[S390] ptrace cleanup

Overhaul program event recording and the code dealing with the ptrace
user space interface.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 187 insertions, 119 deletions

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 019bb714db49..ef86ad243986 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -1,25 +1,9 @@
 /*
- *  arch/s390/kernel/ptrace.c
+ *  Ptrace user space interface.
  *
- *  S390 version
- *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
- *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ *    Copyright IBM Corp. 1999,2010
+ *    Author(s): Denis Joseph Barrow
  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
- *
- *  Based on PowerPC version 
- *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
- *
- *  Derived from "arch/m68k/kernel/ptrace.c"
- *  Copyright (C) 1994 by Hamish Macdonald
- *  Taken from linux/kernel/ptrace.c and modified for M680x0.
- *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
- *
- * Modified by Cort Dougan (cort@cs.nmt.edu) 
- *
- *
- * This file is subject to the terms and conditions of the GNU General
- * Public License.  See the file README.legal in the main directory of
- * this archive for more details.
  */
 
 #include <linux/kernel.h>
@@ -61,76 +45,58 @@ enum s390_regset {
 	REGSET_GENERAL_EXTENDED,
 };
 
-static void
-FixPerRegisters(struct task_struct *task)
+void update_per_regs(struct task_struct *task)
 {
-	struct pt_regs *regs;
-	per_struct *per_info;
-	per_cr_words cr_words;
-
-	regs = task_pt_regs(task);
-	per_info = (per_struct *) &task->thread.per_info;
-	per_info->control_regs.bits.em_instruction_fetch =
-		per_info->single_step | per_info->instruction_fetch;
-	
-	if (per_info->single_step) {
-		per_info->control_regs.bits.starting_addr = 0;
-#ifdef CONFIG_COMPAT
-		if (is_compat_task())
-			per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
-		else
-#endif
-			per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
-	} else {
-		per_info->control_regs.bits.starting_addr =
-			per_info->starting_addr;
-		per_info->control_regs.bits.ending_addr =
-			per_info->ending_addr;
-	}
-	/*
-	 * if any of the control reg tracing bits are on 
-	 * we switch on per in the psw
-	 */
-	if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
-		regs->psw.mask |= PSW_MASK_PER;
-	else
+	static const struct per_regs per_single_step = {
+		.control = PER_EVENT_IFETCH,
+		.start = 0,
+		.end = PSW_ADDR_INSN,
+	};
+	struct pt_regs *regs = task_pt_regs(task);
+	struct thread_struct *thread = &task->thread;
+	const struct per_regs *new;
+	struct per_regs old;
+
+	/* TIF_SINGLE_STEP overrides the user specified PER registers. */
+	new = test_tsk_thread_flag(task, TIF_SINGLE_STEP) ?
+		&per_single_step : &thread->per_user;
+
+	/* Take care of the PER enablement bit in the PSW. */
+	if (!(new->control & PER_EVENT_MASK)) {
 		regs->psw.mask &= ~PSW_MASK_PER;
-
-	if (per_info->control_regs.bits.em_storage_alteration)
-		per_info->control_regs.bits.storage_alt_space_ctl = 1;
-	else
-		per_info->control_regs.bits.storage_alt_space_ctl = 0;
-
-	if (task == current) {
-		__ctl_store(cr_words, 9, 11);
-		if (memcmp(&cr_words, &per_info->control_regs.words,
-			   sizeof(cr_words)) != 0)
-			__ctl_load(per_info->control_regs.words, 9, 11);
+		return;
 	}
+	regs->psw.mask |= PSW_MASK_PER;
+	__ctl_store(old, 9, 11);
+	if (memcmp(new, &old, sizeof(struct per_regs)) != 0)
+		__ctl_load(*new, 9, 11);
 }
 
 void user_enable_single_step(struct task_struct *task)
 {
-	task->thread.per_info.single_step = 1;
-	FixPerRegisters(task);
+	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
+	if (task == current)
+		update_per_regs(task);
 }
 
 void user_disable_single_step(struct task_struct *task)
 {
-	task->thread.per_info.single_step = 0;
-	FixPerRegisters(task);
+	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
+	if (task == current)
+		update_per_regs(task);
 }
 
