[PATCH 4/5] ramoops: support multiple pmsg instances

From: Hiraku Toyooka
Date: Wed Nov 04 2015 - 21:37:08 EST

This patch enables ramoops to deal with multiple pmsg instances.
We can configure the size of each buffers by its module parameter
as follows.

pmsg_size=0x1000,0x2000,...

Then, the ramoops allocates multiple buffers and tells the number
of buffers to pstore to create multiple /dev/pmsg[ID].

Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Anton Vorontsov <anton@xxxxxxxxxx>
Cc: Colin Cross <ccross@xxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
Cc: Seiji Aguchi <seiji.aguchi.tr@xxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
Documentation/ramoops.txt | 22 +++++++
fs/pstore/ram.c | 146 ++++++++++++++++++++++++++++++++++++++------
include/linux/pstore_ram.h | 8 ++
3 files changed, 154 insertions(+), 22 deletions(-)

diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 5d86756..cff6ac7 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -126,3 +126,25 @@ file. Here is an example of usage:
0 ffffffff811d9c54 ffffffff8101a7a0 __const_udelay <- native_machine_emergency_restart+0x110/0x1e0
0 ffffffff811d9c34 ffffffff811d9c80 __delay <- __const_udelay+0x30/0x40
0 ffffffff811d9d14 ffffffff811d9c3f delay_tsc <- __delay+0xf/0x20
+
+6. Pmsg support
+
+Ramoops supports pmsg - logging userspace mesages in persistent store. By
+default, one pmsg area becomes available in ramoops. You can write data into
+/dev/pmsg0, e.g.:
+
+ # echo foo > /dev/pmsg0
+
+After reboot, the stored data can be read from pmsg-ramoops-0 on the pstore
+filesystem.
+
+You can specify size of the pmsg area by additional kernel command line, e.g.:
+
+ "ramoops.pmsg_size=0x1000"
+
+You can also use multiple pmsg areas, e.g.:
+
+ "ramoops.pmsg_size=0x1000,0x2000,..."
+
+Then, pmsg0, pmsg1, ... will appear on /dev. This is useful to control
+individual content aging or priority.
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 89cc90e..1d1378c 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -51,8 +51,8 @@ static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
MODULE_PARM_DESC(ftrace_size, "size of ftrace log");

-static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
-module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
+static char *ramoops_pmsg_size_str;
+module_param_named(pmsg_size, ramoops_pmsg_size_str, charp, 0400);
MODULE_PARM_DESC(pmsg_size, "size of user space message log");

static ulong mem_address;
@@ -86,14 +86,14 @@ struct ramoops_context {
struct persistent_ram_zone **dprzs;
struct persistent_ram_zone *cprz;
struct persistent_ram_zone *fprz;
- struct persistent_ram_zone *mprz;
+ struct persistent_ram_zone **mprzs;
phys_addr_t phys_addr;
unsigned long size;
unsigned int memtype;
size_t record_size;
size_t console_size;
size_t ftrace_size;
- size_t pmsg_size;
+ size_t *pmsg_size;
int dump_oops;
struct persistent_ram_ecc_info ecc_info;
unsigned int max_dump_cnt;
@@ -103,6 +103,7 @@ struct ramoops_context {
unsigned int console_read_cnt;
unsigned int ftrace_read_cnt;
unsigned int pmsg_read_cnt;
+ unsigned int num_pmsg;
struct pstore_info pstore;
};

@@ -220,9 +221,10 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
if (!prz_ok(prz))
prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
1, id, type, PSTORE_TYPE_FTRACE, 0);
- if (!prz_ok(prz))
- prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
- 1, id, type, PSTORE_TYPE_PMSG, 0);
+ while (cxt->pmsg_read_cnt < cxt->num_pmsg && !prz)
+ prz = ramoops_get_next_prz(cxt->mprzs, &cxt->pmsg_read_cnt,
+ cxt->num_pmsg, id, type,
+ PSTORE_TYPE_PMSG, 0);
if (!prz_ok(prz))
return 0;

@@ -286,9 +288,11 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
persistent_ram_write(cxt->fprz, buf, size);
return 0;
} else if (type == PSTORE_TYPE_PMSG) {
- if (!cxt->mprz)
+ if (part >= cxt->num_pmsg)
+ return -EINVAL;
+ if (!cxt->mprzs || !cxt->mprzs[part])
return -ENOMEM;
- persistent_ram_write(cxt->mprz, buf, size);
+ persistent_ram_write(cxt->mprzs[part], buf, size);
return 0;
}

