sparc64:Support User Probes for sparc

Signed-off-by: Eric Saint Etienne <eric.saint.etienne@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/Kconfig

@@ -96,6 +96,7 @@ config KPROBES_ON_FTRACE
 
 config UPROBES
 	def_bool n
+	depends on ARCH_SUPPORTS_UPROBES
 	help
 	  Uprobes is the user-space counterpart to kprobes: they
 	  enable instrumentation applications (such as 'perf probe')

arch/sparc/Kconfig

@@ -155,6 +155,9 @@ config PGTABLE_LEVELS
 	default 4 if 64BIT
 	default 3
 
+config ARCH_SUPPORTS_UPROBES
+	def_bool y if SPARC64
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"

arch/sparc/configs/sparc64_defconfig

@@ -213,6 +213,7 @@ CONFIG_SCHEDSTATS=y
 # CONFIG_RCU_CPU_STALL_DETECTOR is not set
 CONFIG_SYSCTL_SYSCALL_CHECK=y
 CONFIG_BLK_DEV_IO_TRACE=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_KEYS=y
 CONFIG_CRYPTO_NULL=m
 CONFIG_CRYPTO_TEST=m

arch/sparc/include/asm/kdebug_64.h

@@ -10,6 +10,8 @@ enum die_val {
 	DIE_OOPS = 1,
 	DIE_DEBUG,	/* ta 0x70 */
 	DIE_DEBUG_2,	/* ta 0x71 */
+	DIE_BPT,	/* ta 0x73 */
+	DIE_SSTEP,	/* ta 0x74 */
 	DIE_DIE,
 	DIE_TRAP,
 	DIE_TRAP_TL1,

arch/sparc/include/asm/ptrace.h

@@ -61,7 +61,10 @@ extern union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
 #define force_successful_syscall_return() set_thread_noerror(1)
 #define user_mode(regs) (!((regs)->tstate & TSTATE_PRIV))
 #define instruction_pointer(regs) ((regs)->tpc)
-#define instruction_pointer_set(regs, val) ((regs)->tpc = (val))
+#define instruction_pointer_set(regs, val) do { \
+		(regs)->tpc = (val); \
+		(regs)->tnpc = (val)+4; \
+	} while (0)
 #define user_stack_pointer(regs) ((regs)->u_regs[UREG_FP])
 static inline int is_syscall_success(struct pt_regs *regs)
 {
@@ -77,6 +80,36 @@ unsigned long profile_pc(struct pt_regs *);
 #else
 #define profile_pc(regs) instruction_pointer(regs)
 #endif
+
+#define MAX_REG_OFFSET (offsetof(struct pt_regs, magic))
+
+extern int regs_query_register_offset(const char *name);
+
+/**
+ * regs_get_register() - get register value from its offset
+ * @regs:	pt_regs from which register value is gotten
+ * @offset:	offset number of the register.
+ *
+ * regs_get_register returns the value of a register whose
+ * offset from @regs. The @offset is the offset of the register
+ * in struct pt_regs. If @offset is bigger than MAX_REG_OFFSET,
+ * this returns 0.
+ */
+static inline unsigned long regs_get_register(struct pt_regs *regs,
+					     unsigned long offset)
+{
+	if (unlikely(offset >= MAX_REG_OFFSET))
+		return 0;
+	if (offset == PT_V9_Y)
+		return *(unsigned int *)((unsigned long)regs + offset);
+	return *(unsigned long *)((unsigned long)regs + offset);
+}
+
+/* Valid only for Kernel mode traps. */
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+{
+	return regs->u_regs[UREG_I6];
+}
 #else /* __ASSEMBLY__ */
 #endif /* __ASSEMBLY__ */
 #else /* (defined(__sparc__) && defined(__arch64__)) */

