[PATCH v4 02/11] cxl: Drop commands if the PCI channel is not in normal state
Daniel Axtens
dja at axtens.net
Thu Aug 13 14:11:20 AEST 2015
If the PCI channel has gone down, don't attempt to poke the hardware.
We need to guard every time cxl_whatever_(read|write) is called. This
is because a call to those functions will dereference an offset into an
mmio register, and the mmio mappings get invalidated in the EEH
teardown.
Check in the read/write functions in the header.
We give them the same semantics as usual PCI operations:
- a write to a channel that is down is ignored.
- a read from a channel that is down returns all fs.
Also, we try to access the MMIO space of a vPHB device as part of the
PCI disable path. Because that's a read that bypasses most of our usual
checks, we handle it explicitly.
As far as user visible warnings go:
- Check link state in file ops, return -EIO if down.
- Be reasonably quiet if there's an error in a teardown path,
or when we already know the hardware is going down.
- Throw a big WARN if someone tries to start a CXL operation
while the card is down. This gives a useful stacktrace for
debugging whatever is doing that.
Signed-off-by: Daniel Axtens <dja at axtens.net>
---
drivers/misc/cxl/context.c | 6 +++-
drivers/misc/cxl/cxl.h | 44 ++++++++++++++++++++++------
drivers/misc/cxl/file.c | 19 +++++++++++++
drivers/misc/cxl/native.c | 71 ++++++++++++++++++++++++++++++++++++++++++++--
drivers/misc/cxl/vphb.c | 26 +++++++++++++++++
5 files changed, 154 insertions(+), 12 deletions(-)
diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index 1287148629c0..615842115848 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -193,7 +193,11 @@ int __detach_context(struct cxl_context *ctx)
if (status != STARTED)
return -EBUSY;
- WARN_ON(cxl_detach_process(ctx));
+ /* Only warn if we detached while the link was OK.
+ * If detach fails when hw is down, we don't care.
+ */
+ WARN_ON(cxl_detach_process(ctx) &&
+ cxl_adapter_link_ok(ctx->afu->adapter));
flush_work(&ctx->fault_work); /* Only needed for dedicated process */
put_pid(ctx->pid);
cxl_ctx_put();
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 6a93bfbcd826..9b9e89fd02cc 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -531,6 +531,14 @@ struct cxl_process_element {
__be32 software_state;
} __packed;
+static inline bool cxl_adapter_link_ok(struct cxl *cxl)
+{
+ struct pci_dev *pdev;
+
+ pdev = to_pci_dev(cxl->dev.parent);
+ return !pci_channel_offline(pdev);
+}
+
static inline void __iomem *_cxl_p1_addr(struct cxl *cxl, cxl_p1_reg_t reg)
{
WARN_ON(!cpu_has_feature(CPU_FTR_HVMODE));
@@ -539,12 +547,16 @@ static inline void __iomem *_cxl_p1_addr(struct cxl *cxl, cxl_p1_reg_t reg)
static inline void cxl_p1_write(struct cxl *cxl, cxl_p1_reg_t reg, u64 val)
{
- out_be64(_cxl_p1_addr(cxl, reg), val);
+ if (likely(cxl_adapter_link_ok(cxl)))
+ out_be64(_cxl_p1_addr(cxl, reg), val);
}
static inline u64 cxl_p1_read(struct cxl *cxl, cxl_p1_reg_t reg)
{
- return in_be64(_cxl_p1_addr(cxl, reg));
+ if (likely(cxl_adapter_link_ok(cxl)))
+ return in_be64(_cxl_p1_addr(cxl, reg));
+ else
+ return ~0ULL;
}
static inline void __iomem *_cxl_p1n_addr(struct cxl_afu *afu, cxl_p1n_reg_t reg)
@@ -555,12 +567,16 @@ static inline void __iomem *_cxl_p1n_addr(struct cxl_afu *afu, cxl_p1n_reg_t reg