 /*
  * Called by kernel/ptrace.c when detaching..
  *
- * Make sure single step bits etc are not set.
+ * Clear all debugging related fields.
  */
-void
-ptrace_disable(struct task_struct *child)
+void ptrace_disable(struct task_struct *task)
 {
-	/* make sure the single step bit is not set. */
-	user_disable_single_step(child);
+	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
+	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
+	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
+	clear_tsk_thread_flag(task, TIF_PER_TRAP);
 }
 
 #ifndef CONFIG_64BIT
@@ -139,6 +105,47 @@ ptrace_disable(struct task_struct *child)
 # define __ADDR_MASK 7
 #endif
 
+static inline unsigned long __peek_user_per(struct task_struct *child,
+					    addr_t addr)
+{
+	struct per_struct_kernel *dummy = NULL;
+
+	if (addr == (addr_t) &dummy->cr9)
+		/* Control bits of the active per set. */
+		return test_thread_flag(TIF_SINGLE_STEP) ?
+			PER_EVENT_IFETCH : child->thread.per_user.control;
+	else if (addr == (addr_t) &dummy->cr10)
+		/* Start address of the active per set. */
+		return test_thread_flag(TIF_SINGLE_STEP) ?
+			0 : child->thread.per_user.start;
+	else if (addr == (addr_t) &dummy->cr11)
+		/* End address of the active per set. */
+		return test_thread_flag(TIF_SINGLE_STEP) ?
+			PSW_ADDR_INSN : child->thread.per_user.end;
+	else if (addr == (addr_t) &dummy->bits)
+		/* Single-step bit. */
+		return test_thread_flag(TIF_SINGLE_STEP) ?
+			(1UL << (BITS_PER_LONG - 1)) : 0;
+	else if (addr == (addr_t) &dummy->starting_addr)
+		/* Start address of the user specified per set. */
+		return child->thread.per_user.start;
+	else if (addr == (addr_t) &dummy->ending_addr)
+		/* End address of the user specified per set. */
+		return child->thread.per_user.end;
+	else if (addr == (addr_t) &dummy->perc_atmid)
+		/* PER code, ATMID and AI of the last PER trap */
+		return (unsigned long)
+			child->thread.per_event.cause << (BITS_PER_LONG - 16);
+	else if (addr == (addr_t) &dummy->address)
+		/* Address of the last PER trap */
+		return child->thread.per_event.address;
+	else if (addr == (addr_t) &dummy->access_id)
+		/* Access id of the last PER trap */
+		return (unsigned long)
+			child->thread.per_event.paid << (BITS_PER_LONG - 8);
+	return 0;
+}
+
 /*
  * Read the word at offset addr from the user area of a process. The
  * trouble here is that the information is littered over different
@@ -204,10 +211,10 @@ static unsigned long __peek_user(struct task_struct *child, addr_t addr)
 
 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 		/*
-		 * per_info is found in the thread structure
+		 * Handle access to the per_info structure.
 		 */
-		offset = addr - (addr_t) &dummy->regs.per_info;
-		tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
+		addr -= (addr_t) &dummy->regs.per_info;
+		tmp = __peek_user_per(child, addr);
 
 	} else
 		tmp = 0;
@@ -237,6 +244,35 @@ peek_user(struct task_struct *child, addr_t addr, addr_t data)
 	return put_user(tmp, (addr_t __user *) data);
 }
 
