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ia64 SGI-SN2: fix silent data corruption caused by XPC

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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 a BUG_ON statement to help catch
this if a similar situation is encountered.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This commit is contained in:
Dean Nelson
2006-09-06 19:25:46 +02:00
committed by Adrian Bunk
parent a3c94d7700
commit c1646ad43e
5 changed files with 45 additions and 34 deletions
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include/asm-ia64/sn/xp.h
+18 -4
View File
@@ -60,23 +60,37 @@
* the bte_copy() once in the hope that the failure was due to a temporary
* aberration (i.e., the link going down temporarily).
*
* See bte_copy for definition of the input parameters.
* src - physical address of the source of the transfer.
* vdst - virtual address of the destination of the transfer.
* len - number of bytes to transfer from source to destination.
* mode - see bte_copy() for definition.
* notification - see bte_copy() for definition.
*
* Note: xp_bte_copy() should never be called while holding a spinlock.
*/
static inline bte_result_t
xp_bte_copy(u64 src, u64 dest, u64 len, u64 mode, void *notification)
xp_bte_copy(u64 src, u64 vdst, u64 len, u64 mode, void *notification)
{
bte_result_t ret;
u64 pdst = ia64_tpa(vdst);
ret = bte_copy(src, dest, len, mode, notification);
/*
* Ensure that the physically mapped memory is contiguous.
*
* We do this by ensuring that the memory is from region 7 only.
* If the need should arise to use memory from one of the other
* regions, then modify the BUG_ON() statement to ensure that the
* memory from that region is always physically contiguous.
*/
BUG_ON(REGION_NUMBER(vdst) != RGN_KERNEL);
ret = bte_copy(src, pdst, len, mode, notification);
if (ret != BTE_SUCCESS) {
if (!in_interrupt()) {
cond_resched();
}
ret = bte_copy(src, dest, len, mode, notification);
ret = bte_copy(src, pdst, len, mode, notification);
}
return ret;
include/asm-ia64/sn/xpc.h
+2 -1
View File
@@ -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);