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2020-06-02kdb: Remove the misfeature 'KDBFLAGS'Wei Li
Currently, 'KDBFLAGS' is an internal variable of kdb, it is combined by 'KDBDEBUG' and state flags. It will be shown only when 'KDBDEBUG' is set, and the user can define an environment variable named 'KDBFLAGS' too. These are puzzling indeed. After communication with Daniel, it seems that 'KDBFLAGS' is a misfeature. So let's replace 'KDBFLAGS' with 'KDBDEBUG' to just show the value we wrote into. After this modification, we can use `md4c1 kdb_flags` instead, to observe the state flags. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Wei Li <liwei391@huawei.com> Link: https://lore.kernel.org/r/20200521072125.21103-1-liwei391@huawei.com [daniel.thompson@linaro.org: Make kdb_flags unsigned to avoid arithmetic right shift] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02kdb: Cleanup math with KDB_CMD_HISTORY_COUNTDouglas Anderson
From code inspection the math in handle_ctrl_cmd() looks super sketchy because it subjects -1 from cmdptr and then does a "% KDB_CMD_HISTORY_COUNT". It turns out that this code works because "cmdptr" is unsigned and KDB_CMD_HISTORY_COUNT is a nice power of 2. Let's make this a little less sketchy. This patch should be a no-op. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200507161125.1.I2cce9ac66e141230c3644b8174b6c15d4e769232@changeid Reviewed-by: Sumit Garg <sumit.garg@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02serial: amba-pl011: Support kgdboc_earlyconSumit Garg
Implement the read() function in the early console driver. With recently added kgdboc_earlycon feature, this allows you to use kgdb to debug fairly early into the system boot. We only bother implementing this if polling is enabled since kgdb can't be enabled without that. Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200507130644.v4.12.I8ee0811f0e0816dd8bfe7f2f5540b3dba074fae8@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02serial: 8250_early: Support kgdboc_earlyconDouglas Anderson
Implement the read() function in the early console driver. With recent kgdb patches this allows you to use kgdb to debug fairly early into the system boot. We only bother implementing this if polling is enabled since kgdb can't be enabled without that. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200507130644.v4.11.I8f668556c244776523320a95b09373a86eda11b7@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02serial: qcom_geni_serial: Support kgdboc_earlyconDouglas Anderson
Implement the read() function in the early console driver. With recent kgdb patches this allows you to use kgdb to debug fairly early into the system boot. We only bother implementing this if polling is enabled since kgdb can't be enabled without that. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20200507130644.v4.10.If2deff9679a62c1ce1b8f2558a8635dc837adf8c@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02serial: kgdboc: Allow earlycon initialization to be deferredDaniel Thompson
Currently there is no guarantee that an earlycon will be initialized before kgdboc tries to adopt it. Almost the opposite: on systems with ACPI then if earlycon has no arguments then it is guaranteed that earlycon will not be initialized. This patch mitigates the problem by giving kgdboc_earlycon a second chance during console_init(). This isn't quite as good as stopping during early parameter parsing but it is still early in the kernel boot. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200430161741.1832050-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org>
2020-06-02Documentation: kgdboc: Document new kgdboc_earlycon parameterDouglas Anderson
The recent patch ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles") adds a new kernel command line parameter. Document it. Note that the patch adding the feature does some comparing/contrasting of "kgdboc_earlycon" vs. the existing "ekgdboc". See that patch for more details, but briefly "ekgdboc" can be used _instead_ of "kgdboc" and just makes "kgdboc" do its normal initialization early (only works if your tty driver is already ready). The new "kgdboc_earlycon" works in combination with "kgdboc" and is backed by boot consoles. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200507130644.v4.9.I7d5eb42c6180c831d47aef1af44d0b8be3fac559@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02kgdb: Don't call the deinit under spinlockDouglas Anderson