+static inline void __poke_user_per(struct task_struct *child,
+				   addr_t addr, addr_t data)
+{
+	struct per_struct_kernel *dummy = NULL;
+
+	/*
+	 * There are only three fields in the per_info struct that the
+	 * debugger user can write to.
+	 * 1) cr9: the debugger wants to set a new PER event mask
+	 * 2) starting_addr: the debugger wants to set a new starting
+	 *    address to use with the PER event mask.
+	 * 3) ending_addr: the debugger wants to set a new ending
+	 *    address to use with the PER event mask.
+	 * The user specified PER event mask and the start and end
+	 * addresses are used only if single stepping is not in effect.
+	 * Writes to any other field in per_info are ignored.
+	 */
+	if (addr == (addr_t) &dummy->cr9)
+		/* PER event mask of the user specified per set. */
+		child->thread.per_user.control =
+			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
+	else if (addr == (addr_t) &dummy->starting_addr)
+		/* Starting address of the user specified per set. */
+		child->thread.per_user.start = data;
+	else if (addr == (addr_t) &dummy->ending_addr)
+		/* Ending address of the user specified per set. */
+		child->thread.per_user.end = data;
+}
+
 /*
  * Write a word to the user area of a process at location addr. This
  * operation does have an additional problem compared to peek_user.
@@ -311,19 +347,17 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 
 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 		/*
-		 * per_info is found in the thread structure 
+		 * Handle access to the per_info structure.
 		 */
-		offset = addr - (addr_t) &dummy->regs.per_info;
-		*(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
+		addr -= (addr_t) &dummy->regs.per_info;
+		__poke_user_per(child, addr, data);
 
 	}
 
-	FixPerRegisters(child);
 	return 0;
 }
 
-static int
-poke_user(struct task_struct *child, addr_t addr, addr_t data)
+static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
 {
 	addr_t mask;
 
@@ -410,12 +444,53 @@ long arch_ptrace(struct task_struct *child, long request,
  */
 
 /*
+ * Same as peek_user_per but for a 31 bit program.
+ */
+static inline __u32 __peek_user_per_compat(struct task_struct *child,
+					   addr_t addr)
+{
+	struct compat_per_struct_kernel *dummy32 = NULL;
+
+	if (addr == (addr_t) &dummy32->cr9)
+		/* Control bits of the active per set. */
+		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
+			PER_EVENT_IFETCH : child->thread.per_user.control;
+	else if (addr == (addr_t) &dummy32->cr10)
+		/* Start address of the active per set. */
+		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
+			0 : child->thread.per_user.start;
+	else if (addr == (addr_t) &dummy32->cr11)
+		/* End address of the active per set. */
+		return test_thread_flag(TIF_SINGLE_STEP) ?
+			PSW32_ADDR_INSN : child->thread.per_user.end;
+	else if (addr == (addr_t) &dummy32->bits)
+		/* Single-step bit. */
+		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
+			0x80000000 : 0;
+	else if (addr == (addr_t) &dummy32->starting_addr)
+		/* Start address of the user specified per set. */
+		return (__u32) child->thread.per_user.start;
+	else if (addr == (addr_t) &dummy32->ending_addr)
+		/* End address of the user specified per set. */
+		return (__u32) child->thread.per_user.end;
+	else if (addr == (addr_t) &dummy32->perc_atmid)
+		/* PER code, ATMID and AI of the last PER trap */
+		return (__u32) child->thread.per_event.cause << 16;
+	else if (addr == (addr_t) &dummy32->address)
+		/* Address of the last PER trap */
+		return (__u32) child->thread.per_event.address;
+	else if (addr == (addr_t) &dummy32->access_id)
+		/* Access id of the last PER trap */
+		return (__u32) child->thread.per_event.paid << 24;
+	return 0;
+}
+
+/*
  * Same as peek_user but for a 31 bit program.
  */
 static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
 {
-	struct user32 *dummy32 = NULL;
-	per_struct32 *dummy_per32 = NULL;
+	struct compat_user *dummy32 = NULL;
 	addr_t offset;
 	__u32 tmp;
 
