kernel/linux.git/arch/powerpc/include/uapi/asm/elf.h, branch v6.18.22

powerpc/ptrace: Expose HASHKEYR register to ptrace

2023-06-19T07:36:27+00:00

The HASHKEYR register contains a secret per-process key to enable unique hashes per process. In general it should not be exposed to userspace at all and a regular process has no need to know its key. However, checkpoint restore in userspace (CRIU) functionality requires that a process be able to set the HASHKEYR of another process, otherwise existing hashes on the stack would be invalidated by a new random key. Exposing HASHKEYR in this way also makes it appear in core dumps, which is a security concern. Multiple threads may share a key, for example just after a fork() call, where the kernel cannot know if the child is going to return back along the parent's stack. If such a thread is coerced into making a core dump, then the HASHKEYR value will be readable and able to be used against all other threads sharing that key, effectively undoing any protection offered by hashst/hashchk. Therefore we expose HASHKEYR to ptrace when CONFIG_CHECKPOINT_RESTORE is enabled, providing a choice of increased security or migratable ROP protected processes. This is similar to how ARM exposes its PAC keys. Signed-off-by: Benjamin Gray Reviewed-by: Russell Currey Signed-off-by: Michael Ellerman Link: https://msgid.link/20230616034846.311705-8-bgray@linux.ibm.com

powerpc/ptrace: Expose DEXCR and HDEXCR registers to ptrace

2023-06-19T07:36:26+00:00

The DEXCR register is of interest when ptracing processes. Currently it is static, but eventually will be dynamically controllable by a process. If a process can control its own, then it is useful for it to be ptrace-able to (e.g., for checkpoint-restore functionality). It is also relevant to core dumps (the NPHIE aspect in particular), which use the ptrace mechanism (or is it the other way around?) to decide what to dump. The HDEXCR is useful here too, as the NPHIE aspect may be set in the HDEXCR without being set in the DEXCR. Although the HDEXCR is per-cpu and we don't track it in the task struct (it's useless in normal operation), it would be difficult to imagine why a hypervisor would set it to different values within a guest. A hypervisor cannot safely set NPHIE differently at least, as that would break programs. Expose a read-only view of the userspace DEXCR and HDEXCR to ptrace. The HDEXCR is always readonly, and is useful for diagnosing the core dumps (as the HDEXCR may set NPHIE without the DEXCR setting it). Signed-off-by: Benjamin Gray Reviewed-by: Russell Currey [mpe: Use lower_32_bits() rather than open coding] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230616034846.311705-7-bgray@linux.ibm.com

powerpc/64: modules support building with PCREL addresing

2023-04-20T03:21:42+00:00

Build modules using PCREL addressing when CONFIG_PPC_KERNEL_PCREL=y. - The module loader must handle several new relocation types: * R_PPC64_REL24_NOTOC is a function call handled like R_PPC_REL24, but does not restore r2 upon return. The external function call stub is changed to use pcrel addressing to load the function pointer rather than based on the module TOC. * R_PPC64_GOT_PCREL34 is a reference to external data. A GOT table must be built by hand, because the linker adds this during the final link (which is not done for kernel modules). The GOT table is built similarly to the way the external function call stub table is. This section is called .mygot because .got has a special meaning for the linker and can become upset. * R_PPC64_PCREL34 is used for local data addressing, but there is a special case where the percpu section is moved at load-time to the percpu area which is out of range of this relocation. This requires the PCREL34 relocations are converted to use GOT_PCREL34 addressing. Signed-off-by: Nicholas Piggin [mpe: Some coding style & formatting fixups] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230408021752.862660-7-npiggin@gmail.com

powerpc: Remove 'struct ppc64_opd_entry'

2022-02-16T12:25:11+00:00

'struct ppc64_opd_entry' doesn't belong to uapi/asm/elf.h It was initially in module_64.c and commit 2d291e902791 ("Fix compile failure with non modular builds") moved it into asm/elf.h But it was by mistake added outside of __KERNEL__ section, therefore commit c3617f72036c ("UAPI: (Scripted) Disintegrate arch/powerpc/include/asm") moved it to uapi/asm/elf.h Now that it is not used anymore by the kernel, remove it. Signed-off-by: Christophe Leroy Reviewed-by: Kees Cook Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/c309ccee65ec2e3802df7a7fe761d0a298584809.1644928018.git.christophe.leroy@csgroup.eu

powerpc/ptrace: Add memory protection key regset

2018-01-20T11:59:06+00:00

The AMR/IAMR/UAMOR are part of the program context. Allow it to be accessed via ptrace and through core files. Signed-off-by: Ram Pai Signed-off-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11+00:00

Many user space API headers have licensing information, which is either incomplete, badly formatted or just a shorthand for referring to the license under which the file is supposed to be. This makes it hard for compliance tools to determine the correct license. Update these files with an SPDX license identifier. The identifier was chosen based on the license information in the file. GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license identifier with the added 'WITH Linux-syscall-note' exception, which is the officially assigned exception identifier for the kernel syscall exception: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". This exception makes it possible to include GPL headers into non GPL code, without confusing license compliance tools. Headers which have either explicit dual licensing or are just licensed under a non GPL license are updated with the corresponding SPDX identifier and the GPLv2 with syscall exception identifier. The format is: ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE) SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. The update does not remove existing license information as this has to be done on a case by case basis and the copyright holders might have to be consulted. This will happen in a separate step. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

powerpc: Move ARCH_DLINFO out of uapi

2017-02-06T08:46:04+00:00

It's an kernel private macro, it doesn't belong there Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman

powerpc/ptrace: Enable support for Performance Monitor registers

2016-08-01T01:15:24+00:00

This patch enables support for Performance monitor registers related ELF core note NT_PPC_PMU based ptrace requests through PTRACE_GETREGSET, PTRACE_SETREGSET calls. This is achieved through adding one new register sets REGSET_PMU in powerpc corresponding to the ELF core note sections added in this regard. It also implements the get, set and active functions for this new register sets added. Signed-off-by: Anshuman Khandual Signed-off-by: Simon Guo Signed-off-by: Michael Ellerman

powerpc/ptrace: Enable support for EBB registers

2016-08-01T01:15:23+00:00

This patch enables support for EBB state registers related ELF core note NT_PPC_EBB based ptrace requests through PTRACE_GETREGSET, PTRACE_SETREGSET calls. This is achieved through adding one new register sets REGSET_EBB in powerpc corresponding to the ELF core note sections added in this regard. It also implements the get, set and active functions for this new register sets added. Signed-off-by: Anshuman Khandual Signed-off-by: Simon Guo Signed-off-by: Michael Ellerman

powerpc/ptrace: Enable support for TM SPR state

2016-08-01T01:15:21+00:00

This patch enables support for TM SPR state related ELF core note NT_PPC_TM_SPR based ptrace requests through PTRACE_GETREGSET, PTRACE_SETREGSET calls. This is achieved through adding a register set REGSET_TM_SPR in powerpc corresponding to the ELF core note section added. It implements the get, set and active functions for this new register set added. Signed-off-by: Anshuman Khandual Signed-off-by: Simon Guo Signed-off-by: Michael Ellerman