kernel/git/stable/linux-stable.git/arch/x86/tools, branch linux-3.16.y

x86: Treat R_X86_64_PLT32 as R_X86_64_PC32

2020-02-11T20:03:09+00:00

commit b21ebf2fb4cde1618915a97cc773e287ff49173e upstream. On i386, there are 2 types of PLTs, PIC and non-PIC. PIE and shared objects must use PIC PLT. To use PIC PLT, you need to load _GLOBAL_OFFSET_TABLE_ into EBX first. There is no need for that on x86-64 since x86-64 uses PC-relative PLT. On x86-64, for 32-bit PC-relative branches, we can generate PLT32 relocation, instead of PC32 relocation, which can also be used as a marker for 32-bit PC-relative branches. Linker can always reduce PLT32 relocation to PC32 if function is defined locally. Local functions should use PC32 relocation. As far as Linux kernel is concerned, R_X86_64_PLT32 can be treated the same as R_X86_64_PC32 since Linux kernel doesn't use PLT. R_X86_64_PLT32 for 32-bit PC-relative branches has been enabled in binutils master branch which will become binutils 2.31. [ hjl is working on having better documentation on this all, but a few more notes from him: "PLT32 relocation is used as marker for PC-relative branches. Because of EBX, it looks odd to generate PLT32 relocation on i386 when EBX doesn't have GOT. As for symbol resolution, PLT32 and PC32 relocations are almost interchangeable. But when linker sees PLT32 relocation against a protected symbol, it can resolved locally at link-time since it is used on a branch instruction. Linker can't do that for PC32 relocation" but for the kernel use, the two are basically the same, and this commit gets things building and working with the current binutils master - Linus ] Signed-off-by: H.J. Lu Signed-off-by: Linus Torvalds [Woody Suwalski: Backported to 3.16] Signed-off-by: Woody Suwalski Signed-off-by: Ben Hutchings

x86/tools: Fix gcc-7 warning in relocs.c

2018-10-03T03:10:07+00:00

commit 7ebb916782949621ff6819acf373a06902df7679 upstream. gcc-7 warns: In file included from arch/x86/tools/relocs_64.c:17:0: arch/x86/tools/relocs.c: In function ‘process_64’: arch/x86/tools/relocs.c:953:2: warning: argument 1 null where non-null expected [-Wnonnull] qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from arch/x86/tools/relocs.h:6:0, from arch/x86/tools/relocs_64.c:1: /usr/include/stdlib.h:741:13: note: in a call to function ‘qsort’ declared here extern void qsort This happens because relocs16 is not used for ELF_BITS == 64, so there is no point in trying to sort it. Make the sort_relocs(&relocs16) call 32bit only. Signed-off-by: Markus Trippelsdorf Link: http://lkml.kernel.org/r/20161215124513.GA289@x4 Signed-off-by: Thomas Gleixner [bwh: Backported to 3.16: Also make sort_relocs(&relocs64) conditional, which was done upstream in commit 6d24c5f72dfb "x86-64: Handle PC-relative relocations on per-CPU data".] Signed-off-by: Ben Hutchings

x86, build: replace Perl script with Shell script

2015-02-04T10:58:18+00:00

commit d69911a68c865b152a067feaa45e98e6bb0f655b upstream. Commit e6023367d779 ("x86, kaslr: Prevent .bss from overlaping initrd") added Perl to the required build environment. This reimplements in shell the Perl script used to find the size of the kernel with bss and brk added. Signed-off-by: Kees Cook Reported-by: Rob Landley Acked-by: Rob Landley Cc: Anca Emanuel Cc: Fengguang Wu Cc: Junjie Mao Cc: Kees Cook Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques

x86, kaslr: Handle Gold linker for finding bss/brk

2014-12-01T10:26:02+00:00

commit 70b61e362187b5fccac206506d402f3424e3e749 upstream. When building with the Gold linker, the .bss and .brk areas of vmlinux are shown as consecutive instead of having the same file offset. Allow for either state, as long as things add up correctly. Fixes: e6023367d779 ("x86, kaslr: Prevent .bss from overlaping initrd") Reported-by: Markus Trippelsdorf Signed-off-by: Kees Cook Cc: Junjie Mao Link: http://lkml.kernel.org/r/20141118001604.GA25045@www.outflux.net Signed-off-by: Thomas Gleixner Signed-off-by: Luis Henriques

