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Subject[PATCH v3 1/5] I/O Hook: core functions and Register Override
Date
This is the 3rd version of I/O Hook, a patch set aimed at intercepting
h/w access by the OS. Some examples of how it can be used:
1) To emulate h/w events (e.g. hotplug)
2) To inject h/w errors to the kernel
3) To trace h/w access by the OS for performance tuning or debugging
Details of the examples can be found in Documentation/PCI/iohook.txt.

A set of user space tools using I/O Hook for various use cases will be hosted
on https://github.com/iohook. It initially contains inject-aer which takes the
trace event output of /sys/kernel/debug/tracing/events/ras/aer_event/ and
regenerate the same PCIE AER event so that PCIE AER can be easily tested.

This patch provides a hook in the core h/w access functions in the kernel.
It also introduces Register Override, which is a set of bits defined in RAM
to override the real value of a h/w register. With the hook in place, access
to h/w registers can be redirected to Register Overrides with user-defined
values, so that h/w states can be emulated easily.

A Register Override can be defined in whatever bit-width, identified by its
address, bitmask, initial value and attributs like read-only, read-write,
write-clear, etc., similar to how a hardware register behaves when accessed.

Jump Label is used, so when the hook is disabled (by default), this adds
only a NOP to the core functions, with zero performance penalty.

This patch is the first step towards the goal of emulating h/w events.

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
---
arch/Kconfig | 10 +
arch/x86/boot/compressed/Makefile | 1 +
arch/x86/include/asm/io.h | 57 +++++-
arch/x86/vdso/Makefile | 2 +
drivers/misc/Makefile | 1 +
drivers/misc/iohook/Makefile | 1 +
drivers/misc/iohook/iohook.c | 392 +++++++++++++++++++++++++++++++++++++
drivers/misc/iohook/iohook.h | 6 +
drivers/pci/access.c | 66 ++++++
include/linux/reg_ovrd.h | 54 +++++
10 files changed, 588 insertions(+), 2 deletions(-)
create mode 100644 drivers/misc/iohook/Makefile
create mode 100644 drivers/misc/iohook/iohook.c
create mode 100644 drivers/misc/iohook/iohook.h
create mode 100644 include/linux/reg_ovrd.h

diff --git a/arch/Kconfig b/arch/Kconfig
index 97ff872..55b224a 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -46,6 +46,16 @@ config KPROBES
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".

+config IO_HOOK
+ bool "Method for emulating hardware events"
+ default n
+ depends on PCI
+ help
+ I/O Hook is a mechanism to intercept i/o register access functions
+ in the kernel. By overriding h/w register bits with user-defined
+ bits in RAM called Register Override, it is possible to emulate
+ h/w states without modifying the driver specific to that hardware.
+
config JUMP_LABEL
bool "Optimize very unlikely/likely branches"
depends on HAVE_ARCH_JUMP_LABEL
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 0fcd913..ea53270 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -10,6 +10,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
KBUILD_CFLAGS += -fno-strict-aliasing -fPIC
KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
+KBUILD_CFLAGS += -DNO_IO_HOOK
cflags-$(CONFIG_X86_32) := -march=i386
cflags-$(CONFIG_X86_64) := -mcmodel=small
KBUILD_CFLAGS += $(cflags-y)
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index b8237d8..e3db0ab 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -41,14 +41,41 @@
#include <asm/page.h>
#include <asm/early_ioremap.h>

+#if !defined(NO_IO_HOOK) && defined(CONFIG_IO_HOOK)
+#include <linux/jump_label.h>
+#include <linux/reg_ovrd.h>
+
+#define mem_read_ovrd(type, addr) \
+{ \
+ type val;\
+ if (static_key_false(&ovrdhw_enabled) \
+ && !read_ovrd_common(OVRD_SPACE_MEM, (u64)addr, \
+ sizeof(type), &val, NULL)) \
+ return val; \
+}
+
+#define mem_write_ovrd(type, addr, val) \
+{ \
+ if (static_key_false(&ovrdhw_enabled) \
+ && !write_ovrd_common(OVRD_SPACE_MEM, (u64)addr,\
+ sizeof(type), &val, NULL)) \
+ return; \
+}
+#else /* CONFIG_IO_HOOK */
+#define mem_read_ovrd(type, addr)
+#define mem_write_ovrd(type, addr, val)
+#endif /* CONFIG_IO_HOOK */
+
#define build_mmio_read(name, size, type, reg, barrier) \
static inline type name(const volatile void __iomem *addr) \
-{ type ret; asm volatile("mov" size " %1,%0":reg (ret) \
+{ type ret; mem_read_ovrd(type, addr); \
+asm volatile("mov" size " %1,%0" : reg(ret) \
:"m" (*(volatile type __force *)addr) barrier); return ret; }