When I combined kgdboc_earlycon with an inflight patch titled ("soc: qcom-geni-se: Add interconnect support to fix earlycon crash") [1] things went boom. Specifically I got a crash during the transition between kgdboc_earlycon and the main kgdboc that looked like this: Call trace: __schedule_bug+0x68/0x6c __schedule+0x75c/0x924 schedule+0x8c/0xbc schedule_timeout+0x9c/0xfc do_wait_for_common+0xd0/0x160 wait_for_completion_timeout+0x54/0x74 rpmh_write_batch+0x1fc/0x23c qcom_icc_bcm_voter_commit+0x1b4/0x388 qcom_icc_set+0x2c/0x3c apply_constraints+0x5c/0x98 icc_set_bw+0x204/0x3bc icc_put+0x30/0xf8 geni_remove_earlycon_icc_vote+0x6c/0x9c qcom_geni_serial_earlycon_exit+0x10/0x1c kgdboc_earlycon_deinit+0x38/0x58 kgdb_register_io_module+0x11c/0x194 configure_kgdboc+0x108/0x174 kgdboc_probe+0x38/0x60 platform_drv_probe+0x90/0xb0 really_probe+0x130/0x2fc ... The problem was that we were holding the "kgdb_registration_lock" while calling into code that didn't expect to be called in spinlock context. Let's slightly defer when we call the deinit code so that it's not done under spinlock. NOTE: this does mean that the "deinit" call of the old kgdb IO module is now made _after_ the init of the new IO module, but presumably that's OK. [1] https://lkml.kernel.org/r/1588919619-21355-3-git-send-email-akashast@codeaurora.org Fixes: 220995622da5 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles") Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200526142001.1.I523dc33f96589cb9956f5679976d402c8cda36fa@changeid [daniel.thompson@linaro.org: Resolved merge issues by hand] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02kgdboc: Disable all the early code when kgdboc is a moduleDouglas Anderson
When kgdboc is compiled as a module all of the "ekgdboc" and "kgdb_earlycon" code isn't useful and, in fact, breaks compilation. This is because early_param() isn't defined for modules and that's how this code gets configured. It turns out that this was broken by commit eae3e19ca930 ("kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc") and then made worse by commit 220995622da5 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles"). I guess the #ifdef wasn't so useless, even if it wasn't obvious why it was useful. When kgdboc was compiled as a module only "CONFIG_KGDB_SERIAL_CONSOLE_MODULE" was defined, not "CONFIG_KGDB_SERIAL_CONSOLE". That meant that the old module. Let's basically do the same thing that the old code (pre-removal of the #ifdef) did but use "IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)" to make it more obvious what the point of the check is. We'll fix kgdboc_earlycon in a similar way. Fixes: 220995622da5 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles") Fixes: eae3e19ca930 ("kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200519084345.1.I91670accc8a5ddabab227eb63bb4ad3e2e9d2b58@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02perf tools: Remove some duplicated includesTiezhu Yang
There exists some duplicated includes in tools/perf, remove them. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: xuefeng li <lixuefeng@loongson.cn> Link: http://lore.kernel.org/lkml/1591071304-19338-2-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-06-02perf symbols: Fix kernel maps for kcore and eBPFAdrian Hunter
Adjust 'map->pgoff' also when moving a map's start address. Example with v5.4.34 based kernel: Before: $ sudo tools/perf/perf record -a --kcore -e intel_pt//k sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 1.958 MB perf.data ] $ sudo tools/perf/perf script --itrace=e >/dev/null Warning: 961 instruction trace errors After: $ sudo tools/perf/perf script --itrace=e >/dev/null $ Committer testing: # uname -a Linux seventh 5.6.10-100.fc30.x86_64 #1 SMP Mon May 4 15:36:44 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux # Before: # perf record -a --kcore -e intel_pt//k sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.923 MB perf.data ] # perf script --itrace=e >/dev/null Warning: 295 instruction trace errors # After: # perf record -a --kcore -e intel_pt//k sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.919 MB perf.data ] # perf script --itrace=e >/dev/null # Fixes: fb5a88d4131a ("perf tools: Preserve eBPF maps when loading kcore") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/20200602112505.1406-1-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-06-02tools arch x86: Sync the msr-index.h copy with the kernel sourcesArnaldo Carvalho de Melo
To pick up the changes in: 5cde265384ca ("perf/x86/rapl: Add AMD Fam17h RAPL support") Addressing this tools/perf build warning: Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h' diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h With this one will be able to use these new AMD MSRs in filters, by name, e.g.: # perf trace -e msr:* --filter="msr==AMD_PKG_ENERGY_STATUS || msr==AMD_RAPL_POWER_UNIT" Just like it is now possible with other MSRs: [root@five ~]# uname -a Linux five 5.5.17-200.fc31.x86_64 #1 SMP Mon Apr 13 15:29:42 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux [root@five ~]# grep 'model name' -m1 /proc/cpuinfo model name : AMD Ryzen 5 3600X 6-Core Processor [root@five ~]# [root@five ~]# perf trace -e msr:*/max-stack=16/ --filter="msr==AMD_PERF_CTL" --max-events=2 0.000 kworker/1:1-ev/2327824 msr:write_msr(msr: AMD_PERF_CTL, val: 2) do_trace_write_msr ([kernel.kallsyms]) do_trace_write_msr ([kernel.kallsyms]) [0xffffffffc01d71c3] ([acpi_cpufreq]) [0] ([unknown]) __cpufreq_driver_target ([kernel.kallsyms]) od_dbs_update ([kernel.kallsyms]) dbs_work_handler ([kernel.kallsyms]) process_one_work ([kernel.kallsyms]) worker_thread ([kernel.kallsyms]) kthread ([kernel.kallsyms]) ret_from_fork ([kernel.kallsyms]) 8.597 kworker/2:2-ev/2338099 msr:write_msr(msr: AMD_PERF_CTL, val: 2) do_trace_write_msr ([kernel.kallsyms]) do_trace_write_msr ([kernel.kallsyms]) [0] ([unknown]) [0] ([unknown]) __cpufreq_driver_target ([kernel.kallsyms]) od_dbs_update ([kernel.kallsyms]) dbs_work_handler ([kernel.kallsyms]) process_one_work ([kernel.kallsyms]) worker_thread ([kernel.kallsyms]) kthread ([kernel.kallsyms]) ret_from_fork ([kernel.kallsyms]) [root@five ~]# Longer explanation with what happens in the perf build process, automatically after this is made in synch with the kernel sources: $ make -C tools/perf O=/tmp/build/perf install-bin <SNIP> Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h' diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h <SNIP> make: Leaving directory '/home/acme/git/perf/tools/perf' $ $ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before $ $ diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h --- tools/arch/x86/include/asm/msr-index.h 2020-06-02 10:46:36.217782288 -0300 +++ arch/x86/include/asm/msr-index.h 2020-05-28 10:41:23.313794627 -0300 @@ -301,6 +301,9 @@ #define MSR_PP1_ENERGY_STATUS 0x00000641 #define MSR_PP1_POLICY 0x00000642 +#define MSR_AMD_PKG_ENERGY_STATUS 0xc001029b +#define MSR_AMD_RAPL_POWER_UNIT 0xc0010299 + /* Config TDP MSRs */ #define MSR_CONFIG_TDP_NOMINAL 0x00000648 #define MSR_CONFIG_TDP_LEVEL_1 0x00000649 $ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h $ $ make -C tools/perf O=/tmp/build/perf install-bin <SNIP> CC /tmp/build/perf/trace/beauty/tracepoints/x86_msr.o LD /tmp/build/perf/trace/beauty/tracepoints/perf-in.o LD /tmp/build/perf/trace/beauty/perf-in.o LD /tmp/build/perf/perf-in.o LINK /tmp/build/perf/perf <SNIP> make: Leaving directory '/home/acme/git/perf/tools/perf' $ $ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after $ diff -u before after --- before 2020-06-02 10:47:08.486334348 -0300 +++ after 2020-06-02 10:47:33.075008948 -0300 @@ -286,6 +286,8 @@ [0xc0010240 - x86_AMD_V_KVM_MSRs_offset] = "F15H_NB_PERF_CTL", [0xc0010241 - x86_AMD_V_KVM_MSRs_offset] = "F15H_NB_PERF_CTR", [0xc0010280 - x86_AMD_V_KVM_MSRs_offset] = "F15H_PTSC", + [0xc0010299 - x86_AMD_V_KVM_MSRs_offset] = "AMD_RAPL_POWER_UNIT", + [0xc001029b - x86_AMD_V_KVM_MSRs_offset] = "AMD_PKG_ENERGY_STATUS", [0xc00102f0 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PPIN_CTL", [0xc00102f1 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PPIN", }; $ Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Wang Nan <wangnan0@huawei.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-06-02MAINTAINERS: Add Lee Jones as reviewer for the PWM subsystemThierry Reding
Lee has kindly offered his help in sharing the patch review workload for the PWM subsystem. If this works out well between Lee, Uwe and myself it may be a good idea to maintain the subsystem as a group. Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: imx27: Fix rounding behaviorUwe Kleine-König
To not trigger the warnings provided by CONFIG_PWM_DEBUG - use up-rounding in .get_state() - don't divide by the result of a division - don't use the rounded counter value for the period length to calculate the counter value for the duty cycle Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: rockchip: Simplify rockchip_pwm_get_state()Rasmus Villemoes
The way state->enabled is computed is rather convoluted and hard to read - both branches of the if() actually do the exact same thing. So remove the if(), and further simplify "<boolean condition> ? true : false" to "<boolean condition>". Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed caseNavid Emamdoost
Even in failed case of pm_runtime_get_sync(), the usage_count is incremented. In order to keep the usage_count with correct value call appropriate pm_runtime_put(). Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02Merge tag 'gvt-next-fixes-2020-05-28' of https://github.com/intel/gvt-linux ↵Joonas Lahtinen
into drm-intel-next-fixes gvt-next-fixes-2020-05-28 - Fix one clang warning on debug only function (Nathan) - Use ARRAY_SIZE for coccicheck warn (Aishwarya) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> From: Zhenyu Wang <zhenyuw@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200528033559.GG23961@zhen-hp.sh.intel.com
2020-06-02perf stat: Ensure group is defined on top of the same cpu maskJiri Olsa
Jin Yao reported the issue (and posted first versions of this change) with groups being defined over events with different cpu mask. This causes assert aborts in get_group_fd, like: # perf stat -M "C2_Pkg_Residency" -a -- sleep 1 perf: util/evsel.c:1464: get_group_fd: Assertion `!