user/sven/linux.git/arch/powerpc/include/uapi, branch v6.8.4

powerpc/pseries/papr-sysparm: use u8 arrays for payloads

2024-02-05T06:01:25Z

Some PAPR system parameter values are formatted by firmware as nul-terminated strings (e.g. LPAR name, shared processor attributes). But the values returned for other parameters, such as processor module info and TLB block invalidate characteristics, are binary data with parameter-specific layouts. So char[] isn't the appropriate type for the general case. Use u8/__u8. Signed-off-by: Nathan Lynch Fixes: 905b9e48786e ("powerpc/pseries/papr-sysparm: Expose character device to user space") Signed-off-by: Michael Ellerman Link: https://msgid.link/20240202-papr-sysparm-ioblock-data-use-u8-v1-1-f5c6c89f65ec@linux.ibm.com

powerpc/pseries/papr-sysparm: Expose character device to user space

2023-12-13T10:38:21Z

Until now the papr_sysparm APIs have been kernel-internal. But user space needs access to PAPR system parameters too. The only method available to user space today to get or set system parameters is using sys_rtas() and /dev/mem to pass RTAS-addressable buffers between user space and firmware. This is incompatible with lockdown and should be deprecated. So provide an alternative ABI to user space in the form of a /dev/papr-sysparm character device with just two ioctl commands (get and set). The data payloads involved are small enough to fit in the ioctl argument buffer, making the code relatively simple. Exposing the system parameters through sysfs has been considered but it would be too awkward: * The kernel currently does not have to contain an exhaustive list of defined system parameters. This is a convenient property to maintain because we don't have to update the kernel whenever a new parameter is added to PAPR. Exporting a named attribute in sysfs for each parameter would negate this. * Some system parameters are text-based and some are not. * Retrieval of at least one system parameter requires input data, which a simple read-oriented interface can't support. Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-11-e9eafd0c8c6c@linux.ibm.com

powerpc/pseries: Add papr-vpd character driver for VPD retrieval

2023-12-13T10:38:21Z

PowerVM LPARs may retrieve Vital Product Data (VPD) for system components using the ibm,get-vpd RTAS function. We can expose this to user space with a /dev/papr-vpd character device, where the programming model is: struct papr_location_code plc = { .str = "", }; /* obtain all VPD */ int devfd = open("/dev/papr-vpd", O_RDONLY); int vpdfd = ioctl(devfd, PAPR_VPD_CREATE_HANDLE, &plc); size_t size = lseek(vpdfd, 0, SEEK_END); char *buf = malloc(size); pread(devfd, buf, size, 0); When a file descriptor is obtained from ioctl(PAPR_VPD_CREATE_HANDLE), the file contains the result of a complete ibm,get-vpd sequence. The file contents are immutable from the POV of user space. To get a new view of the VPD, the client must create a new handle. This design choice insulates user space from most of the complexities that ibm,get-vpd brings: * ibm,get-vpd must be called more than once to obtain complete results. * Only one ibm,get-vpd call sequence should be in progress at a time; interleaved sequences will disrupt each other. Callers must have a protocol for serializing their use of the function. * A call sequence in progress may receive a "VPD changed, try again" status, requiring the client to abandon the sequence and start over. The memory required for the VPD buffers seems acceptable, around 20KB for all VPD on one of my systems. And the value of the /rtas/ibm,vpd-size DT property (the estimated maximum size of VPD) is consistently 300KB across various systems I've checked. I've implemented support for this new ABI in the rtas_get_vpd() function in librtas, which the vpdupdate command currently uses to populate its VPD database. I've verified that an unmodified vpdupdate binary generates an identical database when using a librtas.so that prefers the new ABI. Along with the papr-vpd.h header exposed to user space, this introduces a common papr-miscdev.h uapi header to share a base ioctl ID with similar drivers to come. Tested-by: Michal Suchánek Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-9-e9eafd0c8c6c@linux.ibm.com

powerpc/ptrace: Expose HASHKEYR register to ptrace

2023-06-19T07:36:27Z

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

2023-06-19T07:36:26Z

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

2023-04-20T03:21:42Z

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/bpf: Fix use of user_pt_regs in uapi