#define build_mmio_write(name, size, type, reg, barrier) \
static inline void name(type val, volatile void __iomem *addr) \
-{ asm volatile("mov" size " %0,%1": :reg (val), \
+{ mem_write_ovrd(type, addr, val); \
+asm volatile("mov" size " %0,%1" : : reg(val), \
"m" (*(volatile type __force *)addr) barrier); }

build_mmio_read(readb, "b", unsigned char, "=q", :"memory")
@@ -266,9 +293,34 @@ static inline void slow_down_io(void)

#endif

+#if !defined(NO_IO_HOOK) && defined(CONFIG_IO_HOOK)
+
+#define io_write_ovrd(type, value, port) \
+{ \
+ if (static_key_false(&ovrdhw_enabled) \
+ && !write_ovrd_common(OVRD_SPACE_IO, (u64)port, \
+ sizeof(type), &value, NULL)) \
+ return; \
+}
+
+#define io_read_ovrd(type, port) \
+{ \
+ type val; \
+ if (static_key_false(&ovrdhw_enabled) \
+ && !read_ovrd_common(OVRD_SPACE_IO, (u64)port, \
+ sizeof(type), &val, NULL)) \
+ return val; \
+}
+
+#else
+#define io_write_ovrd(type, value, port)
+#define io_read_ovrd(type, port)
+#endif
+
#define BUILDIO(bwl, bw, type) \
static inline void out##bwl(unsigned type value, int port) \
{ \
+ io_write_ovrd(type, value, port); \
asm volatile("out" #bwl " %" #bw "0, %w1" \
: : "a"(value), "Nd"(port)); \
} \
@@ -276,6 +328,7 @@ static inline void out##bwl(unsigned type value, int port) \
static inline unsigned type in##bwl(int port) \
{ \
unsigned type value; \
+ io_read_ovrd(type, port); \
asm volatile("in" #bwl " %w1, %" #bw "0" \
: "=a"(value) : "Nd"(port)); \
return value; \
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index c580d12..521405d 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -4,6 +4,8 @@

KBUILD_CFLAGS += $(DISABLE_LTO)

