v2:
-- Move the functions to inst.c in patch #1
-- Pass around union for insns_not_supported(),
insns_need_simulation() and arch_simulate_insn()
v1:
-- Split the RFC patch #2 into two patches
-- Use larch_insn_gen_break() to generate break insns
for kprobes and uprobes
-- Pass around instruction word instead of union for
insns_not_supported(), insns_need_simulation() and
arch_simulate_insn() to avoid type conversion for callers
-- Add a simple test case for uprobes in the commit message
Tiezhu Yang (4):
LoongArch: Move three functions from kprobes.c to inst.c
LoongArch: Add larch_insn_gen_break() to generate break insns
LoongArch: Use larch_insn_gen_break() for kprobes
LoongArch: Add uprobes support
arch/loongarch/Kconfig | 3 +
arch/loongarch/include/asm/inst.h | 16 ++++
arch/loongarch/include/asm/kprobes.h | 2 +-
arch/loongarch/include/asm/uprobes.h | 36 +++++++++
arch/loongarch/kernel/Makefile | 1 +
arch/loongarch/kernel/inst.c | 48 ++++++++++++
arch/loongarch/kernel/kprobes.c | 75 ++++--------------
arch/loongarch/kernel/traps.c | 9 +--
arch/loongarch/kernel/uprobes.c | 142 +++++++++++++++++++++++++++++++++++
9 files changed, 265 insertions(+), 67 deletions(-)
create mode 100644 arch/loongarch/include/asm/uprobes.h
create mode 100644 arch/loongarch/kernel/uprobes.c
--
2.1.0
The functions insns_not_supported(), insns_need_simulation()
and arch_simulate_insn() will be used for uprobes, move them
from kprobes.c to inst.c, this is preparation for later patch,
no functionality change.
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/include/asm/inst.h | 4 ++++
arch/loongarch/kernel/inst.c | 39 +++++++++++++++++++++++++++++++++
arch/loongarch/kernel/kprobes.c | 46 ++-------------------------------------
3 files changed, 45 insertions(+), 44 deletions(-)
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index a04fe75..9ea485b 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -409,6 +409,10 @@ static inline bool is_self_loop_ins(union loongarch_instruction *ip, struct pt_r
void simu_pc(struct pt_regs *regs, union loongarch_instruction insn);
void simu_branch(struct pt_regs *regs, union loongarch_instruction insn);
+bool insns_not_supported(union loongarch_instruction insn);
+bool insns_need_simulation(union loongarch_instruction insn);
+void arch_simulate_insn(union loongarch_instruction insn, struct pt_regs *regs);
+
int larch_insn_read(void *addr, u32 *insnp);
int larch_insn_write(void *addr, u32 insn);
int larch_insn_patch_text(void *addr, u32 insn);
diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
index 258ef26..95219e0 100644
--- a/arch/loongarch/kernel/inst.c
+++ b/arch/loongarch/kernel/inst.c
@@ -133,6 +133,45 @@ void simu_branch(struct pt_regs *regs, union loongarch_instruction insn)
}
}
+bool insns_not_supported(union loongarch_instruction insn)
+{
+ switch (insn.reg2i14_format.opcode) {
+ case llw_op:
+ case lld_op:
+ case scw_op:
+ case scd_op:
+ pr_notice("kprobe: ll and sc instructions are not supported\n");
+ return true;
+ }
+
+ switch (insn.reg1i21_format.opcode) {
+ case bceqz_op:
+ pr_notice("kprobe: bceqz and bcnez instructions are not supported\n");
+ return true;
+ }
+
+ return false;
+}
+
+bool insns_need_simulation(union loongarch_instruction insn)
+{
+ if (is_pc_ins(&insn))
+ return true;
+
+ if (is_branch_ins(&insn))
+ return true;
+
+ return false;
+}
+
+void arch_simulate_insn(union loongarch_instruction insn, struct pt_regs *regs)
+{
+ if (is_pc_ins(&insn))
+ simu_pc(regs, insn);
+ else if (is_branch_ins(&insn))
+ simu_branch(regs, insn);
+}
+
int larch_insn_read(void *addr, u32 *insnp)
{
int ret;
diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
index 56c8c4b..08c78d2 100644
--- a/arch/loongarch/kernel/kprobes.c
+++ b/arch/loongarch/kernel/kprobes.c
@@ -21,48 +21,6 @@ static const union loongarch_instruction singlestep_insn = {
