From 19bc6cb6409289106d38f9ad1b2ecf73980df6b5 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Thu, 29 Jun 2023 20:58:44 +0800 Subject: [PATCH] LoongArch: Add uprobes support Uprobes is the user-space counterpart to kprobes, this patch adds uprobes support for LoongArch. Here is a simple example with CONFIG_UPROBE_EVENTS=y: # cat test.c #include 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 Tested-by: Jeff Xie Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen --- 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 | 153 +++++++++++++++++++++++++++ 5 files changed, 197 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 b787f8fcbac7..94ca147981cf 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -643,6 +643,9 @@ 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 000000000000..c8f59983f702 --- /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 + +typedef u32 uprobe_opcode_t; + +#define MAX_UINSN_BYTES 8 +#define UPROBE_XOL_SLOT_BYTES MAX_UINSN_BYTES + +#define UPROBE_SWBP_INSN larch_insn_gen_break(BRK_UPROBE_BP) +#define UPROBE_SWBP_INSN_SIZE LOONGARCH_INSN_SIZE + +#define UPROBE_XOLBP_INSN larch_insn_gen_break(BRK_UPROBE_XOLBP) + +struct arch_uprobe { + unsigned long resume_era; + u32 insn[2]; + u32 ixol[2]; + 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 1061c36f5ad5..8e279f04f9e7 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -56,6 +56,7 @@ obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_RETHOOK) += rethook.o rethook_trampoline.o +obj-$(CONFIG_UPROBES) += uprobes.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c index e56df45f7202..8fb5e7a77145 100644 --- a/arch/loongarch/kernel/traps.c +++ b/arch/loongarch/kernel/traps.c @@ -47,6 +47,7 @@ #include #include #include +#include #include "access-helper.h" @@ -689,7 +690,6 @@ 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; @@ -711,18 +711,17 @@ 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 000000000000..87abc7137b73 --- /dev/null +++ b/arch/loongarch/kernel/uprobes.c @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include + +#define UPROBE_TRAP_NR UINT_MAX + +int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, + struct mm_struct *mm, unsigned long addr) +{ + int idx; + union loongarch_instruction insn; + + if (addr & 0x3) + return -EILSEQ; + + for (idx = ARRAY_SIZE(auprobe->insn) - 1; idx >= 0; idx--) { + insn.word = auprobe->insn[idx]; + 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); + user_enable_single_step(current); + + return 0; +} + +int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); + current->thread.trap_nr = utask->autask.saved_trap_nr; + + if (auprobe->simulate) + instruction_pointer_set(regs, auprobe->resume_era); + else + instruction_pointer_set(regs, utask->vaddr + LOONGARCH_INSN_SIZE); + + user_disable_single_step(current); + + 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); + user_disable_single_step(current); +} + +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); + auprobe->resume_era = regs->csr_era; + + 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); +}