kernel.git/arch/mips/include/asm/elf.h, branch linux-4.8.y

MIPS: non-exec stack & heap when non-exec PT_GNU_STACK is present

2016-08-02T07:29:27Z

The stack and heap have both been executable by default on MIPS until now. This patch changes the default to be non-executable, but only for ELF binaries with a non-executable PT_GNU_STACK header present. This does apply to both the heap & the stack, despite the name PT_GNU_STACK, and this matches the behaviour of other architectures like ARM & x86. Current MIPS toolchains do not produce the PT_GNU_STACK header, which means that we can rely upon this patch not changing the behaviour of existing binaries. The new default will only take effect for newly compiled binaries once toolchains are updated to support PT_GNU_STACK, and since those binaries are newly compiled they can be compiled expecting the change in default behaviour. Again this matches the way in which the ARM & x86 architectures handled their implementations of non-executable memory. Signed-off-by: Paul Burton Cc: Leonid Yegoshin Cc: Maciej Rozycki Cc: Faraz Shahbazker Cc: Raghu Gandham Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13765/ Signed-off-by: Ralf Baechle

MIPS: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO

2016-07-28T10:06:16Z

AT_VECTOR_SIZE_ARCH should be defined with the maximum number of NEW_AUX_ENT entries that ARCH_DLINFO can contain, but it wasn't defined for MIPS at all even though ARCH_DLINFO will contain one NEW_AUX_ENT for the VDSO address. This shouldn't be a problem as AT_VECTOR_SIZE_BASE includes space for AT_BASE_PLATFORM which MIPS doesn't use, but lets define it now and add the comment above ARCH_DLINFO as found in several other architectures to remind future modifiers of ARCH_DLINFO to keep AT_VECTOR_SIZE_ARCH up to date. Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: James Hogan Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13823/ Signed-off-by: Ralf Baechle

MIPS: ELF: Unify ABI classification macros

2016-05-13T13:30:25Z

Remove a duplicate o32 `elf_check_arch' implementation, move all macro variants to and define them unconditionally under indvidual names, substituting alias `elf_check_arch' definitions in variant code. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13245/ Signed-off-by: Ralf Baechle

MIPS: ELF: Unify __MIPS_O32_FP64_MUST_BE_ZERO definitions

2016-05-13T13:30:25Z

Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13244/ Signed-off-by: Ralf Baechle

MIPS: ELF: Deconditionalise ABI flags definitions

2016-05-13T13:30:25Z

Move the `mips_elf_abiflags_v0' structure and FP ABI flag macros outside #ifndef ELF_ARCH. These are public interfaces. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13243/ Signed-off-by: Ralf Baechle

MIPS: ELF: Restructure personality macros

2016-05-13T12:02:11Z

Update the ELF personality macros used for individual ABIs to make actions in the same order across all of them and match formatting too. Signed-off-by: Maciej W. Rozycki Cc: Andrew Morton Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ralf Baechle

MIPS: Support R_MIPS_PC{21,26} rela-style relocs

2016-05-13T12:01:54Z

MIPS64 code uses rela-style relocs, and MIPS64r6 modules may include the new R_MIPS_PC21 & R_MIPS_PC26 relocations. We thus need to support these relocations in order to load MIPS64r6 kernel modules. They are similar to the existing R_MIPS_PC16 relocation but applying to a wider field. Implement support for them by genericising the existing R_MIPS_PC16 implementation such that it can be used for different field widths, and calling it for all 3 reloc types. Signed-off-by: Paul Burton Cc: Maciej W. Rozycki Cc: Kees Cook Cc: James Hogan Cc: Alex Smith Cc: Steven J. Hill Cc: Andrew Morton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12434/ Signed-off-by: Ralf Baechle

mips: Differentiate between 32 and 64 bit ELF header

2016-02-11T10:38:22Z

Depending on the configuration either the 32 or 64 bit version of elf_check_arch() is defined. parse_crash_elf{32|64}_headers() does some basic verification of the ELF header via vmcore_elf{32|64}_check_arch() which happen to map to elf_check_arch(). Since the implementation 32 and 64 bit version of elf_check_arch() differ, we use the wrong type: In file included from include/linux/elf.h:4:0, from fs/proc/vmcore.c:13: fs/proc/vmcore.c: In function 'parse_crash_elf64_headers': >> arch/mips/include/asm/elf.h:228:23: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types] struct elfhdr *__h = (hdr); \ ^ include/linux/crash_dump.h:41:37: note: in expansion of macro 'elf_check_arch' #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x)) ^ fs/proc/vmcore.c:1015:4: note: in expansion of macro 'vmcore_elf64_check_arch' !vmcore_elf64_check_arch(&ehdr) || ^ Therefore, we rather define vmcore_elf{32|64}_check_arch() as a basic machine check and use it also in binfm_elf?32.c as well. Signed-off-by: Daniel Wagner Suggested-by: Maciej W. Rozycki Reviewed-by: Maciej W. Rozycki Reported-by: Fengguang Wu Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12529/ Signed-off-by: Ralf Baechle

MIPS: Add IEEE Std 754 conformance mode selection

2016-01-19T23:39:20Z

Add an `ieee754=' kernel parameter to control IEEE Std 754 conformance mode. Use separate flags copied from the respective CPU feature flags, and adjusted according to the conformance mode selected, to make binaries requesting individual NaN encoding modes accepted or rejected as needed. Update the initial setting for FCSR and, in the full FPU emulation mode, its read-only mask accordingly. Accept the mode selection requested for legacy processors as well. As with the EF_MIPS_NAN2008 ELF file header flag adjust both ABS2008 and NAN2008 bits at the same time, to match the choice made for hardware currently implemented. Signed-off-by: Maciej W. Rozycki Cc: Andrew Morton Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11481/ Signed-off-by: Ralf Baechle

MIPS: ELF: Interpret the NAN2008 file header flag

2016-01-19T23:39:20Z

Handle the EF_MIPS_NAN2008 ELF file header flag and refuse execution where there is no support in the FPU for the NaN encoding mode requested by a binary invoked. Ensure that the setting of the bit in the binary matches one in any intepreter used. Set the thread's initial FCSR contents according to the value of the EF_MIPS_NAN2008. Set the values of the FCSR ABS2008 and NAN2008 bits both to the same value if possible, to take the approach taken with existing FPU hardware into account. As of now all implementations have both bits hardwired to the same value, that is both are fixed at 0 or both are fixed at 1, even though the architecture allows for implementations where the amount of control implemented with each of these two individual bits is independent of each other. Signed-off-by: Maciej W. Rozycki Cc: Andrew Morton Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11479/ Signed-off-by: Ralf Baechle