1 files changed, 40 insertions, 118 deletions

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index cbc28d1a2e1b..c0d9f12cb441 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -19,13 +19,13 @@
 #include <linux/extable.h>
 #include <linux/kdebug.h>
 #include <linux/slab.h>
-#include <linux/moduleloader.h>
-#include <asm/code-patching.h>
+#include <linux/set_memory.h>
+#include <linux/execmem.h>
+#include <asm/text-patching.h>
 #include <asm/cacheflush.h>
 #include <asm/sstep.h>
 #include <asm/sections.h>
 #include <asm/inst.h>
-#include <asm/set_memory.h>
 #include <linux/uaccess.h>
 
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
@@ -45,7 +45,7 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
 {
 	kprobe_opcode_t *addr = NULL;
 
-#ifdef PPC64_ELF_ABI_v2
+#ifdef CONFIG_PPC64_ELF_ABI_V2
 	/* PPC64 ABIv2 needs local entry point */
 	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);
 	if (addr && !offset) {
@@ -63,7 +63,7 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
 #endif
 			addr = (kprobe_opcode_t *)ppc_function_entry(addr);
 	}
-#elif defined(PPC64_ELF_ABI_v1)
+#elif defined(CONFIG_PPC64_ELF_ABI_V1)
 	/*
 	 * 64bit powerpc ABIv1 uses function descriptors:
 	 * - Check for the dot variant of the symbol first.
@@ -105,42 +105,50 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
 	return addr;
 }
 
-void *alloc_insn_page(void)
+static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset)
 {
-	void *page;
+	unsigned long ip = ftrace_location(addr);
 
-	page = module_alloc(PAGE_SIZE);
-	if (!page)
-		return NULL;
+	if (ip)
+		return offset <= (ip - addr);
+	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
+		return offset <= 8;
+	return !offset;
+}
 
-	if (strict_module_rwx_enabled()) {
-		set_memory_ro((unsigned long)page, 1);
-		set_memory_x((unsigned long)page, 1);
-	}
-	return page;
+/* XXX try and fold the magic of kprobe_lookup_name() in this */
+kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset,
+					 bool *on_func_entry)
+{
+	*on_func_entry = arch_kprobe_on_func_entry(addr, offset);
+	return (kprobe_opcode_t *)(addr + offset);
 }
 
 int arch_prepare_kprobe(struct kprobe *p)
 {
 	int ret = 0;
 	struct kprobe *prev;
-	struct ppc_inst insn = ppc_inst_read(p->addr);
+	ppc_inst_t insn = ppc_inst_read(p->addr);
 
 	if ((unsigned long)p->addr & 0x03) {
 		printk("Attempt to register kprobe at an unaligned address\n");
 		ret = -EINVAL;
-	} else if (IS_MTMSRD(insn) || IS_RFID(insn)) {
-		printk("Cannot register a kprobe on mtmsr[d]/rfi[d]\n");
+	} else if (!can_single_step(ppc_inst_val(insn))) {
+		printk("Cannot register a kprobe on instructions that can't be single stepped\n");
 		ret = -EINVAL;
 	} else if ((unsigned long)p->addr & ~PAGE_MASK &&
 		   ppc_inst_prefixed(ppc_inst_read(p->addr - 1))) {
 		printk("Cannot register a kprobe on the second word of prefixed instruction\n");
 		ret = -EINVAL;
 	}
-	preempt_disable();
 	prev = get_kprobe(p->addr - 1);
-	preempt_enable_no_resched();
-	if (prev && ppc_inst_prefixed(ppc_inst_read(prev->ainsn.insn))) {
+
+	/*
+	 * When prev is a ftrace-based kprobe, we don't have an insn, and it
+	 * doesn't probe for prefixed instruction.
+	 */
+	if (prev && !kprobe_ftrace(prev) &&
+	    ppc_inst_prefixed(ppc_inst_read(prev->ainsn.insn))) {
 		printk("Cannot register a kprobe on the second word of prefixed instruction\n");
 		ret = -EINVAL;
 	}
@@ -218,33 +226,10 @@ static nokprobe_inline void set_current_kprobe(struct kprobe *p, struct pt_regs
 	kcb->kprobe_saved_msr = regs->msr;
 }
 
-bool arch_kprobe_on_func_entry(unsigned long offset)
-{
-#ifdef PPC64_ELF_ABI_v2
-#ifdef CONFIG_KPROBES_ON_FTRACE
-	return offset <= 16;
-#else
-	return offset <= 8;
-#endif
-#else
-	return !offset;
-#endif
-}
-
-void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
-{
-	ri->ret_addr = (kprobe_opcode_t *)regs->link;
-	ri->fp = NULL;
-
-	/* Replace the return addr with trampoline addr */
-	regs->link = (unsigned long)kretprobe_trampoline;
-}
-NOKPROBE_SYMBOL(arch_prepare_kretprobe);
-
 static int try_to_emulate(struct kprobe *p, struct pt_regs *regs)
 {
 	int ret;
-	struct ppc_inst insn = ppc_inst_read(p->ainsn.insn);
+	ppc_inst_t insn = ppc_inst_read(p->ainsn.insn);
 