(fd == -1)' failed. Aborted All the events in the group have to be defined over the same cpus so the group_fd can be found for every leader/member pair. Adding check to ensure this condition is met and removing the group (with warning) if we detect mixed cpus, like: $ sudo perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}' WARNING: event cpu maps do not match, disabling group: anon group { power/energy-cores/, cycles } anon group { instructions, power/energy-cores/ } Ian asked also for cpu maps details, it's displayed in verbose mode: $ sudo perf stat -e '{cycles,power/energy-cores/}' -v WARNING: group events cpu maps do not match, disabling group: anon group { power/energy-cores/, cycles } power/energy-cores/: 0 cycles: 0-7 anon group { instructions, power/energy-cores/ } instructions: 0-7 power/energy-cores/: 0 Committer testing: [root@seventh ~]# perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}' WARNING: grouped events cpus do not match, disabling group: anon group { power/energy-cores/, cycles } anon group { instructions, power/energy-cores/ } ^C Performance counter stats for 'system wide': 12.62 Joules power/energy-cores/ 106,920,637 cycles 80,228,899 instructions # 0.75 insn per cycle 12.62 Joules power/energy-cores/ 14.514476987 seconds time elapsed [root@seventh ~]# But if we put compatible events in each group it works: [root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' -a sleep 2 Performance counter stats for 'system wide': 1.95 Joules power/energy-cores/ 0.92 Joules power/energy-ram/ 29,305,715 instructions # 1.03 insn per cycle 28,423,338 cycles 2.001438142 seconds time elapsed [root@seventh ~]# This needs improvement tho: [root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' sleep 2 Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (power/energy-cores/). /bin/dmesg | grep -i perf may provide additional information. [root@seventh ~]# We need to emit a better message, one stating that the power/ events can't be used for a specific workload, instead it is per-cpu or system wide. Fixes: 6a4bb04caacc8 ("perf tools: Enable grouping logic for parsed events") Co-developed-by: Jin Yao <yao.jin@linux.intel.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20200602101736.GE1112120@krava Signed-off-by: Jin Yao <yao.jin@linux.intel.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-06-02drm/i915/params: fix i915.fake_lmem_start module param sysfs permissionsJani Nikula
fake_lmem_start does not need to be mutable via module param sysfs. It's only used during driver probe. Fixes: 1629224324b6 ("drm/i915/lmem: add the fake lmem region") Cc: Matthew Auld <matthew.auld@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200601215510.18379-2-jani.nikula@intel.com (cherry picked from commit f322e851f20e534cf5305332a9ad5eefadb55d56) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-06-02drm/i915/params: don't expose inject_probe_failure in debugfsJani Nikula
The parameter only makes sense as a module parameter only. Fixes: c43c5a8818d4 ("drm/i915/params: add i915 parameters to debugfs") Cc: Juha-Pekka Heikkilä <juha-pekka.heikkila@intel.com> Cc: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com> Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200601215510.18379-1-jani.nikula@intel.com (cherry picked from commit dbf4081ffb68c0d9b518a34c715a8d8681658411) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-06-02drm/i915: Whitelist context-local timestamp in the gen9 cmdparserChris Wilson
Allow batch buffers to read their own _local_ cumulative HW runtime of their logical context. Fixes: 0f2f39758341 ("drm/i915: Add gen9 BCS cmdparsing") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: <stable@vger.kernel.org> # v5.4+ Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200601161942.30854-1-chris@chris-wilson.co.uk (cherry picked from commit f9496520df11de00fbafc3cbd693b9570d600ab3) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-06-02drm/i915: Fix global state use-after-frees with a refcountVille Syrjälä
While the current locking/serialization of the global state suffices for protecting the obj->state access and the actual hardware reprogramming, we do have a problem with accessing the old/new states during nonblocking commits. The state computation and swap will be protected by the crtc locks, but the commit_tails can finish out of order, thus also causing the atomic states to be cleaned up out of order. This would mean the commit that started first but finished last has had its new state freed as the no-longer-needed old state by the other commit. To fix this let's just refcount the states. obj->state amounts to one reference, and the intel_atomic_state holds extra references to both its new and old global obj states. Fixes: 0ef1905ecf2e ("drm/i915: Introduce better global state handling") Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200527200245.13184-1-ville.syrjala@linux.intel.com Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> (cherry picked from commit f8c86ffa2800adc80adc679c84c45e0c6b027374) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-06-02pwm: tegra: Support dynamic clock frequency configurationSandipan Patra
