Jack Steiner identified a problem where XPC can cause a silent
data corruption. On module load, the placement may cause the
xpc_remote_copy_buffer to span two physical pages. DMA transfers are
done to the start virtual address translated to physical.
This patch changes the buffer from a statically allocated buffer to a
kmalloc'd buffer. Dean Nelson reviewed this before posting. I have
tested it in the configuration that was showing the memory corruption
and verified it works. I also added DBUG_ON statements to help catch
this if a similar situation is encountered.
Signed-off-by: Robin Holt <holt@xxxxxxx>
Signed-off-by: Dean Nelson <dcn@xxxxxxx>
Signed-off-by: Jack Steiner <steiner@xxxxxxx>
Index: linux-2.6/arch/ia64/sn/kernel/xpc_channel.c
===================================================================
--- linux-2.6.orig/arch/ia64/sn/kernel/xpc_channel.c 2006-05-03 19:37:42.430685318 -0500
+++ linux-2.6/arch/ia64/sn/kernel/xpc_channel.c 2006-08-07 10:38:54.827204041 -0500
@@ -255,6 +255,7 @@ xpc_pull_remote_cachelines(struct xpc_pa
DBUG_ON((u64) src != L1_CACHE_ALIGN((u64) src));
DBUG_ON((u64) dst != L1_CACHE_ALIGN((u64) dst));
DBUG_ON(cnt != L1_CACHE_ALIGN(cnt));
+ DBUG_ON((ia64_tpa(dst) + cnt) != ia64_tpa(&((char *) dst)[cnt]));
if (part->act_state == XPC_P_DEACTIVATING) {
return part->reason;
Index: linux-2.6/arch/ia64/sn/kernel/xpc_partition.c
===================================================================
--- linux-2.6.orig/arch/ia64/sn/kernel/xpc_partition.c 2006-05-03 19:37:42.434684918 -0500
+++ linux-2.6/arch/ia64/sn/kernel/xpc_partition.c 2006-08-07 10:38:54.835205009 -0500
@@ -71,13 +71,9 @@ struct xpc_partition xpc_partitions[XP_M
* Generic buffer used to store a local copy of portions of a remote
* partition's reserved page (either its header and part_nasids mask,
* or its vars).
- *
- * xpc_discovery runs only once and is a seperate thread that is
- * very likely going to be processing in parallel with receiving
- * interrupts.
*/
-char ____cacheline_aligned xpc_remote_copy_buffer[XPC_RP_HEADER_SIZE +
- XP_NASID_MASK_BYTES];
+char *xpc_remote_copy_buffer;
+void *xpc_remote_copy_buffer_base;
/*
@@ -125,6 +121,9 @@ xpc_get_rsvd_page_pa(int nasid)
}
}
+ DBUG_ON((ia64_tpa(buf) + buf_len) !=
+ ia64_tpa(&((char *) buf)[buf_len]));
+
bte_res = xp_bte_copy(rp_pa, ia64_tpa(buf), buf_len,
(BTE_NOTIFY | BTE_WACQUIRE), NULL);
if (bte_res != BTE_SUCCESS) {
@@ -424,6 +423,9 @@ xpc_check_remote_hb(void)
continue;
}
+ DBUG_ON((ia64_tpa(remote_vars) + XPC_RP_VARS_SIZE) !=
+ ia64_tpa(&((char *) remote_vars)[XPC_RP_VARS_SIZE]));
+
/* pull the remote_hb cache line */
bres = xp_bte_copy(part->remote_vars_pa,
ia64_tpa((u64) remote_vars),
@@ -475,9 +477,11 @@ xpc_get_remote_rp(int nasid, u64 *discov
return xpcNoRsvdPageAddr;
}
+ DBUG_ON((ia64_tpa(remote_rp + XPC_RP_HEADER_SIZE + xp_nasid_mask_bytes) !=
+ ia64_tpa(&((char *) remote_rp)[XPC_RP_HEADER_SIZE + xp_nasid_mask_bytes])));
- /* pull over the reserved page header and part_nasids mask */
+ /* pull over the reserved page header and part_nasids mask */
bres = xp_bte_copy(*remote_rp_pa, ia64_tpa((u64) remote_rp),
XPC_RP_HEADER_SIZE + xp_nasid_mask_bytes,
(BTE_NOTIFY | BTE_WACQUIRE), NULL);
@@ -533,9 +537,11 @@ xpc_get_remote_vars(u64 remote_vars_pa,
return xpcVarsNotSet;
}
+ DBUG_ON((ia64_tpa(remote_vars) + XPC_RP_VARS_SIZE) !=