 	/* regs->nip is also adjusted if emulate_step returns 1 */
 	ret = emulate_step(regs, insn);
@@ -261,7 +246,7 @@ static int try_to_emulate(struct kprobe *p, struct pt_regs *regs)
 		 * So, we should never get here... but, its still
 		 * good to catch them, just in case...
 		 */
-		printk("Can't step on instruction %s\n", ppc_inst_as_str(insn));
+		printk("Can't step on instruction %08lx\n", ppc_inst_as_ulong(insn));
 		BUG();
 	} else {
 		/*
@@ -292,7 +277,8 @@ int kprobe_handler(struct pt_regs *regs)
 	if (user_mode(regs))
 		return 0;
 
-	if (!(regs->msr & MSR_IR) || !(regs->msr & MSR_DR))
+	if (!IS_ENABLED(CONFIG_BOOKE) &&
+	    (!(regs->msr & MSR_IR) || !(regs->msr & MSR_DR)))
 		return 0;
 
 	/*
@@ -356,7 +342,7 @@ int kprobe_handler(struct pt_regs *regs)
 
 			if (ret > 0) {
 				restore_previous_kprobe(kcb);
-				preempt_enable_no_resched();
+				preempt_enable();
 				return 1;
 			}
 		}
@@ -369,7 +355,7 @@ int kprobe_handler(struct pt_regs *regs)
 	if (p->pre_handler && p->pre_handler(p, regs)) {
 		/* handler changed execution path, so skip ss setup */
 		reset_current_kprobe();
-		preempt_enable_no_resched();
+		preempt_enable();
 		return 1;
 	}
 
@@ -382,7 +368,7 @@ int kprobe_handler(struct pt_regs *regs)
 
 			kcb->kprobe_status = KPROBE_HIT_SSDONE;
 			reset_current_kprobe();
-			preempt_enable_no_resched();
+			preempt_enable();
 			return 1;
 		}
 	}
@@ -391,55 +377,12 @@ int kprobe_handler(struct pt_regs *regs)
 	return 1;
 
 no_kprobe:
-	preempt_enable_no_resched();
+	preempt_enable();
 	return ret;
 }
 NOKPROBE_SYMBOL(kprobe_handler);
 
 /*
- * Function return probe trampoline:
- * 	- init_kprobes() establishes a probepoint here
- * 	- When the probed function returns, this probe
- * 		causes the handlers to fire
- */
-asm(".global kretprobe_trampoline\n"
-	".type kretprobe_trampoline, @function\n"
-	"kretprobe_trampoline:\n"
-	"nop\n"
-	"blr\n"
-	".size kretprobe_trampoline, .-kretprobe_trampoline\n");
-
-/*
- * Called when the probe at kretprobe trampoline is hit
- */
-static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
-{
-	unsigned long orig_ret_address;
-
-	orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
-	/*
-	 * We get here through one of two paths:
-	 * 1. by taking a trap -> kprobe_handler() -> here
-	 * 2. by optprobe branch -> optimized_callback() -> opt_pre_handler() -> here
-	 *
-	 * When going back through (1), we need regs->nip to be setup properly
-	 * as it is used to determine the return address from the trap.
-	 * For (2), since nip is not honoured with optprobes, we instead setup
-	 * the link register properly so that the subsequent 'blr' in
-	 * kretprobe_trampoline jumps back to the right instruction.
-	 *
-	 * For nip, we should set the address to the previous instruction since
-	 * we end up emulating it in kprobe_handler(), which increments the nip
-	 * again.
-	 */
-	regs_set_return_ip(regs, orig_ret_address - 4);
-	regs->link = orig_ret_address;
-
-	return 0;
-}
-NOKPROBE_SYMBOL(trampoline_probe_handler);
-
-/*
  * Called after single-stepping.  p->addr is the address of the
  * instruction whose first byte has been replaced by the "breakpoint"
  * instruction.  To avoid the SMP problems that can occur when we
@@ -477,7 +420,7 @@ int kprobe_post_handler(struct pt_regs *regs)
 	}
 	reset_current_kprobe();
 out:
-	preempt_enable_no_resched();
+	preempt_enable();
 
 	/*
 	 * if somebody else is singlestepping across a probe point, msr
@@ -516,7 +459,7 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 			restore_previous_kprobe(kcb);
 		else
 			reset_current_kprobe();
-		preempt_enable_no_resched();
+		preempt_enable();
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
@@ -541,30 +484,9 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 }
 NOKPROBE_SYMBOL(kprobe_fault_handler);
 
-unsigned long arch_deref_entry_point(void *entry)
-{
-#ifdef PPC64_ELF_ABI_v1
-	if (!kernel_text_address((unsigned long)entry))
-		return ppc_global_function_entry(entry);
-	else
-#endif
-		return (unsigned long)entry;
-}
-NOKPROBE_SYMBOL(arch_deref_entry_point);
-
-static struct kprobe trampoline_p = {
-	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
-	.pre_handler = trampoline_probe_handler
-};
-
-int __init arch_init_kprobes(void)
-{
-	return register_kprobe(&trampoline_p);
-}
-
 int arch_trampoline_kprobe(struct kprobe *p)
 {
-	if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *)&arch_rethook_trampoline)
 		return 1;
 
 	return 0;