DEFINE_PER_CPU(struct kprobe *, current_kprobe);
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-static bool insns_not_supported(union loongarch_instruction insn)
-{
- switch (insn.reg2i14_format.opcode) {
- case llw_op:
- case lld_op:
- case scw_op:
- case scd_op:
- pr_notice("kprobe: ll and sc instructions are not supported\n");
- return true;
- }
-
- switch (insn.reg1i21_format.opcode) {
- case bceqz_op:
- pr_notice("kprobe: bceqz and bcnez instructions are not supported\n");
- return true;
- }
-
- return false;
-}
-NOKPROBE_SYMBOL(insns_not_supported);
-
-static bool insns_need_simulation(struct kprobe *p)
-{
- if (is_pc_ins(&p->opcode))
- return true;
-
- if (is_branch_ins(&p->opcode))
- return true;
-
- return false;
-}
-NOKPROBE_SYMBOL(insns_need_simulation);
-
-static void arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
-{
- if (is_pc_ins(&p->opcode))
- simu_pc(regs, p->opcode);
- else if (is_branch_ins(&p->opcode))
- simu_branch(regs, p->opcode);
-}
-NOKPROBE_SYMBOL(arch_simulate_insn);
-
static void arch_prepare_ss_slot(struct kprobe *p)
{
p->ainsn.insn[0] = *p->addr;
@@ -89,7 +47,7 @@ int arch_prepare_kprobe(struct kprobe *p)
if (insns_not_supported(p->opcode))
return -EINVAL;
- if (insns_need_simulation(p)) {
+ if (insns_need_simulation(p->opcode)) {
p->ainsn.insn = NULL;
} else {
p->ainsn.insn = get_insn_slot();
@@ -220,7 +178,7 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
regs->csr_era = (unsigned long)p->ainsn.insn;
} else {
/* simulate single steping */
- arch_simulate_insn(p, regs);
+ arch_simulate_insn(p->opcode, regs);
/* now go for post processing */
post_kprobe_handler(p, kcb, regs);
}
--
2.1.0
There exist various break insns such as BRK_KPROBE_BP, BRK_KPROBE_SSTEPBP,
BRK_UPROBE_BP and BRK_UPROBE_XOLBP, add larch_insn_gen_break() to generate
break insns simpler, this is preparation for later patch.
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/include/asm/inst.h | 12 ++++++++++++
arch/loongarch/kernel/inst.c | 9 +++++++++
2 files changed, 21 insertions(+)
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index 9ea485b..061c0ea 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -421,6 +421,8 @@ u32 larch_insn_gen_nop(void);
u32 larch_insn_gen_b(unsigned long pc, unsigned long dest);
u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest);
+u32 larch_insn_gen_break(int imm);
+
u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loongarch_gpr rj, enum loongarch_gpr rk);
u32 larch_insn_gen_move(enum loongarch_gpr rd, enum loongarch_gpr rj);
@@ -439,6 +441,16 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
return val < (1UL << bit);
}
+#define DEF_EMIT_REG0I15_FORMAT(NAME, OP) \
+static inline void emit_##NAME(union loongarch_instruction *insn, \
+ int imm) \
+{ \
+ insn->reg0i15_format.opcode = OP; \
+ insn->reg0i15_format.immediate = imm; \
+}
+
+DEF_EMIT_REG0I15_FORMAT(break, break_op)
+
#define DEF_EMIT_REG0I26_FORMAT(NAME, OP) \
static inline void emit_##NAME(union loongarch_instruction *insn, \
int offset) \
diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
index 95219e0..0bdcd46 100644
--- a/arch/loongarch/kernel/inst.c
+++ b/arch/loongarch/kernel/inst.c
@@ -247,6 +247,15 @@ u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest)
return insn.word;
}
+u32 larch_insn_gen_break(int imm)
+{
+ union loongarch_instruction insn;
+
+ emit_break(&insn, imm);
+
+ return insn.word;
+}
+
u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loongarch_gpr rj, enum loongarch_gpr rk)
{
union loongarch_instruction insn;
--
2.1.0
For now, we can use larch_insn_gen_break() to define KPROBE_BP_INSN and
KPROBE_SSTEPBP_INSN. Because larch_insn_gen_break() returns instruction
word, define kprobe_opcode_t as u32, then do some small changes related
with type conversion, no functional change intended.
