Add the following kernel helper functions used to add/delete/query Register
Overrides, and to start/stop the I/O Hook:
        iohook_add_ovrd
        iohook_query_ovrd
        iohook_cleanup_ovrd
        iohook_start_ovrd
        iohook_stop_ovrd
        iohook_get_status

Signed-off-by: Rui Wang <rui.y.w...@intel.com>
---
 drivers/misc/iohook/iohook.c |  151 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 151 insertions(+), 0 deletions(-)

diff --git a/drivers/misc/iohook/iohook.c b/drivers/misc/iohook/iohook.c
index e6a626f..d8c41d0 100644
--- a/drivers/misc/iohook/iohook.c
+++ b/drivers/misc/iohook/iohook.c
@@ -6,6 +6,7 @@
 #include "iohook.h"
 
 static DEFINE_RAW_SPINLOCK(io_hook_lock);
+static DEFINE_RAW_SPINLOCK(engine_lock);
 
 LIST_HEAD(ovrd_io_reg_map);
 LIST_HEAD(ovrd_mem_reg_map);
@@ -14,6 +15,150 @@ LIST_HEAD(ovrd_pci_conf_reg_map);
 struct static_key ovrdhw_enabled = STATIC_KEY_INIT_FALSE;
 EXPORT_SYMBOL(ovrdhw_enabled);
 