static inline void cxl_p1n_write(struct cxl_afu *afu, cxl_p1n_reg_t reg, u64 val)
{
- out_be64(_cxl_p1n_addr(afu, reg), val);
+ if (likely(cxl_adapter_link_ok(afu->adapter)))
+ out_be64(_cxl_p1n_addr(afu, reg), val);
}
static inline u64 cxl_p1n_read(struct cxl_afu *afu, cxl_p1n_reg_t reg)
{
- return in_be64(_cxl_p1n_addr(afu, reg));
+ if (likely(cxl_adapter_link_ok(afu->adapter)))
+ return in_be64(_cxl_p1n_addr(afu, reg));
+ else
+ return ~0ULL;
}
static inline void __iomem *_cxl_p2n_addr(struct cxl_afu *afu, cxl_p2n_reg_t reg)
@@ -570,22 +586,34 @@ static inline void __iomem *_cxl_p2n_addr(struct cxl_afu *afu, cxl_p2n_reg_t reg
static inline void cxl_p2n_write(struct cxl_afu *afu, cxl_p2n_reg_t reg, u64 val)
{
- out_be64(_cxl_p2n_addr(afu, reg), val);
+ if (likely(cxl_adapter_link_ok(afu->adapter)))
+ out_be64(_cxl_p2n_addr(afu, reg), val);
}
static inline u64 cxl_p2n_read(struct cxl_afu *afu, cxl_p2n_reg_t reg)
{
- return in_be64(_cxl_p2n_addr(afu, reg));
+ if (likely(cxl_adapter_link_ok(afu->adapter)))
+ return in_be64(_cxl_p2n_addr(afu, reg));
+ else
+ return ~0ULL;
}
static inline u64 cxl_afu_cr_read64(struct cxl_afu *afu, int cr, u64 off)
{
- return in_le64((afu)->afu_desc_mmio + (afu)->crs_offset + ((cr) * (afu)->crs_len) + (off));
+ if (likely(cxl_adapter_link_ok(afu->adapter)))
+ return in_le64((afu)->afu_desc_mmio + (afu)->crs_offset +
+ ((cr) * (afu)->crs_len) + (off));
+ else
+ return ~0ULL;
}
static inline u32 cxl_afu_cr_read32(struct cxl_afu *afu, int cr, u64 off)
{
- return in_le32((afu)->afu_desc_mmio + (afu)->crs_offset + ((cr) * (afu)->crs_len) + (off));
+ if (likely(cxl_adapter_link_ok(afu->adapter)))
+ return in_le32((afu)->afu_desc_mmio + (afu)->crs_offset +
+ ((cr) * (afu)->crs_len) + (off));
+ else
+ return 0xffffffff;
}
u16 cxl_afu_cr_read16(struct cxl_afu *afu, int cr, u64 off);
u8 cxl_afu_cr_read8(struct cxl_afu *afu, int cr, u64 off);
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index c8c8bfa2679b..57bdb473749f 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -73,6 +73,11 @@ static int __afu_open(struct inode *inode, struct file *file, bool master)
if (!afu->current_mode)
goto err_put_afu;
+ if (!cxl_adapter_link_ok(adapter)) {
+ rc = -EIO;
+ goto err_put_afu;
+ }
+
if (!(ctx = cxl_context_alloc())) {
rc = -ENOMEM;
goto err_put_afu;
@@ -238,6 +243,9 @@ long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (ctx->status == CLOSED)
return -EIO;
+ if (!cxl_adapter_link_ok(ctx->afu->adapter))
+ return -EIO;
+
pr_devel("afu_ioctl\n");
switch (cmd) {
case CXL_IOCTL_START_WORK:
@@ -265,6 +273,9 @@ int afu_mmap(struct file *file, struct vm_area_struct *vm)
if (ctx->status != STARTED)
return -EIO;
+ if (!cxl_adapter_link_ok(ctx->afu->adapter))
+ return -EIO;
+
return cxl_context_iomap(ctx, vm);
}
@@ -309,6 +320,9 @@ ssize_t afu_read(struct file *file, char __user *buf, size_t count,
int rc;
DEFINE_WAIT(wait);
+ if (!cxl_adapter_link_ok(ctx->afu->adapter))
+ return -EIO;
+
if (count < CXL_READ_MIN_SIZE)
return -EINVAL;
@@ -319,6 +333,11 @@ ssize_t afu_read(struct file *file, char __user *buf, size_t count,
if (ctx_event_pending(ctx))
break;
+ if (!cxl_adapter_link_ok(ctx->afu->adapter)) {
+ rc = -EIO;
+ goto out;
+ }
+
if (file->f_flags & O_NONBLOCK) {
rc = -EAGAIN;
goto out;
