Messages in this thread | | | From | Jianhua Liu <> | Date | Mon, 3 Jan 2022 17:03:33 +0800 | Subject | Re: [PATCH v5] arm64: kprobe: Enable OPTPROBE for arm64 |
| |
On Thu, Dec 16, 2021 at 8:26 PM Jianhua Liu <jianhua.ljh@gmail.com> wrote: > > On Thu, Dec 16, 2021 at 7:18 PM liuqi (BA) <liuqi115@huawei.com> wrote: > > > > > > > > On 2021/12/14 23:55, Jianhua Liu wrote: > > > On Tue, Dec 14, 2021 at 8:27 AM Masami Hiramatsu <mhiramat@kernel.org> wrote: > > >> > > >> On Mon, 13 Dec 2021 18:38:52 +0000 > > >> Will Deacon <will@kernel.org> wrote: > > >> > > >>> Hi, > > >>> > > >>> [+Janet Liu] > > >>> > > >>> On Tue, Dec 07, 2021 at 08:40:02PM +0800, Qi Liu wrote: > > >>>> This patch introduce optprobe for ARM64. In optprobe, probed > > >>>> instruction is replaced by a branch instruction to trampoline. > > >>>> > > >>>> Performance of optprobe on Hip08 platform is test using kprobe > > >>>> example module[1] to analyze the latency of a kernel function, > > >>>> and here is the result: > > >>>> > > >>>> common kprobe: > > >>>> [280709.846380] do_empty returned 0 and took 1530 ns to execute > > >>>> [280709.852057] do_empty returned 0 and took 550 ns to execute > > >>>> [280709.857631] do_empty returned 0 and took 440 ns to execute > > >>>> [280709.863215] do_empty returned 0 and took 380 ns to execute > > >>>> [280709.868787] do_empty returned 0 and took 360 ns to execute > > >>>> [280709.874362] do_empty returned 0 and took 340 ns to execute > > >>>> [280709.879936] do_empty returned 0 and took 320 ns to execute > > >>>> [280709.885505] do_empty returned 0 and took 300 ns to execute > > >>>> [280709.891075] do_empty returned 0 and took 280 ns to execute > > >>>> [280709.896646] do_empty returned 0 and took 290 ns to execute > > >>>> > > >>>> optprobe: > > >>>> [ 2965.964572] do_empty returned 0 and took 90 ns to execute > > >>>> [ 2965.969952] do_empty returned 0 and took 80 ns to execute > > >>>> [ 2965.975332] do_empty returned 0 and took 70 ns to execute > > >>>> [ 2965.980714] do_empty returned 0 and took 60 ns to execute > > >>>> [ 2965.986128] do_empty returned 0 and took 80 ns to execute > > >>>> [ 2965.991507] do_empty returned 0 and took 70 ns to execute > > >>>> [ 2965.996884] do_empty returned 0 and took 70 ns to execute > > >>>> [ 2966.002262] do_empty returned 0 and took 80 ns to execute > > >>>> [ 2966.007642] do_empty returned 0 and took 70 ns to execute > > >>>> [ 2966.013020] do_empty returned 0 and took 70 ns to execute > > >>>> [ 2966.018400] do_empty returned 0 and took 70 ns to execute > > >>>> > > >>>> As the result shows, optprobe can greatly reduce the latency. Big > > >>>> latency of common kprobe will significantly impact the real result > > >>>> while doing performance analysis or debugging performance issues > > >>>> in lab, so optprobe is useful in this scenario. > > >>>> > > >>>> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> > > >>>> Signed-off-by: Qi Liu <liuqi115@huawei.com> > > >>>> > > >>>> Note: > > >>>> As branch instruction in Arm64 has a 128M range limitation, optprobe > > >>>> could only used when offset between probe point and trampoline > > >>>> is less than 128M, otherwise kernel will choose common kprobe > > >>>> automaticly. > > >>>> > > >>>> Limitation caused by branch isn't unique to Arm64, but also to > > >>>> x86/arm/powerpc. > > >>>> > > >>>> In fact, Module PLT has been tried to get rid of limiation, but > > >>>> destination of PLT must be a fixed value, and we need to modify > > >>>> the destination (as each optprobe has its own trampoline). > > >>>> > > >>>> As discussed with Masami[2], we can start with core-kernel point > > >>>> (within 128M) as the first step, like other architectures. > > >>>> > > >>>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/samples/kprobes/kretprobe_example.c > > >>>> [2] https://lore.kernel.org/lkml/20211201105001.5164f98ba783e7207df1229c@kernel.org/ > > >>>> --- > > >>>> arch/arm64/Kconfig | 1 + > > >>>> arch/arm64/include/asm/kprobes.h | 21 ++ > > >>>> arch/arm64/kernel/probes/Makefile | 2 + > > >>>> arch/arm64/kernel/probes/opt_arm64.c | 199 ++++++++++++++++++ > > >>>> .../arm64/kernel/probes/optprobe_trampoline.S | 97 +++++++++ > > >>>> include/linux/kprobes.h | 2 + > > >>>> kernel/kprobes.c | 22 ++ > > >>>> 7 files changed, 344 insertions(+) > > >>>> create mode 100644 arch/arm64/kernel/probes/opt_arm64.c > > >>>> create mode 100644 arch/arm64/kernel/probes/optprobe_trampoline.S > > >>> > > >>> I've not looked at these changes in detail, but it looks like there is an > > >>> independent patch from Janet Liu trying to do the same thing: > > >>> > > >>> https://lore.kernel.org/r/1635858706-27320-1-git-send-email-jianhua.ljh@gmail.com > > >>> > > >> > > >> Thanks for noticing. I missed it. > > >> > > >>> The patch here from Qi Liu looks like it's a bit further along, but it > > >>> would be good for Janet to at least test it out and confirm that it works > > >>> for them. > > >> > > >> Yeah, it's now v5. > > >> But it seems Janet's one also has good points. I would like Janet's sharing > > >> save_all_base_regs macro and the comment about the branch instruction. > > >> > > >>> > > >>> Cheers, > > >>> > > >>> Will > > >>> > > >>> [Kept diff inline for Janet] > > >> > > >> Janet, please feel free to review and test it. It is important that you confirm > > >> this can work with your envionment too. > > >> I will review your KPROBE_ON_FTRACE patch. > > >> > > > I have tested these patch on UNISOC s9863a platform before sending. > > > > > > The test case from: > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/samples/kprobes/ > > > > > > And I do the following change for kprobe_example.c before testing: > > > 1. delete function handler_post, > > > kprobe_init does "kp.post_handler = handler_post; ---> > > > p.post_handler = NULL;" > > > 2. handler_pre calls dump_stack. > > > > > > > Hi Jianhua, > > > > Could you kindly review this patch and test it on your UNISOC s9863a > > platform? Let's work together to make arm64 optprobe work : ) > > > > Thanks, > > Qi > > OK, I will review. I have left UNISOC, I get some help from old > colleage to do the test. > Only on weekend, he can do it. So the time will be longer a little. > > Thanks > Jianhua > > Hi Qi, I have tested your patch on UNISOC s9863a. Test case "kprobe_example & kretprobe_example" is OK.