+int    g_ovrd_on;
+/* query a Register Override given spaceid and index */
+struct reg_ovrd *iohook_query_ovrd(int spaceid, int idx)
+{
+       struct list_head *reg_ovrd;
+       struct reg_ovrd *ovrdreg, *regentry;
+       unsigned long lock_flags = 0;
+       int n = 0;
+
+       if (spaceid == OVRD_SPACE_MEM)
+               reg_ovrd = &ovrd_mem_reg_map;
+       else if (spaceid == OVRD_SPACE_IO)
+               reg_ovrd = &ovrd_io_reg_map;
+       else
+               reg_ovrd = &ovrd_pci_conf_reg_map;
+
+       regentry = NULL;
+       raw_spin_lock_irqsave(&io_hook_lock, lock_flags);
+       list_for_each_entry(ovrdreg, reg_ovrd, node) {
+               if (n++ >= idx) {
+                       regentry = ovrdreg;
+                       break;
+               }
+       }
+       raw_spin_unlock_irqrestore(&io_hook_lock, lock_flags);
+
+       pr_info("iohook_query_ovrd() returns %p, idx=%d\n",
+               regentry, idx);
+       return regentry;
+
+}
+
+/* delete all Register Overrides from one space (IO/mem/pciconf) */
+void iohook_cleanup_ovrd(int spaceid)
+{
+       struct list_head *tmp, *next, *ovrd_list;
+
+       if (spaceid == OVRD_SPACE_MEM)
+               ovrd_list = &ovrd_mem_reg_map;
+       else if (spaceid == OVRD_SPACE_IO)
+               ovrd_list = &ovrd_io_reg_map;
+       else
+               ovrd_list = &ovrd_pci_conf_reg_map;
+
+       list_for_each_safe(tmp, next, ovrd_list) {
+               struct reg_ovrd *ovrdreg =
+                   list_entry(tmp, struct reg_ovrd, node);
+               list_del(tmp);
+               kfree(ovrdreg);
+       }
+}
+
+/* for pci config space, address is encoded per PCI_ENCODE_ADDR() */
+void iohook_add_ovrd(int spaceid, u64 address, u64 value, u64 mask,
+               u32 length, u8 attrib)
+{
+       struct list_head *reg_ovrd;
+       struct reg_ovrd *ovrdreg;
+       unsigned long lock_flags = 0;
+
+       if (spaceid == OVRD_SPACE_MEM)
+               reg_ovrd = &ovrd_mem_reg_map;
+       else if (spaceid == OVRD_SPACE_IO)
+               reg_ovrd = &ovrd_io_reg_map;
+       else
+               reg_ovrd = &ovrd_pci_conf_reg_map;
+
+       raw_spin_lock_irqsave(&io_hook_lock, lock_flags);
+       list_for_each_entry(ovrdreg, reg_ovrd, node) {
+               if (ovrdreg->address == address &&
+                       ovrdreg->attrib == attrib &&
+                       ovrdreg->length == length) {
+                       /* if already added the address, just change the bits */
+                       ovrdreg->bit_mask |= mask;
+                       ovrdreg->val |= value;
+                       pr_info("iohook_add_ovrd(): 0x%llx already added, 
changed to 0x%llx, mask:0x%llx, attrib:0x%x\n",
+                               address, ovrdreg->val, ovrdreg->bit_mask,
+                               attrib);
+                       goto out;
+               } else if (address >= ovrdreg->address &&
+                       address < ovrdreg->address + ovrdreg->length) {
+                       pr_info("iohook_add_ovrd(): conflicting reg at 0x%llx, 
length:%llx, mask:0x%llx, attrib:0x%x\n",
+                               address, ovrdreg->val, ovrdreg->bit_mask,
+                               attrib);
+                       goto out;
+               }
+       }
+
+       raw_spin_unlock_irqrestore(&io_hook_lock, lock_flags);
+
+       ovrdreg = kmalloc(sizeof(struct reg_ovrd), GFP_ATOMIC);
+       if (!ovrdreg) {
+               pr_info("failed to alloc Reg Override!\n");
+               return;
+       }
+
+       ovrdreg->address = address;
+       ovrdreg->val = value;
+       ovrdreg->length = length;
+       ovrdreg->bit_mask = mask;
+       ovrdreg->attrib = attrib;
+       raw_spin_lock_irqsave(&io_hook_lock, lock_flags);
+       list_add_tail(&ovrdreg->node, reg_ovrd);
+out:
+       raw_spin_unlock_irqrestore(&io_hook_lock, lock_flags);
+
+}
+
+/* to start the hook */
+void iohook_start_ovrd(void)
+{
+       unsigned long lock_flags = 0;
+
+       raw_spin_lock_irqsave(&engine_lock, lock_flags);
+       if (g_ovrd_on)
+               goto done;
+
+       static_key_slow_inc(&ovrdhw_enabled);
+       g_ovrd_on = 1;
+done:
+       raw_spin_unlock_irqrestore(&engine_lock, lock_flags);
+
+}
+
+/* to stop the hook */
+void iohook_stop_ovrd(void)
+{
+       unsigned long lock_flags = 0;
+
+       raw_spin_lock_irqsave(&engine_lock, lock_flags);
+       if (!g_ovrd_on)
+               goto done;
+       g_ovrd_on = 0;
+       static_key_slow_dec(&ovrdhw_enabled);
+done:
+       raw_spin_unlock_irqrestore(&engine_lock, lock_flags);
+
+}
+
+int iohook_get_status(void)
+{
+       return g_ovrd_on;
+}
+
 /* len should only be 1, 2, 4, 8 */
 static int mem_read(u64 address, int len, void *data)
 {
@@ -170,6 +315,9 @@ int read_ovrd_common(int spaceid, u64 address, int len, 
void *value, void *bus)
 
        ret = -EINVAL;
 
+       if (!g_ovrd_on)
+               return ret;
+
        if (spaceid == OVRD_SPACE_MEM) {
                /* in the case of memory, 'address' is virtual */
                vaddr = address;
@@ -300,6 +448,9 @@ int write_ovrd_common(int spaceid, u64 address, int len, 
void *data, void *bus)
 
        ret = -EINVAL;
 
+       if (!g_ovrd_on)
+               return ret;
+
        if (spaceid == OVRD_SPACE_MEM) {
                /* in the case of memory, 'address' is virtual */
                vaddr = address;
-- 
1.7.5.4

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