Added support for dynamic clock freq configuration in PWM kernel driver. Earlier the PWM driver used to cache boot time clock rate by PWM clock parent during probe. Hence dynamically changing PWM frequency was not possible for all the possible ranges. With this change, dynamic calculation is enabled and it is able to set the requested period from sysfs knob provided the value is supported by clock source. Changes mainly have 2 parts: - Tegra186 and later chips [1] - Tegra210 and prior chips [2] For [1] - Changes implemented to set pwm period dynamically and also checks added to allow only if requested period(ns) is below or equals to higher range. For [2] - Only checks if the requested period(ns) is below or equals to higher range defined by max clock limit. The limitation in Tegra210 or prior chips are due to the reason of having only one PWM controller supporting multiple channels. But later chips have multiple PWM controller instances each having single channel support. Signed-off-by: Sandipan Patra <spatra@nvidia.com> Reviewed-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: jz4740: Add support for the JZ4725BPaul Cercueil
The PWM hardware in the JZ4725B works the same as in the JZ4740, but has only six channels available. Signed-off-by: Paul Cercueil <paul@crapouillou.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: jz4740: Make PWM start with the active partPaul Cercueil
The PWM in Ingenic SoCs starts in inactive state until the internal timer reaches the duty value, then becomes active until the timer reaches the period value. In theory, we should then use (period - duty) as the real duty value, as a high duty value would otherwise result in the PWM pin being inactive most of the time. This is the reason why the duty value was inverted in the driver until now, but it still had the problem that it would not start with the active part. To address this remaining issue, the common trick is to invert the duty, and invert the polarity when the PWM is enabled. Since the duty was already inverted, and we invert it again, we now program the hardware for the requested duty, and simply invert the polarity when the PWM is enabled. Signed-off-by: Paul Cercueil <paul@crapouillou.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: jz4740: Enhance precision in calculation of duty cyclePaul Cercueil
Calculating the hardware value for the duty from the hardware value of the period resulted in a precision loss versus calculating it from the clock rate directly. (Also remove a cast that doesn't really need to be here) Fixes: f6b8a5700057 ("pwm: Add Ingenic JZ4740 support") Cc: <stable@vger.kernel.org> Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Paul Cercueil <paul@crapouillou.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: jz4740: Drop dependency on MACH_INGENICPaul Cercueil
Depending on MACH_INGENIC prevent us from creating a generic kernel that works on more than one MIPS board. Instead, we just depend on MIPS being set. Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Paul Cercueil <paul@crapouillou.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02pwm: lpss: Fix get_state runtime-pm reference handlingHans de Goede
Before commit cfc4c189bc70 ("pwm: Read initial hardware state at request time"), a driver's get_state callback would get called once per PWM from pwmchip_add(). pwm-lpss' runtime-pm code was relying on this, getting a runtime-pm ref for PWMs which are enabled at probe time from within its get_state callback, before enabling runtime-pm. The change to calling get_state at request time causes a number of problems: 1. PWMs enabled at probe time may get runtime suspended before they are requested, causing e.g. a LCD backlight controlled by the PWM to turn off. 2. When the request happens when the PWM has been runtime suspended, the ctrl register will read all 1 / 0xffffffff, causing get_state to store bogus values in the pwm_state. 3. get_state was using an async pm_runtime_get() call, because it assumed that runtime-pm has not been enabled yet. If shortly after the request an apply call is made, then the pwm_lpss_is_updating() check may trigger because the resume triggered by the pm_runtime_get() call is not complete yet, so the ctrl register still reads all 1 / 0xffffffff. This commit fixes these issues by moving the initial pm_runtime_get() call for PWMs which are enabled at probe time to the pwm_lpss_probe() function; and by making get_state take a runtime-pm ref before reading the ctrl reg. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1828927 Fixes: cfc4c189bc70 ("pwm: Read initial hardware state at request time") Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02powerpc/pseries: Make vio and ibmebus initcalls pseries specificOliver O'Halloran
The vio and ibmebus buses are used for pseries specific paravirtualised devices and currently they're initialised by the generic initcall types. This is mostly fine, but it can result in some nuisance errors in dmesg when booting on PowerNV on some OSes, e.g. [ 2.984439] synth uevent: /devices/vio: failed to send uevent [ 2.984442] vio vio: uevent: failed to send synthetic uevent [ 17.968551] synth uevent: /devices/vio: failed to send uevent [ 17.968554] vio vio: uevent: failed to send synthetic uevent We don't see anything similar for the ibmebus because that depends on !CONFIG_LITTLE_ENDIAN. This patch squashes those by switching to using machine_*_initcall() so the bus type is only registered when the kernel is running on a pseries machine. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200421081539.7485-1-oohall@gmail.com
