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authorPratyush Anand <panand@redhat.com>2014-12-30 17:07:12 +0530
committerSteve Capper <steve.capper@linaro.org>2015-01-27 16:46:20 +0000
commitefbdd4967166356c4a9db32e71740506d9a9003d (patch)
treecfacd176e2ce7e40a0ed24a8a45ffe3d98b3e6a6
parente1e8d61666a7ab34dd814beb7c800135b9f5f9cc (diff)
downloadlinux-efbdd4967166356c4a9db32e71740506d9a9003d.tar.gz
ARM64: Add uprobe support
This patch adds support for uprobe on ARM64 architecture. Unit test for following has been done so far and they have been found working 1. Normal instruction, which can be probed like sub, ldr, add etc. 2. Instructions which can be simulated like ret. 3. uretprobe Currently it does not support aarch32 instruction probing. Signed-off-by: Pratyush Anand <panand@redhat.com>
-rw-r--r--arch/arm64/Kconfig3
-rw-r--r--arch/arm64/include/asm/debug-monitors.h2
-rw-r--r--arch/arm64/include/asm/probes.h1
-rw-r--r--arch/arm64/include/asm/thread_info.h5
-rw-r--r--arch/arm64/include/asm/uprobes.h37
-rw-r--r--arch/arm64/kernel/Makefile3
-rw-r--r--arch/arm64/kernel/signal.c4
-rw-r--r--arch/arm64/kernel/uprobes.c211
-rw-r--r--arch/arm64/mm/flush.c6
9 files changed, 270 insertions, 2 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index de4f0561cd1..51b1db7a3bc 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -145,6 +145,9 @@ config KERNEL_MODE_NEON
config FIX_EARLYCON_MEM
def_bool y
+config ARCH_SUPPORTS_UPROBES
+ def_bool y
+
source "init/Kconfig"
source "kernel/Kconfig.freezer"
diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
index 24d2694770b..d149926e060 100644
--- a/arch/arm64/include/asm/debug-monitors.h
+++ b/arch/arm64/include/asm/debug-monitors.h
@@ -39,6 +39,8 @@
#define BRK64_ESR_MASK 0xFFFF
#define BRK64_ESR_KPROBES 0x0004
#define BRK64_OPCODE_KPROBES 0xD4200080 /* "brk 0x4" */
+#define BRK64_ESR_UPROBES 0x0008
+#define BRK64_OPCODE_UPROBES 0xD4200100 /* "brk 0x8" */
/*
* Break point instruction encoding
diff --git a/arch/arm64/include/asm/probes.h b/arch/arm64/include/asm/probes.h
index 38bc32e2b22..54c253ba2d2 100644
--- a/arch/arm64/include/asm/probes.h
+++ b/arch/arm64/include/asm/probes.h
@@ -19,6 +19,7 @@ struct kprobe;
struct arch_specific_insn;
typedef u32 kprobe_opcode_t;
+typedef u32 uprobe_opcode_t;
typedef unsigned long (kprobes_pstate_check_t)(unsigned long);
typedef unsigned long
(kprobes_condition_check_t)(u32 opcode, struct arch_specific_insn *asi,
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 459bf8e5320..3d5d1ec181c 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -108,6 +108,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_NEED_RESCHED 1
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
#define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */
+#define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
#define TIF_NOHZ 7
#define TIF_SYSCALL_TRACE 8
#define TIF_SYSCALL_AUDIT 9
@@ -129,10 +130,12 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
+#define _TIF_UPROBE (1 << TIF_UPROBE)
#define _TIF_32BIT (1 << TIF_32BIT)
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
- _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE)
+ _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
+ _TIF_UPROBE)
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
diff --git a/arch/arm64/include/asm/uprobes.h b/arch/arm64/include/asm/uprobes.h
new file mode 100644
index 00000000000..9d64317d1e2
--- /dev/null
+++ b/arch/arm64/include/asm/uprobes.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2014-2015 Pratyush Anand <panand@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_UPROBES_H
+#define _ASM_UPROBES_H
+
+#include <asm/debug-monitors.h>
+#include <asm/insn.h>
+#include <asm/probes.h>
+
+#define MAX_UINSN_BYTES AARCH64_INSN_SIZE
+
+#define UPROBE_SWBP_INSN BRK64_OPCODE_UPROBES
+#define UPROBE_SWBP_INSN_SIZE 4
+#define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES
+
+struct arch_uprobe_task {
+ unsigned long saved_fault_code;
