| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 11 Nov 2016 14:21:48 -0800
From: Kees Cook <keescook@...omium.org>
To: Joel Fernandes <joelaf@...gle.com>
Cc: Kees Cook <keescook@...omium.org>,
Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Tony Luck <tony.luck@...el.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v3 3/8] pstore: Allow prz to control need for locking
From: Joel Fernandes <joelaf@...gle.com>
In preparation of not locking at all for certain buffers depending on if
there's contention, make locking optional depending on the initialization
of the prz.
Signed-off-by: Joel Fernandes <joelaf@...gle.com>
[kees: moved locking flag into prz instead of via caller arguments]
Signed-off-by: Kees Cook <keescook@...omium.org>
---
fs/pstore/ram.c | 5 +++--
fs/pstore/ram_core.c | 20 +++++++++++++-------
include/linux/pstore_ram.h | 10 +++++++++-
3 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 6d1393965b0a..86ac59066fba 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -432,7 +432,7 @@ static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
for (i = 0; i < cxt->max_dump_cnt; i++) {
cxt->przs[i] = persistent_ram_new(*paddr, cxt->record_size, 0,
&cxt->ecc_info,
- cxt->memtype);
+ cxt->memtype, 0);
if (IS_ERR(cxt->przs[i])) {
err = PTR_ERR(cxt->przs[i]);
dev_err(dev, "failed to request mem region (0x%zx@...llx): %d\n",
@@ -469,7 +469,8 @@ static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
return -ENOMEM;
}
- *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype);
+ *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
+ cxt->memtype, 0);
if (IS_ERR(*prz)) {
int err = PTR_ERR(*prz);
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index cb92055e6016..0cc23cb18719 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -55,7 +55,8 @@ static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
int new;
unsigned long flags;
- raw_spin_lock_irqsave(&prz->buffer_lock, flags);
+ if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+ raw_spin_lock_irqsave(&prz->buffer_lock, flags);
old = atomic_read(&prz->buffer->start);
new = old + a;
@@ -63,7 +64,8 @@ static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
new -= prz->buffer_size;
atomic_set(&prz->buffer->start, new);
- raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
+ if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+ raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
return old;
}
@@ -75,7 +77,8 @@ static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
size_t new;
unsigned long flags;
- raw_spin_lock_irqsave(&prz->buffer_lock, flags);
+ if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+ raw_spin_lock_irqsave(&prz->buffer_lock, flags);
old = atomic_read(&prz->buffer->size);
if (old == prz->buffer_size)
@@ -87,7 +90,8 @@ static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
atomic_set(&prz->buffer->size, new);
exit:
- raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
+ if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+ raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
}
static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
@@ -463,7 +467,8 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
}
static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
- struct persistent_ram_ecc_info *ecc_info)
+ struct persistent_ram_ecc_info *ecc_info,
+ unsigned long flags)
{
int ret;
@@ -492,6 +497,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
prz->buffer->sig = sig;
persistent_ram_zap(prz);
prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
+ prz->flags = flags;
return 0;
}
@@ -516,7 +522,7 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
u32 sig, struct persistent_ram_ecc_info *ecc_info,
- unsigned int memtype)
+ unsigned int memtype, u32 flags)
{
struct persistent_ram_zone *prz;
int ret = -ENOMEM;
@@ -531,7 +537,7 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
if (ret)
goto err;
- ret = persistent_ram_post_init(prz, sig, ecc_info);
+ ret = persistent_ram_post_init(prz, sig, ecc_info, flags);
if (ret)
goto err;
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 244d2423dbaf..4058bf991868 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -24,6 +24,13 @@
#include <linux/list.h>
#include <linux/types.h>
+/*
+ * Choose whether access to the RAM zone requires locking or not. If a zone
+ * can be written to from different CPUs like with ftrace for example, then
+ * PRZ_FLAG_NO_LOCK is used. For all other cases, locking is required.
+ */
+#define PRZ_FLAG_NO_LOCK BIT(0)
+
struct persistent_ram_buffer;
struct rs_control;
@@ -40,6 +47,7 @@ struct persistent_ram_zone {
void *vaddr;
struct persistent_ram_buffer *buffer;
size_t buffer_size;
+ u32 flags;
raw_spinlock_t buffer_lock;
/* ECC correction */
@@ -56,7 +64,7 @@ struct persistent_ram_zone {
struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
u32 sig, struct persistent_ram_ecc_info *ecc_info,
- unsigned int memtype);
+ unsigned int memtype, u32 flags);
void persistent_ram_free(struct persistent_ram_zone *prz);
void persistent_ram_zap(struct persistent_ram_zone *prz);
--
2.7.4
Powered by blists - more mailing lists