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/include/asm/kprobes.h | 2 +-
arch/loongarch/kernel/kprobes.c | 33 ++++++++++++++-------------------
2 files changed, 15 insertions(+), 20 deletions(-)
diff --git a/arch/loongarch/include/asm/kprobes.h b/arch/loongarch/include/asm/kprobes.h
index 798020a..7ef7a0f 100644
--- a/arch/loongarch/include/asm/kprobes.h
+++ b/arch/loongarch/include/asm/kprobes.h
@@ -22,7 +22,7 @@ do { \
#define kretprobe_blacklist_size 0
-typedef union loongarch_instruction kprobe_opcode_t;
+typedef u32 kprobe_opcode_t;
/* Architecture specific copy of original instruction */
struct arch_specific_insn {
diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
index 08c78d2..1835102 100644
--- a/arch/loongarch/kernel/kprobes.c
+++ b/arch/loongarch/kernel/kprobes.c
@@ -4,19 +4,8 @@
#include <linux/preempt.h>
#include <asm/break.h>
-static const union loongarch_instruction breakpoint_insn = {
- .reg0i15_format = {
- .opcode = break_op,
- .immediate = BRK_KPROBE_BP,
- }
-};
-
-static const union loongarch_instruction singlestep_insn = {
- .reg0i15_format = {
- .opcode = break_op,
- .immediate = BRK_KPROBE_SSTEPBP,
- }
-};
+#define KPROBE_BP_INSN larch_insn_gen_break(BRK_KPROBE_BP)
+#define KPROBE_SSTEPBP_INSN larch_insn_gen_break(BRK_KPROBE_SSTEPBP)
DEFINE_PER_CPU(struct kprobe *, current_kprobe);
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -24,7 +13,7 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static void arch_prepare_ss_slot(struct kprobe *p)
{
p->ainsn.insn[0] = *p->addr;
- p->ainsn.insn[1] = singlestep_insn;
+ p->ainsn.insn[1] = KPROBE_SSTEPBP_INSN;
p->ainsn.restore = (unsigned long)p->addr + LOONGARCH_INSN_SIZE;
}
NOKPROBE_SYMBOL(arch_prepare_ss_slot);
@@ -37,17 +26,20 @@ NOKPROBE_SYMBOL(arch_prepare_simulate);
int arch_prepare_kprobe(struct kprobe *p)
{
+ union loongarch_instruction insn;
+
if ((unsigned long)p->addr & 0x3)
return -EILSEQ;
/* copy instruction */
p->opcode = *p->addr;
+ insn.word = p->opcode;
/* decode instruction */
- if (insns_not_supported(p->opcode))
+ if (insns_not_supported(insn))
return -EINVAL;
- if (insns_need_simulation(p->opcode)) {
+ if (insns_need_simulation(insn)) {
p->ainsn.insn = NULL;
} else {
p->ainsn.insn = get_insn_slot();
@@ -68,7 +60,7 @@ NOKPROBE_SYMBOL(arch_prepare_kprobe);
/* Install breakpoint in text */
void arch_arm_kprobe(struct kprobe *p)
{
- *p->addr = breakpoint_insn;
+ *p->addr = KPROBE_BP_INSN;
flush_insn_slot(p);
}
NOKPROBE_SYMBOL(arch_arm_kprobe);
@@ -163,6 +155,8 @@ NOKPROBE_SYMBOL(post_kprobe_handler);
static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb, int reenter)
{
+ union loongarch_instruction insn;
+
if (reenter) {
save_previous_kprobe(kcb);
set_current_kprobe(p);
@@ -178,7 +172,8 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
regs->csr_era = (unsigned long)p->ainsn.insn;
} else {
/* simulate single steping */
- arch_simulate_insn(p->opcode, regs);
+ insn.word = p->opcode;
+ arch_simulate_insn(insn, regs);
/* now go for post processing */
post_kprobe_handler(p, kcb, regs);
}
@@ -253,7 +248,7 @@ bool kprobe_breakpoint_handler(struct pt_regs *regs)
}
}
- if (addr->word != breakpoint_insn.word) {
+ if (*addr != KPROBE_BP_INSN) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
--
2.1.0
Uprobes is the user-space counterpart to kprobes, this commit
adds uprobes support for LoongArch.