arch/sparc/include/asm/thread_info_64.h

@@ -180,7 +180,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define TIF_NEED_RESCHED	3	/* rescheduling necessary */
 /* flag bit 4 is available */
 #define TIF_UNALIGNED		5	/* allowed to do unaligned accesses */
-/* flag bit 6 is available */
+#define TIF_UPROBE		6	/* breakpointed or singlestepped */
 #define TIF_32BIT		7	/* 32-bit binary */
 #define TIF_NOHZ		8	/* in adaptive nohz mode */
 #define TIF_SECCOMP		9	/* secure computing */
@@ -199,6 +199,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
 #define _TIF_UNALIGNED		(1<<TIF_UNALIGNED)
+#define _TIF_UPROBE		(1<<TIF_UPROBE)
 #define _TIF_32BIT		(1<<TIF_32BIT)
 #define _TIF_NOHZ		(1<<TIF_NOHZ)
 #define _TIF_SECCOMP		(1<<TIF_SECCOMP)
@@ -209,7 +210,8 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define _TIF_USER_WORK_MASK	((0xff << TI_FLAG_WSAVED_SHIFT) | \
 				 _TIF_DO_NOTIFY_RESUME_MASK | \
 				 _TIF_NEED_RESCHED)
-#define _TIF_DO_NOTIFY_RESUME_MASK	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING)
+#define _TIF_DO_NOTIFY_RESUME_MASK	(_TIF_NOTIFY_RESUME | \
+					 _TIF_SIGPENDING | _TIF_UPROBE)
 
 #define is_32bit_task()	(test_thread_flag(TIF_32BIT))
 

arch/sparc/include/asm/ttable.h

@@ -186,6 +186,12 @@
 #define KPROBES_TRAP(lvl) TRAP_ARG(bad_trap, lvl)
 #endif
 
+#ifdef CONFIG_UPROBES
+#define UPROBES_TRAP(lvl) TRAP_ARG(uprobe_trap, lvl)
+#else
+#define UPROBES_TRAP(lvl) TRAP_ARG(bad_trap, lvl)
+#endif
+
 #ifdef CONFIG_KGDB
 #define KGDB_TRAP(lvl) TRAP_IRQ(kgdb_trap, lvl)
 #else

arch/sparc/include/asm/uprobes.h

@@ -0,0 +1,59 @@
+#ifndef _ASM_UPROBES_H
+#define _ASM_UPROBES_H
+/*
+ * User-space Probes (UProbes) for sparc
+ *
+ * Copyright (C) 2013 Oracle, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *     Jose E. Marchesi <jose.marchesi@oracle.com>
+ *	Eric Saint Etienne <eric.saint.etienne@oracle.com>
+ */
+
+typedef u32 uprobe_opcode_t;
+
+#define MAX_UINSN_BYTES		4
+#define UPROBE_XOL_SLOT_BYTES	(MAX_UINSN_BYTES * 2)
+
+#define UPROBE_SWBP_INSN_SIZE	4
+#define UPROBE_SWBP_INSN	0x91d02073 /* ta 0x73 */
+#define UPROBE_STP_INSN		0x91d02074 /* ta 0x74 */
+
+#define ANNUL_BIT (1 << 29)
+
+struct arch_uprobe {
+	union {
+		u8  insn[MAX_UINSN_BYTES];
+		u32 ixol;
+	};
+};
+
+struct arch_uprobe_task {
+	u32 saved_tpc;
+	u32 saved_tnpc;
+};
+
+struct task_struct;
+struct notifier_block;
+
+extern int  arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr);
+extern int  arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+extern int  arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk);
+extern int  arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data);
+extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+
+#endif	/* _ASM_UPROBES_H */

arch/sparc/kernel/Makefile

@@ -116,4 +116,5 @@ obj-$(CONFIG_COMPAT)    += $(audit--y)
 pc--$(CONFIG_PERF_EVENTS) := perf_event.o
 obj-$(CONFIG_SPARC64)	+= $(pc--y)
 