+ ia64_tpa(&((char *) remote_vars)[XPC_RP_VARS_SIZE]));
- /* pull over the cross partition variables */
+ /* pull over the cross partition variables */
bres = xp_bte_copy(remote_vars_pa, ia64_tpa((u64) remote_vars),
XPC_RP_VARS_SIZE,
(BTE_NOTIFY | BTE_WACQUIRE), NULL);
@@ -1219,6 +1225,9 @@ xpc_initiate_partid_to_nasids(partid_t p
part_nasid_pa = (u64) XPC_RP_PART_NASIDS(part->remote_rp_pa);
+ DBUG_ON((ia64_tpa(nasid_mask) + xp_nasid_mask_bytes) !=
+ ia64_tpa(&((char *) nasid_mask)[xp_nasid_mask_bytes]));
+
bte_res = xp_bte_copy(part_nasid_pa, ia64_tpa((u64) nasid_mask),
xp_nasid_mask_bytes, (BTE_NOTIFY | BTE_WACQUIRE), NULL);
Index: linux-2.6/arch/ia64/sn/kernel/xpc_main.c
===================================================================
--- linux-2.6.orig/arch/ia64/sn/kernel/xpc_main.c 2006-05-03 19:37:42.434684918 -0500
+++ linux-2.6/arch/ia64/sn/kernel/xpc_main.c 2006-08-07 10:38:54.839205493 -0500
@@ -1053,6 +1053,8 @@ xpc_do_exit(enum xpc_retval reason)
if (xpc_sysctl) {
unregister_sysctl_table(xpc_sysctl);
}
+
+ kfree(xpc_remote_copy_buffer_base);
}
@@ -1213,24 +1215,19 @@ xpc_init(void)
partid_t partid;
struct xpc_partition *part;
pid_t pid;
+ size_t buf_size;
if (!ia64_platform_is("sn2")) {
return -ENODEV;
}
- /*
- * xpc_remote_copy_buffer is used as a temporary buffer for bte_copy'ng
- * various portions of a partition's reserved page. Its size is based
- * on the size of the reserved page header and part_nasids mask. So we
- * need to ensure that the other items will fit as well.
- */
- if (XPC_RP_VARS_SIZE > XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES) {
- dev_err(xpc_part, "xpc_remote_copy_buffer is not big enough\n");
- return -EPERM;
- }
- DBUG_ON((u64) xpc_remote_copy_buffer !=
- L1_CACHE_ALIGN((u64) xpc_remote_copy_buffer));
+
+ buf_size = max(XPC_RP_VARS_SIZE, XPC_RP_HEADER_SIZE + XP_NASID_MASK_BYTES);
+ xpc_remote_copy_buffer = xpc_kmalloc_cacheline_aligned(buf_size, GFP_KERNEL,
+ &xpc_remote_copy_buffer_base);
+ if (xpc_remote_copy_buffer == NULL)
+ return -ENOMEM;
snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
@@ -1294,6 +1291,8 @@ xpc_init(void)
if (xpc_sysctl) {
unregister_sysctl_table(xpc_sysctl);
}
+
+ kfree(xpc_remote_copy_buffer_base);
return -EBUSY;
}
@@ -1312,6 +1311,8 @@ xpc_init(void)
if (xpc_sysctl) {
unregister_sysctl_table(xpc_sysctl);
}
+
+ kfree(xpc_remote_copy_buffer_base);
return -EBUSY;
}
@@ -1363,6 +1364,8 @@ xpc_init(void)
if (xpc_sysctl) {
unregister_sysctl_table(xpc_sysctl);
}
+
+ kfree(xpc_remote_copy_buffer_base);
return -EBUSY;
}
Index: linux-2.6/include/asm-ia64/sn/xpc.h
===================================================================
--- linux-2.6.orig/include/asm-ia64/sn/xpc.h 2006-05-03 19:37:46.650263229 -0500
+++ linux-2.6/include/asm-ia64/sn/xpc.h 2006-08-07 10:38:55.011226303 -0500
@@ -684,7 +684,8 @@ extern struct xpc_vars *xpc_vars;
extern struct xpc_rsvd_page *xpc_rsvd_page;
extern struct xpc_vars_part *xpc_vars_part;
extern struct xpc_partition xpc_partitions[XP_MAX_PARTITIONS + 1];
-extern char xpc_remote_copy_buffer[];
+extern char *xpc_remote_copy_buffer;
+extern void *xpc_remote_copy_buffer_base;
extern struct xpc_rsvd_page *xpc_rsvd_page_init(void);
extern void xpc_allow_IPI_ops(void);
extern void xpc_restrict_IPI_ops(void);
-
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