Commit 74784081 authored by Guo Ren's avatar Guo Ren Committed by Palmer Dabbelt

riscv: Add uprobes supported

This patch adds support for uprobes on riscv architecture.

Just like kprobe, it support single-step and simulate instructions.
Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
Reviewed-by: default avatarPekka Enberg <penberg@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent 829adda5
......@@ -160,6 +160,9 @@ config ARCH_SELECT_MEMORY_MODEL
config ARCH_WANT_GENERAL_HUGETLB
def_bool y
config ARCH_SUPPORTS_UPROBES
def_bool y
config SYS_SUPPORTS_HUGETLBFS
depends on MMU
def_bool y
......
......@@ -34,6 +34,7 @@ struct thread_struct {
unsigned long sp; /* Kernel mode stack */
unsigned long s[12]; /* s[0]: frame pointer */
struct __riscv_d_ext_state fstate;
unsigned long bad_cause;
};
#define INIT_THREAD { \
......
......@@ -75,6 +75,7 @@ struct thread_info {
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing */
#define TIF_SECCOMP 8 /* syscall secure computing */
#define TIF_NOTIFY_SIGNAL 9 /* signal notifications exist */
#define TIF_UPROBE 10 /* uprobe breakpoint or singlestep */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
......@@ -84,10 +85,11 @@ struct thread_info {
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
#define _TIF_UPROBE (1 << TIF_UPROBE)
#define _TIF_WORK_MASK \
(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_SIGNAL)
_TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
#define _TIF_SYSCALL_WORK \
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT | \
......
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _ASM_RISCV_UPROBES_H
#define _ASM_RISCV_UPROBES_H
#include <asm/probes.h>
#include <asm/patch.h>
#include <asm/bug.h>
#define MAX_UINSN_BYTES 8
#ifdef CONFIG_RISCV_ISA_C
#define UPROBE_SWBP_INSN __BUG_INSN_16
#define UPROBE_SWBP_INSN_SIZE 2
#else
#define UPROBE_SWBP_INSN __BUG_INSN_32
#define UPROBE_SWBP_INSN_SIZE 4
#endif
#define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES
typedef u32 uprobe_opcode_t;
struct arch_uprobe_task {
unsigned long saved_cause;
};
struct arch_uprobe {
union {
u8 insn[MAX_UINSN_BYTES];
u8 ixol[MAX_UINSN_BYTES];
};
struct arch_probe_insn api;
unsigned long insn_size;
bool simulate;
};
bool uprobe_breakpoint_handler(struct pt_regs *regs);
bool uprobe_single_step_handler(struct pt_regs *regs);
#endif /* _ASM_RISCV_UPROBES_H */
......@@ -2,4 +2,5 @@
obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o simulate-insn.o
obj-$(CONFIG_KPROBES) += kprobes_trampoline.o
obj-$(CONFIG_KPROBES_ON_FTRACE) += ftrace.o
obj-$(CONFIG_UPROBES) += uprobes.o decode-insn.o simulate-insn.o
CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE)
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/uprobes.h>
#include "decode-insn.h"
#define UPROBE_TRAP_NR UINT_MAX
bool is_swbp_insn(uprobe_opcode_t *insn)
{
#ifdef CONFIG_RISCV_ISA_C
return (*insn & 0xffff) == UPROBE_SWBP_INSN;
#else
return *insn == UPROBE_SWBP_INSN;
#endif
}
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)
{
probe_opcode_t opcode;
opcode = *(probe_opcode_t *)(&auprobe->insn[0]);
auprobe->insn_size = GET_INSN_LENGTH(opcode);
switch (riscv_probe_decode_insn(&opcode, &auprobe->api)) {
case INSN_REJECTED:
return -EINVAL;
case INSN_GOOD_NO_SLOT:
auprobe->simulate = true;
break;
case INSN_GOOD:
auprobe->simulate = false;
break;
default:
return -EINVAL;
}
return 0;
}
int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
struct uprobe_task *utask = current->utask;
utask->autask.saved_cause = current->thread.bad_cause;
current->thread.bad_cause = UPROBE_TRAP_NR;
instruction_pointer_set(regs, utask->xol_vaddr);
regs->status &= ~SR_SPIE;
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.bad_cause != UPROBE_TRAP_NR);
instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
regs->status |= SR_SPIE;
return 0;
}
bool arch_uprobe_xol_was_trapped(struct task_struct *t)
{
if (t->thread.bad_cause != UPROBE_TRAP_NR)
return true;
return false;
}
bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
probe_opcode_t insn;
unsigned long addr;
if (!auprobe->simulate)
return false;
insn = *(probe_opcode_t *)(&auprobe->insn[0]);
addr = instruction_pointer(regs);
if (auprobe->api.handler)
auprobe->api.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;
/*
* Task has received a fatal signal, so reset back to probbed
* address.
*/
instruction_pointer_set(regs, utask->vaddr);
regs->status &= ~SR_SPIE;
}
bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
struct pt_regs *regs)
{
if (ctx == RP_CHECK_CHAIN_CALL)
return regs->sp <= ret->stack;
else
return regs->sp < ret->stack;
}
unsigned long
arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
struct pt_regs *regs)
{
unsigned long ra;
ra = regs->ra;
regs->ra = trampoline_vaddr;
return ra;
}
int arch_uprobe_exception_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return NOTIFY_DONE;
}
bool uprobe_breakpoint_handler(struct pt_regs *regs)
{
if (uprobe_pre_sstep_notifier(regs))
return true;
return false;
}
bool uprobe_single_step_handler(struct pt_regs *regs)
{
if (uprobe_post_sstep_notifier(regs))
return true;
return false;
}
void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
void *src, unsigned long len)
{
/* Initialize the slot */
void *kaddr = kmap_atomic(page);
void *dst = kaddr + (vaddr & ~PAGE_MASK);
memcpy(dst, src, len);
/* Add ebreak behind opcode to simulate singlestep */
if (vaddr) {
dst += GET_INSN_LENGTH(*(probe_opcode_t *)src);
*(uprobe_opcode_t *)dst = __BUG_INSN_32;
}
kunmap_atomic(kaddr);
/*
* We probably need flush_icache_user_page() but it needs vma.
* This should work on most of architectures by default. If
* architecture needs to do something different it can define
* its own version of the function.
*/
flush_dcache_page(page);
}
......@@ -309,6 +309,9 @@ static void do_signal(struct pt_regs *regs)
asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
unsigned long thread_info_flags)
{
if (thread_info_flags & _TIF_UPROBE)
uprobe_notify_resume(regs);
/* Handle pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
do_signal(regs);
......
......@@ -76,6 +76,8 @@ void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
static void do_trap_error(struct pt_regs *regs, int signo, int code,
unsigned long addr, const char *str)
{
current->thread.bad_cause = regs->cause;
if (user_mode(regs)) {
do_trap(regs, signo, code, addr);
} else {
......@@ -153,6 +155,14 @@ asmlinkage __visible void do_trap_break(struct pt_regs *regs)
if (kprobe_breakpoint_handler(regs))
return;
#endif
#ifdef CONFIG_UPROBES
if (uprobe_single_step_handler(regs))
return;
if (uprobe_breakpoint_handler(regs))
return;
#endif
current->thread.bad_cause = regs->cause;
if (user_mode(regs))
force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
......
......@@ -240,6 +240,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
* in an atomic region, then we must not take the fault.
*/
if (unlikely(faulthandler_disabled() || !mm)) {
tsk->thread.bad_cause = cause;
no_context(regs, addr);
return;
}
......@@ -262,16 +263,19 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
mmap_read_lock(mm);
vma = find_vma(mm, addr);
if (unlikely(!vma)) {
tsk->thread.bad_cause = cause;
bad_area(regs, mm, code, addr);
return;
}
if (likely(vma->vm_start <= addr))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
tsk->thread.bad_cause = cause;
bad_area(regs, mm, code, addr);
return;
}
if (unlikely(expand_stack(vma, addr))) {
tsk->thread.bad_cause = cause;
bad_area(regs, mm, code, addr);
return;
}
......@@ -284,6 +288,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
code = SEGV_ACCERR;
if (unlikely(access_error(cause, vma))) {
tsk->thread.bad_cause = cause;
bad_area(regs, mm, code, addr);
return;
}
......@@ -317,6 +322,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
mmap_read_unlock(mm);
if (unlikely(fault & VM_FAULT_ERROR)) {
tsk->thread.bad_cause = cause;
mm_fault_error(regs, addr, fault);
return;
}
......
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