2020-06-02pwm: sun4i: Support direct clock output on Allwinner A64Peter Vasil
Allwinner A64 is capable of a direct clock output on PWM (see A64 User Manual chapter 3.10). Add support for this in the sun4i PWM driver. Signed-off-by: Peter Vasil <peter.vasil@gmail.com> Acked-by: Maxime Ripard <mripard@kernel.org> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-02vfio-ccw: Refactor IRQ handlersEric Farman
To simplify future expansion. Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20200505122745.53208-6-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2020-06-02vfio-ccw: Introduce a new schib regionFarhan Ali
The schib region can be used by userspace to get the subchannel- information block (SCHIB) for the passthrough subchannel. This can be useful to get information such as channel path information via the SCHIB.PMCW fields. Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20200505122745.53208-5-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2020-06-02vfio-ccw: Refactor the unregister of the async regionsEric Farman
This is mostly for the purposes of a later patch, since we'll need to do the same thing later. While we are at it, move the resulting function call to ahead of the unregistering of the IOMMU notifier, so that it's done in the reverse order of how it was created. Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20200505122745.53208-4-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2020-06-02vfio-ccw: Register a chp_event callback for vfio-ccwFarhan Ali
Register the chp_event callback to receive channel path related events for the subchannels managed by vfio-ccw. Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20200505122745.53208-3-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2020-06-02vfio-ccw: Introduce new helper functions to free/destroy regionsFarhan Ali
Consolidate some of the cleanup code for the regions, so that as more are added we reduce code duplication. Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20200505122745.53208-2-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2020-06-02vfio-ccw: document possible errorsCornelia Huck
Interacting with the I/O and the async regions can yield a number of errors, which had been undocumented so far. These are part of the api, so remedy that. Signed-off-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Message-Id: <20200407111605.1795-1-cohuck@redhat.com>
2020-06-02vfio-ccw: Enable transparent CCW IPL from DASDJared Rossi
Remove the explicit prefetch check when using vfio-ccw devices. This check does not trigger in practice as all Linux channel programs are intended to use prefetch. It is expected that all ORBs issued by Linux will request prefetch. Although non-prefetching ORBs are not rejected, they will prefetch nonetheless. A warning is issued up to once per 5 seconds when a forced prefetch occurs. A non-prefetch ORB does not necessarily result in an error, however frequent encounters with non-prefetch ORBs indicate that channel programs are being executed in a way that is inconsistent with what the guest is requesting. While there is currently no known case of an error caused by forced prefetch, it is possible in theory that forced prefetch could result in an error if applied to a channel program that is dependent on non-prefetch. Signed-off-by: Jared Rossi <jrossi@linux.ibm.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Message-Id: <20200506212440.31323-2-jrossi@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2020-06-02cxl: Remove dead Kconfig optionsAndrew Donnellan
The CXL_AFU_DRIVER_OPS and CXL_LIB Kconfig options were added to coordinate merging of new features. They no longer serve any purpose, so remove them. Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200602040341.10152-1-ajd@linux.ibm.com
2020-06-02powerpc: Add POWER10 architected modeAlistair Popple
PVR value of 0x0F000006 means we are arch v3.1 compliant (i.e. POWER10). This is used by phyp and kvm when booting as a pseries guest to detect the presence of new P10 features and to enable the appropriate hwcap and facility bits. Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Cédric Le Goater <clg@kaod.org> [mpe: Fall through to __init_FSCR rather than duplicating it, drop hack to set current->thread.fscr now that is handled elsewhere.] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200521014341.29095-8-alistair@popple.id.au
2020-06-02powerpc/dt_cpu_ftrs: Add MMA featureAlistair Popple
Matrix multiple assist (MMA) is a new feature added to ISAv3.1 and POWER10. Support on powernv can be selected via a firmware CPU device tree feature which enables it via a PCR bit. Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200521014341.29095-7-alistair@popple.id.au
2020-06-02powerpc/dt_cpu_ftrs: Enable Prefixed InstructionsAlistair Popple
Prefix instructions have their own FSCR bit which needs to be enabled via a CPU feature. The kernel will save the FSCR for problem state but it needs to be enabled initially. Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200521014341.29095-6-alistair@popple.id.au
2020-06-02powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selectedAlistair Popple
