything special in the boot loader. Linux distributions, for one thing, regularly run only 32-bit kernels on their live media. Despite having only one 'handover_offset' field in the kernel header, EFI boot loaders use two separate entry points to enter the kernel based on the architecture the boot loader was compiled for, (1) 32-bit loader: handover_offset (2) 64-bit loader: handover_offset + 512 Since we already have two entry points, we can leverage them to infer the bitness of the firmware we're running on, without requiring any boot loader modifications, by making (1) and (2) valid entry points for both CONFIG_X86_32 and CONFIG_X86_64 kernels. To be clear, a 32-bit boot loader will always use (1) and a 64-bit boot loader will always use (2). It's just that, if a single kernel image supports (1) and (2) that image can be used with both 32-bit and 64-bit boot loaders, and hence both 32-bit and 64-bit EFI. (1) and (2) must be 512 bytes apart at all times, but that is already part of the boot ABI and we could never change that delta without breaking existing boot loaders anyhow. Signed-off-by: Matt Fleming

Merge commit 'f4bcd8ccddb02833340652e9f46f5127828eb79d' into x86/build

2014-01-29T17:07:00Z

Bring in upstream merge of x86/kaslr for future patches. Signed-off-by: H. Peter Anvin

x86: Remove duplication of 16-bit CFLAGS

2014-01-22T12:21:45Z

Define them once in arch/x86/Makefile instead of twice. Signed-off-by: David Woodhouse Link: http://lkml.kernel.org/r/1389180083-23249-1-git-send-email-David.Woodhouse@intel.com Signed-off-by: H. Peter Anvin

Merge branch 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-01-20T22:45:50Z

Pull x86 kernel address space randomization support from Peter Anvin: "This enables kernel address space randomization for x86" * 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, kaslr: Clarify RANDOMIZE_BASE_MAX_OFFSET x86, kaslr: Remove unused including x86, kaslr: Use char array to gain sizeof sanity x86, kaslr: Add a circular multiply for better bit diffusion x86, kaslr: Mix entropy sources together as needed x86/relocs: Add percpu fixup for GNU ld 2.23 x86, boot: Rename get_flags() and check_flags() to *_cpuflags() x86, kaslr: Raise the maximum virtual address to -1 GiB on x86_64 x86, kaslr: Report kernel offset on panic x86, kaslr: Select random position from e820 maps x86, kaslr: Provide randomness functions x86, kaslr: Return location from decompress_kernel x86, boot: Move CPU flags out of cpucheck x86, relocs: Add more per-cpu gold special cases

x86, build: Pass in additional -mno-mmx, -mno-sse options

2013-12-09T23:52:39Z

In checkin 5551a34e5aea x86-64, build: Always pass in -mno-sse we unconditionally added -mno-sse to the main build, to keep newer compilers from generating SSE instructions from autovectorization. However, this did not extend to the special environments (arch/x86/boot, arch/x86/boot/compressed, and arch/x86/realmode/rm). Add -mno-sse to the compiler command line for these environments, and add -mno-mmx to all the environments as well, as we don't want a compiler to generate MMX code either. This patch also removes a $(cc-option) call for -m32, since we have long since stopped supporting compilers too old for the -m32 option, and in fact hardcode it in other places in the Makefiles. Reported-by: Kevin B. Smith Cc: Sunil K. Pandey Signed-off-by: H. Peter Anvin Cc: H. J. Lu Link: http://lkml.kernel.org/n/tip-j21wzqv790q834n7yc6g80j1@git.kernel.org Cc: # build fix only

x86, boot: Move CPU flags out of cpucheck

2013-10-13T10:12:02Z

Refactor the CPU flags handling out of the cpucheck routines so that they can be reused by the future ASLR routines (in order to detect CPU features like RDRAND and RDTSC). This reworks has_eflag() and has_fpu() to be used on both 32-bit and 64-bit, and refactors the calls to cpuid to make them PIC-safe on 32-bit. Signed-off-by: Kees Cook Link: http://lkml.kernel.org/r/1381450698-28710-2-git-send-email-keescook@chromium.org Signed-off-by: H. Peter Anvin

x86, build: move build output statistics away from stderr

2013-09-26T21:05:41Z

When building on x86, the final image building step always emits stats to stderr, even though this information is neither a warning nor an error: BUILD arch/x86/boot/bzImage Setup is 16188 bytes (padded to 16384 bytes). System is 6368 kB CRC cbe50c61 Validating automated builds would be cleaner if stderr did not have to filter out these lines. Instead, change how tools/build is called, and make the zoffset header unconditional, and write to a specified file instead of to stdout, which can then be used for statistics, leaving stderr open for legitimate warnings and errors, like the output from die(). Signed-off-by: Kees Cook Link: http://lkml.kernel.org/r/20130906181532.GA31260@www.outflux.net Signed-off-by: H. Peter Anvin

x86, build: Dynamically find entry points in compressed startup code

2013-01-28T04:19:37Z

We have historically hard-coded entry points in head.S just so it's easy to build the executable/bzImage headers with references to them. Unfortunately, this leads to boot loaders abusing these "known" addresses even when they are *explicitly* told that they "should look at the ELF header to find this address, as it may change in the future". And even when the address in question *has* actually been changed in the past, without fanfare or thought to compatibility. Thus we have bootloaders doing stunningly broken things like jumping to offset 0x200 in the kernel startup code in 64-bit mode, *hoping* that startup_64 is still there (it has moved at least once before). And hoping that it's actually a 64-bit kernel despite the fact that we don't give them any indication of that fact. This patch should hopefully remove the temptation to abuse internal addresses in future, where sternly worded comments have not sufficed. Instead of having hard-coded addresses and saying "please don't abuse these", we actually pull the addresses out of the ELF payload into zoffset.h, and make build.c shove them back into the right places in the bzImage header. Rather than including zoffset.h into build.c and thus having to rebuild the tool for every kernel build, we parse it instead. The parsing code is small and simple. This patch doesn't actually move any of the interesting entry points, so any offending bootloader will still continue to "work" after this patch is applied. For some version of "work" which includes jumping into the compressed payload and crashing, if the bzImage it's given is a 32-bit kernel. No change there then. [ hpa: some of the issues in the description are addressed or retconned by the 2.12 boot protocol. This patch has been edited to only remove fixed addresses that were *not* thus retconned. ] Signed-off-by: David Woodhouse Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.org Signed-off-by: H. Peter Anvin Cc: Matt Fleming

x86, boot: Explicitly include autoconf.h for hostprogs

2012-10-14T19:41:28Z

The hostprogs need access to the CONFIG_* symbols found in include/generated/autoconf.h. But commit abbf1590de22 ("UAPI: Partition the header include path sets and add uapi/ header directories") replaced $(LINUXINCLUDE) with $(USERINCLUDE) which doesn't contain the necessary include paths. This has the undesirable effect of breaking the EFI boot stub because the #ifdef CONFIG_EFI_STUB code in arch/x86/boot/tools/build.c is never compiled. It should also be noted that because $(USERINCLUDE) isn't exported by the top-level Makefile it's actually empty in arch/x86/boot/Makefile. Cc: H. Peter Anvin Cc: Ingo Molnar Acked-by: David Howells Signed-off-by: Matt Fleming Signed-off-by: Linus Torvalds