[PATCH] scsi: pm8001: Fix phys_to_virt() usage on dma_addr_t

John Garry
2021-11-26T15:42:48Z

The driver supports a "direct" mode of operation, where the SMP req frame
is directly copied into the command payload (and vice-versa for the SMP
resp).

To get at the SMP req frame data in the scatterlist the driver uses
phys_to_virt() on the DMA mapped memory dma_addr_t . This is broken,
and subsequently crashes as follows when an IOMMU is enabled:

Unable to handle kernel paging request at virtual address
ffff0000fcebfb00
...
pc : pm80xx_chip_smp_req+0x2d0/0x3d0
lr : pm80xx_chip_smp_req+0xac/0x3d0
pm80xx_chip_smp_req+0x2d0/0x3d0
pm8001_task_exec.constprop.0+0x368/0x520
pm8001_queue_command+0x1c/0x30
smp_execute_task_sg+0xdc/0x204
sas_discover_expander.part.0+0xac/0x6cc
sas_discover_root_expander+0x8c/0x150
sas_discover_domain+0x3ac/0x6a0
process_one_work+0x1d0/0x354
worker_thread+0x13c/0x470
kthread+0x17c/0x190
ret_from_fork+0x10/0x20
Code: 371806e1 910006d6 6b16033f 54000249 (38766b05)
---[ end trace b91d59aaee98ea2d ]---
note: kworker/u192:0[7] exited with preempt_count 1

Instead use kmap{_atomic}().

Signed-off-by: John Garry <john.garry@huawei.com>
--
I would appreciate if someone could test this change a bit more.

Even though my system boots and I can mount the disks now, SCSI error
handling kicks eventually in for some erroneously completed tasks.
That's even on my x86 machine, IIRC. I think the card FW needs updating.

diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c b/drivers/scsi/pm8001/pm80xx_hwi.c
index b9f6d83ff380..0e2221b4f411 100644
--- a/drivers/scsi/pm8001/pm80xx_hwi.c
+++ b/drivers/scsi/pm8001/pm80xx_hwi.c
@@ -3053,7 +3053,6 @@ mpi_smp_completion(struct pm8001_hba_info *pm8001_ha, void *piomb)
struct smp_completion_resp *psmpPayload;
struct task_status_struct *ts;
struct pm8001_device *pm8001_dev;
- char *pdma_respaddr = NULL;

psmpPayload = (struct smp_completion_resp *)(piomb + 4);
status = le32_to_cpu(psmpPayload->status);
@@ -3080,19 +3079,23 @@ mpi_smp_completion(struct pm8001_hba_info *pm8001_ha, void *piomb)
if (pm8001_dev)
atomic_dec(&pm8001_dev->running_req);
if (pm8001_ha->smp_exp_mode == SMP_DIRECT) {
+ struct scatterlist *sg_resp = &t->smp_task.smp_resp;
+ u8 *payload;
+ void *to;
+
pm8001_dbg(pm8001_ha, IO,
"DIRECT RESPONSE Length:%d\n",
param);
- pdma_respaddr = (char *)(phys_to_virt(cpu_to_le64
- ((u64)sg_dma_address
- (&t->smp_task.smp_resp))));
+ to = kmap_atomic(sg_page(sg_resp));
+ payload = to + sg_resp->offset;
for (i = 0; i < param; i++) {
- *(pdma_respaddr+i) = psmpPayload->_r_a[i];
+ *(payload + i) = psmpPayload->_r_a[i];
pm8001_dbg(pm8001_ha, IO,
"SMP Byte%d DMA data 0x%x psmp 0x%x\n",
- i, *(pdma_respaddr + i),
+ i, *(payload + i),
psmpPayload->_r_a[i]);
}
+ kunmap_atomic(to);
}
break;
case IO_ABORTED:
@@ -4236,14 +4239,14 @@ static int pm80xx_chip_smp_req(struct pm8001_hba_info *pm8001_ha,
struct sas_task *task = ccb->task;
struct domain_device *dev = task->dev;
struct pm8001_device *pm8001_dev = dev->lldd_dev;
- struct scatterlist *sg_req, *sg_resp;
+ struct scatterlist *sg_req, *sg_resp, *smp_req;
u32 req_len, resp_len;
struct smp_req smp_cmd;
u32 opc;
struct inbound_queue_table *circularQ;
- char *preq_dma_addr = NULL;
- __le64 tmp_addr;
u32 i, length;
+ u8 *payload;
+ u8 *to;

memset(&smp_cmd, 0, sizeof(smp_cmd));
/*
@@ -4280,8 +4283,9 @@ static int pm80xx_chip_smp_req(struct pm8001_hba_info *pm8001_ha,
pm8001_ha->smp_exp_mode = SMP_INDIRECT;

- tmp_addr = cpu_to_le64((u64)sg_dma_address(&task->smp_task.smp_req));
- preq_dma_addr = (char *)phys_to_virt(tmp_addr);
+ smp_req = &task->smp_task.smp_req;
+ to = kmap(sg_page(smp_req));
+ payload = to + smp_req->offset;

/* INDIRECT MODE command settings. Use DMA */
if (pm8001_ha->smp_exp_mode == SMP_INDIRECT) {
@@ -4289,7 +4293,7 @@ static int pm80xx_chip_smp_req(struct pm8001_hba_info *pm8001_ha,
/* for SPCv indirect mode. Place the top 4 bytes of
* SMP Request header here. */
for (i = 0; i < 4; i++)
- smp_cmd.smp_req16[i] = *(preq_dma_addr + i);
+ smp_cmd.smp_req16[i] = *(payload + i);
/* exclude top 4 bytes for SMP req header */
smp_cmd.long_smp_req.long_req_addr =
cpu_to_le64((u64)sg_dma_address
@@ -4320,20 +4324,20 @@ static int pm80xx_chip_smp_req(struct pm8001_hba_info *pm8001_ha,
pm8001_dbg(pm8001_ha, IO, "SMP REQUEST DIRECT MODE\n");
for (i = 0; i < length; i++)
if (i < 16) {
- smp_cmd.smp_req16[i] = *(preq_dma_addr+i);
+ smp_cmd.smp_req16[i] = *(payload+i);
pm8001_dbg(pm8001_ha, IO,
"Byte[%d]:%x (DMA data:%x)\n",
i, smp_cmd.smp_req16[i],
- *(preq_dma_addr));
+ *(payload));
} else {
- smp_cmd.smp_req[i] = *(preq_dma_addr+i);
+ smp_cmd.smp_req[i] = *(payload+i);
pm8001_dbg(pm8001_ha, IO,
"Byte[%d]:%x (DMA data:%x)\n",
i, smp_cmd.smp_req[i],
- *(preq_dma_addr));
+ *(payload));
}
}
-
+ kunmap(sg_page(smp_req));
build_smp_cmd(pm8001_dev->device_id, smp_cmd.tag,
&smp_cmd, pm8001_ha->smp_exp_mode, length);
rc = pm8001_mpi_build_cmd(pm8001_ha, circularQ, opc, &smp_cmd,
--
2.17.1