On 19/10/2021 12:42, Will Deacon wrote:
On Tue, Oct 19, 2021 at 12:36:48PM +0100, Suzuki K Poulose wrote:
On 19/10/2021 12:02, Will Deacon wrote:
On Thu, Oct 14, 2021 at 11:31:13PM +0100, Suzuki K Poulose wrote:
@@ -558,6 +570,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE, CAP_MIDR_RANGE_LIST(trbe_overwrite_fill_mode_cpus), }, +#endif +#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILRE
You still haven't fixed this typo...
Sorry about that. I thought it was about selecting the Kconfig entries, which was fixed. I will fix this.
Sorry, I thought it was such a howler that it would've jumped out ;) That's what made me think we should make sure the series compiles without the coresight changes, so we can catch these problems early.
Seriously, I get compile warnings from this -- are you not seeing them?
No, I don't get any warnings. Is there something that I am missing ?
Interesting. I see the warning below in my bisection testing, since the typo means that the midr lookup table isn't used. Maybe you're only compiling the end result?
No, I was compiling this at the commit. Also, please note that the TSB flush failure config is enabled with the patch, unlike the TRBE errata ones.
My GCC is :
gcc version 9.3.1 20200408 (Red Hat 9.3.1-2) (GCC)
$ grep TSB arch/arm64/Kconfig arch/arm64/kernel/cpu_errata.c .config arch/arm64/Kconfig:config ARM64_WORKAROUND_TSB_FLUSH_FAILURE arch/arm64/Kconfig: bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace" arch/arm64/Kconfig: select ARM64_WORKAROUND_TSB_FLUSH_FAILURE arch/arm64/Kconfig: Affected cores may fail to flush the trace data on a TSB instruction, when arch/arm64/Kconfig: Workaround is to issue two TSB consecutively on affected cores. arch/arm64/Kconfig: bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace" arch/arm64/Kconfig: select ARM64_WORKAROUND_TSB_FLUSH_FAILURE arch/arm64/Kconfig: Affected cores may fail to flush the trace data on a TSB instruction, when arch/arm64/Kconfig: Workaround is to issue two TSB consecutively on affected cores. arch/arm64/kernel/cpu_errata.c:#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE arch/arm64/kernel/cpu_errata.c:#endif /* CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE */ arch/arm64/kernel/cpu_errata.c:#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILRE arch/arm64/kernel/cpu_errata.c: .capability = ARM64_WORKAROUND_TSB_FLUSH_FAILURE, .config:CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE=y suzuki@ewhatever:coresight$ git log --oneline -1 89e0c94bd734 (HEAD) arm64: errata: Add workaround for TSB flush failures
Will
--->8
+arch/arm64/kernel/cpu_errata.c:356:32: warning: ‘tsb_flush_fail_cpus’ defined but not used [-Wunused-const-variable=]
- 356 | static const struct midr_range tsb_flush_fail_cpus[] = {
| ^~~~~~~~~~~~~~~~~~~
That looks a valid warning. Hmm, strange.
It does complain for an unused function though.
$ make -j16 CALL scripts/atomic/check-atomics.sh CALL scripts/checksyscalls.sh CHK include/generated/compile.h CC arch/arm64/kernel/cpu_errata.o arch/arm64/kernel/cpu_errata.c:90:13: error: ‘here_is_an_unused_function’ defined but not used [-Werror=unused-function] static void here_is_an_unused_function(void) ^~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors make[2]: *** [scripts/Makefile.build:277: arch/arm64/kernel/cpu_errata.o] Error 1 make[1]: *** [scripts/Makefile.build:540: arch/arm64/kernel] Error 2 make: *** [Makefile:1874: arch/arm64] Error 2 make: *** Waiting for unfinished jobs....
--8>--
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index aaa66c9eee24..57c83e84b274 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -87,12 +87,20 @@ has_mismatched_cache_type(const struct arm64_cpu_capabilities *entry, return (ctr_real != sys) && (ctr_raw != sys); }
+static void here_is_an_unused_function(void) +{ + pr_crit("I am unused\n"); +} + static void cpu_enable_trap_ctr_access(const struct arm64_cpu_capabilities *cap) { u64 mask = arm64_ftr_reg_ctrel0.strict_mask; bool enable_uct_trap = false;
+#ifdef CONFIG_UNUSED_FUNCTION + here_is_an_unused_function(); +#endif
Cheers Suzuki