On powernv hardware support for ISAv3.1 is advertised via a cpu feature bit in the device tree. This patch enables the associated HWCAP bit if the device tree indicates ISAv3.1 is available. Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200521014341.29095-4-alistair@popple.id.au
2020-06-02powerpc: Add support for ISA v3.1Alistair Popple
Newer ISA versions are enabled by clearing all bits in the PCR associated with previous versions of the ISA. Enable ISA v3.1 support by updating the PCR mask to include ISA v3.0. This ensures all PCR bits corresponding to earlier architecture versions get cleared thereby enabling ISA v3.1 if supported by the hardware. Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200521014341.29095-3-alistair@popple.id.au
2020-06-02powerpc: Add new HWCAP bitsAlistair Popple
POWER10 introduces two new architectural features - ISAv3.1 and matrix multiply assist (MMA) instructions. Userspace detects the presence of these features via two HWCAP bits introduced in this patch. These bits have been agreed to by the compiler and binutils team. According to ISAv3.1 MMA is an optional feature and software that makes use of it should first check for availability via this HWCAP bit and use alternate code paths if unavailable. Signed-off-by: Alistair Popple <alistair@popple.id.au> Tested-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200521014341.29095-2-alistair@popple.id.au
2020-06-02powerpc/64s: Don't set FSCR bits in INIT_THREADMichael Ellerman
Since the previous commit that saves the value of FSCR configured at boot into init_task.thread.fscr, the static initialisation in INIT_THREAD now no longer has any effect. So remove it. For non DT CPU features, the end result is the same, because __init_FSCR() is called on all CPUs that have an FSCR (Power8, Power9), and it sets FSCR_TAR & FSCR_EBB. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200527145843.2761782-4-mpe@ellerman.id.au
2020-06-02powerpc/64s: Save FSCR to init_task.thread.fscr after feature initMichael Ellerman
At boot the FSCR is initialised via one of two paths. On most systems it's set to a hard coded value in __init_FSCR(). On newer skiboot systems we use the device tree CPU features binding, where firmware can tell Linux what bits to set in FSCR (and HFSCR). In both cases the value that's configured at boot is not propagated into the init_task.thread.fscr value prior to the initial fork of init (pid 1), which means the value is not used by any processes other than swapper (the idle task). For the __init_FSCR() case this is OK, because the value in init_task.thread.fscr is initialised to something sensible. However it does mean that the value set in __init_FSCR() is not used other than for swapper, which is odd and confusing. The bigger problem is for the device tree CPU features case it prevents firmware from setting (or clearing) FSCR bits for use by user space. This means all existing kernels can not have features enabled/disabled by firmware if those features require setting/clearing FSCR bits. We can handle both cases by saving the FSCR value into init_task.thread.fscr after we have initialised it at boot. This fixes the bug for device tree CPU features, and will allow us to simplify the initialisation for the __init_FSCR() case in a future patch. Fixes: 5a61ef74f269 ("powerpc/64s: Support new device tree binding for discovering CPU features") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200527145843.2761782-3-mpe@ellerman.id.au
2020-06-02powerpc/64s: Don't let DT CPU features set FSCR_DSCRMichael Ellerman
The device tree CPU features binding includes FSCR bit numbers which Linux is instructed to set by firmware. Whether that's a good idea or not, in the case of the DSCR the Linux implementation has a hard requirement that the FSCR_DSCR bit not be set by default. We use it to track when a process reads/writes to DSCR, so it must be clear to begin with. So if firmware tells us to set FSCR_DSCR we must ignore it. Currently this does not cause a bug in our DSCR handling because the value of FSCR that the device tree CPU features code establishes is only used by swapper. All other tasks use the value hard coded in init_task.thread.fscr. However we'd like to fix that in a future commit, at which point this will become necessary. Fixes: 5a61ef74f269 ("powerpc/64s: Support new device tree binding for discovering CPU features") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200527145843.2761782-2-mpe@ellerman.id.au
2020-06-02powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()Michael Ellerman