+KBUILD_CFLAGS += -DNO_IO_HOOK
+
VDSO64-$(CONFIG_X86_64) := y
VDSOX32-$(CONFIG_X86_X32_ABI) := y
VDSO32-$(CONFIG_X86_32) := y
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7eb4b69..baaa135 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -49,6 +49,7 @@ obj-y += carma/
obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o
obj-$(CONFIG_ALTERA_STAPL) +=altera-stapl/
obj-$(CONFIG_INTEL_MEI) += mei/
+obj-$(CONFIG_IO_HOOK) += iohook/
obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/
obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o
obj-$(CONFIG_SRAM) += sram.o
diff --git a/drivers/misc/iohook/Makefile b/drivers/misc/iohook/Makefile
new file mode 100644
index 0000000..80e2a7d
--- /dev/null
+++ b/drivers/misc/iohook/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_IO_HOOK) += iohook.o
diff --git a/drivers/misc/iohook/iohook.c b/drivers/misc/iohook/iohook.c
new file mode 100644
index 0000000..e6a626f
--- /dev/null
+++ b/drivers/misc/iohook/iohook.c
@@ -0,0 +1,392 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/reg_ovrd.h>
+#include <linux/pci.h>
+#include "iohook.h"
+
+static DEFINE_RAW_SPINLOCK(io_hook_lock);
+
+LIST_HEAD(ovrd_io_reg_map);
+LIST_HEAD(ovrd_mem_reg_map);
+LIST_HEAD(ovrd_pci_conf_reg_map);
+
+struct static_key ovrdhw_enabled = STATIC_KEY_INIT_FALSE;
+EXPORT_SYMBOL(ovrdhw_enabled);
+
+/* len should only be 1, 2, 4, 8 */
+static int mem_read(u64 address, int len, void *data)
+{
+ int ret = 0;
+
+ switch (len) {
+ case 1:
+ *(u8 *)data = *(u8 *)address;
+ break;
+ case 2:
+ *(u16 *)data = *(u16 *)address;
+ break;
+ case 4:
+ *(u32 *)data = *(u32 *)address;
+ break;
+ case 8:
+ *(u64 *)data = *(u64 *)address;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+
+}
+
+static int mem_write(u64 address, int len, void *value)
+{
+ int ret = 0;
+
+ switch (len) {
+ case 1:
+ *(u8 *)address = *(u8 *)value;
+ break;
+ case 2:
+ *(u16 *)address = *(u16 *)value;
+ break;
+ case 4:
+ *(u32 *)address = *(u32 *)value;
+ break;
+ case 8:
+ *(u64 *)address = *(u64 *)value;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+
+}
+
+#ifdef CONFIG_X86
+
+/* len should only be 1, 2, 4 */
+static int io_read(u64 address, int len, void *data)
+{
+ int ret = 0;
+ u16 port;
+ u8 bvalue;
+ u16 wvalue;
+ u32 lvalue;
+
+
+ port = (u16)address;
+
+ switch (len) {
+ case 1:
+ asm volatile ("inb %w1, %b0" : "=a"(bvalue) : "Nd"(port));
+ *(u8 *)data = bvalue;
+ break;
+ case 2:
+ asm volatile ("inw %w1, %w0" : "=a"(wvalue) : "Nd"(port));
+ *(u16 *)data = wvalue;
+ break;
+ case 4:
+ asm volatile ("inl %w1, %0" : "=a"(lvalue) : "Nd"(port));
+ *(u32 *)data = lvalue;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+
+}
+
+static int io_write(u64 address, int len, void *data)
+{
+ int ret = 0;
+ u8 bvalue;
+ u16 wvalue, port;
+ u32 lvalue;
+
+ port = (u16)address;
+
+ switch (len) {
+ case 1:
+ bvalue = *(u8 *)data;
+ asm volatile ("outb %b0, %w1" : : "a"(bvalue), "Nd"(port));
+ break;
+ case 2:
+ wvalue = *(u16 *)data;
+ asm volatile ("outw %w0, %w1" : : "a"(wvalue), "Nd"(port));
+ break;
+ case 4:
+ lvalue = *(u32 *)data;
+ asm volatile ("outl %0, %w1" : : "a"(lvalue), "Nd"(port));
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+
