* [PATCH v10 1/4] LoongArch: Simulate branch and PC instructions
2022-12-09 8:52 [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Tiezhu Yang
@ 2022-12-09 8:52 ` Tiezhu Yang
2022-12-21 7:42 ` Jinyang He
2022-12-09 8:52 ` [PATCH v10 2/4] LoongArch: Add kprobe support Tiezhu Yang
` (4 subsequent siblings)
5 siblings, 1 reply; 16+ messages in thread
From: Tiezhu Yang @ 2022-12-09 8:52 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui, Masami Hiramatsu; +Cc: loongarch, linux-kernel
According to LoongArch Reference Manual, simulate branch and
PC instructions, this is preparation for later patch.
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#branch-instructions
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_pcaddi_pcaddu121_pcaddu18l_pcalau12i
Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
arch/loongarch/include/asm/inst.h | 5 ++
arch/loongarch/include/asm/ptrace.h | 1 +
arch/loongarch/kernel/inst.c | 123 ++++++++++++++++++++++++++++++++++++
3 files changed, 129 insertions(+)
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index c00e151..e25fd54 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -7,6 +7,7 @@
#include <linux/types.h>
#include <asm/asm.h>
+#include <asm/ptrace.h>
#define INSN_NOP 0x03400000
#define INSN_BREAK 0x002a0000
@@ -32,6 +33,7 @@ enum reg1i20_op {
lu12iw_op = 0x0a,
lu32id_op = 0x0b,
pcaddi_op = 0x0c,
+ pcalau12i_op = 0x0d,
pcaddu12i_op = 0x0e,
pcaddu18i_op = 0x0f,
};
@@ -367,6 +369,9 @@ u32 larch_insn_gen_lu32id(enum loongarch_gpr rd, int imm);
u32 larch_insn_gen_lu52id(enum loongarch_gpr rd, enum loongarch_gpr rj, int imm);
u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsigned long pc, unsigned long dest);
+void simu_branch(struct pt_regs *regs, union loongarch_instruction insn);
+void simu_pc(struct pt_regs *regs, union loongarch_instruction insn);
+
static inline bool signed_imm_check(long val, unsigned int bit)
{
return -(1L << (bit - 1)) <= val && val < (1L << (bit - 1));
diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/asm/ptrace.h
index 59c4608..58596c4 100644
--- a/arch/loongarch/include/asm/ptrace.h
+++ b/arch/loongarch/include/asm/ptrace.h
@@ -6,6 +6,7 @@
#define _ASM_PTRACE_H
#include <asm/page.h>
+#include <asm/irqflags.h>
#include <asm/thread_info.h>
#include <uapi/asm/ptrace.h>
diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
index 512579d..af48faf 100644
--- a/arch/loongarch/kernel/inst.c
+++ b/arch/loongarch/kernel/inst.c
@@ -165,3 +165,126 @@ u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsigned l
return insn.word;
}
+
+void simu_branch(struct pt_regs *regs, union loongarch_instruction insn)
+{
+ unsigned int imm, imm_l, imm_h, rd, rj;
+ unsigned long pc = regs->csr_era;
+
+ if (pc & 3) {
+ pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
+ return;
+ }
+
+ imm_l = insn.reg0i26_format.immediate_l;
+ imm_h = insn.reg0i26_format.immediate_h;
+ switch (insn.reg0i26_format.opcode) {
+ case b_op:
+ regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 27);
+ return;
+ case bl_op:
+ regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 27);
+ regs->regs[1] = pc + LOONGARCH_INSN_SIZE;
+ return;
+ }
+
+ imm_l = insn.reg1i21_format.immediate_l;
+ imm_h = insn.reg1i21_format.immediate_h;
+ rj = insn.reg1i21_format.rj;
+ switch (insn.reg1i21_format.opcode) {
+ case beqz_op:
+ if (regs->regs[rj] == 0)
+ regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 22);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ return;
+ case bnez_op:
+ if (regs->regs[rj] != 0)
+ regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 22);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ return;
+ }
+
+ imm = insn.reg2i16_format.immediate;
+ rj = insn.reg2i16_format.rj;
+ rd = insn.reg2i16_format.rd;
+ switch (insn.reg2i16_format.opcode) {
+ case beq_op:
+ if (regs->regs[rj] == regs->regs[rd])
+ regs->csr_era = pc + sign_extend(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bne_op:
+ if (regs->regs[rj] != regs->regs[rd])
+ regs->csr_era = pc + sign_extend(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case blt_op:
+ if ((long)regs->regs[rj] < (long)regs->regs[rd])
+ regs->csr_era = pc + sign_extend(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bge_op:
+ if ((long)regs->regs[rj] >= (long)regs->regs[rd])
+ regs->csr_era = pc + sign_extend(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bltu_op:
+ if (regs->regs[rj] < regs->regs[rd])
+ regs->csr_era = pc + sign_extend(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case bgeu_op:
+ if (regs->regs[rj] >= regs->regs[rd])
+ regs->csr_era = pc + sign_extend(imm << 2, 17);
+ else
+ regs->csr_era = pc + LOONGARCH_INSN_SIZE;
+ break;
+ case jirl_op:
+ regs->csr_era = regs->regs[rj] + sign_extend(imm << 2, 17);
+ regs->regs[rd] = pc + LOONGARCH_INSN_SIZE;
+ break;
+ default:
+ pr_info("%s: unknown opcode\n", __func__);
+ return;
+ }
+}
+
+void simu_pc(struct pt_regs *regs, union loongarch_instruction insn)
+{
+ unsigned long pc = regs->csr_era;
+ unsigned int rd = insn.reg1i20_format.rd;
+ unsigned int imm = insn.reg1i20_format.immediate;
+
+ if (pc & 3) {
+ pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
+ return;
+ }
+
+ switch (insn.reg1i20_format.opcode) {
+ case pcaddi_op:
+ regs->regs[rd] = pc + sign_extend(imm << 2, 21);
+ break;
+ case pcaddu12i_op:
+ regs->regs[rd] = pc + sign_extend(imm << 12, 31);
+ break;
+ case pcaddu18i_op:
+ regs->regs[rd] = pc + sign_extend(imm << 18, 37);
+ break;
+ case pcalau12i_op:
+ regs->regs[rd] = pc + sign_extend(imm << 12, 31);
+ regs->regs[rd] &= ~((1 << 12) - 1);
+ break;
+ default:
+ pr_info("%s: unknown opcode\n", __func__);
+ return;
+ }
+
+ regs->csr_era += LOONGARCH_INSN_SIZE;
+}
--
2.1.0
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 1/4] LoongArch: Simulate branch and PC instructions
2022-12-09 8:52 ` [PATCH v10 1/4] LoongArch: Simulate branch and PC instructions Tiezhu Yang
@ 2022-12-21 7:42 ` Jinyang He
0 siblings, 0 replies; 16+ messages in thread
From: Jinyang He @ 2022-12-21 7:42 UTC (permalink / raw)
To: Tiezhu Yang, Huacai Chen, WANG Xuerui, Masami Hiramatsu
Cc: loongarch, linux-kernel
On 2022-12-09 16:52, Tiezhu Yang wrote:
> According to LoongArch Reference Manual, simulate branch and
> PC instructions, this is preparation for later patch.
>
> Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#branch-instructions
> Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_pcaddi_pcaddu121_pcaddu18l_pcalau12i
>
> Co-developed-by: Jinyang He <hejinyang@loongson.cn>
> Signed-off-by: Jinyang He <hejinyang@loongson.cn>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
> arch/loongarch/include/asm/inst.h | 5 ++
> arch/loongarch/include/asm/ptrace.h | 1 +
> arch/loongarch/kernel/inst.c | 123 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 129 insertions(+)
>
> diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
> index c00e151..e25fd54 100644
> --- a/arch/loongarch/include/asm/inst.h
> +++ b/arch/loongarch/include/asm/inst.h
> @@ -7,6 +7,7 @@
>
> #include <linux/types.h>
> #include <asm/asm.h>
> +#include <asm/ptrace.h>
>
> #define INSN_NOP 0x03400000
> #define INSN_BREAK 0x002a0000
> @@ -32,6 +33,7 @@ enum reg1i20_op {
> lu12iw_op = 0x0a,
> lu32id_op = 0x0b,
> pcaddi_op = 0x0c,
> + pcalau12i_op = 0x0d,
> pcaddu12i_op = 0x0e,
> pcaddu18i_op = 0x0f,
> };
> @@ -367,6 +369,9 @@ u32 larch_insn_gen_lu32id(enum loongarch_gpr rd, int imm);
> u32 larch_insn_gen_lu52id(enum loongarch_gpr rd, enum loongarch_gpr rj, int imm);
> u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsigned long pc, unsigned long dest);
>
> +void simu_branch(struct pt_regs *regs, union loongarch_instruction insn);
> +void simu_pc(struct pt_regs *regs, union loongarch_instruction insn);
> +
> static inline bool signed_imm_check(long val, unsigned int bit)
> {
> return -(1L << (bit - 1)) <= val && val < (1L << (bit - 1));
> diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/asm/ptrace.h
> index 59c4608..58596c4 100644
> --- a/arch/loongarch/include/asm/ptrace.h
> +++ b/arch/loongarch/include/asm/ptrace.h
> @@ -6,6 +6,7 @@
> #define _ASM_PTRACE_H
>
> #include <asm/page.h>
> +#include <asm/irqflags.h>
> #include <asm/thread_info.h>
> #include <uapi/asm/ptrace.h>
>
> diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
> index 512579d..af48faf 100644
> --- a/arch/loongarch/kernel/inst.c
> +++ b/arch/loongarch/kernel/inst.c
> @@ -165,3 +165,126 @@ u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsigned l
>
> return insn.word;
> }
> +
> +void simu_branch(struct pt_regs *regs, union loongarch_instruction insn)
> +{
> + unsigned int imm, imm_l, imm_h, rd, rj;
> + unsigned long pc = regs->csr_era;
> +
> + if (pc & 3) {
> + pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
> + return;
> + }
> +
> + imm_l = insn.reg0i26_format.immediate_l;
> + imm_h = insn.reg0i26_format.immediate_h;
> + switch (insn.reg0i26_format.opcode) {
> + case b_op:
> + regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 27);
Hi, Tiezhu,
We can use sign_extend64() in linux/bitops.h. Its assembly sequence
is slli.d+srai.d, which is more efficient and clear.