Here is a simple example with CONFIG_UPROBE_EVENTS=y:
# cat test.c
#include <stdio.h>
int add(int a, int b)
{
return a + b;
}
int main()
{
return add(2, 7);
}
# gcc test.c -o /tmp/test
# nm /tmp/test | grep add
0000000120004194 T add
# cd /sys/kernel/debug/tracing
# echo > uprobe_events
# echo "p:myuprobe /tmp/test:0x4194 %r4 %r5" > uprobe_events
# echo "r:myuretprobe /tmp/test:0x4194 %r4" >> uprobe_events
# echo 1 > events/uprobes/enable
# echo 1 > tracing_on
# /tmp/test
# cat trace
...
# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
test-1060 [001] DNZff 1015.770620: myuprobe: (0x120004194) arg1=0x2 arg2=0x7
test-1060 [001] DNZff 1015.770930: myuretprobe: (0x1200041f0 <- 0x120004194) arg1=0x9
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/Kconfig | 3 +
arch/loongarch/include/asm/uprobes.h | 36 +++++++++
arch/loongarch/kernel/Makefile | 1 +
arch/loongarch/kernel/traps.c | 9 +--
arch/loongarch/kernel/uprobes.c | 142 +++++++++++++++++++++++++++++++++++
5 files changed, 186 insertions(+), 5 deletions(-)
create mode 100644 arch/loongarch/include/asm/uprobes.h
create mode 100644 arch/loongarch/kernel/uprobes.c
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 7fd5125..ab66ad2 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -574,6 +574,9 @@ config ARCH_MMAP_RND_BITS_MIN
config ARCH_MMAP_RND_BITS_MAX
default 18
+config ARCH_SUPPORTS_UPROBES
+ def_bool y
+
menu "Power management options"
config ARCH_SUSPEND_POSSIBLE
diff --git a/arch/loongarch/include/asm/uprobes.h b/arch/loongarch/include/asm/uprobes.h
new file mode 100644
index 0000000..c6ffcb7
--- /dev/null
+++ b/arch/loongarch/include/asm/uprobes.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_LOONGARCH_UPROBES_H
+#define __ASM_LOONGARCH_UPROBES_H
+
+#include <asm/inst.h>
+
+typedef u32 uprobe_opcode_t;
+
+#define MAX_UINSN_BYTES LOONGARCH_INSN_SIZE
+#define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES
+
+#define UPROBE_XOLBP_INSN larch_insn_gen_break(BRK_UPROBE_XOLBP)
+#define UPROBE_SWBP_INSN larch_insn_gen_break(BRK_UPROBE_BP)
+#define UPROBE_SWBP_INSN_SIZE LOONGARCH_INSN_SIZE
+
+struct arch_uprobe {
+ union {
+ u32 insn[MAX_UINSN_BYTES];
+ u32 ixol[MAX_UINSN_BYTES];
+ };
+ bool simulate;
+};
+
+struct arch_uprobe_task {
+ unsigned long saved_trap_nr;
+};
+
+#ifdef CONFIG_UPROBES
+bool uprobe_breakpoint_handler(struct pt_regs *regs);
+bool uprobe_singlestep_handler(struct pt_regs *regs);
+#else /* !CONFIG_UPROBES */
+static inline bool uprobe_breakpoint_handler(struct pt_regs *regs) { return false; }
+static inline bool uprobe_singlestep_handler(struct pt_regs *regs) { return false; }
+#endif /* CONFIG_UPROBES */
+
+#endif /* __ASM_LOONGARCH_UPROBES_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 78d4e33..67b9c26 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -53,5 +53,6 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_KPROBES) += kprobes.o kprobes_trampoline.o
+obj-$(CONFIG_UPROBES) += uprobes.o
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index de8ebe2..cfc2e0c 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -45,6 +45,7 @@
#include <asm/tlb.h>
#include <asm/types.h>
#include <asm/unwind.h>
+#include <asm/uprobes.h>
#include "access-helper.h"
