mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

cxl: Fix PSL error due to duplicate segment table entries 

In certain circumstances the PSL (Power Service Layer, which provides
translation services for CXL hardware) can send an interrupt for a
segment miss that the kernel has already handled. This can happen if
multiple translations for the same segment are queued in the PSL before
the kernel has restarted the first translation.

The CXL driver does not expect this situation and does not check if a
segment had already been handled. This could cause a duplicate segment
table entry which in turn caused a PSL error taking down the card.

This patch fixes the issue by checking for existing entries in the
segment table that match the segment we are trying to insert, so as to
avoid inserting duplicate entries.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Ian Munsie 2014-10-28 14:25:30 +11:00 committed by Michael Ellerman
parent 03f5439797
commit eb01d4c238
1 changed files with 22 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/misc/cxl/fault.c
View File

@ -21,11 +21,20 @@
#include "cxl.h"
/* This finds a free SSTE for the given SLB */
static bool sste_matches(struct cxl_sste *sste, struct copro_slb *slb)
{
return ((sste->vsid_data == cpu_to_be64(slb->vsid)) &&
(sste->esid_data == cpu_to_be64(slb->esid)));
}
/*
* This finds a free SSTE for the given SLB, or returns NULL if it's already in
* the segment table.
*/
static struct cxl_sste* find_free_sste(struct cxl_context *ctx,
struct copro_slb *slb)
{
struct cxl_sste *primary, *sste;
struct cxl_sste *primary, *sste, *ret = NULL;
unsigned int mask = (ctx->sst_size >> 7) - 1; /* SSTP0[SegTableSize] */
unsigned int entry;
unsigned int hash;
@ -38,15 +47,19 @@ static struct cxl_sste* find_free_sste(struct cxl_context *ctx,
primary = ctx->sstp + (hash << 3);
for (entry = 0, sste = primary; entry < 8; entry++, sste++) {
if (!(be64_to_cpu(sste->esid_data) & SLB_ESID_V))
return sste;
if (!ret && !(be64_to_cpu(sste->esid_data) & SLB_ESID_V))
ret = sste;
if (sste_matches(sste, slb))
return NULL;
}
if (ret)
return ret;
/* Nothing free, select an entry to cast out */
sste = primary + ctx->sst_lru;
ret = primary + ctx->sst_lru;
ctx->sst_lru = (ctx->sst_lru + 1) & 0x7;
return sste;
return ret;
}
static void cxl_load_segment(struct cxl_context *ctx, struct copro_slb *slb)
@ -57,12 +70,15 @@ static void cxl_load_segment(struct cxl_context *ctx, struct copro_slb *slb)
spin_lock_irqsave(&ctx->sste_lock, flags);
sste = find_free_sste(ctx, slb);
if (!sste)
goto out_unlock;
pr_devel("CXL Populating SST[%li]: %#llx %#llx\n",
sste - ctx->sstp, slb->vsid, slb->esid);
sste->vsid_data = cpu_to_be64(slb->vsid);
sste->esid_data = cpu_to_be64(slb->esid);
out_unlock:
spin_unlock_irqrestore(&ctx->sste_lock, flags);
}