Jinyang
> + return;
> + case bl_op:
> + regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 27);
> + regs->regs[1] = pc + LOONGARCH_INSN_SIZE;
> + return;
> + }
> +
> + imm_l = insn.reg1i21_format.immediate_l;
> + imm_h = insn.reg1i21_format.immediate_h;
> + rj = insn.reg1i21_format.rj;
> + switch (insn.reg1i21_format.opcode) {
> + case beqz_op:
> + if (regs->regs[rj] == 0)
> + regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 22);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + return;
> + case bnez_op:
> + if (regs->regs[rj] != 0)
> + regs->csr_era = pc + sign_extend((imm_h << 16 | imm_l) << 2, 22);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + return;
> + }
> +
> + imm = insn.reg2i16_format.immediate;
> + rj = insn.reg2i16_format.rj;
> + rd = insn.reg2i16_format.rd;
> + switch (insn.reg2i16_format.opcode) {
> + case beq_op:
> + if (regs->regs[rj] == regs->regs[rd])
> + regs->csr_era = pc + sign_extend(imm << 2, 17);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + break;
> + case bne_op:
> + if (regs->regs[rj] != regs->regs[rd])
> + regs->csr_era = pc + sign_extend(imm << 2, 17);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + break;
> + case blt_op:
> + if ((long)regs->regs[rj] < (long)regs->regs[rd])
> + regs->csr_era = pc + sign_extend(imm << 2, 17);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + break;
> + case bge_op:
> + if ((long)regs->regs[rj] >= (long)regs->regs[rd])
> + regs->csr_era = pc + sign_extend(imm << 2, 17);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + break;
> + case bltu_op:
> + if (regs->regs[rj] < regs->regs[rd])
> + regs->csr_era = pc + sign_extend(imm << 2, 17);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + break;
> + case bgeu_op:
> + if (regs->regs[rj] >= regs->regs[rd])
> + regs->csr_era = pc + sign_extend(imm << 2, 17);
> + else
> + regs->csr_era = pc + LOONGARCH_INSN_SIZE;
> + break;
> + case jirl_op:
> + regs->csr_era = regs->regs[rj] + sign_extend(imm << 2, 17);
> + regs->regs[rd] = pc + LOONGARCH_INSN_SIZE;
> + break;
> + default:
> + pr_info("%s: unknown opcode\n", __func__);
> + return;
> + }
> +}
> +
> +void simu_pc(struct pt_regs *regs, union loongarch_instruction insn)
> +{
> + unsigned long pc = regs->csr_era;
> + unsigned int rd = insn.reg1i20_format.rd;
> + unsigned int imm = insn.reg1i20_format.immediate;
> +
> + if (pc & 3) {
> + pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
> + return;
> + }
> +
> + switch (insn.reg1i20_format.opcode) {
> + case pcaddi_op:
> + regs->regs[rd] = pc + sign_extend(imm << 2, 21);
> + break;
> + case pcaddu12i_op:
> + regs->regs[rd] = pc + sign_extend(imm << 12, 31);
> + break;
> + case pcaddu18i_op:
> + regs->regs[rd] = pc + sign_extend(imm << 18, 37);
> + break;
> + case pcalau12i_op:
> + regs->regs[rd] = pc + sign_extend(imm << 12, 31);
> + regs->regs[rd] &= ~((1 << 12) - 1);
> + break;
> + default:
> + pr_info("%s: unknown opcode\n", __func__);
> + return;
> + }
> +
> + regs->csr_era += LOONGARCH_INSN_SIZE;
> +}
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v10 2/4] LoongArch: Add kprobe support
2022-12-09 8:52 [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Tiezhu Yang
2022-12-09 8:52 ` [PATCH v10 1/4] LoongArch: Simulate branch and PC instructions Tiezhu Yang
@ 2022-12-09 8:52 ` Tiezhu Yang
2022-12-14 7:28 ` Masami Hiramatsu
2022-12-09 8:53 ` [PATCH v10 3/4] LoongArch: Add kretprobe support Tiezhu Yang
` (3 subsequent siblings)
5 siblings, 1 reply; 16+ messages in thread
From: Tiezhu Yang @ 2022-12-09 8:52 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui, Masami Hiramatsu; +Cc: loongarch, linux-kernel
Kprobes allows you to trap at almost any kernel address and
execute a callback function, this commit adds kprobe support
for LoongArch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/inst.h | 15 ++
arch/loongarch/include/asm/kprobes.h | 59 ++++++
arch/loongarch/kernel/Makefile | 2 +
arch/loongarch/kernel/kprobes.c | 340 +++++++++++++++++++++++++++++++++++
arch/loongarch/kernel/traps.c | 13 +-
arch/loongarch/mm/fault.c | 3 +
7 files changed, 429 insertions(+), 4 deletions(-)
create mode 100644 arch/loongarch/include/asm/kprobes.h
create mode 100644 arch/loongarch/kernel/kprobes.c
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 16bf1b6..f6fc156 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -102,6 +102,7 @@ config LOONGARCH
select HAVE_IOREMAP_PROT
select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_IRQ_TIME_ACCOUNTING
+ select HAVE_KPROBES
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_PCI
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index e25fd54..a7c85df 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -24,6 +24,10 @@
#define ADDR_IMM(addr, INSN) ((addr & ADDR_IMMMASK_##INSN) >> ADDR_IMMSHIFT_##INSN)
+enum reg0i15_op {
+ break_op = 0x54,
+};
+
enum reg0i26_op {
b_op = 0x14,
bl_op = 0x15,
@@ -180,6 +184,11 @@ enum reg3sa2_op {
alsld_op = 0x16,
};
+struct reg0i15_format {
+ unsigned int immediate : 15;
+ unsigned int opcode : 17;
+};
+
struct reg0i26_format {
unsigned int immediate_h : 10;
unsigned int immediate_l : 16;
@@ -265,6 +274,7 @@ struct reg3sa2_format {
union loongarch_instruction {
unsigned int word;
+ struct reg0i15_format reg0i15_format;
struct reg0i26_format reg0i26_format;
struct reg1i20_format reg1i20_format;
struct reg1i21_format reg1i21_format;
@@ -335,6 +345,11 @@ static inline bool is_branch_ins(union loongarch_instruction *ip)
ip->reg1i21_format.opcode <= bgeu_op;
}
+static inline bool is_break_ins(union loongarch_instruction *ip)
+{
+ return ip->reg0i15_format.opcode == break_op;
+}
+
static inline bool is_ra_save_ins(union loongarch_instruction *ip)
{
/* st.d $ra, $sp, offset */
diff --git a/arch/loongarch/include/asm/kprobes.h b/arch/loongarch/include/asm/kprobes.h
new file mode 100644
index 0000000..d3903f3
--- /dev/null
+++ b/arch/loongarch/include/asm/kprobes.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_LOONGARCH_KPROBES_H
+#define __ASM_LOONGARCH_KPROBES_H
+
+#include <asm-generic/kprobes.h>
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_KPROBES
+
+#include <asm/inst.h>
+
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE 2
+
+#define flush_insn_slot(p) \
+do { \
+ if (p->addr) \
+ flush_icache_range((unsigned long)p->addr, \
+ (unsigned long)p->addr + \
+ (MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \
+} while (0)
+
+#define kretprobe_blacklist_size 0
+
+typedef union loongarch_instruction kprobe_opcode_t;
+
+/* Architecture specific copy of original instruction */
+struct arch_specific_insn {
+ /* copy of the original instruction */
+ kprobe_opcode_t *insn;
+};
+
+struct prev_kprobe {
+ struct kprobe *kp;
+ unsigned long status;
+ unsigned long saved_irq;
+ unsigned long saved_era;
+};
+
+/* per-cpu kprobe control block */
+struct kprobe_ctlblk {
+ unsigned long kprobe_status;
+ unsigned long kprobe_saved_irq;
+ unsigned long kprobe_saved_era;
+ struct prev_kprobe prev_kprobe;
+};
+
+void arch_remove_kprobe(struct kprobe *p);
+bool kprobe_fault_handler(struct pt_regs *regs, int trapnr);
+bool kprobe_breakpoint_handler(struct pt_regs *regs);
+bool kprobe_singlestep_handler(struct pt_regs *regs);
+
+#else /* !CONFIG_KPROBES */
+
+static inline bool kprobe_breakpoint_handler(struct pt_regs *regs) { return 0; }
+static inline bool kprobe_singlestep_handler(struct pt_regs *regs) { return 0; }
+
+#endif /* CONFIG_KPROBES */
+#endif /* __ASM_LOONGARCH_KPROBES_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index fcaa024..6fe4a4e 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -47,4 +47,6 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
+obj-$(CONFIG_KPROBES) += kprobes.o
+
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
new file mode 100644
index 0000000..546a3c3
--- /dev/null
+++ b/arch/loongarch/kernel/kprobes.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#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_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);
+
+int arch_prepare_kprobe(struct kprobe *p)
+{
+ union loongarch_instruction insn;
+
+ insn = p->addr[0];
+ if (insns_not_supported(insn))
+ return -EINVAL;
+
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+
+ p->ainsn.insn[0] = *p->addr;
+ p->ainsn.insn[1] = singlestep_insn;
+
+ p->opcode = *p->addr;
+
+ return 0;
+}
+NOKPROBE_SYMBOL(arch_prepare_kprobe);
+
+/* Install breakpoint in text */
+void arch_arm_kprobe(struct kprobe *p)
+{
+ *p->addr = breakpoint_insn;
+ flush_insn_slot(p);
+}
+NOKPROBE_SYMBOL(arch_arm_kprobe);
+
+/* Remove breakpoint from text */
+void arch_disarm_kprobe(struct kprobe *p)
+{
+ *p->addr = p->opcode;
+ flush_insn_slot(p);
+}
+NOKPROBE_SYMBOL(arch_disarm_kprobe);
+
+void arch_remove_kprobe(struct kprobe *p)
+{
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, 0);
+ p->ainsn.insn = NULL;
+ }
+}
+NOKPROBE_SYMBOL(arch_remove_kprobe);
+
+static void save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.saved_irq = kcb->kprobe_saved_irq;
+ kcb->prev_kprobe.saved_era = kcb->kprobe_saved_era;
+}
+NOKPROBE_SYMBOL(save_previous_kprobe);
+
+static void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_saved_irq = kcb->prev_kprobe.saved_irq;
+ kcb->kprobe_saved_era = kcb->prev_kprobe.saved_era;
+}
+NOKPROBE_SYMBOL(restore_previous_kprobe);
+
+static void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __this_cpu_write(current_kprobe, p);
+ kcb->kprobe_saved_irq = regs->csr_prmd & CSR_PRMD_PIE;
+ kcb->kprobe_saved_era = regs->csr_era;
+}
+NOKPROBE_SYMBOL(set_current_kprobe);
+
+static bool insns_not_simulated(struct kprobe *p, struct pt_regs *regs)
+{
+ if (is_branch_ins(&p->opcode)) {
+ simu_branch(regs, p->opcode);
+ return false;
+ } else if (is_pc_ins(&p->opcode)) {
+ simu_pc(regs, p->opcode);
+ return false;
+ } else {
+ return true;
+ }
+}
+NOKPROBE_SYMBOL(insns_not_simulated);
+
+static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb, int reenter)
+{
+ if (reenter) {
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_REENTER;
+ } else {
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ }
+
+ regs->csr_prmd &= ~CSR_PRMD_PIE;
+
+ if (p->ainsn.insn->word == breakpoint_insn.word) {
+ regs->csr_prmd |= kcb->kprobe_saved_irq;
+ preempt_enable_no_resched();
+ return;
+ }
+
+ if (insns_not_simulated(p, regs)) {
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ regs->csr_era = (unsigned long)&p->ainsn.insn[0];
+ } else {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ if (p->post_handler)
+ p->post_handler(p, regs, 0);
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ }
+}
+NOKPROBE_SYMBOL(setup_singlestep);
+
+static bool reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SSDONE:
+ case KPROBE_HIT_ACTIVE:
+ kprobes_inc_nmissed_count(p);
+ setup_singlestep(p, regs, kcb, 1);
+ break;
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ pr_warn("Failed to recover from reentered kprobes.\n");
+ dump_kprobe(p);
+ BUG();
+ break;
+ default:
+ WARN_ON(1);
+ return false;
+ }
+
+ return true;
+}
+NOKPROBE_SYMBOL(reenter_kprobe);
+
+bool kprobe_breakpoint_handler(struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb;
+ struct kprobe *p, *cur_kprobe;
+ kprobe_opcode_t *addr = (kprobe_opcode_t *)regs->csr_era;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing.