x86, kaslr: Prevent .bss from overlaping initrd

2014-11-20T12:01:52+00:00

commit e6023367d779060fddc9a52d1f474085b2b36298 upstream. When choosing a random address, the current implementation does not take into account the reversed space for .bss and .brk sections. Thus the relocated kernel may overlap other components in memory. Here is an example of the overlap from a x86_64 kernel in qemu (the ranges of physical addresses are presented): Physical Address 0x0fe00000 --+--------------------+ <-- randomized base / | relocated kernel | vmlinux.bin | (from vmlinux.bin) | 0x1336d000 (an ELF file) +--------------------+-- \ | | \ 0x1376d870 --+--------------------+ | | relocs table | | 0x13c1c2a8 +--------------------+ .bss and .brk | | | 0x13ce6000 +--------------------+ | | | / 0x13f77000 | initrd |-- | | 0x13fef374 +--------------------+ The initrd image will then be overwritten by the memset during early initialization: [ 1.655204] Unpacking initramfs... [ 1.662831] Initramfs unpacking failed: junk in compressed archive This patch prevents the above situation by requiring a larger space when looking for a random kernel base, so that existing logic can effectively avoids the overlap. [kees: switched to perl to avoid hex translation pain in mawk vs gawk] [kees: calculated overlap without relocs table] Fixes: 82fa9637a2 ("x86, kaslr: Select random position from e820 maps") Reported-by: Fengguang Wu Signed-off-by: Junjie Mao Signed-off-by: Kees Cook Cc: Josh Triplett Cc: Matt Fleming Cc: Ard Biesheuvel Cc: Vivek Goyal Cc: Andi Kleen Link: http://lkml.kernel.org/r/1414762838-13067-1-git-send-email-eternal.n08@gmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Luis Henriques

x86/build: Supress "Nothing to be done for ..." messages

2014-04-14T09:44:36+00:00

When we build an already built kernel again, arch/x86/syscalls/Makefile and arch/x86/tools/Makefile emits "Nothing to be done for ..." messages. Here is the command log: $ make defconfig [ snip ] $ make [ snip ] $ make make[1]: Nothing to be done for `all'. <----- make[1]: Nothing to be done for `relocs'. <----- CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h Besides not emitting those, "all" and "relocs" should be added to PHONY as well. Signed-off-by: Masahiro Yamada Acked-by: Peter Foley Acked-by: Michal Marek Link: http://lkml.kernel.org/r/1397093742-11144-1-git-send-email-yamada.m@jp.panasonic.com Signed-off-by: Ingo Molnar

x86, vdso: Make vsyscall_gtod_data handling x86 generic

2014-03-18T19:51:52+00:00

This patch move the vsyscall_gtod_data handling out of vsyscall_64.c into an additonal file vsyscall_gtod.c to make the functionality available for x86 32 bit kernel. It also adds a new vsyscall_32.c which setup the VVAR page. Reviewed-by: Andy Lutomirski Signed-off-by: Stefani Seibold Link: http://lkml.kernel.org/r/1395094933-14252-2-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin

Merge commit 'f4bcd8ccddb02833340652e9f46f5127828eb79d' into x86/build

2014-01-29T17:07:00+00:00

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

x86, relocs: Add manual debug mode

2014-01-22T12:21:45+00:00

Improve the debuggability of relocations output. When trying to compare the output between different linkers, it's handy to be able to see the section names in output. Signed-off-by: Michael Davidson Link: http://lkml.kernel.org/r/20140121203223.GA12649@www.outflux.net Signed-off-by: Kees Cook Signed-off-by: H. Peter Anvin

x86/relocs: Add percpu fixup for GNU ld 2.23

2013-10-18T06:45:09+00:00

The GNU linker tries to put __per_cpu_load into the percpu area, resulting in a lack of its relocation. Force this symbol to be relocated. Seen starting with GNU ld 2.23 and later. Reported-by: Ingo Molnar Signed-off-by: Kees Cook Cc: Michael Davidson Cc: Cong Ding Link: http://lkml.kernel.org/r/20131016064314.GA2739@www.outflux.net Signed-off-by: Ingo Molnar