File it-revert-dyn_patching.patch of Package itrace

---
 src/driver/Makefile          |    2 -
 src/driver/ppc64/pi_itrace.c |   65 +++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 64 insertions(+), 3 deletions(-)

--- a/src/driver/Makefile
+++ b/src/driver/Makefile
@@ -1,5 +1,5 @@
 src := $(ITRACE_DIR)/obj/ppc64
-EXTRA_CFLAGS += -D_LINUX -D_ST_ITRACE_ONLY
+EXTRA_CFLAGS += -D_LINUX -D_ST_ITRACE_ONLY -D_NO_DYNAMIC_PATCHING
 EXTRA_CFLAGS += -I$(src)/../../include
 # for hooks.h
 EXTRA_CFLAGS += -I$(src)
--- a/src/driver/ppc64/pi_itrace.c
+++ b/src/driver/ppc64/pi_itrace.c
@@ -52,6 +52,9 @@
  * 06/03/08     Karthik Ganesan Changed the way in which the instructions that clear the
  *				MSRRI are handled. We switch to branch mode within such
  *				unsafe areas of code.
+ * 10/21/08     Maynard Johnson Reinstate skipping around reservations.  Default behavior
+ *				will still use dynamic patching, but a compile switch
+ *				will control which method.
  */
                 
 /* TODO: summarize PMC usage */
@@ -223,7 +226,28 @@ int reservation_inst(unsigned int instr)
 #endif
 #endif // STAP_ITRACE BODY
 
+#ifdef _NO_DYNAMIC_PATCHING
+void skip_trace_section(struct pt_regs *regs)
+{
+        unsigned int mmcr0 = mfspr(SPRN_MMCR0);
+        mmcr0 |= MMCR0_PMXE;
+        mmcr0 |= 0x4000;        /* set PMCjCE bit */
+        mtspr(SPRN_MMCR0, mmcr0);
+
+        if (__is_processor(PV_POWER5) || __is_processor(PV_POWER5p) ||
+		 __is_processor(PV_POWER6)) {
+                unsigned int mmcr1 = mfspr(SPRN_MMCR1);
+                mmcr1 &= ~(0xff0000); /* clear out PMC2SEL */
+                mmcr1 |= 0x020000;      /* set PMC2SEL to 00000010 bits */
+                mtspr(SPRN_MMCR1, mmcr1);
+
+                mtspr(SPRN_PMC2, 0x7fffff40); /* set up to overflow soon */
+        } else
+                mtspr(SPRN_PMC4, 0x7ffffff0);   /* set up to overflow soon */
 
+        regs->msr |= MSR_PM;
+}
+#endif
 
 //
 // is_stepping_safe_ss()
@@ -240,6 +264,13 @@ int is_stepping_safe_ss(struct pt_regs *
 	if (clears_msrri(regs, instr, 1))
 		return 0;
 
+#ifdef _NO_DYNAMIC_PATCHING
+	if (reservation_inst(instr)) {
+		skip_trace_section(regs);
+		return 0;
+	}
+#endif
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)
 	/* 2.6.20 and earlier kernels (which includes SLES 9 and RHEL 4 kernels)
 	 * had a problem in ret_from_except where if you take an exception after
@@ -258,6 +289,23 @@ int is_stepping_safe_ss(struct pt_regs *
 	return 1;
 }
 
+#ifdef _NO_DYNAMIC_PATCHING
+/* Returns 1 if it's safe to continue branch stepping, 0 otherwise. */
+int is_stepping_safe_br(struct pt_regs *regs)
+{
+	unsigned long current_addr;
+
+	for (current_addr = regs->nip - 0x20;
+		current_addr <= (regs->nip + 0x20); current_addr += 4)
+		if (reservation_inst(*((unsigned int *)current_addr))) {
+			skip_trace_section(regs);
+			return 0;
+		}
+
+	return 1;
+}
+#endif
+
 
 //
 // ITrace_branch_hook()
@@ -335,15 +383,22 @@ int ITrace_branch_hook(struct pt_regs *
         }        
         
 	if (pi_itrace_pids[current->pid] & PIDS_ITRACE_ENABLE) {
+#ifdef _NO_DYNAMIC_PATCHING
+                if (!is_stepping_safe_br(regs)) {
+                        regs->msr &= ~MSR_BE;
+                        goto out;
+                }
+#endif
 		regs->msr |= MSR_BE;
 		pi_itrace_pids[current->pid] |= PIDS_ITRACE_ACTIVE;
 	} else {
 		regs->msr &= ~MSR_BE;
 	}
+out:
 
 	/* Reset the counter. Counting will start when the msr is restored */
 	mtspr(SPRN_PMC1, 0);
-	
+
 	put_cpu();
 	return 1;
 }
@@ -474,8 +529,10 @@ int ITrace_branch_hook_ss(struct pt_regs
 		   // Switch Single Stepping off 
 		   regs->msr &= ~MSR_SE;
 
+#ifndef _NO_DYNAMIC_PATCHING
 		   // Switch Branch Stepping On
 		   regs->msr |= MSR_BE; 
+#endif
 		}	
 	}
 	put_cpu();
@@ -799,7 +856,7 @@ int ITrace_install(uint32_t flag)
 		PDEBUG("Itrace already installed.\n");
 		return (PU_SUCCESS);
 	}	
-
+#ifndef _NO_DYNAMIC_PATCHING
 	PDEBUG("ItraceInstall: start\n");
 
         if (pi_install_stdcx_patch() != PU_SUCCESS) {
@@ -809,6 +866,7 @@ int ITrace_install(uint32_t flag)
 	if (pi_install_trapbrk_patch() != PU_SUCCESS) {
                 printk("WARNING: trapbrk_patch not installed, ignore unless on RHEL\n");
         }
+#endif
                 
 	if (flag & PI_ITRACE_FLAG_SS) {
 		printk(KERN_NOTICE "PI: ITrace installed - single step mode\n");
@@ -862,8 +920,11 @@ int ITrace_remove(void)
 #else
 	release_pmc_hardware();
 #endif
+
+#ifndef _NO_DYNAMIC_PATCHING
 	pi_remove_stdcx_patch();
 	pi_remove_trapbrk_patch();
+#endif
 	
 	return (PU_SUCCESS);
 }