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+ cur_kprobe = kprobe_running();
+
+ p = get_kprobe(addr);
+ if (p) {
+ if (cur_kprobe) {
+ if (reenter_kprobe(p, regs, kcb))
+ return true;
+ } else {
+ /* Probe hit */
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ /*
+ * If we have no pre-handler or it returned 0, we
+ * continue with normal processing. If we have a
+ * pre-handler and it returned non-zero, it will
+ * modify the execution path and no need to single
+ * stepping. Let's just reset current kprobe and exit.
+ *
+ * pre_handler can hit a breakpoint and can step thru
+ * before return.
+ */
+ if (!p->pre_handler || !p->pre_handler(p, regs)) {
+ setup_singlestep(p, regs, kcb, 0);
+ } else {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ }
+ }
+ return true;
+ }
+
+ if (!is_break_ins(addr)) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Return back to original instruction, and continue.
+ */
+ preempt_enable_no_resched();
+ return true;
+ }
+
+ preempt_enable_no_resched();
+ return false;
+}
+NOKPROBE_SYMBOL(kprobe_breakpoint_handler);
+
+bool kprobe_singlestep_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return false;
+
+ /* Restore back the original saved kprobes variables and continue */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+
+ /* Call post handler */
+ if (cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ regs->csr_era = kcb->kprobe_saved_era + LOONGARCH_INSN_SIZE;
+ regs->csr_prmd |= kcb->kprobe_saved_irq;
+
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+ return true;
+}
+NOKPROBE_SYMBOL(kprobe_singlestep_handler);
+
+bool kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the ip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->csr_era = (unsigned long) cur->addr;
+ BUG_ON(!instruction_pointer(regs));
+
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ } else {
+ regs->csr_prmd |= kcb->kprobe_saved_irq;
+ reset_current_kprobe();
+ }
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ if (fixup_exception(regs))
+ return true;
+
+ /*
+ * If fixup_exception() could not handle it,
+ * let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+ return false;
+}
+NOKPROBE_SYMBOL(kprobe_fault_handler);
+
+/*
+ * Provide a blacklist of symbols identifying ranges which cannot be kprobed.
+ * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
+ */
+int __init arch_populate_kprobe_blacklist(void)
+{
+ return kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
+ (unsigned long)__irqentry_text_end);
+}
+
+int __init arch_init_kprobes(void)
+{
+ return 0;
+}
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index a19bb32..4d9f775 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -448,14 +448,12 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
*/
switch (bcode) {
case BRK_KPROBE_BP:
- if (notify_die(DIE_BREAK, "Kprobe", regs, bcode,
- current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ if (kprobe_breakpoint_handler(regs))
goto out;
else
break;
case BRK_KPROBE_SSTEPBP:
- if (notify_die(DIE_SSTEPBP, "Kprobe_SingleStep", regs, bcode,
- current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ if (kprobe_singlestep_handler(regs))
goto out;
else
break;
@@ -479,6 +477,13 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
break;
}
+ if (bcode == BRK_KPROBE_BP) {
+ if (__get_inst(&opcode, (u32 *)era, user))
+ goto out_sigsegv;
+
+ bcode = (opcode & 0x7fff);
+ }
+
switch (bcode) {
case BRK_BUG:
bug_handler(regs);
diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c
index 1ccd536..449087b 100644
--- a/arch/loongarch/mm/fault.c
+++ b/arch/loongarch/mm/fault.c
@@ -135,6 +135,9 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
struct vm_area_struct *vma = NULL;
vm_fault_t fault;
+ if (kprobe_page_fault(regs, current->thread.trap_nr))
+ return;
+
/*
* We fault-in kernel-space virtual memory on-demand. The
* 'reference' page table is init_mm.pgd.
--
2.1.0
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 2/4] LoongArch: Add kprobe support
2022-12-09 8:52 ` [PATCH v10 2/4] LoongArch: Add kprobe support Tiezhu Yang
@ 2022-12-14 7:28 ` Masami Hiramatsu
2022-12-16 9:33 ` Tiezhu Yang
0 siblings, 1 reply; 16+ messages in thread
From: Masami Hiramatsu @ 2022-12-14 7:28 UTC (permalink / raw)
To: Tiezhu Yang; +Cc: Huacai Chen, WANG Xuerui, loongarch, linux-kernel
Hi,
On Fri, 9 Dec 2022 16:52:59 +0800
Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> Kprobes allows you to trap at almost any kernel address and
> execute a callback function, this commit adds kprobe support
> for LoongArch.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
> arch/loongarch/Kconfig | 1 +
> arch/loongarch/include/asm/inst.h | 15 ++
> arch/loongarch/include/asm/kprobes.h | 59 ++++++
> arch/loongarch/kernel/Makefile | 2 +
> arch/loongarch/kernel/kprobes.c | 340 +++++++++++++++++++++++++++++++++++
> arch/loongarch/kernel/traps.c | 13 +-
> arch/loongarch/mm/fault.c | 3 +
> 7 files changed, 429 insertions(+), 4 deletions(-)
> create mode 100644 arch/loongarch/include/asm/kprobes.h
> create mode 100644 arch/loongarch/kernel/kprobes.c
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 16bf1b6..f6fc156 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -102,6 +102,7 @@ config LOONGARCH
> select HAVE_IOREMAP_PROT
> select HAVE_IRQ_EXIT_ON_IRQ_STACK
> select HAVE_IRQ_TIME_ACCOUNTING
> + select HAVE_KPROBES
> select HAVE_MOD_ARCH_SPECIFIC
> select HAVE_NMI
> select HAVE_PCI
> diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
> index e25fd54..a7c85df 100644
> --- a/arch/loongarch/include/asm/inst.h
> +++ b/arch/loongarch/include/asm/inst.h
> @@ -24,6 +24,10 @@
>
> #define ADDR_IMM(addr, INSN) ((addr & ADDR_IMMMASK_##INSN) >> ADDR_IMMSHIFT_##INSN)
>
> +enum reg0i15_op {
> + break_op = 0x54,
> +};
> +
> enum reg0i26_op {
> b_op = 0x14,
> bl_op = 0x15,
> @@ -180,6 +184,11 @@ enum reg3sa2_op {
> alsld_op = 0x16,
> };
>
> +struct reg0i15_format {
> + unsigned int immediate : 15;
> + unsigned int opcode : 17;
> +};
> +
> struct reg0i26_format {
> unsigned int immediate_h : 10;
> unsigned int immediate_l : 16;
> @@ -265,6 +274,7 @@ struct reg3sa2_format {
>
> union loongarch_instruction {
> unsigned int word;
> + struct reg0i15_format reg0i15_format;
> struct reg0i26_format reg0i26_format;
> struct reg1i20_format reg1i20_format;
> struct reg1i21_format reg1i21_format;
> @@ -335,6 +345,11 @@ static inline bool is_branch_ins(union loongarch_instruction *ip)
> ip->reg1i21_format.opcode <= bgeu_op;
> }
>
> +static inline bool is_break_ins(union loongarch_instruction *ip)
> +{
> + return ip->reg0i15_format.opcode == break_op;
> +}
> +
> static inline bool is_ra_save_ins(union loongarch_instruction *ip)
> {
> /* st.d $ra, $sp, offset */
> diff --git a/arch/loongarch/include/asm/kprobes.h b/arch/loongarch/include/asm/kprobes.h
> new file mode 100644
> index 0000000..d3903f3
> --- /dev/null
> +++ b/arch/loongarch/include/asm/kprobes.h
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef __ASM_LOONGARCH_KPROBES_H
> +#define __ASM_LOONGARCH_KPROBES_H
> +
> +#include <asm-generic/kprobes.h>
> +#include <asm/cacheflush.h>
> +
> +#ifdef CONFIG_KPROBES
> +
> +#include <asm/inst.h>
> +
> +#define __ARCH_WANT_KPROBES_INSN_SLOT
> +#define MAX_INSN_SIZE 2
> +
> +#define flush_insn_slot(p) \
> +do { \
> + if (p->addr) \
> + flush_icache_range((unsigned long)p->addr, \
> + (unsigned long)p->addr + \
> + (MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \
> +} while (0)
> +
> +#define kretprobe_blacklist_size 0
> +
> +typedef union loongarch_instruction kprobe_opcode_t;
> +
> +/* Architecture specific copy of original instruction */
> +struct arch_specific_insn {
> + /* copy of the original instruction */
> + kprobe_opcode_t *insn;
> +};
> +
> +struct prev_kprobe {
> + struct kprobe *kp;
> + unsigned long status;
> + unsigned long saved_irq;
> + unsigned long saved_era;
> +};
> +
> +/* per-cpu kprobe control block */
> +struct kprobe_ctlblk {
> + unsigned long kprobe_status;
> + unsigned long kprobe_saved_irq;
> + unsigned long kprobe_saved_era;
> + struct prev_kprobe prev_kprobe;
> +};
> +
> +void arch_remove_kprobe(struct kprobe *p);
> +bool kprobe_fault_handler(struct pt_regs *regs, int trapnr);
> +bool kprobe_breakpoint_handler(struct pt_regs *regs);
> +bool kprobe_singlestep_handler(struct pt_regs *regs);
> +
> +#else /* !CONFIG_KPROBES */
> +
> +static inline bool kprobe_breakpoint_handler(struct pt_regs *regs) { return 0; }
> +static inline bool kprobe_singlestep_handler(struct pt_regs *regs) { return 0; }
bool should return true or false.