+obj-$(CONFIG_UPROBES)	+= uprobes.o
 obj-$(CONFIG_SPARC64)	+= jump_label.o

arch/sparc/kernel/ptrace_64.c

@@ -46,6 +46,43 @@
 
 /* #define ALLOW_INIT_TRACING */
 
+struct pt_regs_offset {
+	const char *name;
+	int offset;
+};
+
+#define REG_OFFSET_NAME(n, r) \
+	{.name = n, .offset = (PT_V9_##r)}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+	REG_OFFSET_NAME("g0", G0),
+	REG_OFFSET_NAME("g1", G1),
+	REG_OFFSET_NAME("g2", G2),
+	REG_OFFSET_NAME("g3", G3),
+	REG_OFFSET_NAME("g4", G4),
+	REG_OFFSET_NAME("g5", G5),
+	REG_OFFSET_NAME("g6", G6),
+	REG_OFFSET_NAME("g7", G7),
+
+	REG_OFFSET_NAME("i0", I0),
+	REG_OFFSET_NAME("i1", I1),
+	REG_OFFSET_NAME("i2", I2),
+	REG_OFFSET_NAME("i3", I3),
+	REG_OFFSET_NAME("i4", I4),
+	REG_OFFSET_NAME("i5", I5),
+	REG_OFFSET_NAME("i6", I6),
+	REG_OFFSET_NAME("i7", I7),
+
+	REG_OFFSET_NAME("tstate", TSTATE),
+	REG_OFFSET_NAME("pc", TPC),
+	REG_OFFSET_NAME("npc", TNPC),
+	REG_OFFSET_NAME("y", Y),
+	REG_OFFSET_NAME("lr", I7),
+
+	REG_OFFSET_END,
+};
+
 /*
  * Called by kernel/ptrace.c when detaching..
  *
@@ -1107,3 +1144,20 @@ asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 	if (test_thread_flag(TIF_NOHZ))
 		user_enter();
 }
+
+/**
+ * regs_query_register_offset() - query register offset from its name
+ * @name:	the name of a register
+ *
+ * regs_query_register_offset() returns the offset of a register in struct
+ * pt_regs from its name. If the name is invalid, this returns -EINVAL;
+ */
+int regs_query_register_offset(const char *name)
+{
+	const struct pt_regs_offset *roff;
+
+	for (roff = regoffset_table; roff->name != NULL; roff++)
+		if (!strcmp(roff->name, name))
+			return roff->offset;
+	return -EINVAL;
+}

arch/sparc/kernel/signal_64.c

@@ -545,6 +545,8 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
 {
 	user_exit();
+	if (thread_info_flags & _TIF_UPROBE)
+		uprobe_notify_resume(regs);
 	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs, orig_i0);
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

arch/sparc/kernel/ttable_64.S

@@ -165,7 +165,7 @@ tl0_resv169:	BTRAP(0x169) BTRAP(0x16a) BTRAP(0x16b) BTRAP(0x16c)
 tl0_linux64:	LINUX_64BIT_SYSCALL_TRAP
 tl0_gsctx:	TRAP(sparc64_get_context) TRAP(sparc64_set_context)
 tl0_resv170:	KPROBES_TRAP(0x170) KPROBES_TRAP(0x171) KGDB_TRAP(0x172)
-tl0_resv173:	BTRAP(0x173) BTRAP(0x174) BTRAP(0x175) BTRAP(0x176) BTRAP(0x177)
+tl0_resv173:	UPROBES_TRAP(0x173) UPROBES_TRAP(0x174) BTRAP(0x175) BTRAP(0x176) BTRAP(0x177)
 tl0_resv178:	BTRAP(0x178) BTRAP(0x179) BTRAP(0x17a) BTRAP(0x17b) BTRAP(0x17c)
 tl0_resv17d:	BTRAP(0x17d) BTRAP(0x17e) BTRAP(0x17f)
 #define BTRAPS(x) BTRAP(x) BTRAP(x+1) BTRAP(x+2) BTRAP(x+3) BTRAP(x+4) BTRAP(x+5) BTRAP(x+6) BTRAP(x+7)