Add Feather-Trace x86_32 architecture dependent code

Add x86_32 architecture dependent code and add the infrastructure
for x86_32 - x86_64 integration.

2 files changed, 114 insertions, 0 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index d8e5d0cdd678..a99b34d1b3b8 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -117,6 +117,8 @@ obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
 
 obj-$(CONFIG_SWIOTLB)                   += pci-swiotlb.o
 
+obj-$(CONFIG_FEATHER_TRACE)     += ft_event.o
+
 ###
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/ft_event.c b/arch/x86/kernel/ft_event.c
new file mode 100644
index 000000000000..e07ee30dfff9
--- /dev/null
+++ b/arch/x86/kernel/ft_event.c
@@ -0,0 +1,112 @@
+#include <linux/types.h>
+
+#include <litmus/feather_trace.h>
+
+#ifdef __ARCH_HAS_FEATHER_TRACE
+/* the feather trace management functions assume
+ * exclusive access to the event table
+ */
+
+
+#define BYTE_JUMP      0xeb
+#define BYTE_JUMP_LEN  0x02
+
+/* for each event, there is an entry in the event table */
+struct trace_event {
+        long    id;
+        long    count;
+        long    start_addr;
+        long    end_addr;
+};
+
+extern struct trace_event  __start___event_table[];
+extern struct trace_event  __stop___event_table[];
+
+int ft_enable_event(unsigned long id)
+{
+        struct trace_event* te = __start___event_table;
+        int count = 0;
+        char* delta;
+        unsigned char* instr;
+
+        while (te < __stop___event_table) {
+                if (te->id == id && ++te->count == 1) {
+                        instr  = (unsigned char*) te->start_addr;
+                        /* make sure we don't clobber something wrong */
+                        if (*instr == BYTE_JUMP) {
+                                delta  = (((unsigned char*) te->start_addr) + 1);
+                                *delta = 0;
+                        }
+                }
+                if (te->id == id)
+                        count++;
+                te++;
+        }
+
+        printk(KERN_DEBUG "ft_enable_event: enabled %d events\n", count);
+        return count;
+}
+
+int ft_disable_event(unsigned long id)
+{
+        struct trace_event* te = __start___event_table;
+        int count = 0;
+        char* delta;
+        unsigned char* instr;
+
+        while (te < __stop___event_table) {
+                if (te->id == id && --te->count == 0) {
+                        instr  = (unsigned char*) te->start_addr;
+                        if (*instr == BYTE_JUMP) {
+                                delta  = (((unsigned char*) te->start_addr) + 1);
+                                *delta = te->end_addr - te->start_addr -
+                                        BYTE_JUMP_LEN;
+                        }
+                }
+                if (te->id == id)
+                        count++;
+                te++;
+        }
+
+        printk(KERN_DEBUG "ft_disable_event: disabled %d events\n", count);
+        return count;
+}
+
+int ft_disable_all_events(void)
+{
+        struct trace_event* te = __start___event_table;
+        int count = 0;
+        char* delta;
+        unsigned char* instr;
+
+        while (te < __stop___event_table) {
+                if (te->count) {
+                        instr  = (unsigned char*) te->start_addr;
+                        if (*instr == BYTE_JUMP) {
+                                delta  = (((unsigned char*) te->start_addr)
+                                          + 1);
+                                *delta = te->end_addr - te->start_addr -
+                                        BYTE_JUMP_LEN;
+                                te->count = 0;
+                                count++;
+                        }
+                }
+                te++;
+        }
+        return count;
+}
+
+int ft_is_event_enabled(unsigned long id)
+{
+        struct trace_event* te = __start___event_table;
+
+        while (te < __stop___event_table) {
+                if (te->id == id)
+                        return te->count;
+                te++;
+        }
+        return 0;
+}
+
+#endif
+