> +
> +#endif /* CONFIG_KPROBES */
> +#endif /* __ASM_LOONGARCH_KPROBES_H */
> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> index fcaa024..6fe4a4e 100644
> --- a/arch/loongarch/kernel/Makefile
> +++ b/arch/loongarch/kernel/Makefile
> @@ -47,4 +47,6 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
>
> obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
>
> +obj-$(CONFIG_KPROBES) += kprobes.o
> +
> CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
> diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
> new file mode 100644
> index 0000000..546a3c3
> --- /dev/null
> +++ b/arch/loongarch/kernel/kprobes.c
> @@ -0,0 +1,340 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include <linux/kprobes.h>
> +#include <linux/kdebug.h>
> +#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_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);
> +
> +int arch_prepare_kprobe(struct kprobe *p)
> +{
> + union loongarch_instruction insn;
> +
> + insn = p->addr[0];
> + if (insns_not_supported(insn))
> + return -EINVAL;
> +
> + p->ainsn.insn = get_insn_slot();
> + if (!p->ainsn.insn)
> + return -ENOMEM;
> +
> + p->ainsn.insn[0] = *p->addr;
> + p->ainsn.insn[1] = singlestep_insn;
> +
> + p->opcode = *p->addr;
> +
> + return 0;
> +}
> +NOKPROBE_SYMBOL(arch_prepare_kprobe);
> +
> +/* Install breakpoint in text */
> +void arch_arm_kprobe(struct kprobe *p)
> +{
> + *p->addr = breakpoint_insn;
> + flush_insn_slot(p);
> +}
> +NOKPROBE_SYMBOL(arch_arm_kprobe);
> +
> +/* Remove breakpoint from text */
> +void arch_disarm_kprobe(struct kprobe *p)
> +{
> + *p->addr = p->opcode;
> + flush_insn_slot(p);
> +}
> +NOKPROBE_SYMBOL(arch_disarm_kprobe);
> +
> +void arch_remove_kprobe(struct kprobe *p)
> +{
> + if (p->ainsn.insn) {
> + free_insn_slot(p->ainsn.insn, 0);
> + p->ainsn.insn = NULL;
> + }
> +}
> +NOKPROBE_SYMBOL(arch_remove_kprobe);
> +
> +static void save_previous_kprobe(struct kprobe_ctlblk *kcb)
> +{
> + kcb->prev_kprobe.kp = kprobe_running();
> + kcb->prev_kprobe.status = kcb->kprobe_status;
> + kcb->prev_kprobe.saved_irq = kcb->kprobe_saved_irq;
> + kcb->prev_kprobe.saved_era = kcb->kprobe_saved_era;
> +}
> +NOKPROBE_SYMBOL(save_previous_kprobe);
> +
> +static void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
> +{
> + __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
> + kcb->kprobe_status = kcb->prev_kprobe.status;
> + kcb->kprobe_saved_irq = kcb->prev_kprobe.saved_irq;
> + kcb->kprobe_saved_era = kcb->prev_kprobe.saved_era;
> +}
> +NOKPROBE_SYMBOL(restore_previous_kprobe);
> +
> +static void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
> + struct kprobe_ctlblk *kcb)
> +{
> + __this_cpu_write(current_kprobe, p);
> + kcb->kprobe_saved_irq = regs->csr_prmd & CSR_PRMD_PIE;
> + kcb->kprobe_saved_era = regs->csr_era;
> +}
> +NOKPROBE_SYMBOL(set_current_kprobe);
> +
> +static bool insns_not_simulated(struct kprobe *p, struct pt_regs *regs)
I recommend this as "insn_simulate()" and return false if it is NOT
simulated, since this actually simulates the instruction,
> +{
> + if (is_branch_ins(&p->opcode)) {
> + simu_branch(regs, p->opcode);
> + return false;
> + } else if (is_pc_ins(&p->opcode)) {
> + simu_pc(regs, p->opcode);
> + return false;
> + } else {
> + return true;
> + }
> +}
> +NOKPROBE_SYMBOL(insns_not_simulated);
> +
> +static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
> + struct kprobe_ctlblk *kcb, int reenter)
> +{
> + if (reenter) {
> + save_previous_kprobe(kcb);
> + set_current_kprobe(p, regs, kcb);
> + kcb->kprobe_status = KPROBE_REENTER;
> + } else {
> + kcb->kprobe_status = KPROBE_HIT_SS;
> + }
> +
> + regs->csr_prmd &= ~CSR_PRMD_PIE;
> +
> + if (p->ainsn.insn->word == breakpoint_insn.word) {
Would you mean there is already another kprobe on the same address
and it is copied? The kprobe arch-independent code already checked
that and if you see this when registering new one in the arch
code, it should be rejected.
> + regs->csr_prmd |= kcb->kprobe_saved_irq;
> + preempt_enable_no_resched();
> + return;
> + }
> +
> + if (insns_not_simulated(p, regs)) {
if (!insn_simulate(p, regs)) {
/* fall back to normal single stepping */
> + kcb->kprobe_status = KPROBE_HIT_SS;
No, if reentered == true, it should be KPROBE_REENTER during the
single stepping.
> + regs->csr_era = (unsigned long)&p->ainsn.insn[0];
> + } else {
> + kcb->kprobe_status = KPROBE_HIT_SSDONE;
You also missed reentering case. If the kprobes hits in another kprobe
handler, it must be in KPROBE_REENTER state and do not call any user
handler.
> + if (p->post_handler)
> + p->post_handler(p, regs, 0);
> + reset_current_kprobe();
> + preempt_enable_no_resched();
> + }
> +}
> +NOKPROBE_SYMBOL(setup_singlestep);
> +
> +static bool reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
> + struct kprobe_ctlblk *kcb)
> +{
> + switch (kcb->kprobe_status) {
> + case KPROBE_HIT_SSDONE:
> + case KPROBE_HIT_ACTIVE:
> + kprobes_inc_nmissed_count(p);
> + setup_singlestep(p, regs, kcb, 1);
> + break;
> + case KPROBE_HIT_SS:
> + case KPROBE_REENTER:
> + pr_warn("Failed to recover from reentered kprobes.\n");
> + dump_kprobe(p);
> + BUG();
> + break;
> + default:
> + WARN_ON(1);
> + return false;
> + }
> +
> + return true;
> +}
> +NOKPROBE_SYMBOL(reenter_kprobe);
> +
> +bool kprobe_breakpoint_handler(struct pt_regs *regs)
> +{
> + struct kprobe_ctlblk *kcb;
> + struct kprobe *p, *cur_kprobe;
> + kprobe_opcode_t *addr = (kprobe_opcode_t *)regs->csr_era;
> +
> + /*
> + * We don't want to be preempted for the entire
> + * duration of kprobe processing.
> + */
> + preempt_disable();
> + kcb = get_kprobe_ctlblk();
> + cur_kprobe = kprobe_running();
> +
> + p = get_kprobe(addr);
> + if (p) {
> + if (cur_kprobe) {
> + if (reenter_kprobe(p, regs, kcb))
> + return true;
even if reenter_kprobe() doesn't return true, this function
eventually return true.
> + } else {
> + /* Probe hit */
> + set_current_kprobe(p, regs, kcb);
> + kcb->kprobe_status = KPROBE_HIT_ACTIVE;
> +
> + /*
> + * If we have no pre-handler or it returned 0, we
> + * continue with normal processing. If we have a
> + * pre-handler and it returned non-zero, it will
> + * modify the execution path and no need to single
> + * stepping. Let's just reset current kprobe and exit.
> + *
> + * pre_handler can hit a breakpoint and can step thru
> + * before return.
> + */
> + if (!p->pre_handler || !p->pre_handler(p, regs)) {
> + setup_singlestep(p, regs, kcb, 0);
> + } else {
> + reset_current_kprobe();
> + preempt_enable_no_resched();
> + }
> + }
> + return true;
^Here.
> + }
> +
> + if (!is_break_ins(addr)) {
> + /*
> + * The breakpoint instruction was removed right
> + * after we hit it. Another cpu has removed
> + * either a probepoint or a debugger breakpoint
> + * at this address. In either case, no further
> + * handling of this interrupt is appropriate.
> + * Return back to original instruction, and continue.
> + */
> + preempt_enable_no_resched();
> + return true;
> + }
> +
> + preempt_enable_no_resched();
> + return false;
> +}
> +NOKPROBE_SYMBOL(kprobe_breakpoint_handler);
> +
> +bool kprobe_singlestep_handler(struct pt_regs *regs)
> +{
> + struct kprobe *cur = kprobe_running();
> + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
> +
> + if (!cur)
> + return false;
> +
> + /* Restore back the original saved kprobes variables and continue */
> + if (kcb->kprobe_status == KPROBE_REENTER) {
> + restore_previous_kprobe(kcb);
> + goto out;
> + }
> +
> + /* Call post handler */
> + if (cur->post_handler) {
> + kcb->kprobe_status = KPROBE_HIT_SSDONE;
> + cur->post_handler(cur, regs, 0);
> + }
> +
> + regs->csr_era = kcb->kprobe_saved_era + LOONGARCH_INSN_SIZE;
> + regs->csr_prmd |= kcb->kprobe_saved_irq;
> +
> + reset_current_kprobe();
> +out:
> + preempt_enable_no_resched();
> + return true;
> +}
> +NOKPROBE_SYMBOL(kprobe_singlestep_handler);
> +
> +bool kprobe_fault_handler(struct pt_regs *regs, int trapnr)
> +{
> + struct kprobe *cur = kprobe_running();
> + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
> +
> + switch (kcb->kprobe_status) {
> + case KPROBE_HIT_SS:
> + case KPROBE_REENTER:
> + /*
> + * We are here because the instruction being single
> + * stepped caused a page fault. We reset the current
> + * kprobe and the ip points back to the probe address
> + * and allow the page fault handler to continue as a
> + * normal page fault.
> + */
> + regs->csr_era = (unsigned long) cur->addr;
> + BUG_ON(!instruction_pointer(regs));
> +
> + if (kcb->kprobe_status == KPROBE_REENTER) {
> + restore_previous_kprobe(kcb);
> + } else {
> + regs->csr_prmd |= kcb->kprobe_saved_irq;
> + reset_current_kprobe();
> + }
> + preempt_enable_no_resched();
> + break;
> + case KPROBE_HIT_ACTIVE:
> + case KPROBE_HIT_SSDONE:
Recently, I removed these cases because this page fault will be finally
handled by the generic pagefault handler.
