From 8badbc54394359d64f89ac87bb39fb0a5dbc3027 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 13 May 2020 14:35:03 -0700 Subject: [PATCH] pstore/ram: Introduce max_reason and convert dump_oops Now that pstore_register() can correctly pass max_reason to the kmesg dump facility, introduce a new "max_reason" module parameter and "max-reason" Device Tree field. The "dump_oops" module parameter and "dump-oops" Device Tree field are now considered deprecated, but are now automatically converted to their corresponding max_reason values when present, though the new max_reason setting has precedence. For struct ramoops_platform_data, the "dump_oops" member is entirely replaced by a new "max_reason" member, with the only existing user updated in place. Additionally remove the "reason" filter logic from ramoops_pstore_write(), as that is not specifically needed anymore, though technically this is a change in behavior for any ramoops users also setting the printk.always_kmsg_dump boot param, which will cause ramoops to behave as if max_reason was set to KMSG_DUMP_MAX. Co-developed-by: Pavel Tatashin Signed-off-by: Pavel Tatashin Link: https://lore.kernel.org/lkml/20200515184434.8470-6-keescook@chromium.org/ Signed-off-by: Kees Cook --- Documentation/admin-guide/ramoops.rst | 14 ++++-- drivers/platform/chrome/chromeos_pstore.c | 2 +- fs/pstore/ram.c | 58 +++++++++++++++-------- include/linux/pstore_ram.h | 2 +- 4 files changed, 51 insertions(+), 25 deletions(-) diff --git a/Documentation/admin-guide/ramoops.rst b/Documentation/admin-guide/ramoops.rst index 4efd7ce77565..bdd2e0b93393 100755 --- a/Documentation/admin-guide/ramoops.rst +++ b/Documentation/admin-guide/ramoops.rst @@ -32,11 +32,17 @@ memory to be mapped strongly ordered, and atomic operations on strongly ordered memory are implementation defined, and won't work on many ARMs such as omaps. The memory area is divided into ``record_size`` chunks (also rounded down to -power of two) and each oops/panic writes a ``record_size`` chunk of +power of two) and each kmesg dump writes a ``record_size`` chunk of information. -Dumping both oopses and panics can be done by setting 1 in the ``dump_oops`` -variable while setting 0 in that variable dumps only the panics. +Limiting which kinds of kmsg dumps are stored can be controlled via +the ``max_reason`` value, as defined in include/linux/kmsg_dump.h's +``enum kmsg_dump_reason``. For example, to store both Oopses and Panics, +``max_reason`` should be set to 2 (KMSG_DUMP_OOPS), to store only Panics +``max_reason`` should be set to 1 (KMSG_DUMP_PANIC). Setting this to 0 +(KMSG_DUMP_UNDEF), means the reason filtering will be controlled by the +``printk.always_kmsg_dump`` boot param: if unset, it'll be KMSG_DUMP_OOPS, +otherwise KMSG_DUMP_MAX. The module uses a counter to record multiple dumps but the counter gets reset on restart (i.e. new dumps after the restart will overwrite old ones). @@ -90,7 +96,7 @@ Setting the ramoops parameters can be done in several different manners: .mem_address = <...>, .mem_type = <...>, .record_size = <...>, - .dump_oops = <...>, + .max_reason = <...>, .ecc = <...>, }; diff --git a/drivers/platform/chrome/chromeos_pstore.c b/drivers/platform/chrome/chromeos_pstore.c index b0693fdec8c6..a3dbf8f9e2f1 100755 --- a/drivers/platform/chrome/chromeos_pstore.c +++ b/drivers/platform/chrome/chromeos_pstore.c @@ -62,7 +62,7 @@ static struct ramoops_platform_data chromeos_ramoops_data = { .record_size = 0x40000, .console_size = 0x20000, .ftrace_size = 0x20000, - .dump_oops = 1, + .max_reason = KMSG_DUMP_OOPS, }; static struct platform_device chromeos_ramoops = { diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index dfb718e7fa13..fc40e20ba761 100755 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -71,10 +71,10 @@ module_param(mem_type, uint, 0400); MODULE_PARM_DESC(mem_type, "set to 1 to try to use unbuffered memory (default 0)"); -static int dump_oops = 1; -module_param(dump_oops, int, 0400); -MODULE_PARM_DESC(dump_oops, - "set to 1 to dump oopses, 0 to only dump panics (default 1)"); +static int ramoops_max_reason = -1; +module_param_named(max_reason, ramoops_max_reason, int, 0400); +MODULE_PARM_DESC(max_reason, + "maximum reason for kmsg dump (default 2: Oops and Panic) "); static int ramoops_ecc; module_param_named(ecc, ramoops_ecc, int, 0400); @@ -83,6 +83,11 @@ MODULE_PARM_DESC(ramoops_ecc, "ECC buffer size in bytes (1 is a special value, means 16 " "bytes ECC)"); +static int ramoops_dump_oops = -1; +module_param_named(dump_oops, ramoops_dump_oops, int, 