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 0c94ba27e658..cd1dda5fcd3a 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -41,6 +41,12 @@ static int afu_control(struct cxl_afu *afu, u64 command,
rc = -EBUSY;
goto out;
}
+ if (!cxl_adapter_link_ok(afu->adapter)) {
+ afu->enabled = enabled;
+ rc = -EIO;
+ goto out;
+ }
+
pr_devel_ratelimited("AFU control... (0x%.16llx)\n",
AFU_Cntl | command);
cpu_relax();
@@ -85,6 +91,10 @@ int __cxl_afu_reset(struct cxl_afu *afu)
int cxl_afu_check_and_enable(struct cxl_afu *afu)
{
+ if (!cxl_adapter_link_ok(afu->adapter)) {
+ WARN(1, "Refusing to enable afu while link down!\n");
+ return -EIO;
+ }
if (afu->enabled)
return 0;
return afu_enable(afu);
@@ -103,6 +113,12 @@ int cxl_psl_purge(struct cxl_afu *afu)
pr_devel("PSL purge request\n");
+ if (!cxl_adapter_link_ok(afu->adapter)) {
+ dev_warn(&afu->dev, "PSL Purge called with link down, ignoring\n");
+ rc = -EIO;
+ goto out;
+ }
+
if ((AFU_Cntl & CXL_AFU_Cntl_An_ES_MASK) != CXL_AFU_Cntl_An_ES_Disabled) {
WARN(1, "psl_purge request while AFU not disabled!\n");
cxl_afu_disable(afu);
@@ -119,6 +135,11 @@ int cxl_psl_purge(struct cxl_afu *afu)
rc = -EBUSY;
goto out;
}
+ if (!cxl_adapter_link_ok(afu->adapter)) {
+ rc = -EIO;
+ goto out;
+ }
+
dsisr = cxl_p2n_read(afu, CXL_PSL_DSISR_An);
pr_devel_ratelimited("PSL purging... PSL_CNTL: 0x%.16llx PSL_DSISR: 0x%.16llx\n", PSL_CNTL, dsisr);
if (dsisr & CXL_PSL_DSISR_TRANS) {
@@ -215,6 +236,8 @@ int cxl_tlb_slb_invalidate(struct cxl *adapter)
dev_warn(&adapter->dev, "WARNING: CXL adapter wide TLBIA timed out!\n");
return -EBUSY;
}
+ if (!cxl_adapter_link_ok(adapter))
+ return -EIO;
cpu_relax();
}
@@ -224,6 +247,8 @@ int cxl_tlb_slb_invalidate(struct cxl *adapter)
dev_warn(&adapter->dev, "WARNING: CXL adapter wide SLBIA timed out!\n");
return -EBUSY;
}
+ if (!cxl_adapter_link_ok(adapter))
+ return -EIO;
cpu_relax();
}
return 0;
@@ -240,6 +265,11 @@ int cxl_afu_slbia(struct cxl_afu *afu)
dev_warn(&afu->dev, "WARNING: CXL AFU SLBIA timed out!\n");
return -EBUSY;
}
+ /* If the adapter has gone down, we can assume that we
+ * will PERST it and that will invalidate everything.
+ */
+ if (!cxl_adapter_link_ok(afu->adapter))
+ return -EIO;
cpu_relax();
}
return 0;
@@ -279,6 +309,8 @@ static void slb_invalid(struct cxl_context *ctx)
cxl_p1_write(adapter, CXL_PSL_SLBIA, CXL_TLB_SLB_IQ_LPIDPID);
while (1) {
+ if (!cxl_adapter_link_ok(adapter))
+ break;
slbia = cxl_p1_read(adapter, CXL_PSL_SLBIA);
if (!(slbia & CXL_TLB_SLB_P))
break;
@@ -308,6 +340,11 @@ static int do_process_element_cmd(struct cxl_context *ctx,
rc = -EBUSY;
goto out;
}
+ if (!cxl_adapter_link_ok(ctx->afu->adapter)) {
+ dev_warn(&ctx->afu->dev, "WARNING: Device link down, aborting Process Element Command!\n");
+ rc = -EIO;
+ goto out;
+ }
state = be64_to_cpup(ctx->afu->sw_command_status);
if (state == ~0ULL) {
pr_err("cxl: Error adding process element to AFU\n");
@@ -355,8 +392,13 @@ static int terminate_process_element(struct cxl_context *ctx)
mutex_lock(&ctx->afu->spa_mutex);
pr_devel("%s Terminate pe: %i started\n", __func__, ctx->pe);
- rc = do_process_element_cmd(ctx, CXL_SPA_SW_CMD_TERMINATE,
- CXL_PE_SOFTWARE_STATE_V | CXL_PE_SOFTWARE_STATE_T);
+ /* We could be asked to terminate when the hw is down. That
+ * should always succeed: it's not running if the hw has gone
+ * away and is being reset.