Thank you,
> + /*
> + * In case the user-specified fault handler returned
> + * zero, try to fix up.
> + */
> + if (fixup_exception(regs))
> + return true;
> +
> + /*
> + * If fixup_exception() could not handle it,
> + * let do_page_fault() fix it.
> + */
> + break;
> + default:
> + break;
> + }
> + return false;
> +}
> +NOKPROBE_SYMBOL(kprobe_fault_handler);
> +
> +/*
> + * Provide a blacklist of symbols identifying ranges which cannot be kprobed.
> + * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
> + */
> +int __init arch_populate_kprobe_blacklist(void)
> +{
> + return kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
> + (unsigned long)__irqentry_text_end);
> +}
> +
> +int __init arch_init_kprobes(void)
> +{
> + return 0;
> +}
> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> index a19bb32..4d9f775 100644
> --- a/arch/loongarch/kernel/traps.c
> +++ b/arch/loongarch/kernel/traps.c
> @@ -448,14 +448,12 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
> */
> switch (bcode) {
> case BRK_KPROBE_BP:
> - if (notify_die(DIE_BREAK, "Kprobe", regs, bcode,
> - current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
> + if (kprobe_breakpoint_handler(regs))
> goto out;
> else
> break;
> case BRK_KPROBE_SSTEPBP:
> - if (notify_die(DIE_SSTEPBP, "Kprobe_SingleStep", regs, bcode,
> - current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
> + if (kprobe_singlestep_handler(regs))
> goto out;
> else
> break;
> @@ -479,6 +477,13 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
> break;
> }
>
> + if (bcode == BRK_KPROBE_BP) {
> + if (__get_inst(&opcode, (u32 *)era, user))
> + goto out_sigsegv;
> +
> + bcode = (opcode & 0x7fff);
> + }
> +
> switch (bcode) {
> case BRK_BUG:
> bug_handler(regs);
> diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c
> index 1ccd536..449087b 100644
> --- a/arch/loongarch/mm/fault.c
> +++ b/arch/loongarch/mm/fault.c
> @@ -135,6 +135,9 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
> struct vm_area_struct *vma = NULL;
> vm_fault_t fault;
>
> + if (kprobe_page_fault(regs, current->thread.trap_nr))
> + return;
> +
> /*
> * We fault-in kernel-space virtual memory on-demand. The
> * 'reference' page table is init_mm.pgd.
> --
> 2.1.0
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 2/4] LoongArch: Add kprobe support
2022-12-14 7:28 ` Masami Hiramatsu
@ 2022-12-16 9:33 ` Tiezhu Yang
2022-12-17 2:08 ` Huacai Chen
0 siblings, 1 reply; 16+ messages in thread
From: Tiezhu Yang @ 2022-12-16 9:33 UTC (permalink / raw)
To: Masami Hiramatsu (Google)
Cc: Huacai Chen, WANG Xuerui, loongarch, linux-kernel
On 12/14/2022 03:28 PM, Masami Hiramatsu (Google) wrote:
> Hi,
>
> On Fri, 9 Dec 2022 16:52:59 +0800
> Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
>> Kprobes allows you to trap at almost any kernel address and
>> execute a callback function, this commit adds kprobe support
>> for LoongArch.
...
>> + case KPROBE_HIT_ACTIVE:
>> + case KPROBE_HIT_SSDONE:
>
> Recently, I removed these cases because this page fault will be finally
> handled by the generic pagefault handler.
>
Hi Masami,
I have addressed all your comments on my local machine, the code logic
looks much more clear now, thank you very much.
When I test kprobe_example.ko with a C function like "kernel_clone",
it works well, but the kernel hangs [1] when test with an assembler
function like "__memset_fast" [2].
Just did some quick research and it seems the bug is related with
kallsyms_lookup_name(), I'm looking for a solution.
[1]
https://lore.kernel.org/loongarch/CAEr6+EC2wPAtK8zb3=e1mUiya3gv0UhqF9J_ySYx9p_96pB+tg@mail.gmail.com/
[2]
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git/tree/arch/loongarch/lib/memset.S?h=loongarch-next#n56
Thanks,
Tiezhu
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v10 2/4] LoongArch: Add kprobe support
2022-12-16 9:33 ` Tiezhu Yang
@ 2022-12-17 2:08 ` Huacai Chen
0 siblings, 0 replies; 16+ messages in thread
From: Huacai Chen @ 2022-12-17 2:08 UTC (permalink / raw)
To: Tiezhu Yang
Cc: Masami Hiramatsu (Google), WANG Xuerui, loongarch, linux-kernel
Hi, all,
This series seems have too many problems, so I will drop it. So Tiezhu
please export the latest patches from
https://github.com/loongson/linux/commits/loongarch-next, and do
modifications on top of them.
Huacai
On Fri, Dec 16, 2022 at 5:33 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
>
>
> On 12/14/2022 03:28 PM, Masami Hiramatsu (Google) wrote:
> > Hi,
> >
> > On Fri, 9 Dec 2022 16:52:59 +0800
> > Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> >
> >> Kprobes allows you to trap at almost any kernel address and
> >> execute a callback function, this commit adds kprobe support
> >> for LoongArch.
>
> ...
>
> >> + case KPROBE_HIT_ACTIVE:
> >> + case KPROBE_HIT_SSDONE:
> >
> > Recently, I removed these cases because this page fault will be finally
> > handled by the generic pagefault handler.
> >
>
> Hi Masami,
>
> I have addressed all your comments on my local machine, the code logic
> looks much more clear now, thank you very much.
>
> When I test kprobe_example.ko with a C function like "kernel_clone",
> it works well, but the kernel hangs [1] when test with an assembler
> function like "__memset_fast" [2].
>
> Just did some quick research and it seems the bug is related with
> kallsyms_lookup_name(), I'm looking for a solution.
>
> [1]
> https://lore.kernel.org/loongarch/CAEr6+EC2wPAtK8zb3=e1mUiya3gv0UhqF9J_ySYx9p_96pB+tg@mail.gmail.com/
> [2]
> https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git/tree/arch/loongarch/lib/memset.S?h=loongarch-next#n56
>
> Thanks,
> Tiezhu
>
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v10 3/4] LoongArch: Add kretprobe support
2022-12-09 8:52 [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Tiezhu Yang
2022-12-09 8:52 ` [PATCH v10 1/4] LoongArch: Simulate branch and PC instructions Tiezhu Yang
2022-12-09 8:52 ` [PATCH v10 2/4] LoongArch: Add kprobe support Tiezhu Yang
@ 2022-12-09 8:53 ` Tiezhu Yang
2022-12-09 8:53 ` [PATCH v10 4/4] samples/kprobes: Add LoongArch support Tiezhu Yang
` (2 subsequent siblings)
5 siblings, 0 replies; 16+ messages in thread
From: Tiezhu Yang @ 2022-12-09 8:53 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui, Masami Hiramatsu; +Cc: loongarch, linux-kernel
Use the generic kretprobe trampoline handler to add kretprobe
support for LoongArch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/kernel/Makefile | 2 +-
arch/loongarch/kernel/kprobes.c | 24 ++++++++
arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++++++++++++++++++++++++
4 files changed, 122 insertions(+), 1 deletion(-)
create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index f6fc156..12571ee 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -103,6 +103,7 @@ config LOONGARCH
select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_IRQ_TIME_ACCOUNTING
select HAVE_KPROBES
+ select HAVE_KRETPROBES
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_PCI
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 6fe4a4e..7ca6519 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -47,6 +47,6 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
-obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KPROBES) += kprobes.o kprobes_trampoline.o
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c
index 546a3c3..a8ee861 100644
--- a/arch/loongarch/kernel/kprobes.c
+++ b/arch/loongarch/kernel/kprobes.c
@@ -334,6 +334,30 @@ int __init arch_populate_kprobe_blacklist(void)
(unsigned long)__irqentry_text_end);
}
+/* Called from __kretprobe_trampoline */
+void __used *trampoline_probe_handler(struct pt_regs *regs)
+{
+ return (void *)kretprobe_trampoline_handler(regs, NULL);
+}
+NOKPROBE_SYMBOL(trampoline_probe_handler);
+
+void arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *)regs->regs[1];
+ ri->fp = NULL;
+
+ /* Replace the return addr with trampoline addr */
+ regs->regs[1] = (unsigned long)&__kretprobe_trampoline;
+}
+NOKPROBE_SYMBOL(arch_prepare_kretprobe);
+
+int arch_trampoline_kprobe(struct kprobe *p)
+{
+ return 0;
+}
+NOKPROBE_SYMBOL(arch_trampoline_kprobe);
+
int __init arch_init_kprobes(void)
{
return 0;
diff --git a/arch/loongarch/kernel/kprobes_trampoline.S b/arch/loongarch/kernel/kprobes_trampoline.S
new file mode 100644
index 0000000..af94b0d
--- /dev/null
+++ b/arch/loongarch/kernel/kprobes_trampoline.S
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#include <linux/linkage.h>
+#include <asm/stackframe.h>
+
+ .text
+
+ .macro save_all_base_regs
+ cfi_st ra, PT_R1
+ cfi_st tp, PT_R2
+ cfi_st a0, PT_R4
+ cfi_st a1, PT_R5
+ cfi_st a2, PT_R6
+ cfi_st a3, PT_R7
+ cfi_st a4, PT_R8
+ cfi_st a5, PT_R9
+ cfi_st a6, PT_R10
+ cfi_st a7, PT_R11
+ cfi_st t0, PT_R12
+ cfi_st t1, PT_R13
+ cfi_st t2, PT_R14
+ cfi_st t3, PT_R15
+ cfi_st t4, PT_R16
+ cfi_st t5, PT_R17
+ cfi_st t6, PT_R18
+ cfi_st t7, PT_R19
+ cfi_st t8, PT_R20
+ cfi_st u0, PT_R21
+ cfi_st fp, PT_R22
+ cfi_st s0, PT_R23
+ cfi_st s1, PT_R24
+ cfi_st s2, PT_R25
+ cfi_st s3, PT_R26
+ cfi_st s4, PT_R27
+ cfi_st s5, PT_R28
+ cfi_st s6, PT_R29
+ cfi_st s7, PT_R30
+ cfi_st s8, PT_R31
+ csrrd t0, LOONGARCH_CSR_CRMD
+ andi t0, t0, 0x7 /* extract bit[1:0] PLV, bit[2] IE */
+ LONG_S t0, sp, PT_CRMD
+ .endm
+
+ .macro restore_all_base_regs
+ cfi_ld tp, PT_R2
+ cfi_ld a0, PT_R4
+ cfi_ld a1, PT_R5
+ cfi_ld a2, PT_R6
+ cfi_ld a3, PT_R7
+ cfi_ld a4, PT_R8
+ cfi_ld a5, PT_R9
+ cfi_ld a6, PT_R10
+ cfi_ld a7, PT_R11
+ cfi_ld t0, PT_R12
+ cfi_ld t1, PT_R13
+ cfi_ld t2, PT_R14
+ cfi_ld t3, PT_R15
+ cfi_ld t4, PT_R16
+ cfi_ld t5, PT_R17
+ cfi_ld t6, PT_R18
+ cfi_ld t7, PT_R19
+ cfi_ld t8, PT_R20
+ cfi_ld u0, PT_R21
+ cfi_ld fp, PT_R22
+ cfi_ld s0, PT_R23
+ cfi_ld s1, PT_R24
+ cfi_ld s2, PT_R25
+ cfi_ld s3, PT_R26
+ cfi_ld s4, PT_R27
+ cfi_ld s5, PT_R28
+ cfi_ld s6, PT_R29
+ cfi_ld s7, PT_R30
+ cfi_ld s8, PT_R31
+ LONG_L t0, sp, PT_CRMD
+ li.d t1, 0x7 /* mask bit[1:0] PLV, bit[2] IE */
+ csrxchg t0, t1, LOONGARCH_CSR_CRMD
+ .endm
+
+SYM_CODE_START(__kretprobe_trampoline)
+ addi.d sp, sp, -PT_SIZE
+ save_all_base_regs
+
+ addi.d t0, sp, PT_SIZE
+ LONG_S t0, sp, PT_R3
+
+ move a0, sp /* pt_regs */
+
+ bl trampoline_probe_handler
+
+ /* use the result as the return-address */
+ move ra, a0
+
+ restore_all_base_regs
+ addi.d sp, sp, PT_SIZE
+
+ jr ra
+SYM_CODE_END(__kretprobe_trampoline)
--
2.1.0
^ permalink raw reply [flat|nested] 16+ messages in thread* [PATCH v10 4/4] samples/kprobes: Add LoongArch support
2022-12-09 8:52 [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Tiezhu Yang
` (2 preceding siblings ...)