0400); +MODULE_PARM_DESC(dump_oops, + "(deprecated: use max_reason instead) set to 1 to dump oopses & panics, 0 to only dump panics"); + struct ramoops_context { struct persistent_ram_zone **dprzs; /* Oops dump zones */ struct persistent_ram_zone *cprz; /* Console zone */ @@ -95,7 +100,6 @@ struct ramoops_context { size_t console_size; size_t ftrace_size; size_t pmsg_size; - int dump_oops; u32 flags; struct persistent_ram_ecc_info ecc_info; unsigned int max_dump_cnt; @@ -406,16 +410,14 @@ static int notrace ramoops_pstore_write(struct pstore_record *record) return -EINVAL; /* - * Out of the various dmesg dump types, ramoops is currently designed - * to only store crash logs, rather than storing general kernel logs. + * We could filter on record->reason here if we wanted to (which + * would duplicate what happened before the "max_reason" setting + * was added), but that would defeat the purpose of a system + * changing printk.always_kmsg_dump, so instead log everything that + * the kmsg dumper sends us, since it should be doing the filtering + * based on the combination of printk.always_kmsg_dump and our + * requested "max_reason". */ - if (record->reason != KMSG_DUMP_OOPS && - record->reason != KMSG_DUMP_PANIC) - return -EINVAL; - - /* Skip Oopes when configured to do so. */ - if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops) - return -EINVAL; /* * Explicitly only take the first part of any new crash. @@ -704,7 +706,14 @@ static int ramoops_parse_dt(struct platform_device *pdev, pdata->mem_size = resource_size(res); pdata->mem_address = res->start; pdata->mem_type = of_property_read_bool(of_node, "unbuffered"); - pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops"); + /* + * Setting "no-dump-oops" is deprecated and will be ignored if + * "max_reason" is also specified. + */ + if (of_property_read_bool(of_node, "no-dump-oops")) + pdata->max_reason = KMSG_DUMP_PANIC; + else + pdata->max_reason = KMSG_DUMP_OOPS; #define parse_u32(name, field, default_value) { \ ret = ramoops_parse_dt_u32(pdev, name, default_value, \ @@ -720,6 +729,7 @@ static int ramoops_parse_dt(struct platform_device *pdev, parse_u32("pmsg-size", pdata->pmsg_size, 0); parse_u32("ecc-size", pdata->ecc_info.ecc_size, 0); parse_u32("flags", pdata->flags, 0); + parse_u32("max-reason", pdata->max_reason, pdata->max_reason); #undef parse_u32 @@ -789,7 +799,6 @@ static int ramoops_probe(struct platform_device *pdev) cxt->console_size = pdata->console_size; cxt->ftrace_size = pdata->ftrace_size; cxt->pmsg_size = pdata->pmsg_size; - cxt->dump_oops = pdata->dump_oops; cxt->flags = pdata->flags; cxt->ecc_info = pdata->ecc_info; @@ -832,8 +841,10 @@ static int ramoops_probe(struct platform_device *pdev) * the single region size is how to check. */ cxt->pstore.flags = 0; - if (cxt->max_dump_cnt) + if (cxt->max_dump_cnt) { cxt->pstore.flags |= PSTORE_FLAGS_DMESG; + cxt->pstore.max_reason = pdata->max_reason; + } if (cxt->console_size) cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE; if (cxt->max_ftrace_cnt) @@ -869,7 +880,7 @@ static int ramoops_probe(struct platform_device *pdev) mem_size = pdata->mem_size; mem_address = pdata->mem_address; record_size = pdata->record_size; - dump_oops = pdata->dump_oops; + ramoops_max_reason = pdata->max_reason; ramoops_console_size = pdata->console_size; ramoops_pmsg_size = pdata->pmsg_size; ramoops_ftrace_size = pdata->ftrace_size; @@ -944,7 +955,16 @@ static void ramoops_register_dummy(void) dummy_data->console_size = ramoops_console_size; dummy_data->ftrace_size = ramoops_ftrace_size; dummy_data->pmsg_size = ramoops_pmsg_size; - dummy_data->dump_oops = dump_oops; + /* If "max_reason" is set, its value has priority over "dump_oops". */ + if (ramoops_max_reason >= 0) + dummy_data->max_reason = ramoops_max_reason; + /* Otherwise, if "dump_oops" is set, parse it into "max_reason". */ + else if (ramoops_dump_oops != -1) + dummy_data->max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS + : KMSG_DUMP_PANIC; + /* And if neither are explicitly set, use the default. */ + else + dummy_data->max_reason = KMSG_DUMP_OOPS; dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU; /* diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h index 10fe2e28701f..ec270529a888 100755 --- a/include/linux/pstore_ram.h +++ b/include/linux/pstore_ram.h @@ -98,7 +98,7 @@ struct ramoops_platform_data { unsigned long console_size; unsigned long ftrace_size; unsigned long pmsg_size; - int dump_oops; + int max_reason; u32 flags; struct persistent_ram_ecc_info ecc_info; };