lwn.git/arch/powerpc/include/asm/ftrace.h, branch docs-6.9

powerpc/ftrace: Fix indentation in ftrace.h

2023-12-13T10:49:22+00:00

Replace seven spaces with a tab character to fix an indentation issue reported by the kernel test robot. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202311221731.alUwTDIm-lkp@intel.com/ Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/9f058227bd9243f0842786ef7228d87ab10d29f6.1702045299.git.naveen@kernel.org

powerpc/ftrace: Add support for -fpatchable-function-entry

2023-08-21T14:09:06+00:00

GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to emit nops after the local entry point, rather than before it. This allows us to use this in the kernel for ftrace purposes. A new script is added under arch/powerpc/tools/ to help detect if nops are emitted after the function local entry point, or before the global entry point. With -fpatchable-function-entry, we no longer have the profiling instructions generated at function entry, so we only need to validate the presence of two nops at the ftrace location in ftrace_init_nop(). We patch the preceding instruction with 'mflr r0' to match the -mprofile-kernel ABI for subsequent ftrace use. This changes the profiling instructions used on ppc32. The default -pg option emits an additional 'stw' instruction after 'mflr r0' and before the branch to _mcount 'bl _mcount'. This is very similar to the original -mprofile-kernel implementation on ppc64le, where an additional 'std' instruction was used to save LR to its save location in the caller's stackframe. Subsequently, this additional store was removed in later compiler versions for performance reasons. The same reasons apply for ppc32 so we only patch in a 'mflr r0'. Signed-off-by: Naveen N Rao Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org

powerpc/ftrace: Add separate ftrace_init_nop() with additional validation

2023-08-21T14:09:06+00:00

Currently, we validate instructions around the ftrace location every time we have to enable/disable ftrace. Introduce ftrace_init_nop() to instead perform all the validation during ftrace initialization. This allows us to simply patch the necessary instructions during enabling/disabling ftrace. Signed-off-by: Naveen N Rao Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/f373684081e8e98be09b7f44d2d93069768324dc.1687166935.git.naveen@kernel.org

powerpc/ftrace: Extend ftrace support for large kernels to ppc32

2023-08-21T14:09:05+00:00

Commit 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs") added ftrace support for ppc64 kernel images with a text section larger than 32MB. The approach itself isn't specific to ppc64, so extend the same to also work on ppc32. While at it, reduce the space reserved for the stub from 64 bytes to 32 bytes since the different stub variants are all less than 8 instructions. To reduce use of #ifdef, a stub implementation is provided for kernel_toc_address() and -SZ_2G is cast to 'long long' to prevent errors on ppc32. Signed-off-by: Naveen N Rao Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/9fa3258cbb9105cf8a0a8135214d44ffbc75fe84.1687166935.git.naveen@kernel.org

powerpc/ftrace: Fix dropping weak symbols with older toolchains

2023-08-21T14:09:05+00:00

The minimum level of gcc supported for building the kernel is v5.1. v5.x releases of gcc emitted a three instruction sequence for -mprofile-kernel: mflr r0 std r0, 16(r1) bl _mcount It is only with the v6.x releases that gcc started emitting the two instruction sequence for -mprofile-kernel, omitting the second store instruction. With the older three instruction sequence, the actual ftrace location can be the 5th instruction into a function. Update the allowed offset for ftrace location from 12 to 16 to accommodate the same. Cc: stable@vger.kernel.org Fixes: 7af82ff90a2b06 ("powerpc/ftrace: Ignore weak functions") Signed-off-by: Naveen N Rao Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/7b265908a9461e38fc756ef9b569703860a80621.1687166935.git.naveen@kernel.org

Merge tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2022-12-19T13:13:33+00:00

