From: Dean Nelson Date: Tue, 8 Aug 2006 20:03:29 +0000 (-0500) Subject: [IA64-SGI] Silent data corruption caused by XPC V2. X-Git-Tag: v2.6.18-rc6~36^2~3 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7682a4c624e0011b5f3e8dd3021dc54961260d97;p=linux-2.6 [IA64-SGI] Silent data corruption caused by XPC V2. 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 Signed-off-by: Dean Nelson Signed-off-by: Jack Steiner Signed-off-by: Tony Luck --- diff --git a/arch/ia64/sn/kernel/xpc_channel.c b/arch/ia64/sn/kernel/xpc_channel.c index c2f69f7942..1f3540826e 100644 --- a/arch/ia64/sn/kernel/xpc_channel.c +++ b/arch/ia64/sn/kernel/xpc_channel.c @@ -279,8 +279,8 @@ xpc_pull_remote_cachelines(struct xpc_partition *part, void *dst, return part->reason; } - bte_ret = xp_bte_copy((u64) src, (u64) ia64_tpa((u64) dst), - (u64) cnt, (BTE_NORMAL | BTE_WACQUIRE), NULL); + bte_ret = xp_bte_copy((u64) src, (u64) dst, (u64) cnt, + (BTE_NORMAL | BTE_WACQUIRE), NULL); if (bte_ret == BTE_SUCCESS) { return xpcSuccess; } diff --git a/arch/ia64/sn/kernel/xpc_main.c b/arch/ia64/sn/kernel/xpc_main.c index 5e8e59efb3..4d026f9dd9 100644 --- a/arch/ia64/sn/kernel/xpc_main.c +++ b/arch/ia64/sn/kernel/xpc_main.c @@ -1052,6 +1052,8 @@ xpc_do_exit(enum xpc_retval reason) if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } + + kfree(xpc_remote_copy_buffer_base); } @@ -1212,24 +1214,20 @@ 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"); @@ -1293,6 +1291,8 @@ xpc_init(void) if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } + + kfree(xpc_remote_copy_buffer_base); return -EBUSY; } @@ -1311,6 +1311,8 @@ xpc_init(void) if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } + + kfree(xpc_remote_copy_buffer_base); return -EBUSY; } @@ -1362,6 +1364,8 @@ xpc_init(void) if (xpc_sysctl) { unregister_sysctl_table(xpc_sysctl); } + + kfree(xpc_remote_copy_buffer_base); return -EBUSY; } diff --git a/arch/ia64/sn/kernel/xpc_partition.c b/arch/ia64/sn/kernel/xpc_partition.c index 2a89cfce49..57c723f5cb 100644 --- a/arch/ia64/sn/kernel/xpc_partition.c +++ b/arch/ia64/sn/kernel/xpc_partition.c @@ -71,19 +71,15 @@ struct xpc_partition xpc_partitions[XP_MAX_PARTITIONS + 1]; * 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; /* * Guarantee that the kmalloc'd memory is cacheline aligned. */ -static void * +void * xpc_kmalloc_cacheline_aligned(size_t size, gfp_t flags, void **base) { /* see if kmalloc will give us cachline aligned memory by default */ @@ -148,7 +144,7 @@ xpc_get_rsvd_page_pa(int nasid) } } - bte_res = xp_bte_copy(rp_pa, ia64_tpa(buf), buf_len, + bte_res = xp_bte_copy(rp_pa, buf, buf_len, (BTE_NOTIFY | BTE_WACQUIRE), NULL); if (bte_res != BTE_SUCCESS) { dev_dbg(xpc_part, "xp_bte_copy failed %i\n", bte_res); @@ -447,7 +443,7 @@ xpc_check_remote_hb(void) /* pull the remote_hb cache line */ bres = xp_bte_copy(part->remote_vars_pa, - ia64_tpa((u64) remote_vars), + (u64) remote_vars, XPC_RP_VARS_SIZE, (BTE_NOTIFY | BTE_WACQUIRE), NULL); if (bres != BTE_SUCCESS) { @@ -498,8 +494,7 @@ xpc_get_remote_rp(int nasid, u64 *discovered_nasids, /* pull over the reserved page header and part_nasids mask */ - - bres = xp_bte_copy(*remote_rp_pa, ia64_tpa((u64) remote_rp), + bres = xp_bte_copy(*remote_rp_pa, (u64) remote_rp, XPC_RP_HEADER_SIZE + xp_nasid_mask_bytes, (BTE_NOTIFY | BTE_WACQUIRE), NULL); if (bres != BTE_SUCCESS) { @@ -554,11 +549,8 @@ xpc_get_remote_vars(u64 remote_vars_pa, struct xpc_vars *remote_vars) return xpcVarsNotSet; } - /* pull over the cross partition variables */ - - bres = xp_bte_copy(remote_vars_pa, ia64_tpa((u64) remote_vars), - XPC_RP_VARS_SIZE, + bres = xp_bte_copy(remote_vars_pa, (u64) remote_vars, XPC_RP_VARS_SIZE, (BTE_NOTIFY | BTE_WACQUIRE), NULL); if (bres != BTE_SUCCESS) { return xpc_map_bte_errors(bres); @@ -1239,7 +1231,7 @@ xpc_initiate_partid_to_nasids(partid_t partid, void *nasid_mask) part_nasid_pa = (u64) XPC_RP_PART_NASIDS(part->remote_rp_pa); - bte_res = xp_bte_copy(part_nasid_pa, ia64_tpa((u64) nasid_mask), + bte_res = xp_bte_copy(part_nasid_pa, (u64) nasid_mask, xp_nasid_mask_bytes, (BTE_NOTIFY | BTE_WACQUIRE), NULL); return xpc_map_bte_errors(bte_res); diff --git a/include/asm-ia64/sn/xp.h b/include/asm-ia64/sn/xp.h index 9bd2f9bf32..6f807e0193 100644 --- a/include/asm-ia64/sn/xp.h +++ b/include/asm-ia64/sn/xp.h @@ -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; diff --git a/include/asm-ia64/sn/xpc.h b/include/asm-ia64/sn/xpc.h index b72af59787..35e1386f37 100644 --- a/include/asm-ia64/sn/xpc.h +++ b/include/asm-ia64/sn/xpc.h @@ -683,7 +683,9 @@ 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 void *xpc_kmalloc_cacheline_aligned(size_t, gfp_t, void **); extern struct xpc_rsvd_page *xpc_rsvd_page_init(void); extern void xpc_allow_IPI_ops(void); extern void xpc_restrict_IPI_ops(void);