+}
+
+#else
+
+static int io_read(u64 address, int len, void *data)
+{
+ return -EINVAL;
+}
+
+static int io_write(u64 address, int len, void *data)
+{
+ return -EINVAL;
+}
+
+#endif /* CONFIG_X86 */
+
+static u64 v2p(u64 vaddr)
+{
+ return slow_virt_to_phys((void *)vaddr);
+}
+
+/* shift left if i>=0, otherwise shift right */
+#define BYTE_SHIFT(value, i) \
+ ((i) >= 0 ? (value) << (i)*8 : (value) >> (-i)*8)
+
+int read_ovrd_common(int spaceid, u64 address, int len, void *value, void *bus)
+{
+ struct list_head *ovrd_list;
+ struct reg_ovrd *ovrd_reg;
+ struct pci_bus *pcib;
+ unsigned long lock_flags = 0, flags = 0;
+ u64 faddress, vaddr = 0;
+ u64 data, bit_mask, attrib, val;
+ unsigned int devfn = 0, pos = 0;
+ int i, flength, res, ret;
+
+ ret = -EINVAL;
+
+ if (spaceid == OVRD_SPACE_MEM) {
+ /* in the case of memory, 'address' is virtual */
+ vaddr = address;
+ address = v2p(address);
+ ovrd_list = &ovrd_mem_reg_map;
+ } else if (spaceid == OVRD_SPACE_IO) {
+ ovrd_list = &ovrd_io_reg_map;
+ } else if (spaceid == OVRD_SPACE_PCICONF) {
+ devfn = PCI_DECODE_DEVFN(address);
+ pos = PCI_DECODE_POS(address);
+ ovrd_list = &ovrd_pci_conf_reg_map;
+ } else {
+ return ret;
+ }
+
+ raw_spin_lock_irqsave(&io_hook_lock, lock_flags);
+ list_for_each_entry(ovrd_reg, ovrd_list, node) {
+
+ faddress = ovrd_reg->address;
+ flength = ovrd_reg->length;
+ val = ovrd_reg->val;
+ bit_mask = ovrd_reg->bit_mask;
+ attrib = ovrd_reg->attrib;
+
+ if (address >= faddress + flength ||
+ address + len <= faddress) {
+ /* no overlap, skip */
+ continue;
+ }
+
+ raw_spin_unlock_irqrestore(&io_hook_lock,
+ lock_flags);
+
+ /* at least one byte falls into the overridden range */
+ data = 0;
+ ret = 0;
+ if (!(address >= faddress && address+len <= faddress+flength &&
+ bit_mask == (u64)((1<<flength*8) - 1))) {
+ /* partially overridden. Read from HW for real bits */
+
+ if (spaceid == OVRD_SPACE_MEM) {
+ res = mem_read(vaddr, len, &data);
+ } else if (spaceid == OVRD_SPACE_IO) {
+ res = io_read(address, len, &data);
+ } else if (spaceid == OVRD_SPACE_PCICONF) {
+ raw_spin_lock_irqsave(&pci_lock, flags);
+ pcib = (struct pci_bus *)bus;
+ res = pcib->ops->read(pcib, devfn, pos, len,
+ (u32 *)&data);
+ raw_spin_unlock_irqrestore(&pci_lock, flags);
+ } else
+ goto out;
+
+ if (res) {
+ /* failed to read from HW, clear the result */
+ data = 0;
+ }
+ }
+
+ for (i = 0; i < len; i++) {
+ if (address+i >= faddress &&
+ address+i < faddress+flength) {
+ int j, k;
+
+ j = address + i - faddress;
+ k = faddress - address;
+ if (flength <= 8) {
+ /* <= 8 bytes, use bit_mask */
+ u64 byte_mask;
+
+ byte_mask =
+ bit_mask & BYTE_SHIFT(0xff, j);
+ data &= ~BYTE_SHIFT(byte_mask, k);
+ data |= BYTE_SHIFT(val & byte_mask, k);
+ if (attrib == OVRD_RC)
+ ovrd_reg->val &= ~byte_mask;
+
+ } else {
+ /* If flength is > 8, this is
+ * used to override a consecutive
+ * range of readonly identical
+ * bytes.
+ */
+ data |= (val & 0xff) << i*8;
+ }
+ }
+ }
+
+ switch (len) {
+ case 1:
+ *(u8 *)value = (u8)data;
+ break;
+ case 2:
+ *(u16 *)value = (u16)data;
+ break;
+ case 4:
+ *(u32 *)value = (u32)data;
+ break;
+ case 8:
+ *(u64 *)value = data;
+ break;