+};
+
+struct arch_uprobe {
+ union {
+ u8 insn[MAX_UINSN_BYTES];
+ u8 ixol[MAX_UINSN_BYTES];
+ };
+ struct arch_specific_insn ainsn;
+ bool simulate;
+};
+
+extern void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,
+ void *kaddr, unsigned long len);
+#endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 6e4dcde2774..b70533a0c4d 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -34,6 +34,9 @@ arm64-obj-$(CONFIG_KGDB) += kgdb.o
arm64-obj-$(CONFIG_KPROBES) += kprobes.o kprobes-arm64.o \
probes-simulate-insn.o \
probes-condn-check.o
+arm64-obj-$(CONFIG_UPROBES) += uprobes.o kprobes-arm64.o \
+ probes-simulate-insn.o \
+ probes-condn-check.o
arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o
arm64-obj-$(CONFIG_PCI) += pci.o
arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 6fa792137ed..2d1e18b0cc1 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -409,6 +409,9 @@ static void do_signal(struct pt_regs *regs)
asmlinkage void do_notify_resume(struct pt_regs *regs,
unsigned int thread_flags)
{
+ if (thread_flags & _TIF_UPROBE)
+ uprobe_notify_resume(regs);
+
if (thread_flags & _TIF_SIGPENDING)
do_signal(regs);
@@ -419,5 +422,4 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
if (thread_flags & _TIF_FOREIGN_FPSTATE)
fpsimd_restore_current_state();
-
}
diff --git a/arch/arm64/kernel/uprobes.c b/arch/arm64/kernel/uprobes.c
new file mode 100644
index 00000000000..97e9d17d22b
--- /dev/null
+++ b/arch/arm64/kernel/uprobes.c
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2014-2015 Pratyush Anand <panand@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/highmem.h>
+#include <linux/ptrace.h>
+#include <linux/uprobes.h>
+
+#include "kprobes-arm64.h"
+
+#define UPROBE_INV_FAULT_CODE UINT_MAX
+
+void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
+ void *src, unsigned long len)
+{
+ void *xol_page_kaddr = kmap_atomic(page);
+ void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK);
+
+ preempt_disable();
+
+ /* Initialize the slot */
+ memcpy(dst, src, len);
+
+ /* flush caches (dcache/icache) */
+ flush_uprobe_xol_access(page, vaddr, dst, len);
+
+ preempt_enable();
+
+ kunmap_atomic(xol_page_kaddr);
+}
+
+unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
+{
+ return instruction_pointer(regs);
+}
+
+int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
+ unsigned long addr)
+{
+ kprobe_opcode_t insn;
+
+ /* TODO: Currently we do not support AARCH32 instruction probing */
+
+ if (!IS_ALIGNED(addr, AARCH64_INSN_SIZE))
+ return -EINVAL;
+
+ insn = *(kprobe_opcode_t *)(&auprobe->insn[0]);
+
+ switch (arm_kprobe_decode_insn(insn, &auprobe->ainsn)) {
+ case INSN_REJECTED:
+ return -EINVAL;
+
+ case INSN_GOOD_NO_SLOT:
+ auprobe->simulate = true;
+ if (auprobe->ainsn.prepare)
+ auprobe->ainsn.prepare(insn, &auprobe->ainsn);
+ break;
+
+ case INSN_GOOD:
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ /* saved fault code is restored in post_xol */
+ utask->autask.saved_fault_code = current->thread.fault_code;
+
+ /* An invalid fault code between pre/post xol event */
+ current->thread.fault_code = UPROBE_INV_FAULT_CODE;
+
+ /* Instruction point to execute ol */
+ instruction_pointer_set(regs, utask->xol_vaddr);
+
+ user_enable_single_step(current);
+
+ return 0;
+}
+
+int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ WARN_ON_ONCE(current->thread.fault_code != UPROBE_INV_FAULT_CODE);
+
+ /* restore fault code */
+ current->thread.fault_code = utask->autask.saved_fault_code;
+
+ /* Instruction point to execute next to breakpoint address */
+ instruction_pointer_set(regs, utask->vaddr + 4);
+
+ user_disable_single_step(current);
+
+ return 0;
+}
+bool arch_uprobe_xol_was_trapped(struct task_struct *t)
+{
+ /*
+ * Between arch_uprobe_pre_xol and arch_uprobe_post_xol, if an xol
+ * insn itself is trapped, then detect the case with the help of
+ * invalid fault code which is being set in arch_uprobe_pre_xol and
+ * restored in arch_uprobe_post_xol.