Pull powerpc updates from Michael Ellerman: - Add powerpc qspinlock implementation optimised for large system scalability and paravirt. See the merge message for more details - Enable objtool to be built on powerpc to generate mcount locations - Use a temporary mm for code patching with the Radix MMU, so the writable mapping is restricted to the patching CPU - Add an option to build the 64-bit big-endian kernel with the ELFv2 ABI - Sanitise user registers on interrupt entry on 64-bit Book3S - Many other small features and fixes Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET, Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang, Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A. R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin, Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng, XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu, and Wolfram Sang. * tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits) powerpc/code-patching: Fix oops with DEBUG_VM enabled powerpc/qspinlock: Fix 32-bit build powerpc/prom: Fix 32-bit build powerpc/rtas: mandate RTAS syscall filtering powerpc/rtas: define pr_fmt and convert printk call sites powerpc/rtas: clean up includes powerpc/rtas: clean up rtas_error_log_max initialization powerpc/pseries/eeh: use correct API for error log size powerpc/rtas: avoid scheduling in rtas_os_term() powerpc/rtas: avoid device tree lookups in rtas_os_term() powerpc/rtasd: use correct OF API for event scan rate powerpc/rtas: document rtas_call() powerpc/pseries: unregister VPA when hot unplugging a CPU powerpc/pseries: reset the RCU watchdogs after a LPM powerpc: Take in account addition CPU node when building kexec FDT powerpc: export the CPU node count powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state powerpc/dts/fsl: Fix pca954x i2c-mux node names cxl: Remove unnecessary cxl_pci_window_alignment() selftests/powerpc: Fix resource leaks ...

powerpc/ftrace: fix syscall tracing on PPC64_ELF_ABI_V1

2022-12-02T09:57:09+00:00

In v5.7 the powerpc syscall entry/exit logic was rewritten in C, on PPC64_ELF_ABI_V1 this resulted in the symbols in the syscall table changing from their dot prefixed variant to the non-prefixed ones. Since ftrace prefixes a dot to the syscall names when matching them to build its syscall event list, this resulted in no syscall events being available. Remove the PPC64_ELF_ABI_V1 specific version of arch_syscall_match_sym_name to have the same behavior across all powerpc variants. Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C") Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Michael Jeanson Reviewed-by: Mathieu Desnoyers Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221201161442.2127231-1-mjeanson@efficios.com

powerpc/ftrace: Ignore weak functions

2022-11-24T12:31:46+00:00

Extend commit b39181f7c6907d ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function") to ppc32 and ppc64 -mprofile-kernel by defining FTRACE_MCOUNT_MAX_OFFSET. For ppc64 -mprofile-kernel ABI, we can have two instructions at function entry for TOC setup followed by 'mflr r0' and 'bl _mcount'. So, the mcount location is at most the 4th instruction in a function. For ppc32, mcount location is always the 3rd instruction in a function, preceded by 'mflr r0' and 'stw r0,4(r1)'. With this patch, and with ppc64le_guest_defconfig and some ftrace/bpf config items enabled: # grep __ftrace_invalid_address available_filter_functions | wc -l 79 Signed-off-by: Naveen N. Rao Acked-by: Steven Rostedt (Google) Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220809105425.424045-1-naveen.n.rao@linux.vnet.ibm.com

ftrace: abstract DYNAMIC_FTRACE_WITH_ARGS accesses

2022-11-18T13:56:41+00:00

In subsequent patches we'll arrange for architectures to have an ftrace_regs which is entirely distinct from pt_regs. In preparation for this, we need to minimize the use of pt_regs to where strictly necessary in the core ftrace code. This patch adds new ftrace_regs_{get,set}_*() helpers which can be used to manipulate ftrace_regs. When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y, these can always be used on any ftrace_regs, and when CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n these can be used when regs are available. A new ftrace_regs_has_args(fregs) helper is added which code can use to check when these are usable. Co-developed-by: Florent Revest Signed-off-by: Florent Revest Signed-off-by: Mark Rutland Cc: Masami Hiramatsu Cc: Steven Rostedt Reviewed-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20221103170520.931305-4-mark.rutland@arm.com Signed-off-by: Will Deacon

ftrace: rename ftrace_instruction_pointer_set() -> ftrace_regs_set_instruction_pointer()

2022-11-18T13:56:41+00:00

In subsequent patches we'll add a sew of ftrace_regs_{get,set}_*() helpers. In preparation, this patch renames ftrace_instruction_pointer_set() to ftrace_regs_set_instruction_pointer(). There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Florent Revest Cc: Masami Hiramatsu Cc: Steven Rostedt Reviewed-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20221103170520.931305-3-mark.rutland@arm.com Signed-off-by: Will Deacon