@@ -465,19 +540,10 @@ static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
 
 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 		/*
-		 * per_info is found in the thread structure
+		 * Handle access to the per_info structure.
 		 */
-		offset = addr - (addr_t) &dummy32->regs.per_info;
-		/* This is magic. See per_struct and per_struct32. */
-		if ((offset >= (addr_t) &dummy_per32->control_regs &&
-		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
-		    (offset >= (addr_t) &dummy_per32->starting_addr &&
-		     offset <= (addr_t) &dummy_per32->ending_addr) ||
-		    offset == (addr_t) &dummy_per32->lowcore.words.address)
-			offset = offset*2 + 4;
-		else
-			offset = offset*2;
-		tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
+		addr -= (addr_t) &dummy32->regs.per_info;
+		tmp = __peek_user_per_compat(child, addr);
 
 	} else
 		tmp = 0;
@@ -498,13 +564,32 @@ static int peek_user_compat(struct task_struct *child,
 }
 
 /*
+ * Same as poke_user_per but for a 31 bit program.
+ */
+static inline void __poke_user_per_compat(struct task_struct *child,
+					  addr_t addr, __u32 data)
+{
+	struct compat_per_struct_kernel *dummy32 = NULL;
+
+	if (addr == (addr_t) &dummy32->cr9)
+		/* PER event mask of the user specified per set. */
+		child->thread.per_user.control =
+			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
+	else if (addr == (addr_t) &dummy32->starting_addr)
+		/* Starting address of the user specified per set. */
+		child->thread.per_user.start = data;
+	else if (addr == (addr_t) &dummy32->ending_addr)
+		/* Ending address of the user specified per set. */
+		child->thread.per_user.end = data;
+}
+
+/*
  * Same as poke_user but for a 31 bit program.
  */
 static int __poke_user_compat(struct task_struct *child,
 			      addr_t addr, addr_t data)
 {
-	struct user32 *dummy32 = NULL;
-	per_struct32 *dummy_per32 = NULL;
+	struct compat_user *dummy32 = NULL;
 	__u32 tmp = (__u32) data;
 	addr_t offset;
 
@@ -561,37 +646,20 @@ static int __poke_user_compat(struct task_struct *child,
 
 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 		/*
-		 * per_info is found in the thread structure.
-		 */
-		offset = addr - (addr_t) &dummy32->regs.per_info;
-		/*
-		 * This is magic. See per_struct and per_struct32.
-		 * By incident the offsets in per_struct are exactly
-		 * twice the offsets in per_struct32 for all fields.
-		 * The 8 byte fields need special handling though,
-		 * because the second half (bytes 4-7) is needed and
-		 * not the first half.
+		 * Handle access to the per_info structure.
 		 */
-		if ((offset >= (addr_t) &dummy_per32->control_regs &&
-		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
-		    (offset >= (addr_t) &dummy_per32->starting_addr &&
-		     offset <= (addr_t) &dummy_per32->ending_addr) ||
-		    offset == (addr_t) &dummy_per32->lowcore.words.address)
-			offset = offset*2 + 4;
-		else
-			offset = offset*2;
-		*(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
-
+		addr -= (addr_t) &dummy32->regs.per_info;
+		__poke_user_per_compat(child, addr, data);
 	}
 
-	FixPerRegisters(child);
 	return 0;
 }
 
 static int poke_user_compat(struct task_struct *child,
 			    addr_t addr, addr_t data)
 {
-	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user32) - 3)
+	if (!is_compat_task() || (addr & 3) ||
+	    addr > sizeof(struct compat_user) - 3)
 		return -EIO;
 
 	return __poke_user_compat(child, addr, data);
@@ -602,7 +670,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 {
 	unsigned long addr = caddr;
 	unsigned long data = cdata;
-	ptrace_area_emu31 parea; 
+	compat_ptrace_area parea;
 	int copied, ret;
 
 	switch (request) {