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csky: Add uprobes support
This patch adds support for uprobes on csky architecture. Just like kprobe, it support single-step and simulate instructions. Signed-off-by: Guo Ren <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Steven Rostedt (VMware) <[email protected]>
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8 files changed

+201
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‎arch/csky/Kconfig

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Original file line numberDiff line numberDiff line change
@@ -75,6 +75,9 @@ config CSKY
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config LOCKDEP_SUPPORT
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def_bool y
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78+
config ARCH_SUPPORTS_UPROBES
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def_bool y if !CPU_CK610
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config CPU_HAS_CACHEV2
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bool
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‎arch/csky/include/asm/thread_info.h

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@@ -57,6 +57,7 @@ static inline struct thread_info *current_thread_info(void)
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#define TIF_SYSCALL_TRACE 3 /* syscall trace active */
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#define TIF_SYSCALL_TRACEPOINT 4 /* syscall tracepoint instrumentation */
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#define TIF_SYSCALL_AUDIT 5 /* syscall auditing */
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#define TIF_UPROBE 6 /* uprobe breakpoint or singlestep */
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#define TIF_POLLING_NRFLAG 16 /* poll_idle() is TIF_NEED_RESCHED */
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#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
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#define TIF_RESTORE_SIGMASK 20 /* restore signal mask in do_signal() */
@@ -68,6 +69,7 @@ static inline struct thread_info *current_thread_info(void)
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#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_UPROBE (1 << TIF_UPROBE)
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#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
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#define _TIF_MEMDIE (1 << TIF_MEMDIE)
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#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)

‎arch/csky/include/asm/uprobes.h

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,33 @@
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/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_CSKY_UPROBES_H
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#define __ASM_CSKY_UPROBES_H
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#include <asm/probes.h>
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#define MAX_UINSN_BYTES 4
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#define UPROBE_SWBP_INSN USR_BKPT
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#define UPROBE_SWBP_INSN_SIZE 2
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#define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES
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typedef u32 uprobe_opcode_t;
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struct arch_uprobe_task {
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unsigned long saved_trap_no;
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};
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struct arch_uprobe {
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union {
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u8 insn[MAX_UINSN_BYTES];
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u8 ixol[MAX_UINSN_BYTES];
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};
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struct arch_probe_insn api;
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unsigned long insn_size;
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bool simulate;
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};
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int uprobe_breakpoint_handler(struct pt_regs *regs);
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int uprobe_single_step_handler(struct pt_regs *regs);
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#endif /* __ASM_CSKY_UPROBES_H */

‎arch/csky/kernel/entry.S

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -221,7 +221,7 @@ ret_from_exception:
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andn r9, r10
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223223
ldw r12, (r9, TINFO_FLAGS)
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andi r12, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
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andi r12, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | _TIF_UPROBE)
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cmpnei r12, 0
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bt exit_work
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1:

‎arch/csky/kernel/probes/Makefile

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2,5 +2,6 @@
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obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o simulate-insn.o
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obj-$(CONFIG_KPROBES) += kprobes_trampoline.o
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obj-$(CONFIG_KPROBES_ON_FTRACE) += ftrace.o
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obj-$(CONFIG_UPROBES) += uprobes.o decode-insn.o simulate-insn.o
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CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE)