+ default:
+ ret = -EINVAL;
+ goto out;
+ }
+
+ raw_spin_lock_irqsave(&io_hook_lock,
+ lock_flags);
+ }
+
+ raw_spin_unlock_irqrestore(&io_hook_lock, lock_flags);
+out:
+ return ret;
+}
+EXPORT_SYMBOL(read_ovrd_common);
+
+int write_ovrd_common(int spaceid, u64 address, int len, void *data, void *bus)
+{
+ struct list_head *ovrd_list;
+ struct reg_ovrd *ovrd_reg;
+ struct pci_bus *pcib;
+ unsigned long lock_flags = 0, flags = 0;
+ u64 faddress, vaddr = 0;
+ u64 bit_mask, val, attrib;
+ unsigned int devfn = 0, pos = 0;
+ int i, flength, res, ret;
+ u64 value;
+
+ ret = -EINVAL;
+
+ if (spaceid == OVRD_SPACE_MEM) {
+ /* in the case of memory, 'address' is virtual */
+ vaddr = address;
+ address = v2p(address);
+ ovrd_list = &ovrd_mem_reg_map;
+ } else if (spaceid == OVRD_SPACE_IO) {
+ ovrd_list = &ovrd_io_reg_map;
+ } else if (spaceid == OVRD_SPACE_PCICONF) {
+ devfn = PCI_DECODE_DEVFN(address);
+ pos = PCI_DECODE_POS(address);
+ ovrd_list = &ovrd_pci_conf_reg_map;
+ } else {
+ return ret;
+ }
+
+ raw_spin_lock_irqsave(&io_hook_lock, lock_flags);
+ list_for_each_entry(ovrd_reg, ovrd_list, node) {
+
+ faddress = ovrd_reg->address;
+ flength = ovrd_reg->length;
+ val = ovrd_reg->val;
+ bit_mask = ovrd_reg->bit_mask;
+ attrib = ovrd_reg->attrib;
+ value = *(u64 *)data;
+
+ if (address >= faddress + flength ||
+ address + len <= faddress) {
+ /* no overlap, skip */
+ continue;
+ }
+
+ ret = 0;
+
+ if (!(address >= faddress && address+len <= faddress+flength &&
+ bit_mask == (u64)((1<<flength*8) - 1))) {
+ /* partially overridden. write to HW for real bits */
+ if (spaceid == OVRD_SPACE_MEM) {
+ res = mem_write(vaddr, len, data);
+ } else if (spaceid == OVRD_SPACE_IO) {
+ res = io_write(address, len, data);
+ } else if (spaceid == OVRD_SPACE_PCICONF) {
+ raw_spin_unlock_irqrestore(&io_hook_lock,
+ lock_flags);
+ raw_spin_lock_irqsave(&pci_lock, flags);
+ pcib = (struct pci_bus *)bus;
+ pcib->ops->write(pcib, devfn, pos, len,
+ (u32)value);
+ raw_spin_unlock_irqrestore(&pci_lock, flags);
+ raw_spin_lock_irqsave(&io_hook_lock,
+ lock_flags);
+ } else
+ break;
+ }
+
+ for (i = 0; i < len; i++) {
+ if (address+i >= faddress &&
+ address+i < faddress+flength) {
+ int j, k;
+
+ j = address + i - faddress;
+ k = faddress - address;
+ if (flength <= 8) {
+ /* <= 8 bytes, use bit_mask */
+ u64 byte_mask;
+
+ byte_mask =
+ bit_mask & BYTE_SHIFT(0xff, j);
+ if (attrib == OVRD_RW) {
+ ovrd_reg->val &= ~byte_mask;
+ ovrd_reg->val |=
+ BYTE_SHIFT(value, k)
+ & byte_mask;
+ } else if (attrib == OVRD_WC) {
+ ovrd_reg->val &=
+ ~(BYTE_SHIFT(value, k)
+ & byte_mask);
+ }
+
+ }
+ /* if flength > 8, must be OVRD_RO */
+ }
+ }
+
+ }
+
+ raw_spin_unlock_irqrestore(&io_hook_lock, lock_flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(write_ovrd_common);
diff --git a/drivers/misc/iohook/iohook.h b/drivers/misc/iohook/iohook.h
new file mode 100644
index 0000000..46c97be
--- /dev/null
+++ b/drivers/misc/iohook/iohook.h
@@ -0,0 +1,6 @@
+#ifndef _IOHOOK_H
+#define _IOHOOK_H
+
+extern raw_spinlock_t pci_lock;
+
+#endif
diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 7f8b78c..c1e0a2b 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -15,6 +15,68 @@