+ */
+ if (cxl_adapter_link_ok(ctx->afu->adapter))
+ rc = do_process_element_cmd(ctx, CXL_SPA_SW_CMD_TERMINATE,
+ CXL_PE_SOFTWARE_STATE_V | CXL_PE_SOFTWARE_STATE_T);
ctx->elem->software_state = 0; /* Remove Valid bit */
pr_devel("%s Terminate pe: %i finished\n", __func__, ctx->pe);
mutex_unlock(&ctx->afu->spa_mutex);
@@ -369,7 +411,14 @@ static int remove_process_element(struct cxl_context *ctx)
mutex_lock(&ctx->afu->spa_mutex);
pr_devel("%s Remove pe: %i started\n", __func__, ctx->pe);
- if (!(rc = do_process_element_cmd(ctx, CXL_SPA_SW_CMD_REMOVE, 0)))
+
+ /* We could be asked to remove when the hw is down. Again, if
+ * the hw is down, the PE is gone, so we succeed.
+ */
+ if (cxl_adapter_link_ok(ctx->afu->adapter))
+ rc = do_process_element_cmd(ctx, CXL_SPA_SW_CMD_REMOVE, 0);
+
+ if (!rc)
ctx->pe_inserted = false;
slb_invalid(ctx);
pr_devel("%s Remove pe: %i finished\n", __func__, ctx->pe);
@@ -612,6 +661,11 @@ int cxl_afu_activate_mode(struct cxl_afu *afu, int mode)
if (!(mode & afu->modes_supported))
return -EINVAL;
+ if (!cxl_adapter_link_ok(afu->adapter)) {
+ WARN(1, "Device link is down, refusing to activate!\n");
+ return -EIO;
+ }
+
if (mode == CXL_MODE_DIRECTED)
return activate_afu_directed(afu);
if (mode == CXL_MODE_DEDICATED)
@@ -622,6 +676,11 @@ int cxl_afu_activate_mode(struct cxl_afu *afu, int mode)
int cxl_attach_process(struct cxl_context *ctx, bool kernel, u64 wed, u64 amr)
{
+ if (!cxl_adapter_link_ok(ctx->afu->adapter)) {
+ WARN(1, "Device link is down, refusing to attach process!\n");
+ return -EIO;
+ }
+
ctx->kernel = kernel;
if (ctx->afu->current_mode == CXL_MODE_DIRECTED)
return attach_afu_directed(ctx, wed, amr);
@@ -666,6 +725,12 @@ int cxl_get_irq(struct cxl_afu *afu, struct cxl_irq_info *info)
{
u64 pidtid;
+ /* If the adapter has gone away, we can't get any meaningful
+ * information.
+ */
+ if (!cxl_adapter_link_ok(afu->adapter))
+ return -EIO;
+
info->dsisr = cxl_p2n_read(afu, CXL_PSL_DSISR_An);
info->dar = cxl_p2n_read(afu, CXL_PSL_DAR_An);
info->dsr = cxl_p2n_read(afu, CXL_PSL_DSR_An);
diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
index 2eba002b580b..2930911c1e42 100644
--- a/drivers/misc/cxl/vphb.c
+++ b/drivers/misc/cxl/vphb.c
@@ -138,6 +138,26 @@ static int cxl_pcie_config_info(struct pci_bus *bus, unsigned int devfn,
return 0;
}
+
+static inline bool cxl_config_link_ok(struct pci_bus *bus)
+{
+ struct pci_controller *phb;
+ struct cxl_afu *afu;
+
+ /* Config space IO is based on phb->cfg_addr, which is based on
+ * afu_desc_mmio. This isn't safe to read/write when the link
+ * goes down, as EEH tears down MMIO space.
+ *
+ * Check if the link is OK before proceeding.
+ */
+
+ phb = pci_bus_to_host(bus);
+ if (phb == NULL)
+ return false;
+ afu = (struct cxl_afu *)phb->private_data;
+ return cxl_adapter_link_ok(afu->adapter);
+}
+
static int cxl_pcie_read_config(struct pci_bus *bus, unsigned int devfn,
int offset, int len, u32 *val)
{
@@ -150,6 +170,9 @@ static int cxl_pcie_read_config(struct pci_bus *bus, unsigned int devfn,
if (rc)
return rc;
+ if (!cxl_config_link_ok(bus))
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
/* Can only read 32 bits */
*val = (in_le32(ioaddr) >> shift) & mask;
return PCIBIOS_SUCCESSFUL;
@@ -167,6 +190,9 @@ static int cxl_pcie_write_config(struct pci_bus *bus, unsigned int devfn,
if (rc)
return rc;
+ if (!cxl_config_link_ok(bus))
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
/* Can only write 32 bits so do read-modify-write */
mask <<= shift;
val <<= shift;
--
2.1.4
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