@@ -440,7 +441,6 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
if (regs->csr_prmd & CSR_PRMD_PIE)
local_irq_enable();
- current->thread.trap_nr = read_csr_excode();
if (__get_inst(&opcode, (u32 *)era, user))
goto out_sigsegv;
@@ -462,18 +462,17 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
else
break;
case BRK_UPROBE_BP:
- if (notify_die(DIE_UPROBE, "Uprobe", regs, bcode,
- current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ if (uprobe_breakpoint_handler(regs))
goto out;
else
break;
case BRK_UPROBE_XOLBP:
- if (notify_die(DIE_UPROBE_XOL, "Uprobe_XOL", regs, bcode,
- current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ if (uprobe_singlestep_handler(regs))
goto out;
else
break;
default:
+ current->thread.trap_nr = read_csr_excode();
if (notify_die(DIE_TRAP, "Break", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
goto out;
diff --git a/arch/loongarch/kernel/uprobes.c b/arch/loongarch/kernel/uprobes.c
new file mode 100644
index 0000000..628c39d
--- /dev/null
+++ b/arch/loongarch/kernel/uprobes.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/highmem.h>
+#include <linux/ptrace.h>
+#include <linux/uprobes.h>
+#include <linux/sched.h>
+#include <asm/cacheflush.h>
+
+#define UPROBE_TRAP_NR UINT_MAX
+
+int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe,
+ struct mm_struct *mm, unsigned long addr)
+{
+ union loongarch_instruction insn;
+
+ if (addr & 0x3)
+ return -EILSEQ;
+
+ insn.word = auprobe->insn[0];
+
+ if (insns_not_supported(insn))
+ return -EINVAL;
+
+ if (insns_need_simulation(insn)) {
+ auprobe->ixol[0] = larch_insn_gen_nop();
+ auprobe->simulate = true;
+ } else {
+ auprobe->ixol[0] = auprobe->insn[0];
+ auprobe->simulate = false;
+ }
+
+ auprobe->ixol[1] = UPROBE_XOLBP_INSN;
+
+ return 0;
+}
+
+int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ utask->autask.saved_trap_nr = current->thread.trap_nr;
+ current->thread.trap_nr = UPROBE_TRAP_NR;
+ instruction_pointer_set(regs, utask->xol_vaddr);
+
+ 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.trap_nr != UPROBE_TRAP_NR);
+ current->thread.trap_nr = utask->autask.saved_trap_nr;
+ instruction_pointer_set(regs, utask->vaddr + LOONGARCH_INSN_SIZE);
+
+ return 0;
+}
+
+void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ current->thread.trap_nr = utask->autask.saved_trap_nr;
+ instruction_pointer_set(regs, utask->vaddr);
+}
+
+bool arch_uprobe_xol_was_trapped(struct task_struct *t)
+{
+ if (t->thread.trap_nr != UPROBE_TRAP_NR)
+ return true;
+
+ return false;
+}
+
+bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ union loongarch_instruction insn;
+
+ if (!auprobe->simulate)
+ return false;
+
+ insn.word = auprobe->insn[0];
+ arch_simulate_insn(insn, regs);
+
+ return true;
+}
+
+unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
+ struct pt_regs *regs)
+{
+ unsigned long ra = regs->regs[1];
+
+ regs->regs[1] = trampoline_vaddr;
+
+ return ra;
+}
+
+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->regs[3] <= ret->stack;
+ else
+ return regs->regs[3] < ret->stack;
+}
+
+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_singlestep_handler(struct pt_regs *regs)
+{
+ if (uprobe_post_sstep_notifier(regs))
+ return true;
+
+ return false;
+}
+
+unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
+{
+ return instruction_pointer(regs);
+}
+
+void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
+ void *src, unsigned long len)
+{
+ void *kaddr = kmap_local_page(page);
+ void *dst = kaddr + (vaddr & ~PAGE_MASK);
+
+ memcpy(dst, src, len);
+ flush_icache_range((unsigned long)dst, (unsigned long)dst + len);
+ kunmap_local(kaddr);
+}
--
2.1.0
Hi, Tiezhu
On 04/14/2023 05:33 PM, Tiezhu Yang wrote:
/* snip */
> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> index de8ebe2..cfc2e0c 100644
> --- a/arch/loongarch/kernel/traps.c
> +++ b/arch/loongarch/kernel/traps.c
> @@ -45,6 +45,7 @@
> #include <asm/tlb.h>
> #include <asm/types.h>
> #include <asm/unwind.h>
> +#include <asm/uprobes.h>
>
> #include "access-helper.h"
>
> @@ -440,7 +441,6 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
> if (regs->csr_prmd & CSR_PRMD_PIE)
> local_irq_enable();
>
> - current->thread.trap_nr = read_csr_excode();
> if (__get_inst(&opcode, (u32 *)era, user))
> goto out_sigsegv;
>
> @@ -462,18 +462,17 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
> else
> break;
> case BRK_UPROBE_BP:
> - if (notify_die(DIE_UPROBE, "Uprobe", regs, bcode,
> - current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
> + if (uprobe_breakpoint_handler(regs))
> goto out;
> else
> break;
> case BRK_UPROBE_XOLBP:
> - if (notify_die(DIE_UPROBE_XOL, "Uprobe_XOL", regs, bcode,
> - current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
> + if (uprobe_singlestep_handler(regs))
After the above modification, we should remove the DIE_UPROBE and
DIE_UPROBE_XOL definitions in arch/loongarch/include/asm/kdebug.h.
At the same time DIE_BREAK, DIE_SSTEPBP and DIE_PAGE_FAULT also need to
be removed after 6d4cc40fb5f581 ("LoongArch: Add kprobes support").
Thanks,
Youling
> goto out;
> else
> break;
> default:
> + current->thread.trap_nr = read_csr_excode();
> if (notify_die(DIE_TRAP, "Break", regs, bcode,
> current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
> goto out;
Hi Tiezhu:
On 2023/4/14 17:32, Tiezhu Yang wrote:
> v2:
> -- Move the functions to inst.c in patch #1
> -- Pass around union for insns_not_supported(),
> insns_need_simulation() and arch_simulate_insn()
>
> v1:
> -- Split the RFC patch #2 into two patches
> -- Use larch_insn_gen_break() to generate break insns
> for kprobes and uprobes
> -- Pass around instruction word instead of union for
> insns_not_supported(), insns_need_simulation() and
> arch_simulate_insn() to avoid type conversion for callers
> -- Add a simple test case for uprobes in the commit message
>
> Tiezhu Yang (4):
> LoongArch: Move three functions from kprobes.c to inst.c
> LoongArch: Add larch_insn_gen_break() to generate break insns
> LoongArch: Use larch_insn_gen_break() for kprobes
> LoongArch: Add uprobes support
>
> arch/loongarch/Kconfig | 3 +
> arch/loongarch/include/asm/inst.h | 16 ++++
> arch/loongarch/include/asm/kprobes.h | 2 +-
> arch/loongarch/include/asm/uprobes.h | 36 +++++++++
> arch/loongarch/kernel/Makefile | 1 +
> arch/loongarch/kernel/inst.c | 48 ++++++++++++
> arch/loongarch/kernel/kprobes.c | 75 ++++--------------
> arch/loongarch/kernel/traps.c | 9 +--
> arch/loongarch/kernel/uprobes.c | 142 +++++++++++++++++++++++++++++++++++