__init_FSCR() was added originally in commit 2468dcf641e4 ("powerpc: Add support for context switching the TAR register") (Feb 2013), and only set FSCR_TAR. At that point FSCR (Facility Status and Control Register) was not context switched, so the setting was permanent after boot. Later we added initialisation of FSCR_DSCR to __init_FSCR(), in commit 54c9b2253d34 ("powerpc: Set DSCR bit in FSCR setup") (Mar 2013), again that was permanent after boot. Then commit 2517617e0de6 ("powerpc: Fix context switch DSCR on POWER8") (Aug 2013) added a limited context switch of FSCR, just the FSCR_DSCR bit was context switched based on thread.dscr_inherit. That commit said "This clears the H/FSCR DSCR bit initially", but it didn't, it left the initialisation of FSCR_DSCR in __init_FSCR(). However the initial context switch from init_task to pid 1 would clear FSCR_DSCR because thread.dscr_inherit was 0. That commit also introduced the requirement that FSCR_DSCR be clear for user processes, so that we can take the facility unavailable interrupt in order to manage dscr_inherit. Then in commit 152d523e6307 ("powerpc: Create context switch helpers save_sprs() and restore_sprs()") (Dec 2015) FSCR was added to thread_struct. However it still wasn't fully context switched, we just took the existing value and set FSCR_DSCR if the new thread had dscr_inherit set. FSCR was still initialised at boot to FSCR_DSCR | FSCR_TAR, but that value was not propagated into the thread_struct, so the initial context switch set FSCR_DSCR back to 0. Finally commit b57bd2de8c6c ("powerpc: Improve FSCR init and context switching") (Jun 2016) added a full context switch of the FSCR, and added an initialisation of init_task.thread.fscr to FSCR_TAR | FSCR_EBB, but omitted FSCR_DSCR. The end result is that swapper runs with FSCR_DSCR set because of the initialisation in __init_FSCR(), but no other processes do, they use the value from init_task.thread.fscr. Having FSCR_DSCR set for swapper allows it to access SPR 3 from userspace, but swapper never runs userspace, so it has no useful effect. It's also confusing to have the value initialised in two places to two different values. So remove FSCR_DSCR from __init_FSCR(), this at least gets us to the point where there's a single value of FSCR, even if it's still set in two places. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Alistair Popple <alistair@popple.id.au> Link: https://lore.kernel.org/r/20200527145843.2761782-1-mpe@ellerman.id.au
2020-06-02powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUGChristophe Leroy
'thread' doesn't exist in kuap_check() macro. Use 'current' instead. Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection") Cc: stable@vger.kernel.org Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b459e1600b969047a74e34251a84a3d6fdf1f312.1590858925.git.christophe.leroy@csgroup.eu
2020-06-02powerpc/module_64: Use special stub for _mcount() with -mprofile-kernelNaveen N. Rao
Since commit c55d7b5e64265f ("powerpc: Remove STRICT_KERNEL_RWX incompatibility with RELOCATABLE"), powerpc kernels with -mprofile-kernel can crash in certain scenarios with a trace like below: BUG: Unable to handle kernel instruction fetch (NULL pointer?) Faulting instruction address: 0x00000000 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 DEBUG_PAGEALLOC NUMA PowerNV <snip> NIP [0000000000000000] 0x0 LR [c0080000102c0048] ext4_iomap_end+0x8/0x30 [ext4] Call Trace: iomap_apply+0x20c/0x920 (unreliable) iomap_bmap+0xfc/0x160 ext4_bmap+0xa4/0x180 [ext4] bmap+0x4c/0x80 jbd2_journal_init_inode+0x44/0x1a0 [jbd2] ext4_load_journal+0x440/0x860 [ext4] ext4_fill_super+0x342c/0x3ab0 [ext4] mount_bdev+0x25c/0x290 ext4_mount+0x28/0x50 [ext4] legacy_get_tree+0x4c/0xb0 vfs_get_tree+0x4c/0x130 do_mount+0xa18/0xc50 sys_mount+0x158/0x180 system_call+0x5c/0x68 The NIP points to NULL, or a random location (data even), while the LR always points to the LEP of a function (with an offset of 8), indicating that something went wrong with ftrace. However, ftrace is not necessarily active when such crashes occur. The kernel OOPS sometimes follows a warning from ftrace indicating that some module functions could not be patched with a nop. Other times, if a module is loaded early during boot, instruction patching can fail due to a separate bug, but the error is not reported due to missing error reporting. In all the above cases when instruction patching fails, ftrace will be disabled but certain kernel module functions will be left with default calls to _mcount(). This is not a problem with ELFv1. However, with -mprofile-kernel, the default stub is problematic since it depends on a valid module TOC in r2. If the kernel (or a different module) calls into a function that does not use the TOC, the function won't have a prologue to setup the module TOC. When that function calls into _mcount(), we will end up in the relocation stub that will use the previous TOC, and end up trying to jump into a random location. From the above trace: iomap_apply+0x20c/0x920 [kernel TOC] | V ext4_iomap_end+0x8/0x30 [no GEP == kernel TOC] | V _mcount() stub [uses kernel TOC -> random entry] To address this, let's change over to using the special stub that is used for ftrace_[regs_]caller() for _mcount(). This ensures that we are not dependent on a valid module TOC in r2 for default _mcount() handling. Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Tested-by: Qian Cai <cai@lca.pw> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/8affd4298d22099bbd82544fab8185700a6222b1.1587488954.git.naveen.n.rao@linux.vnet.ibm.com
generated by cgit (git 2.34.1) at 2025-09-19 02:11:34 +0000