Messages in this thread | | | Date | Mon, 13 Jan 2020 11:14:29 +0530 | From | Sai Prakash Ranjan <> | Subject | Re: [PATCH 2/2] drivers: edac: Add EDAC support for Kryo CPU caches |
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Hi Boris,
Thanks for the review comments.
On 2019-12-30 17:20, Borislav Petkov wrote: > On Thu, Dec 05, 2019 at 09:53:18AM +0000, Sai Prakash Ranjan wrote: >> Kryo{3,4}XX CPU cores implement RAS extensions to support >> Error Correcting Code(ECC). Currently all Kryo{3,4}XX CPU >> cores (gold/silver a.k.a big/LITTLE) support ECC via RAS. > > via RAS what? ARM64_RAS_EXTN? > > In any case, this needs James to look at and especially if there's some > ARM-generic functionality in there which should be shared, of course. >
Yes it is ARM64_RAS_EXTN and I have been hoping if James can provide the feedback, it has been some time now since I posted this out.
>> This adds an interrupt based driver for those CPUs and > > s/This adds/Add/ >
Will correct.
>> + >> +config EDAC_QCOM_KRYO_POLL >> + depends on EDAC_QCOM_KRYO >> + bool "Poll on Kryo ECC registers" >> + help >> + This option chooses whether or not you want to poll on the Kryo >> ECC >> + registers. When this is enabled, the polling rate can be set as a >> + module parameter. By default, it will call the polling function >> every >> + second. > > Why is this a separate option and why should people use that? > > Can the polling/irq be switched automatically? >
No it cannot be switched automatically. It is used in case some SoCs do not support an irq based mechanism for EDAC. But I am contradicting myself because I am telling that atleast one interrupt should be specified in bindings, so it is best if I drop this polling option for now.
>> + >> config EDAC_ASPEED >> tristate "Aspeed AST 2500 SoC" >> depends on MACH_ASPEED_G5 >> diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile >> index d77200c9680b..29edcfa6ec0e 100644 >> --- a/drivers/edac/Makefile >> +++ b/drivers/edac/Makefile >> @@ -85,5 +85,6 @@ obj-$(CONFIG_EDAC_SYNOPSYS) += synopsys_edac.o >> obj-$(CONFIG_EDAC_XGENE) += xgene_edac.o >> obj-$(CONFIG_EDAC_TI) += ti_edac.o >> obj-$(CONFIG_EDAC_QCOM) += qcom_edac.o >> +obj-$(CONFIG_EDAC_QCOM_KRYO) += qcom_kryo_edac.o > > What is the difference between this new driver and the qcom_edac one? > Can > functionality be shared? > > Should this new one be called simply kryo_edac instead? >
qcom_edac driver is for QCOM system cache(last level cache), it should be renamed to qcom_llcc_edac.c. This new driver is for QCOM Kryo CPU core caches(L1,L2,L3).
Functionality cannot be shared as these two are different IP blocks and best kept separate.
>> + >> +#define DRV_NAME "qcom_kryo_edac" >> + >> +/* >> + * ARM Cortex-A55, Cortex-A75, Cortex-A76 TRM Chapter B3.3 > > Chapter? Where? URL? >
I chose this because these TRMs are openly available and if you search for these above terms like "Cortex-A76 TRM Chapter B3.3" in google, then the first search result will be the TRM pdf, otherwise I would have to specify the long URL for the pdf and we do not know how long that URL link will be active.
>> + >> +static const struct error_type err_type[] = { >> + { edac_device_handle_ce, "Kryo L1 Corrected Error" }, >> + { edac_device_handle_ue, "Kryo L1 Uncorrected Error" }, >> + { edac_device_handle_ue, "Kryo L1 Deferred Error" }, >> + { edac_device_handle_ce, "Kryo L2 Corrected Error" }, >> + { edac_device_handle_ue, "Kryo L2 Uncorrected Error" }, >> + { edac_device_handle_ue, "Kryo L2 Deferred Error" }, >> + { edac_device_handle_ce, "L3 Corrected Error" }, >> + { edac_device_handle_ue, "L3 Uncorrected Error" }, >> + { edac_device_handle_ue, "L3 Deferred Error" }, >> +}; >> + > > All that is not really needed - you can put the whole error type > detection and dumping in kryo_check_err_type() in nicely readable > switch-case statement. No need for the function pointers and special > structs. >
How is this not easily readable? If I put this in kryo_check_err_type, then there will be nested switch which I think is not so great in terms of readability since it will not fit in one screen and is just more lines of code.