@@ -348,7 +352,9 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
prz = cxt->fprz;
break;
case PSTORE_TYPE_PMSG:
- prz = cxt->mprz;
+ if (id >= cxt->num_pmsg)
+ return -EINVAL;
+ prz = cxt->mprzs[id];
break;
default:
return -EINVAL;
@@ -426,6 +432,39 @@ fail_prz:
return err;
}

+static int ramoops_init_mprzs(struct device *dev, struct ramoops_context *cxt,
+ phys_addr_t *paddr, unsigned long total)
+{
+ int err = -ENOMEM;
+ int i;
+
+ if (!total)
+ return 0;
+
+ if (*paddr + total - cxt->phys_addr > cxt->size) {
+ dev_err(dev, "no room for pmsg\n");
+ return -ENOMEM;
+ }
+
+ cxt->mprzs = kcalloc(cxt->num_pmsg, sizeof(*cxt->mprzs), GFP_KERNEL);
+ if (!cxt->mprzs) {
+ dev_err(dev, "failed to initialize a mprz array for pmsg\n");
+ goto fail_prz;
+ }
+
+ for (i = 0; i < cxt->num_pmsg; i++) {
+ err = __ramoops_init_prz(dev, cxt, &cxt->mprzs[i], paddr,
+ cxt->pmsg_size[i], 0, true);
+ if (err)
+ goto fail_prz;
+ }
+
+ return 0;
+fail_prz:
+ ramoops_free_przs(cxt->mprzs);
+ return err;
+}
+
static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
struct persistent_ram_zone **prz,
phys_addr_t *paddr, size_t sz, u32 sig)
@@ -472,6 +511,8 @@ static int ramoops_probe(struct platform_device *pdev)
size_t dump_mem_sz;
phys_addr_t paddr;
int err = -EINVAL;
+ unsigned long pmsg_size_total = 0;
+ unsigned int num_pmsg = 0;

/* Only a single ramoops area allowed at a time, so fail extra
* probes.
@@ -492,8 +533,18 @@ static int ramoops_probe(struct platform_device *pdev)
pdata->console_size = rounddown_pow_of_two(pdata->console_size);
if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
- if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
- pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
+ if (pdata->pmsg_size) {
+ for (;; num_pmsg++) {
+ unsigned long size = pdata->pmsg_size[num_pmsg];
+
+ if (!size)
+ break;
+ if (!is_power_of_2(size))
+ pdata->pmsg_size[num_pmsg]
+ = rounddown_pow_of_two(size);
+ pmsg_size_total += size;
+ }
+ }

cxt->size = pdata->mem_size;
cxt->phys_addr = pdata->mem_address;
@@ -501,17 +552,26 @@ static int ramoops_probe(struct platform_device *pdev)
cxt->record_size = pdata->record_size;
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->ecc_info = pdata->ecc_info;
+ cxt->num_pmsg = num_pmsg;
+ if (num_pmsg) {
+ cxt->pmsg_size = kcalloc(num_pmsg, sizeof(size_t), GFP_KERNEL);
+ if (!cxt->pmsg_size) {
+ err = -ENOMEM;
+ goto fail_out;
+ }
+ memcpy(cxt->pmsg_size, pdata->pmsg_size,
+ sizeof(size_t) * num_pmsg);
+ }

paddr = cxt->phys_addr;

dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
- - cxt->pmsg_size;
+ - pmsg_size_total;
err = ramoops_init_dprzs(dev, cxt, &paddr, dump_mem_sz);
if (err)
- goto fail_out;
+ goto fail_init_dprzs;

err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
cxt->console_size, 0);
@@ -523,11 +583,12 @@ static int ramoops_probe(struct platform_device *pdev)
if (err)
goto fail_init_fprz;