2022-06-29T10:43:04Z

Trying to build a .c file that includes : $ cat test_bpf_headers.c #include throws the below error: /usr/include/linux/bpf_perf_event.h:14:28: error: field ‘regs’ has incomplete type 14 | bpf_user_pt_regs_t regs; | ^~~~ This is because we typedef bpf_user_pt_regs_t to 'struct user_pt_regs' in arch/powerpc/include/uaps/asm/bpf_perf_event.h, but 'struct user_pt_regs' is not exposed to userspace. Powerpc has both pt_regs and user_pt_regs structures. However, unlike arm64 and s390, we expose user_pt_regs to userspace as just 'pt_regs'. As such, we should typedef bpf_user_pt_regs_t to 'struct pt_regs' for userspace. Within the kernel though, we want to typedef bpf_user_pt_regs_t to 'struct user_pt_regs'. Remove arch/powerpc/include/uapi/asm/bpf_perf_event.h so that the uapi/asm-generic version of the header is exposed to userspace. Introduce arch/powerpc/include/asm/bpf_perf_event.h so that we can typedef bpf_user_pt_regs_t to 'struct user_pt_regs' for use within the kernel. Note that this was not showing up with the bpf selftest build since tools/include/uapi/asm/bpf_perf_event.h didn't include the powerpc variant. Fixes: a6460b03f945ee ("powerpc/bpf: Fix broken uapi for BPF_PROG_TYPE_PERF_EVENT") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Naveen N. Rao [mpe: Use typical naming for header include guard] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220627191119.142867-1-naveen.n.rao@linux.vnet.ibm.com

Merge tag 'tty-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2022-06-03T18:08:40Z

Pull tty and serial driver updates from Greg KH: "Here is the big set of tty and serial driver updates for 5.19-rc1. Lots of tiny cleanups in here, the major stuff is: - termbit cleanups and unification by Ilpo. A much needed change that goes a long way to making things simpler for all of the different arches - tty documentation cleanups and movements to their own place in the documentation tree - old tty driver cleanups and fixes from Jiri to bring some existing drivers into the modern world - RS485 cleanups and unifications to make it easier for individual drivers to support this mode instead of having to duplicate logic in each driver - Lots of 8250 driver updates and additions - new device id additions - n_gsm continued fixes and cleanups - other minor serial driver updates and cleanups All of these have been in linux-next for weeks with no reported issues" * tag 'tty-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (166 commits) tty: Rework receive flow control char logic pcmcia: synclink_cs: Don't allow CS5-6 serial: stm32-usart: Correct CSIZE, bits, and parity serial: st-asc: Sanitize CSIZE and correct PARENB for CS7 serial: sifive: Sanitize CSIZE and c_iflag serial: sh-sci: Don't allow CS5-6 serial: txx9: Don't allow CS5-6 serial: rda-uart: Don't allow CS5-6 serial: digicolor-usart: Don't allow CS5-6 serial: uartlite: Fix BRKINT clearing serial: cpm_uart: Fix build error without CONFIG_SERIAL_CPM_CONSOLE serial: core: Do stop_rx in suspend path for console if console_suspend is disabled tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate. dt-bindings: serial: renesas,em-uart: Add RZ/V2M clock to access the registers serial: 8250_fintek: Check SER_RS485_RTS_* only with RS485 Revert "serial: 8250_mtk: Make sure to select the right FEATURE_SEL" serial: msm_serial: disable interrupts in __msm_console_write() serial: meson: acquire port->lock in startup() serial: 8250_dw: Use dev_err_probe() serial: 8250_dw: Use devm_add_action_or_reset() ...

Merge tag 'asm-generic-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2022-06-02T22:32:26Z

Pull asm-generic fixes from Arnd Bergmann: "The header cleanup series from Masahiro Yamada ended up causing some regressions in the ABI because of an ambigous uid_t type. This was only caught after the original patches got merged, but at least the fixes are trivial and hopefully complete" * tag 'asm-generic-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: binder: fix sender_euid type in uapi header sparc: fix mis-use of __kernel_{uid,gid}_t in uapi/asm/stat.h powerpc: use __kernel_{uid,gid}32_t in uapi/asm/stat.h mips: use __kernel_{uid,gid}32_t in uapi/asm/stat.h

powerpc: use __kernel_{uid,gid}32_t in uapi/asm/stat.h

2022-06-02T15:38:15Z

Commit c01013a2f8dd ("powerpc: add asm/stat.h to UAPI compile-test coverage") converted as follows: uid_t --> __kernel_uid_t gid_t --> __kernel_gid_t The bit width of __kernel_{uid,gid}_t is 16 or 32-bits depending on architectures. PPC uses 32-bits for them as in include/uapi/asm-generic/posix_types.h, so the previous conversion is probably fine, but let's stick to the arch-independent conversion just in case. The safe replacements across all architectures are: uid_t --> __kernel_uid32_t gid_t --> __kernel_gid32_t as defined in include/linux/types.h. A similar issue was reported for the android binder. [1] [1]: https://lore.kernel.org/all/20220601010017.2639048-1-cmllamas@google.com/ Fixes: c01013a2f8dd ("powerpc: add asm/stat.h to UAPI compile-test coverage") Signed-off-by: Masahiro Yamada Signed-off-by: Arnd Bergmann