> 9 files changed, 265 insertions(+), 67 deletions(-)
> create mode 100644 arch/loongarch/include/asm/uprobes.h
> create mode 100644 arch/loongarch/kernel/uprobes.c
>
I've test this series and found one corner case:
#include <pthread.h>
#include <stdio.h>
#include <thread>
static pthread_spinlock_t lock;
static int count = 0;
static const int n = 10000;
int main()
{
int ret;
ret = pthread_spin_init(&lock, PTHREAD_PROCESS_PRIVATE);
if (ret)
return -1;
auto t1 = std::thread([&](){
for (auto i = 0; i < n; i++) {
pthread_spin_lock(&lock);
count++;
pthread_spin_unlock(&lock);
}
});
auto t2 = std::thread([&](){
for (auto i = 0; i < n; i++) {
pthread_spin_lock(&lock);
count++;
pthread_spin_unlock(&lock);
}
});
auto t3 = std::thread([&](){
for (auto i = 0; i < n; i++) {
pthread_spin_lock(&lock);
count++;
pthread_spin_unlock(&lock);
}
});
t1.join();
t2.join();
t3.join();
pthread_spin_destroy(&lock);
printf("%d\n", count);
return 0;
}
When I try to uprobe the pthread_spin_lock calls, the application core dumped.
On X86, this will return -EINVAL instead of crashing the userspace application.
Probably, we should add more opcode to insns_not_supported().
Cheers,
---
Hengqi
On 04/17/2023 10:04 AM, Youling Tang wrote:
> Hi, Tiezhu
>
> On 04/14/2023 05:33 PM, Tiezhu Yang wrote:
>
> /* snip */
>
>> diff --git a/arch/loongarch/kernel/traps.c
>> b/arch/loongarch/kernel/traps.c
>> index de8ebe2..cfc2e0c 100644
>> --- a/arch/loongarch/kernel/traps.c
>> +++ b/arch/loongarch/kernel/traps.c
>> @@ -45,6 +45,7 @@
>> #include <asm/tlb.h>
>> #include <asm/types.h>
>> #include <asm/unwind.h>
>> +#include <asm/uprobes.h>
>>
>> #include "access-helper.h"
>>
>> @@ -440,7 +441,6 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
>> if (regs->csr_prmd & CSR_PRMD_PIE)
>> local_irq_enable();
>>
>> - current->thread.trap_nr = read_csr_excode();
>> if (__get_inst(&opcode, (u32 *)era, user))
>> goto out_sigsegv;
>>
>> @@ -462,18 +462,17 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
>> else
>> break;
>> case BRK_UPROBE_BP:
>> - if (notify_die(DIE_UPROBE, "Uprobe", regs, bcode,
>> - current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
>> + if (uprobe_breakpoint_handler(regs))
>> goto out;
>> else
>> break;
>> case BRK_UPROBE_XOLBP:
>> - if (notify_die(DIE_UPROBE_XOL, "Uprobe_XOL", regs, bcode,
>> - current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
>> + if (uprobe_singlestep_handler(regs))
>
> After the above modification, we should remove the DIE_UPROBE and
> DIE_UPROBE_XOL definitions in arch/loongarch/include/asm/kdebug.h.
>
> At the same time DIE_BREAK, DIE_SSTEPBP and DIE_PAGE_FAULT also need to
> be removed after 6d4cc40fb5f581 ("LoongArch: Add kprobes support").
>
OK, thank you, will do it.
Thanks,
Tiezhu
On 04/17/2023 11:17 AM, Hengqi Chen wrote:
> Hi Tiezhu:
>
...
>
> When I try to uprobe the pthread_spin_lock calls, the application core dumped.
> On X86, this will return -EINVAL instead of crashing the userspace application.
> Probably, we should add more opcode to insns_not_supported().
>
Yes, the atomic memory access instructions such as amswap_db.w
should not be supported, like llsc instructions, let me add them
in insns_not_supported(), thank you.
Thanks,
Tiezhu