2022-12-09 8:53 ` [PATCH v10 3/4] LoongArch: Add kretprobe support Tiezhu Yang
@ 2022-12-09 8:53 ` Tiezhu Yang
2022-12-09 10:01 ` [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Huacai Chen
2022-12-12 8:41 ` Hengqi Chen
5 siblings, 0 replies; 16+ messages in thread
From: Tiezhu Yang @ 2022-12-09 8:53 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui, Masami Hiramatsu; +Cc: loongarch, linux-kernel
Add LoongArch specific info in handler_pre() and handler_post().
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
samples/kprobes/kprobe_example.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
index fd346f5..ef44c61 100644
--- a/samples/kprobes/kprobe_example.c
+++ b/samples/kprobes/kprobe_example.c
@@ -55,6 +55,10 @@ static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
pr_info("<%s> p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
p->symbol_name, p->addr, regs->psw.addr, regs->flags);
#endif
+#ifdef CONFIG_LOONGARCH
+ pr_info("<%s> p->addr = 0x%p, era = 0x%lx, estat = 0x%lx\n",
+ p->symbol_name, p->addr, regs->csr_era, regs->csr_estat);
+#endif
/* A dump_stack() here will give a stack backtrace */
return 0;
@@ -92,6 +96,10 @@ static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
pr_info("<%s> p->addr, 0x%p, flags = 0x%lx\n",
p->symbol_name, p->addr, regs->flags);
#endif
+#ifdef CONFIG_LOONGARCH
+ pr_info("<%s> p->addr = 0x%p, estat = 0x%lx\n",
+ p->symbol_name, p->addr, regs->csr_estat);
+#endif
}
static int __init kprobe_init(void)
--
2.1.0
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-09 8:52 [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Tiezhu Yang
` (3 preceding siblings ...)
2022-12-09 8:53 ` [PATCH v10 4/4] samples/kprobes: Add LoongArch support Tiezhu Yang
@ 2022-12-09 10:01 ` Huacai Chen
2022-12-09 10:34 ` WANG Xuerui
` (2 more replies)
2022-12-12 8:41 ` Hengqi Chen
5 siblings, 3 replies; 16+ messages in thread
From: Huacai Chen @ 2022-12-09 10:01 UTC (permalink / raw)
To: Tiezhu Yang, Jeff Xie
Cc: WANG Xuerui, Masami Hiramatsu, loongarch, linux-kernel
Hi, Masami,
This series looks good to me now, but I'm not familiar with kprobes.
So, if you have any comments, please let me know.
And Jeff,
As we all know, you are an expert in this domain, so could you please
help me to test this series?
If there are no objections, I plan to merge this series in a few days.
But since the next merge window will be open soon, if there are any
problems, I will revert the patches to wait for the next cycle.
Thanks,
Huacai
On Fri, Dec 9, 2022 at 4:53 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> v10:
> -- Remove sign_extend() based on the latest code
> -- Rename insns_are_not_supported() to insns_not_supported()
> -- Rename insns_are_not_simulated() to insns_not_simulated()
> -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
> -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
>
> v9:
> -- Rename sign_extended() to sign_extend()
> -- Modify kprobe_fault_handler() to handle all of kprobe_status
>
> v8:
> -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
> -- Add code comment of preempt_disable()
> -- Put kprobe_page_fault() in __do_page_fault()
> -- Modify the check condition of break insn in kprobe_breakpoint_handler()
>
> v7:
> -- Remove stop_machine_cpuslocked() related code
>
> v6:
> -- Add a new patch to redefine larch_insn_patch_text() with
> stop_machine_cpuslocked()
> -- Modify kprobe_breakpoint_handler() to consider the original
> insn is break and return the correct value
> -- Modify do_bp() to refresh bcode when original insn is break
>
> v5:
> -- Rebase on the latest code
> -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
>
> v4:
> -- Remove kprobe_exceptions_notify() in kprobes.c
> -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
> in do_bp()
>
> v3:
> -- Rebase on the latest code
> -- Check the alignment of PC in simu_branch() and simu_pc()
> -- Add ibar in flush_insn_slot()
> -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
> -- Add preempt_disable() and preempt_enable_no_resched()
> -- Remove r0 save/restore and do some minor changes
> in kprobes_trampoline.S
> -- Do not enable CONFIG_KPROBES by default
>
> v2:
> -- Split simu_branch() and simu_pc() into a single patch
> -- Call kprobe_page_fault() in do_page_fault()
> -- Add kprobes_trampoline.S for kretprobe
>
> Tiezhu Yang (4):
> LoongArch: Simulate branch and PC instructions
> LoongArch: Add kprobe support
> LoongArch: Add kretprobe support
> samples/kprobes: Add LoongArch support
>
> arch/loongarch/Kconfig | 2 +
> arch/loongarch/include/asm/inst.h | 20 ++
> arch/loongarch/include/asm/kprobes.h | 59 +++++
> arch/loongarch/include/asm/ptrace.h | 1 +
> arch/loongarch/kernel/Makefile | 2 +
> arch/loongarch/kernel/inst.c | 123 ++++++++++
> arch/loongarch/kernel/kprobes.c | 364 +++++++++++++++++++++++++++++
> arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++
> arch/loongarch/kernel/traps.c | 13 +-
> arch/loongarch/mm/fault.c | 3 +
> samples/kprobes/kprobe_example.c | 8 +
> 11 files changed, 687 insertions(+), 4 deletions(-)
> create mode 100644 arch/loongarch/include/asm/kprobes.h
> create mode 100644 arch/loongarch/kernel/kprobes.c
> create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
>
> --
> 2.1.0
>
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-09 10:01 ` [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Huacai Chen
@ 2022-12-09 10:34 ` WANG Xuerui
2022-12-10 13:54 ` Jeff Xie
2022-12-13 3:10 ` Masami Hiramatsu
2 siblings, 0 replies; 16+ messages in thread
From: WANG Xuerui @ 2022-12-09 10:34 UTC (permalink / raw)
To: Huacai Chen, Tiezhu Yang, Jeff Xie
Cc: Masami Hiramatsu, loongarch, linux-kernel
On 2022/12/9 18:01, Huacai Chen wrote:
> Hi, Masami,
>
> This series looks good to me now, but I'm not familiar with kprobes.
> So, if you have any comments, please let me know.
>
> And Jeff,
>
> As we all know, you are an expert in this domain, so could you please
> help me to test this series?
>
> If there are no objections, I plan to merge this series in a few days.
> But since the next merge window will be open soon, if there are any
> problems, I will revert the patches to wait for the next cycle.
Sorry for jumping in so late, but due to the imminence of the merge
window, and Linus having *specifically* asked for readiness of all 6.2
material upfront due to holidays, IMHO it could be more prudent to wait
one more cycle. Especially considering some other people's code probably
already made the respective maintainers more cautious due to the compile
warnings, and hurried fixes to some other similarly hurried commits...
--
WANG "xen0n" Xuerui
Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-09 10:01 ` [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Huacai Chen
2022-12-09 10:34 ` WANG Xuerui
@ 2022-12-10 13:54 ` Jeff Xie
2022-12-13 3:10 ` Masami Hiramatsu
2 siblings, 0 replies; 16+ messages in thread
From: Jeff Xie @ 2022-12-10 13:54 UTC (permalink / raw)
To: Huacai Chen
Cc: Tiezhu Yang, WANG Xuerui, Masami Hiramatsu, loongarch, linux-kernel
On Fri, Dec 9, 2022 at 6:01 PM Huacai Chen <chenhuacai@kernel.org> wrote:
>
> Hi, Masami,
>
> This series looks good to me now, but I'm not familiar with kprobes.
> So, if you have any comments, please let me know.
>
> And Jeff,
>
> As we all know, you are an expert in this domain, so could you please
> help me to test this series?
>
> If there are no objections, I plan to merge this series in a few days.
> But since the next merge window will be open soon, if there are any
> problems, I will revert the patches to wait for the next cycle.
