From: Roland McGrath <roland@redhat.com>
Date: Tue, 13 Nov 2007 00:33:33 -0800
Subject: [ppc64] fixes PTRACE_SET_DEBUGREG request
Message-id: 20071114073249.A80EB26F8DE@magilla.localdomain
O-Subject: [RHEL5.2 PATCH] RHBZ#253117: powerpc PTRACE_SET_DEBUGREG
Bugzilla: 253117

This fixes the PTRACE_SET_DEBUGREG request on powerpc.
It never worked right in RHEL5, a regression from upstream and RHEL4.

Thanks,
Roland

diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
index 5dc92cb..24c1999 100644
--- a/arch/i386/kernel/ptrace.c
+++ b/arch/i386/kernel/ptrace.c
@@ -787,7 +787,7 @@ int arch_ptrace(long *req, struct task_struct *child,
 	case PTRACE_SET_THREAD_AREA:
 		return ptrace_onereg_access(child, engine,
 					    utrace_native_view(current), 3,
-					    addr, (void __user *)data,
+					    addr, (void __user *)data, NULL,
 					    *req == PTRACE_SET_THREAD_AREA);
 	}
 	return -ENOSYS;
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 4056dd1..3f8536e 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -501,11 +501,14 @@ int arch_ptrace(long *request, struct task_struct *child,
 					    *request == PPC_PTRACE_SETFPREGS);
 #ifdef CONFIG_PPC64
 	case PTRACE_GET_DEBUGREG:
-	case PTRACE_SET_DEBUGREG:
 		return ptrace_onereg_access(child, engine,
 					    utrace_native_view(current), 3,
 					    addr, (unsigned long __user *)data,
-					    *request == PTRACE_SET_DEBUGREG);
+					    NULL, 0);
+	case PTRACE_SET_DEBUGREG:
+		return ptrace_onereg_access(child, engine,
+					    utrace_native_view(current), 3,
+					    addr, NULL, &data, 1);
 #endif /* CONFIG_PPC64 */
 #ifdef CONFIG_ALTIVEC
 	case PTRACE_GETVRREGS:
@@ -576,13 +579,15 @@ int arch_compat_ptrace(compat_long_t *request,
 		return ptrace_whole_regset(child, engine, data, 2, 1);
 #endif
 	case PTRACE_GET_DEBUGREG:
-	case PTRACE_SET_DEBUGREG:
 		return ptrace_onereg_access(child, engine,
 					    utrace_native_view(current), 3,
 					    addr,
-					    (unsigned long __user *)
-					    (unsigned long) data,
-					    *request == PTRACE_SET_DEBUGREG);
+					    (u32 __user *) (unsigned long) data,
+					    NULL, 0);
+	case PTRACE_SET_DEBUGREG:
+		return ptrace_onereg_access(child, engine,
+					    utrace_native_view(current), 3,
+					    addr, NULL, &data, 1);
 
 	/*
 	 * Read 4 bytes of the other process' storage
diff --git a/arch/x86_64/ia32/ptrace32.c b/arch/x86_64/ia32/ptrace32.c
index 85eef8f..cdd4aaa 100644
--- a/arch/x86_64/ia32/ptrace32.c
+++ b/arch/x86_64/ia32/ptrace32.c
@@ -641,6 +641,7 @@ int arch_compat_ptrace(compat_long_t *req, struct task_struct *child,
 					    &utrace_ia32_view, 3,
 					    addr,
 					    (void __user *)(unsigned long)data,
+					    NULL,
 					    *req == PTRACE_SET_THREAD_AREA);
 	}
 	return -ENOSYS;
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
index 68706ad..f0e3e05 100644
--- a/arch/x86_64/kernel/ptrace.c
+++ b/arch/x86_64/kernel/ptrace.c
@@ -746,7 +746,7 @@ int arch_ptrace(long *req, struct task_struct *child,
 	case PTRACE_SET_THREAD_AREA:
 		return ptrace_onereg_access(child, engine,
 					    &utrace_ia32_view, 3,
-					    addr, (void __user *)data,
+					    addr, (void __user *)data, NULL,
 					    *req == PTRACE_SET_THREAD_AREA);
 #endif
 		/* normal 64bit interface to access TLS data.
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index a11b3df..664f2d9 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -117,7 +117,7 @@ extern int ptrace_onereg_access(struct task_struct *child,
 				struct utrace_attached_engine *engine,
 				const struct utrace_regset_view *view,
 				int setno, unsigned long regno,
-				void __user *data, int write);
+				void __user *udata, void *kdata, int write);
 
 
 /*
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index aa69d64..136fd85 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -721,7 +721,7 @@ ptrace_onereg_access(struct task_struct *target,
 		     struct utrace_attached_engine *engine,
 		     const struct utrace_regset_view *view,
 		     int setno, unsigned long regno,
-		     void __user *data, int write)
+		     void __user *udata, void *kdata, int write)
 {
 	const struct utrace_regset *regset = utrace_regset(target, engine,
 							   view, setno);
@@ -737,18 +737,20 @@ ptrace_onereg_access(struct task_struct *target,
 	pos = (regno - regset->bias) * regset->size;
 
 	if (write) {
-		if (!access_ok(VERIFY_READ, data, regset->size))
+		if (kdata == NULL &&
+		    !access_ok(VERIFY_READ, udata, regset->size))
 			ret = -EIO;
 		else
 			ret = (*regset->set)(target, regset, pos, regset->size,
-					     NULL, data);
+					     kdata, udata);
 	}
 	else {
-		if (!access_ok(VERIFY_WRITE, data, regset->size))
+		if (kdata == NULL &&
+		    !access_ok(VERIFY_WRITE, udata, regset->size))
 			ret = -EIO;
 		else
 			ret = (*regset->get)(target, regset, pos, regset->size,
-					     NULL, data);
+					     kdata, udata);
 	}
 
 	return ret;