>> +static struct edac_device_ctl_info __percpu *edac_dev; >> +static struct edac_device_ctl_info *drv_edev_ctl; >> + >> +static const char *get_error_msg(u64 errxstatus) >> +{ >> + const struct error_record *rec; >> + u32 errxstatus_serr; >> + >> + errxstatus_serr = FIELD_GET(KRYO_ERRXSTATUS_SERR, errxstatus); >> + >> + for (rec = serror_record; rec->error_code; rec++) { >> + if (errxstatus_serr == rec->error_code) >> + return rec->error_msg; >> + } >> + >> + return NULL; >> +} >> + >> +static void dump_syndrome_reg(int error_type, int level, >> + u64 errxstatus, u64 errxmisc, >> + struct edac_device_ctl_info *edev_ctl) >> +{ >> + char msg[KRYO_EDAC_MSG_MAX]; >> + const char *error_msg; >> + int cpu; >> + >> + cpu = raw_smp_processor_id(); > > Why raw_? >
Because we will be calling smp_processor_id in preemptible context and if we enable CONFIG_DEBUG_PREEMPT, we would get a nice backtrace.
[ 3.747468] BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1 [ 3.755527] caller is qcom_kryo_edac_probe+0x138/0x2b8 [ 3.760819] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G S 5.4.0-rc7-next-20191113-00009-g8666855d6a5b-dirty #107 [ 3.772323] Hardware name: Qualcomm Technologies, Inc. SM8150 MTP (DT) [ 3.779030] Call trace: [ 3.781556] dump_backtrace+0x0/0x158 [ 3.785331] show_stack+0x14/0x20 [ 3.788741] dump_stack+0xb0/0xf4 [ 3.792164] debug_smp_processor_id+0xd8/0xe0 [ 3.796639] qcom_kryo_edac_probe+0x138/0x2b8 [ 3.801116] platform_drv_probe+0x50/0xa8 [ 3.805236] really_probe+0x108/0x360 [ 3.808999] driver_probe_device+0x58/0x100 [ 3.813304] device_driver_attach+0x6c/0x78 [ 3.817606] __driver_attach+0xb0/0xf0 [ 3.821459] bus_for_each_dev+0x68/0xc8 [ 3.825407] driver_attach+0x20/0x28 [ 3.829083] bus_add_driver+0x160/0x1f0 [ 3.833030] driver_register+0x60/0x110 [ 3.836976] __platform_driver_register+0x40/0x48 [ 3.841813] qcom_kryo_edac_driver_init+0x18/0x20 [ 3.846645] do_one_initcall+0x58/0x1a0 [ 3.850596] kernel_init_freeable+0x19c/0x240 [ 3.855075] kernel_init+0x10/0x108 [ 3.858665] ret_from_fork+0x10/0x1c
>> +static int kryo_l1_l2_setup_irq(struct platform_device *pdev, >> + struct edac_device_ctl_info *edev_ctl) >> +{ >> + int cpu, errirq, faultirq, ret; >> + >> + edac_dev = devm_alloc_percpu(&pdev->dev, *edac_dev); >> + if (!edac_dev) >> + return -ENOMEM; >> + >> + for_each_possible_cpu(cpu) { >> + preempt_disable(); >> + per_cpu(edac_dev, cpu) = edev_ctl; >> + preempt_enable(); >> + } > > That sillyness doesn't belong here, if at all. >
Sorry but I do not understand the sillyness here. Could you please explain?
> ... > >> +static void kryo_poll_cache_error(struct edac_device_ctl_info >> *edev_ctl) >> +{ >> + if (!edev_ctl) >> + edev_ctl = drv_edev_ctl; > > That's silly. >
Actually its not silly. In case, polling is enabled and on PM exit edev_ctl could be NULL.
>> + >> + on_each_cpu(kryo_check_l1_l2_ecc, edev_ctl, 1); >> + kryo_check_l3_scu_ecc(edev_ctl); >> +} > > ... > >> +static int qcom_kryo_edac_probe(struct platform_device *pdev) >> +{ >> + struct edac_device_ctl_info *edev_ctl; >> + struct device *dev = &pdev->dev; >> + int ret; >> + >> + qcom_kryo_edac_setup(); > > This function needs to have a return value saying whether it did setup > the hw properly or not and the probe function needs to return here if > not.
Ok will add a return check.
Thanks, Sai
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