[PATCH v3 4/8] pstore: Make ramoops_init_przs generic for other prz arrays

From: Kees Cook
Date: Fri Nov 11 2016 - 17:28:57 EST


Currently ramoops_init_przs() is hard wired only for panic dump zone
array. In preparation for the ftrace zone array (one zone per-cpu) and pmsg
zone array, make the function more generic to be able to handle this case.

Heavily based on similar work from Joel Fernandes.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/pstore/ram.c | 82 +++++++++++++++++++++++++++++++++++++--------------------
1 file changed, 54 insertions(+), 28 deletions(-)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 86ac59066fba..34294c32af0b 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -405,53 +405,78 @@ static void ramoops_free_przs(struct ramoops_context *cxt)
}

static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
- phys_addr_t *paddr, size_t dump_mem_sz)
+ struct persistent_ram_zone ***przs,
+ phys_addr_t *paddr, size_t mem_sz,
+ ssize_t record_size,
+ unsigned int *cnt, u32 sig, u32 flags)
{
int err = -ENOMEM;
int i;
+ size_t zone_sz;
+ struct persistent_ram_zone **prz_ar;

- if (!cxt->record_size)
+ /* Allocate nothing for 0 mem_sz or 0 record_size. */
+ if (mem_sz == 0 || record_size == 0) {
+ *cnt = 0;
return 0;
-
- if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
- dev_err(dev, "no room for dumps\n");
- return -ENOMEM;
}

- cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
- if (!cxt->max_dump_cnt)
- return -ENOMEM;
+ /*
+ * If we have a negative record size, calculate it based on
+ * mem_sz / *cnt. If we have a positive record size, calculate
+ * cnt from mem_sz / record_size.
+ */
+ if (record_size < 0) {
+ if (*cnt == 0)
+ return 0;
+ record_size = mem_sz / *cnt;
+ if (record_size == 0)
+ goto fail;
+ } else {
+ *cnt = mem_sz / record_size;
+ if (*cnt == 0)
+ goto fail;
+ }

- cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
- GFP_KERNEL);
- if (!cxt->przs) {
- dev_err(dev, "failed to initialize a prz array for dumps\n");
- goto fail_mem;
+ if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
+ dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
+ mem_sz, (unsigned long long)*paddr,
+ cxt->size, (unsigned long long)cxt->phys_addr);
+ goto fail;
}

- for (i = 0; i < cxt->max_dump_cnt; i++) {
- cxt->przs[i] = persistent_ram_new(*paddr, cxt->record_size, 0,
+ zone_sz = mem_sz / *cnt;
+ if (!zone_sz)
+ goto fail;
+
+ prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
+ if (!prz_ar)
+ goto fail;
+
+ for (i = 0; i < *cnt; i++) {
+ prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
&cxt->ecc_info,
- cxt->memtype, 0);
- if (IS_ERR(cxt->przs[i])) {
- err = PTR_ERR(cxt->przs[i]);
+ cxt->memtype, flags);
+ if (IS_ERR(prz_ar[i])) {
+ err = PTR_ERR(prz_ar[i]);
dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
- cxt->record_size, (unsigned long long)*paddr, err);
+ record_size, (unsigned long long)*paddr, err);

while (i > 0) {
i--;
- persistent_ram_free(cxt->przs[i]);
+ persistent_ram_free(prz_ar[i]);
}
- goto fail_prz;
+ kfree(prz_ar);
+ goto fail;
}
- *paddr += cxt->record_size;
+ *paddr += zone_sz;
}

+ *przs = prz_ar;
return 0;
-fail_prz:
- kfree(cxt->przs);
-fail_mem:
- cxt->max_dump_cnt = 0;
+
+fail:
+ *cnt = 0;
return err;
}

@@ -605,7 +630,8 @@ static int ramoops_probe(struct platform_device *pdev)

dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
- cxt->pmsg_size;
- err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
+ err = ramoops_init_przs(dev, cxt, &cxt->przs, &paddr, dump_mem_sz,
+ cxt->record_size, &cxt->max_dump_cnt, 0, 0);
if (err)
goto fail_out;

--
2.7.4