+ */
+ if (t->thread.fault_code != UPROBE_INV_FAULT_CODE)
+ return true;
+
+ return false;
+}
+
+bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ kprobe_opcode_t insn;
+ unsigned long addr;
+
+ if (!auprobe->simulate)
+ return false;
+
+ insn = *(kprobe_opcode_t *)(&auprobe->insn[0]);
+ addr = instruction_pointer(regs);
+
+ if (auprobe->ainsn.handler)
+ auprobe->ainsn.handler(insn, addr, regs);
+
+ return true;
+}
+
+void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ current->thread.fault_code = utask->autask.saved_fault_code;
+ /*
+ * Task has received a fatal signal, so reset back to probbed
+ * address.
+ */
+ instruction_pointer_set(regs, utask->vaddr);
+
+ user_disable_single_step(current);
+}
+
+unsigned long
+arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
+ struct pt_regs *regs)
+{
+ unsigned long orig_ret_vaddr;
+
+ orig_ret_vaddr = procedure_link_pointer(regs);
+ /* Replace the return addr with trampoline addr */
+ procedure_link_pointer_set(regs, trampoline_vaddr);
+
+ return orig_ret_vaddr;
+}
+
+int arch_uprobe_exception_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ return NOTIFY_DONE;
+}
+
+static int __kprobes uprobe_breakpoint_handler(struct pt_regs *regs,
+ unsigned int esr)
+{
+ if (user_mode(regs) && uprobe_pre_sstep_notifier(regs))
+ return DBG_HOOK_HANDLED;
+
+ return DBG_HOOK_ERROR;
+}
+
+static int __kprobes uprobe_single_step_handler(struct pt_regs *regs,
+ unsigned int esr)
+{
+ if (user_mode(regs)) {
+ WARN_ON(instruction_pointer(regs) !=
+ current->utask->xol_vaddr + 4);
+
+ if (uprobe_post_sstep_notifier(regs))
+ return DBG_HOOK_HANDLED;
+ }
+
+ return DBG_HOOK_ERROR;
+}
+
+/* uprobe breakpoint handler hook */
+static struct break_hook uprobes_break_hook = {
+ .esr_mask = BRK64_ESR_MASK,
+ .esr_val = BRK64_ESR_UPROBES,
+ .fn = uprobe_breakpoint_handler,
+};
+
+/* uprobe single step handler hook */
+static struct step_hook uprobes_step_hook = {
+ .fn = uprobe_single_step_handler,
+};
+
+static int __init arch_init_uprobes(void)
+{
+ register_break_hook(&uprobes_break_hook);
+ register_step_hook(&uprobes_step_hook);
+
+ return 0;
+}
+
+device_initcall(arch_init_uprobes);
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index 9a4dd6f39cf..04fe6671907 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -55,6 +55,12 @@ static void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
__flush_ptrace_access(page, uaddr, kaddr, len);
}
+void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,
+ void *kaddr, unsigned long len)
+{
+ __flush_ptrace_access(page, uaddr, kaddr, len);
+}
+
/*
* Copy user data from/to a page which is mapped into a different processes
* address space. Really, we want to allow our "user space" model to handle