I can't use the kprobe function normally now, tested the function from
the branch: https://github.com/loongson/linux/commits/loongarch-next
steps:
1. Try to probe __memset_fast()
[root@loongarch ]# cat /proc/kallsyms | grep __memset_fast
90000000012c75f0 T __memset_fast
./samples/kprobes/kprobe_example.c
static char symbol[KSYM_NAME_LEN] = "__memset_fast";
2. Loading the kprobe_example.ko
[root@loongarch mnt]# insmod ./kprobe_example.ko
*** The system will keep hanging ***
dmesg-messages:
gef➤ lx-dmesg
[ 12.348047] handler_pre: <__memset_fast> p->addr =
0x(____ptrval____), era = 0x90000000012c75f0, estat = 0xc0000
[ 12.348512] handler_post: <__memset_fast> p->addr =
0x(____ptrval____), estat = 0xc0000
[ 12.348525] handler_post: <__memset_fast> p->addr =
0x(____ptrval____), estat = 0xc0000
[ 12.349248] handler_pre: <__memset_fast> p->addr =
0x(____ptrval____), era = 0x90000000012c75f0, estat = 0xc0000
[ 12.349259] handler_post: <__memset_fast> p->addr =
0x(____ptrval____), estat = 0xc0000
call trace:
gef➤ bt
#0 0x90000000012f45f8 in queued_spin_lock_slowpath
(lock=0x9000000001cc0018 <die_lock>, val=0x1) at
kernel/locking/qspinlock.c:383
#1 0x9000000000223b2c in die (str=str@entry=0x90000000017e3488 "Break
instruction in kernel code", regs=regs@entry=0x900000010fd735f0) at
arch/loongarch/kernel/traps.c:240
#2 0x90000000012e3968 in die_if_kernel (regs=<optimized out>,
str=<optimized out>) at ./arch/loongarch/include/asm/ptrace.h:131
#3 do_bp (regs=0x900000010fd735f0) at arch/loongarch/kernel/traps.c:485
#4 0x9000000001cb1924 in exception_handlers ()
Backtrace stopped: frame did not save the PC
> Thanks,
> Huacai
>
> On Fri, Dec 9, 2022 at 4:53 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> >
> > v10:
> > -- Remove sign_extend() based on the latest code
> > -- Rename insns_are_not_supported() to insns_not_supported()
> > -- Rename insns_are_not_simulated() to insns_not_simulated()
> > -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
> > -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
> >
> > v9:
> > -- Rename sign_extended() to sign_extend()
> > -- Modify kprobe_fault_handler() to handle all of kprobe_status
> >
> > v8:
> > -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
> > -- Add code comment of preempt_disable()
> > -- Put kprobe_page_fault() in __do_page_fault()
> > -- Modify the check condition of break insn in kprobe_breakpoint_handler()
> >
> > v7:
> > -- Remove stop_machine_cpuslocked() related code
> >
> > v6:
> > -- Add a new patch to redefine larch_insn_patch_text() with
> > stop_machine_cpuslocked()
> > -- Modify kprobe_breakpoint_handler() to consider the original
> > insn is break and return the correct value
> > -- Modify do_bp() to refresh bcode when original insn is break
> >
> > v5:
> > -- Rebase on the latest code
> > -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
> >
> > v4:
> > -- Remove kprobe_exceptions_notify() in kprobes.c
> > -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
> > in do_bp()
> >
> > v3:
> > -- Rebase on the latest code
> > -- Check the alignment of PC in simu_branch() and simu_pc()
> > -- Add ibar in flush_insn_slot()
> > -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
> > -- Add preempt_disable() and preempt_enable_no_resched()
> > -- Remove r0 save/restore and do some minor changes
> > in kprobes_trampoline.S
> > -- Do not enable CONFIG_KPROBES by default
> >
> > v2:
> > -- Split simu_branch() and simu_pc() into a single patch
> > -- Call kprobe_page_fault() in do_page_fault()
> > -- Add kprobes_trampoline.S for kretprobe
> >
> > Tiezhu Yang (4):
> > LoongArch: Simulate branch and PC instructions
> > LoongArch: Add kprobe support
> > LoongArch: Add kretprobe support
> > samples/kprobes: Add LoongArch support
> >
> > arch/loongarch/Kconfig | 2 +
> > arch/loongarch/include/asm/inst.h | 20 ++
> > arch/loongarch/include/asm/kprobes.h | 59 +++++
> > arch/loongarch/include/asm/ptrace.h | 1 +
> > arch/loongarch/kernel/Makefile | 2 +
> > arch/loongarch/kernel/inst.c | 123 ++++++++++
> > arch/loongarch/kernel/kprobes.c | 364 +++++++++++++++++++++++++++++
> > arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++
> > arch/loongarch/kernel/traps.c | 13 +-
> > arch/loongarch/mm/fault.c | 3 +
> > samples/kprobes/kprobe_example.c | 8 +
> > 11 files changed, 687 insertions(+), 4 deletions(-)
> > create mode 100644 arch/loongarch/include/asm/kprobes.h
> > create mode 100644 arch/loongarch/kernel/kprobes.c
> > create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
> >
> > --
> > 2.1.0
> >
--
Thanks,
JeffXie
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-09 10:01 ` [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Huacai Chen
2022-12-09 10:34 ` WANG Xuerui
2022-12-10 13:54 ` Jeff Xie
@ 2022-12-13 3:10 ` Masami Hiramatsu
2022-12-17 2:28 ` Huacai Chen
2 siblings, 1 reply; 16+ messages in thread
From: Masami Hiramatsu @ 2022-12-13 3:10 UTC (permalink / raw)
To: Huacai Chen
Cc: Tiezhu Yang, Jeff Xie, WANG Xuerui, Masami Hiramatsu, loongarch,
linux-kernel
On Fri, 9 Dec 2022 18:01:44 +0800
Huacai Chen <chenhuacai@kernel.org> wrote:
> Hi, Masami,
>
> This series looks good to me now, but I'm not familiar with kprobes.
> So, if you have any comments, please let me know.
Sorry I missed this series. Let me add some comments.
BTW, I don't have any board to run the loongarch, so I'll make
comments just about style issues.
Thanks,
>
> And Jeff,
>
> As we all know, you are an expert in this domain, so could you please
> help me to test this series?
>
> If there are no objections, I plan to merge this series in a few days.
> But since the next merge window will be open soon, if there are any
> problems, I will revert the patches to wait for the next cycle.
>
> Thanks,
> Huacai
>
> On Fri, Dec 9, 2022 at 4:53 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> >
> > v10:
> > -- Remove sign_extend() based on the latest code
> > -- Rename insns_are_not_supported() to insns_not_supported()
> > -- Rename insns_are_not_simulated() to insns_not_simulated()
> > -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
> > -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
> >
> > v9:
> > -- Rename sign_extended() to sign_extend()
> > -- Modify kprobe_fault_handler() to handle all of kprobe_status
> >
> > v8:
> > -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
> > -- Add code comment of preempt_disable()
> > -- Put kprobe_page_fault() in __do_page_fault()
> > -- Modify the check condition of break insn in kprobe_breakpoint_handler()
> >
> > v7:
> > -- Remove stop_machine_cpuslocked() related code
> >
> > v6:
> > -- Add a new patch to redefine larch_insn_patch_text() with
> > stop_machine_cpuslocked()
> > -- Modify kprobe_breakpoint_handler() to consider the original
> > insn is break and return the correct value
> > -- Modify do_bp() to refresh bcode when original insn is break
> >
> > v5:
> > -- Rebase on the latest code
> > -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
> >
> > v4:
> > -- Remove kprobe_exceptions_notify() in kprobes.c
> > -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
> > in do_bp()
> >
> > v3:
> > -- Rebase on the latest code
> > -- Check the alignment of PC in simu_branch() and simu_pc()
> > -- Add ibar in flush_insn_slot()
> > -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
> > -- Add preempt_disable() and preempt_enable_no_resched()
> > -- Remove r0 save/restore and do some minor changes
> > in kprobes_trampoline.S
> > -- Do not enable CONFIG_KPROBES by default
> >
> > v2:
> > -- Split simu_branch() and simu_pc() into a single patch
> > -- Call kprobe_page_fault() in do_page_fault()
> > -- Add kprobes_trampoline.S for kretprobe
> >
> > Tiezhu Yang (4):
> > LoongArch: Simulate branch and PC instructions
> > LoongArch: Add kprobe support
> > LoongArch: Add kretprobe support
> > samples/kprobes: Add LoongArch support
> >
> > arch/loongarch/Kconfig | 2 +
> > arch/loongarch/include/asm/inst.h | 20 ++
> > arch/loongarch/include/asm/kprobes.h | 59 +++++
> > arch/loongarch/include/asm/ptrace.h | 1 +
> > arch/loongarch/kernel/Makefile | 2 +
> > arch/loongarch/kernel/inst.c | 123 ++++++++++
> > arch/loongarch/kernel/kprobes.c | 364 +++++++++++++++++++++++++++++
> > arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++
> > arch/loongarch/kernel/traps.c | 13 +-
> > arch/loongarch/mm/fault.c | 3 +
> > samples/kprobes/kprobe_example.c | 8 +
> > 11 files changed, 687 insertions(+), 4 deletions(-)
> > create mode 100644 arch/loongarch/include/asm/kprobes.h
> > create mode 100644 arch/loongarch/kernel/kprobes.c
> > create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
> >
> > --
> > 2.1.0
> >
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-13 3:10 ` Masami Hiramatsu
@ 2022-12-17 2:28 ` Huacai Chen
0 siblings, 0 replies; 16+ messages in thread
From: Huacai Chen @ 2022-12-17 2:28 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Tiezhu Yang, Jeff Xie, WANG Xuerui, loongarch, linux-kernel
Hi, Masami,
On Tue, Dec 13, 2022 at 11:10 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> On Fri, 9 Dec 2022 18:01:44 +0800
> Huacai Chen <chenhuacai@kernel.org> wrote:
>
> > Hi, Masami,
> >
> > This series looks good to me now, but I'm not familiar with kprobes.
> > So, if you have any comments, please let me know.
>
> Sorry I missed this series. Let me add some comments.
> BTW, I don't have any board to run the loongarch, so I'll make
> comments just about style issues.
You needn't say sorry, and you can use qemu to run loongarch if needed.
Huacai
>
> Thanks,
>
> >
> > And Jeff,
> >
> > As we all know, you are an expert in this domain, so could you please
> > help me to test this series?
> >
> > If there are no objections, I plan to merge this series in a few days.
> > But since the next merge window will be open soon, if there are any
> > problems, I will revert the patches to wait for the next cycle.