- err = ramoops_init_prz(dev, cxt, &cxt->mprz, &paddr, cxt->pmsg_size, 0);
+ err = ramoops_init_mprzs(dev, cxt, &paddr, pmsg_size_total);
if (err)
- goto fail_init_mprz;
+ goto fail_init_mprzs;

cxt->pstore.data = cxt;
+ cxt->pstore.num_pmsg = num_pmsg;
/*
* Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
* have to handle dumps, we must have at least record_size buffer. And
@@ -560,7 +621,6 @@ static int ramoops_probe(struct platform_device *pdev)
record_size = pdata->record_size;
dump_oops = pdata->dump_oops;
ramoops_console_size = pdata->console_size;
- ramoops_pmsg_size = pdata->pmsg_size;
ramoops_ftrace_size = pdata->ftrace_size;

pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
@@ -573,14 +633,16 @@ fail_buf:
kfree(cxt->pstore.buf);
fail_clear:
cxt->pstore.bufsize = 0;
- persistent_ram_free(cxt->mprz);
-fail_init_mprz:
+ ramoops_free_przs(cxt->mprzs);
+fail_init_mprzs:
persistent_ram_free(cxt->fprz);
fail_init_fprz:
persistent_ram_free(cxt->cprz);
fail_init_cprz:
cxt->max_dump_cnt = 0;
ramoops_free_przs(cxt->dprzs);
+fail_init_dprzs:
+ kfree(cxt->pmsg_size);
fail_out:
return err;
}
@@ -600,6 +662,7 @@ static int __exit ramoops_remove(struct platform_device *pdev)
/* TODO(kees): When pstore supports unregistering, call it here. */
kfree(cxt->pstore.buf);
cxt->pstore.bufsize = 0;
+ kfree(cxt->pmsg_size);

return 0;
#endif
@@ -614,6 +677,38 @@ static struct platform_driver ramoops_driver = {
},
};

+static unsigned long *parse_size_str(char *size_str)
+{
+ int i, ret;
+ unsigned long *size_array, count = 1;
+
+ if (size_str) {
+ char *s = size_str;
+ /* Necessary array size is the number of commas + 1 */
+ for (; (s = strchr(s, ',')); s++)
+ count++;
+ }
+
+ size_array = kcalloc(count + 1, sizeof(unsigned long), GFP_KERNEL);
+ if (!size_array)
+ goto out;
+
+ if (size_str) {
+ for (i = 0; i < count; i++) {
+ ret = get_option(&size_str, (int *)&size_array[i]);
+ if (ret == 1)
+ break;
+ else if (ret != 2) {
+ size_array[i] = 0;
+ break;
+ }
+ }
+ } else
+ size_array[0] = MIN_MEM_SIZE;
+out:
+ return size_array;
+}
+
static void ramoops_register_dummy(void)
{
if (!mem_size)
@@ -633,7 +728,9 @@ static void ramoops_register_dummy(void)
dummy_data->record_size = record_size;
dummy_data->console_size = ramoops_console_size;
dummy_data->ftrace_size = ramoops_ftrace_size;
- dummy_data->pmsg_size = ramoops_pmsg_size;
+ dummy_data->pmsg_size = parse_size_str(ramoops_pmsg_size_str);
+ if (!dummy_data->pmsg_size)
+ goto fail_pmsg_size;
dummy_data->dump_oops = dump_oops;
/*
* For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
@@ -646,7 +743,13 @@ static void ramoops_register_dummy(void)
if (IS_ERR(dummy)) {
pr_info("could not create platform device: %ld\n",
PTR_ERR(dummy));
+ goto fail_pdev;
}
+ return;
+fail_pdev:
+ kfree(dummy_data->pmsg_size);
+fail_pmsg_size:
+ kfree(dummy_data);
}

static int __init ramoops_init(void)
@@ -660,6 +763,7 @@ static void __exit ramoops_exit(void)
{
platform_driver_unregister(&ramoops_driver);
platform_device_unregister(dummy);
+ kfree(dummy_data->pmsg_size);
kfree(dummy_data);
}
module_exit(ramoops_exit);
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 9c9d6c1..e808789 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -72,6 +72,12 @@ ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
* Ramoops platform data
* @mem_size memory size for ramoops
* @mem_address physical memory address to contain ramoops
+ * @pmsg_size array containing size of each pmsg area. 0 value in the array
+ * indicates the end of the content. For example, if the following
+ * array is given,
+ * .pmsg_size = { 0x1000, 0x2000, 0x0, 0x3000, };
+ * then, pmsg areas are allocated for the first two size values
+ * and '0x3000' is just ignored.
*/

struct ramoops_platform_data {
@@ -81,7 +87,7 @@ struct ramoops_platform_data {
unsigned long record_size;
unsigned long console_size;
unsigned long ftrace_size;
- unsigned long pmsg_size;
+ unsigned long *pmsg_size;
int dump_oops;
struct persistent_ram_ecc_info ecc_info;
};

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