‎arch/csky/kernel/probes/uprobes.c

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,150 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2014-2016 Pratyush Anand <[email protected]>
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*/
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#include <linux/highmem.h>
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#include <linux/ptrace.h>
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#include <linux/uprobes.h>
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#include <asm/cacheflush.h>
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#include "decode-insn.h"
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#define UPROBE_TRAP_NR UINT_MAX
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unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
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{
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return instruction_pointer(regs);
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}
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int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
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unsigned long addr)
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{
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probe_opcode_t insn;
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insn = *(probe_opcode_t *)(&auprobe->insn[0]);
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auprobe->insn_size = is_insn32(insn) ? 4 : 2;
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switch (csky_probe_decode_insn(&insn, &auprobe->api)) {
29+
case INSN_REJECTED:
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return -EINVAL;
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case INSN_GOOD_NO_SLOT:
33+
auprobe->simulate = true;
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break;
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default:
37+
break;
38+
}
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return 0;
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}
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int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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struct uprobe_task *utask = current->utask;
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utask->autask.saved_trap_no = current->thread.trap_no;
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current->thread.trap_no = UPROBE_TRAP_NR;
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instruction_pointer_set(regs, utask->xol_vaddr);
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user_enable_single_step(current);
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return 0;
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}
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int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
59+
struct uprobe_task *utask = current->utask;
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WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
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instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
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user_disable_single_step(current);
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return 0;
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}
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bool arch_uprobe_xol_was_trapped(struct task_struct *t)
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{
72+
if (t->thread.trap_no != UPROBE_TRAP_NR)
73+
return true;
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return false;
76+
}
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bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
80+
probe_opcode_t insn;
81+
unsigned long addr;
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83+
if (!auprobe->simulate)
84+
return false;
85+
86+
insn = *(probe_opcode_t *)(&auprobe->insn[0]);
87+
addr = instruction_pointer(regs);
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89+
if (auprobe->api.handler)
90+
auprobe->api.handler(insn, addr, regs);
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return true;
93+
}
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void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
96+
{
97+
struct uprobe_task *utask = current->utask;
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/*
100+
* Task has received a fatal signal, so reset back to probbed
101+
* address.
102+
*/
103+
instruction_pointer_set(regs, utask->vaddr);
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105+
user_disable_single_step(current);
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}
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bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
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struct pt_regs *regs)
110+
{
111+
if (ctx == RP_CHECK_CHAIN_CALL)
112+
return regs->usp <= ret->stack;
113+
else
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return regs->usp < ret->stack;
115+
}
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unsigned long
118+
arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
119+
struct pt_regs *regs)
120+
{
121+
unsigned long ra;
122+
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ra = regs->lr;
124+
125+
regs->lr = trampoline_vaddr;
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127+
return ra;
128+
}
129+
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int arch_uprobe_exception_notify(struct notifier_block *self,
131+
unsigned long val, void *data)
132+
{
133+
return NOTIFY_DONE;
134+
}
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136+
int uprobe_breakpoint_handler(struct pt_regs *regs)
137+
{
138+
if (uprobe_pre_sstep_notifier(regs))
139+
return 1;
140+
141+
return 0;
142+
}
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144+
int uprobe_single_step_handler(struct pt_regs *regs)
145+
{
146+
if (uprobe_post_sstep_notifier(regs))
147+
return 1;
148+
149+
return 0;
150+
}

‎arch/csky/kernel/signal.c

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -253,6 +253,9 @@ static void do_signal(struct pt_regs *regs)
253253
asmlinkage void do_notify_resume(struct pt_regs *regs,
254254
unsigned long thread_info_flags)
255255
{
256+
if (thread_info_flags & _TIF_UPROBE)
257+
uprobe_notify_resume(regs);
258+
256259
/* Handle pending signal delivery */
257260
if (thread_info_flags & _TIF_SIGPENDING)
258261
do_signal(regs);

‎arch/csky/kernel/traps.c

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,10 @@ asmlinkage void trap_c(struct pt_regs *regs)
129129
#ifdef CONFIG_KPROBES
130130
if (kprobe_single_step_handler(regs))
131131
return;
132+
#endif
133+
#ifdef CONFIG_UPROBES
134+
if (uprobe_single_step_handler(regs))
135+
return;
132136
#endif
133137
info.si_code = TRAP_TRACE;
134138
sig = SIGTRAP;
@@ -138,6 +142,10 @@ asmlinkage void trap_c(struct pt_regs *regs)
138142
#ifdef CONFIG_KPROBES
139143
if (kprobe_breakpoint_handler(regs))
140144
return;
145+
#endif
146+
#ifdef CONFIG_UPROBES
147+
if (uprobe_breakpoint_handler(regs))
148+
return;
141149
#endif
142150
die_if_kernel("Kernel mode ILLEGAL", regs, vector);
143151
#ifndef CONFIG_CPU_NO_USER_BKPT

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