> >
> > Thanks,
> > Huacai
> >
> > On Fri, Dec 9, 2022 at 4:53 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> > >
> > > v10:
> > > -- Remove sign_extend() based on the latest code
> > > -- Rename insns_are_not_supported() to insns_not_supported()
> > > -- Rename insns_are_not_simulated() to insns_not_simulated()
> > > -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
> > > -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
> > >
> > > v9:
> > > -- Rename sign_extended() to sign_extend()
> > > -- Modify kprobe_fault_handler() to handle all of kprobe_status
> > >
> > > v8:
> > > -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
> > > -- Add code comment of preempt_disable()
> > > -- Put kprobe_page_fault() in __do_page_fault()
> > > -- Modify the check condition of break insn in kprobe_breakpoint_handler()
> > >
> > > v7:
> > > -- Remove stop_machine_cpuslocked() related code
> > >
> > > v6:
> > > -- Add a new patch to redefine larch_insn_patch_text() with
> > > stop_machine_cpuslocked()
> > > -- Modify kprobe_breakpoint_handler() to consider the original
> > > insn is break and return the correct value
> > > -- Modify do_bp() to refresh bcode when original insn is break
> > >
> > > v5:
> > > -- Rebase on the latest code
> > > -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
> > >
> > > v4:
> > > -- Remove kprobe_exceptions_notify() in kprobes.c
> > > -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
> > > in do_bp()
> > >
> > > v3:
> > > -- Rebase on the latest code
> > > -- Check the alignment of PC in simu_branch() and simu_pc()
> > > -- Add ibar in flush_insn_slot()
> > > -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
> > > -- Add preempt_disable() and preempt_enable_no_resched()
> > > -- Remove r0 save/restore and do some minor changes
> > > in kprobes_trampoline.S
> > > -- Do not enable CONFIG_KPROBES by default
> > >
> > > v2:
> > > -- Split simu_branch() and simu_pc() into a single patch
> > > -- Call kprobe_page_fault() in do_page_fault()
> > > -- Add kprobes_trampoline.S for kretprobe
> > >
> > > Tiezhu Yang (4):
> > > LoongArch: Simulate branch and PC instructions
> > > LoongArch: Add kprobe support
> > > LoongArch: Add kretprobe support
> > > samples/kprobes: Add LoongArch support
> > >
> > > arch/loongarch/Kconfig | 2 +
> > > arch/loongarch/include/asm/inst.h | 20 ++
> > > arch/loongarch/include/asm/kprobes.h | 59 +++++
> > > arch/loongarch/include/asm/ptrace.h | 1 +
> > > arch/loongarch/kernel/Makefile | 2 +
> > > arch/loongarch/kernel/inst.c | 123 ++++++++++
> > > arch/loongarch/kernel/kprobes.c | 364 +++++++++++++++++++++++++++++
> > > arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++
> > > arch/loongarch/kernel/traps.c | 13 +-
> > > arch/loongarch/mm/fault.c | 3 +
> > > samples/kprobes/kprobe_example.c | 8 +
> > > 11 files changed, 687 insertions(+), 4 deletions(-)
> > > create mode 100644 arch/loongarch/include/asm/kprobes.h
> > > create mode 100644 arch/loongarch/kernel/kprobes.c
> > > create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
> > >
> > > --
> > > 2.1.0
> > >
>
>
> --
> Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-09 8:52 [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Tiezhu Yang
` (4 preceding siblings ...)
2022-12-09 10:01 ` [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch Huacai Chen
@ 2022-12-12 8:41 ` Hengqi Chen
2022-12-12 9:35 ` Qing Zhang
5 siblings, 1 reply; 16+ messages in thread
From: Hengqi Chen @ 2022-12-12 8:41 UTC (permalink / raw)
To: Tiezhu Yang, Huacai Chen, WANG Xuerui, Masami Hiramatsu
Cc: loongarch, linux-kernel
Hi, Tiezhu:
I tested this patchset from BPF side, failed with EINVAL:
$ cat /sys/kernel/tracing/error_log
[ 262.299093] trace_kprobe: error: Failed to register probe event
Command: p:kprobes/libbpf_4609_inet_bind_0x0_0 inet_bind+0x0
^
--
Hengqi
On 2022/12/9 16:52, Tiezhu Yang wrote:
> v10:
> -- Remove sign_extend() based on the latest code
> -- Rename insns_are_not_supported() to insns_not_supported()
> -- Rename insns_are_not_simulated() to insns_not_simulated()
> -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
> -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
>
> v9:
> -- Rename sign_extended() to sign_extend()
> -- Modify kprobe_fault_handler() to handle all of kprobe_status
>
> v8:
> -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
> -- Add code comment of preempt_disable()
> -- Put kprobe_page_fault() in __do_page_fault()
> -- Modify the check condition of break insn in kprobe_breakpoint_handler()
>
> v7:
> -- Remove stop_machine_cpuslocked() related code
>
> v6:
> -- Add a new patch to redefine larch_insn_patch_text() with
> stop_machine_cpuslocked()
> -- Modify kprobe_breakpoint_handler() to consider the original
> insn is break and return the correct value
> -- Modify do_bp() to refresh bcode when original insn is break
>
> v5:
> -- Rebase on the latest code
> -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
>
> v4:
> -- Remove kprobe_exceptions_notify() in kprobes.c
> -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
> in do_bp()
>
> v3:
> -- Rebase on the latest code
> -- Check the alignment of PC in simu_branch() and simu_pc()
> -- Add ibar in flush_insn_slot()
> -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
> -- Add preempt_disable() and preempt_enable_no_resched()
> -- Remove r0 save/restore and do some minor changes
> in kprobes_trampoline.S
> -- Do not enable CONFIG_KPROBES by default
>
> v2:
> -- Split simu_branch() and simu_pc() into a single patch
> -- Call kprobe_page_fault() in do_page_fault()
> -- Add kprobes_trampoline.S for kretprobe
>
> Tiezhu Yang (4):
> LoongArch: Simulate branch and PC instructions
> LoongArch: Add kprobe support
> LoongArch: Add kretprobe support
> samples/kprobes: Add LoongArch support
>
> arch/loongarch/Kconfig | 2 +
> arch/loongarch/include/asm/inst.h | 20 ++
> arch/loongarch/include/asm/kprobes.h | 59 +++++
> arch/loongarch/include/asm/ptrace.h | 1 +
> arch/loongarch/kernel/Makefile | 2 +
> arch/loongarch/kernel/inst.c | 123 ++++++++++
> arch/loongarch/kernel/kprobes.c | 364 +++++++++++++++++++++++++++++
> arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++
> arch/loongarch/kernel/traps.c | 13 +-
> arch/loongarch/mm/fault.c | 3 +
> samples/kprobes/kprobe_example.c | 8 +
> 11 files changed, 687 insertions(+), 4 deletions(-)
> create mode 100644 arch/loongarch/include/asm/kprobes.h
> create mode 100644 arch/loongarch/kernel/kprobes.c
> create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
>
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch
2022-12-12 8:41 ` Hengqi Chen
@ 2022-12-12 9:35 ` Qing Zhang
0 siblings, 0 replies; 16+ messages in thread
From: Qing Zhang @ 2022-12-12 9:35 UTC (permalink / raw)
To: Hengqi Chen, Tiezhu Yang, Huacai Chen, WANG Xuerui, Masami Hiramatsu
Cc: loongarch, linux-kernel
Hi, Hengqi
On 2022/12/12 下午4:41, Hengqi Chen wrote:
> Hi, Tiezhu:
>
> I tested this patchset from BPF side, failed with EINVAL:
>
> $ cat /sys/kernel/tracing/error_log
> [ 262.299093] trace_kprobe: error: Failed to register probe event
> Command: p:kprobes/libbpf_4609_inet_bind_0x0_0 inet_bind+0x0
>
This is because KPROBE_ON_FTRACE is not yet supported. Trace Event
cannot be used now.
We will support it soon, if you want to test it by install
kprobe_example.ko as jeff did.
Thanks
-Qing ^
> --
> Hengqi
>
> On 2022/12/9 16:52, Tiezhu Yang wrote:
>> v10:
>> -- Remove sign_extend() based on the latest code
>> -- Rename insns_are_not_supported() to insns_not_supported()
>> -- Rename insns_are_not_simulated() to insns_not_simulated()
>> -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
>> -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
>>
>> v9:
>> -- Rename sign_extended() to sign_extend()
>> -- Modify kprobe_fault_handler() to handle all of kprobe_status
>>
>> v8:
>> -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
>> -- Add code comment of preempt_disable()
>> -- Put kprobe_page_fault() in __do_page_fault()
>> -- Modify the check condition of break insn in kprobe_breakpoint_handler()
>>
>> v7:
>> -- Remove stop_machine_cpuslocked() related code
>>
>> v6:
>> -- Add a new patch to redefine larch_insn_patch_text() with
>> stop_machine_cpuslocked()
>> -- Modify kprobe_breakpoint_handler() to consider the original
>> insn is break and return the correct value
>> -- Modify do_bp() to refresh bcode when original insn is break
>>
>> v5:
>> -- Rebase on the latest code
>> -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
>>
>> v4:
>> -- Remove kprobe_exceptions_notify() in kprobes.c
>> -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
>> in do_bp()
>>
>> v3:
>> -- Rebase on the latest code
>> -- Check the alignment of PC in simu_branch() and simu_pc()
>> -- Add ibar in flush_insn_slot()
>> -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
>> -- Add preempt_disable() and preempt_enable_no_resched()
>> -- Remove r0 save/restore and do some minor changes
>> in kprobes_trampoline.S
>> -- Do not enable CONFIG_KPROBES by default
>>
>> v2:
>> -- Split simu_branch() and simu_pc() into a single patch
>> -- Call kprobe_page_fault() in do_page_fault()
>> -- Add kprobes_trampoline.S for kretprobe
>>
>> Tiezhu Yang (4):
>> LoongArch: Simulate branch and PC instructions
>> LoongArch: Add kprobe support
>> LoongArch: Add kretprobe support
>> samples/kprobes: Add LoongArch support
>>
>> arch/loongarch/Kconfig | 2 +
>> arch/loongarch/include/asm/inst.h | 20 ++
>> arch/loongarch/include/asm/kprobes.h | 59 +++++
>> arch/loongarch/include/asm/ptrace.h | 1 +
>> arch/loongarch/kernel/Makefile | 2 +
>> arch/loongarch/kernel/inst.c | 123 ++++++++++
>> arch/loongarch/kernel/kprobes.c | 364 +++++++++++++++++++++++++++++
>> arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++
>> arch/loongarch/kernel/traps.c | 13 +-
>> arch/loongarch/mm/fault.c | 3 +
>> samples/kprobes/kprobe_example.c | 8 +
>> 11 files changed, 687 insertions(+), 4 deletions(-)
>> create mode 100644 arch/loongarch/include/asm/kprobes.h
>> create mode 100644 arch/loongarch/kernel/kprobes.c
>> create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
>>
^ permalink raw reply [flat|nested] 16+ messages in thread