[PATCH v5 2/3] ACPI, APEI, EINJ: Add CXL 1.1 EINJ error type support

Ben Cheatham
2023-09-25T20:02:23Z

Add support for CXL EINJ error types for CXL 1.1 hosts added in ACPI
v6.5. Because these error types target memory-mapped CXL 1.1 compliant
downstream ports and not physical (normal/persistent) memory, these
error types are not currently allowed through the memory range
validation done by the EINJ driver.

The MMIO address of a CXL 1.1 downstream port can be found in the
cxl_rcrb_addr file in the corresponding dport directory under
/sys/bus/cxl/devices/portX. CXL 1.1 error types follow the same
procedure as a memory error type, but with param1 set to the
downstream port MMIO address.

Example usage:
$ cd /sys/kernel/debug/apei/einj
$ cat available_error_type
0x00000008 Memory Correctable
0x00000010 Memory Uncorrectable non-fatal
0x00000020 Memory Uncorrectable fatal
0x00000040 PCI Express Correctable
0x00000080 PCI Express Uncorrectable non-fatal
0x00000100 PCI Express Uncorrectable fatal
0x00008000 CXL.mem Protocol Correctable
0x00020000 CXL.mem Protocol Uncorrectable fatal
$ echo 0x8000 > error_type
$ echo 0xfffffffffffff000 > param2
$ echo 0x2 > flags
$ cat /sys/bus/cxl/devices/portX/dportY/cxl_rcrb_addr
0xb2f00000
$ echo 0xb2f00000 > param1
$ echo 1 > error_inject

Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
---
drivers/acpi/apei/Kconfig | 2 ++
drivers/acpi/apei/einj.c | 24 +++++++++++++++++++++++-
drivers/cxl/acpi.c | 1 +
drivers/cxl/core/port.c | 17 +++++++++++++++++
drivers/cxl/cxl.h | 1 +
include/linux/cxl.h | 11 +++++++++++
6 files changed, 55 insertions(+), 1 deletion(-)
create mode 100644 include/linux/cxl.h

diff --git a/drivers/acpi/apei/Kconfig b/drivers/acpi/apei/Kconfig
index 6b18f8bc7be3..eb9cc7157342 100644
--- a/drivers/acpi/apei/Kconfig
+++ b/drivers/acpi/apei/Kconfig
@@ -55,6 +55,8 @@ config ACPI_APEI_MEMORY_FAILURE
config ACPI_APEI_EINJ
tristate "APEI Error INJection (EINJ)"
depends on ACPI_APEI && DEBUG_FS
+ imply CXL_BUS
+ imply CXL_ACPI
help
EINJ provides a hardware error injection mechanism, it is
mainly used for debugging and testing the other parts of
diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c
index 013eb621dc92..8000417a5f26 100644
--- a/drivers/acpi/apei/einj.c
+++ b/drivers/acpi/apei/einj.c
@@ -21,6 +21,7 @@
#include <linux/nmi.h>
#include <linux/delay.h>
#include <linux/mm.h>
+#include <linux/cxl.h>
#include <asm/unaligned.h>

#include "apei-internal.h"
@@ -36,6 +37,7 @@
#define MEM_ERROR_MASK (ACPI_EINJ_MEMORY_CORRECTABLE | \
ACPI_EINJ_MEMORY_UNCORRECTABLE | \
ACPI_EINJ_MEMORY_FATAL)
+#define CXL_ERROR_MASK GENMASK(17, 12)

/*
* ACPI version 5 provides a SET_ERROR_TYPE_WITH_ADDRESS action.
@@ -512,6 +514,22 @@ static int __einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
return rc;
}

+static int is_valid_cxl_addr(u64 addr)
+{
+ struct cxl_dport *dport;
+
+ if (IS_REACHABLE(CONFIG_CXL_ACPI))
+ dport = cxl_find_rch_dport_by_rcrb((resource_size_t) addr);
+ else
+ return 0;
+
+ if (!IS_ERR_OR_NULL(dport))
+ return 1;
+
+ pr_info("Could not find dport with rcrb 0x%llx\n", addr);
+ return 0;
+}
+
/* Inject the specified hardware error */
static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
u64 param3, u64 param4)
@@ -537,8 +555,11 @@ static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
if (type & ACPI5_VENDOR_BIT) {
if (vendor_flags != SETWA_FLAGS_MEM)
goto inject;
- } else if (!(type & MEM_ERROR_MASK) && !(flags & SETWA_FLAGS_MEM))
+ } else if (!(type & MEM_ERROR_MASK) && !(flags & SETWA_FLAGS_MEM)) {
goto inject;
+ } else if (type & CXL_ERROR_MASK && is_valid_cxl_addr(param1)) {
+ goto inject;
+ }

/*
* Disallow crazy address masks that give BIOS leeway to pick
@@ -807,3 +828,4 @@ module_exit(einj_exit);
MODULE_AUTHOR("Huang Ying");
MODULE_DESCRIPTION("APEI Error INJection support");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(CXL);
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 3e2ca946bf47..a7adf3d9814e 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -756,6 +756,7 @@ static void __exit cxl_acpi_exit(void)
{
platform_driver_unregister(&cxl_acpi_driver);
cxl_bus_drain();
+ set_cxl_root(NULL);
}

/* load before dax_hmem sees 'Soft Reserved' CXL ranges */
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index c3914e73f67e..cb653cb1a1ea 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -1147,6 +1147,23 @@ struct cxl_dport *devm_cxl_add_rch_dport(struct cxl_port *port,
}
EXPORT_SYMBOL_NS_GPL(devm_cxl_add_rch_dport, CXL);

+struct cxl_dport *cxl_find_rch_dport_by_rcrb(resource_size_t rcrb_base)
+{
+ struct cxl_dport *dport;
+ unsigned long index;
+
+ if (!cxl_root)
+ return ERR_PTR(-ENODEV);
+
+ xa_for_each(&cxl_root->dports, index, dport)
+ if ((dport->rch && dport->rcrb.base != CXL_RESOURCE_NONE)
+ && dport->rcrb.base == rcrb_base)
+ return dport;
+
+ return NULL;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_find_rch_dport_by_rcrb, CXL);
+
static int add_ep(struct cxl_ep *new)
{
struct cxl_port *port = new->dport->port;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 4d5bce4bae7e..3e6779dbcd23 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -8,6 +8,7 @@
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/log2.h>
+#include <linux/cxl.h>
#include <linux/io.h>

/**
diff --git a/include/linux/cxl.h b/include/linux/cxl.h
new file mode 100644
index 000000000000..6702caa78e7a
--- /dev/null
+++ b/include/linux/cxl.h
@@ -0,0 +1,11 @@
+#ifndef _LINUX_CXL_H
+#define _LINUX_CXL_H
+
+#include <linux/xarray.h>
+#include <linux/errno.h>
+
+struct cxl_dport;
+
+struct cxl_dport *cxl_find_rch_dport_by_rcrb(resource_size_t rcrb_base);
+
+#endif
--
2.34.1