DEFINE_RAW_SPINLOCK(pci_lock);

+#ifdef CONFIG_IO_HOOK
+#include <linux/reg_ovrd.h>
+#include <linux/jump_label.h>
+
+int pci_bus_read_config_ovrd(struct pci_bus *bus, unsigned int devfn,
+ int pos, int len, void *value)
+{
+ u64 address;
+ int ret;
+
+ address = PCI_ENCODE_ADDR(pci_domain_nr(bus), bus->number, devfn, pos);
+
+ ret = read_ovrd_common(OVRD_SPACE_PCICONF, address, len,
+ value, (void *)bus);
+ if (!ret)
+ pr_info("read from %x:%x+%x-%x, ret=%x, val=0x%x\n",
+ bus->number, devfn, pos, len, ret, *(u32 *)value);
+ return ret;
+
+}
+
+int pci_bus_write_config_ovrd(struct pci_bus *bus, unsigned int devfn,
+ int pos, int len, u32 value)
+{
+ u64 address;
+ int ret;
+
+ address = PCI_ENCODE_ADDR(pci_domain_nr(bus), bus->number, devfn, pos);
+ ret = write_ovrd_common(OVRD_SPACE_PCICONF, address, len,
+ &value, (void *)bus);
+ if (!ret)
+ pr_info("write to %x:%x+%x-%x, ret=0x%x, val=0x%x\n",
+ bus->number, devfn, pos, len, ret, value);
+ return ret;
+
+
+}
+
+
+#define pci_read_ovrd(bus, devfn, pos, len, value) \
+{ \
+ if (static_key_false(&ovrdhw_enabled) \
+ && !pci_bus_read_config_ovrd(bus, devfn, pos, \
+ len, value)) \
+ return 0; \
+}
+
+#define pci_write_ovrd(bus, devfn, pos, len, value) \
+{ \
+ if (static_key_false(&ovrdhw_enabled) \
+ && !pci_bus_write_config_ovrd(bus, devfn, pos, \
+ len, value)) \
+ return 0; \
+}
+
+#else
+
+#define pci_read_ovrd(bus, devfn, pos, len, value)
+#define pci_write_ovrd(bus, devfn, pos, len, value)
+
+#endif /* CONFIG_IO_HOOK */
+
/*
* Wrappers for all PCI configuration access functions. They just check
* alignment, do locking and call the low-level functions pointed to
@@ -33,6 +95,7 @@ int pci_bus_read_config_##size \
unsigned long flags; \
u32 data = 0; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
+ pci_read_ovrd(bus, devfn, pos, len, value); \
raw_spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->read(bus, devfn, pos, len, &data); \
*value = (type)data; \
@@ -47,6 +110,7 @@ int pci_bus_write_config_##size \
int res; \
unsigned long flags; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
+ pci_write_ovrd(bus, devfn, pos, len, value) \
raw_spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->write(bus, devfn, pos, len, value); \
raw_spin_unlock_irqrestore(&pci_lock, flags); \
@@ -152,6 +216,7 @@ int pci_user_read_config_##size \
u32 data = -1; \
if (PCI_##size##_BAD) \
return -EINVAL; \
+ pci_read_ovrd(dev->bus, dev->devfn, pos, sizeof(type), (void *)val);\
raw_spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_cfg_access)) \
pci_wait_cfg(dev); \
@@ -173,6 +238,7 @@ int pci_user_write_config_##size \
int ret = -EIO; \
if (PCI_##size##_BAD) \
return -EINVAL; \
+ pci_write_ovrd(dev->bus, dev->devfn, pos, sizeof(type), val);\
raw_spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_cfg_access)) \
pci_wait_cfg(dev); \
diff --git a/include/linux/reg_ovrd.h b/include/linux/reg_ovrd.h
new file mode 100644
index 0000000..2707d6c
--- /dev/null
+++ b/include/linux/reg_ovrd.h
@@ -0,0 +1,54 @@
+#ifndef __REG_OVRD_H__
+#define __REG_OVRD_H__
+
+#include <linux/types.h>
+#include <linux/spinlock_types.h>
+
+enum ovrd_attrib {
+ OVRD_RW, /* readwrite */
+ OVRD_RO, /* readonly */
+ OVRD_RC, /* read clear */
+ OVRD_WC, /* write clear */
+ OVRD_TC, /* trace only */
+};
+
+/*
+ * address - Starting phys address of the h/w register
+ * length - # of bytes to be overridden
+ * val - When length <= 8, use (val & bit_mask) as the overridden value.
+ When length > 8, we're overriding a range of bytes to a single
+ readonly value. So attrib must be OVRD_RO, and (val & 0xff)
+ is the contiguous readonly value.
+ * bit_mask - used when length <= 8 to indicate which bits are being overridden.
+ unused when length > 8
+ * attrib - when length <=8, is the common attribute of the overridden
+ bits matching bit_mask. When length > 8, must be OVRD_RO
+ */
+struct reg_ovrd {
+ struct list_head node;
+ u64 address;
+ u64 val;
+ u64 bit_mask;
+ u32 length;
+ u8 attrib;
+};
+
+/* address space id */
+#define OVRD_SPACE_IO 0
+#define OVRD_SPACE_MEM 1
+#define OVRD_SPACE_PCICONF 2
+
+#define PCI_ENCODE_ADDR(domain, bus, devfn, pos) \
+ (((u64)(domain))<<32|(bus)<<20|(devfn)<<12|(pos))
+#define PCI_DECODE_POS(x) ((u16)((x) & ((1 << 12) - 1)))
+#define PCI_DECODE_DEVFN(x) ((u8)(((x) >> 12) & 0xff))
+#define PCI_DECODE_BUSN(x) ((u8)(((x) >> 20) & 0xff))
+#define PCI_DECODE_DOMAIN(x) ((u32)((x) >> 32))
+
+extern int read_ovrd_common(int spaceid, u64 address, int len, void *value,
+ void *bus);
+extern int write_ovrd_common(int spaceid, u64 address, int len, void *data,
+ void *bus);
+extern struct static_key ovrdhw_enabled;
+
+#endif /* __REG_OVRD_H__ */
--
1.7.5.4


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