Two point: 1. backtrace is not perfect. optprobe_common does not saved frame pointer, backtrace lacks two calls. such as for dup_mm: lack copy_process-->dup_mm dup_mm backtrace from your patch: [ 832.387066] CPU: 0 PID: 296 Comm: sh Not tainted 5.16.0-rc5+ #8 [ 832.387078] Hardware name: Spreadtrum SP9863A-1H10 Board (DT) [ 832.387083] Call trace: [ 832.387086] dump_backtrace+0x0/0x1e0 [ 832.387103] show_stack+0x24/0x30 [ 832.387112] dump_stack_lvl+0x68/0x84 [ 832.387123] dump_stack+0x18/0x34 [ 832.387131] handler_pre+0x40/0x50 [kprobe_example] [ 832.387143] opt_pre_handler+0x84/0xc0 [ 832.387154] optprobe_optimized_callback+0xec/0x164 [ 832.387164] optprobe_common+0x70/0xc4 [ 832.387173] kernel_clone+0x98/0x440 [ 832.387182] __do_sys_clone+0x54/0x80 [ 832.387191] __arm64_sys_clone+0x2c/0x40 [ 832.387199] invoke_syscall+0x50/0x120 [ 832.387208] el0_svc_common.constprop.0+0x4c/0xf4 [ 832.387217] do_el0_svc+0x30/0x9c [ 832.387225] el0_svc+0x20/0x60 [ 832.387235] el0t_64_sync_handler+0xe8/0xf0 [ 832.387242] el0t_64_sync+0x1a0/0x1a4
dup_mm backtrace from other: [ 173.352294] CPU: 6 PID: 309 Comm: sh Not tainted 5.16.0-rc5+ #19 [ 173.352301] Hardware name: Spreadtrum SP9863A-1H10 Board (DT) [ 173.352304] Call trace: [ 173.352307] dump_backtrace+0x0/0x1d4 [ 173.352319] show_stack+0x18/0x24 [ 173.352326] dump_stack_lvl+0x68/0x84 [ 173.352333] dump_stack+0x18/0x34 [ 173.352338] handler_pre+0x38/0x48 [kprobe_example] [ 173.352347] opt_pre_handler+0x74/0xb0 [ 173.352354] optimized_callback+0x108/0x130 [ 173.352361] optinsn_slot+0x258/0x1000 [ 173.352366] dup_mm+0x4/0x4b0 [ 173.352373] copy_process+0x1284/0x1360 [ 173.352378] kernel_clone+0x5c/0x3c0 [ 173.352384] __do_sys_clone+0x54/0x80 [ 173.352390] __arm64_sys_clone+0x24/0x30 [ 173.352396] invoke_syscall+0x48/0x114 [ 173.352402] el0_svc_common.constprop.0+0x44/0xec [ 173.352408] do_el0_svc+0x24/0x90 [ 173.352413] el0_svc+0x20/0x60 [ 173.352420] el0t_64_sync_handler+0xe8/0xf0 [ 173.352427] el0t_64_sync+0x1a0/0x1a4
2. The reserve memory "OPT_SLOT_SIZE - PAGE_SIZE" is waste. kernel/kprobe.c used only one PAGE_SIZE slot memory.
Thanks Jianhua
> > Thanks for the review. > > > > > >> Thank you, > > >> > > >>> > > >>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > >>>> index c4207cf9bb17..6b68ec498e67 100644 > > >>>> --- a/arch/arm64/Kconfig > > >>>> +++ b/arch/arm64/Kconfig > > >>>> @@ -200,6 +200,7 @@ config ARM64 > > >>>> select HAVE_STACKPROTECTOR > > >>>> select HAVE_SYSCALL_TRACEPOINTS > > >>>> select HAVE_KPROBES > > >>>> + select HAVE_OPTPROBES > > >>>> select HAVE_KRETPROBES > > >>>> select HAVE_GENERIC_VDSO > > >>>> select IOMMU_DMA if IOMMU_SUPPORT > > >>>> diff --git a/arch/arm64/include/asm/kprobes.h b/arch/arm64/include/asm/kprobes.h > > >>>> index 05cd82eeca13..3838e4317877 100644 > > >>>> --- a/arch/arm64/include/asm/kprobes.h > > >>>> +++ b/arch/arm64/include/asm/kprobes.h > > >>>> @@ -39,6 +39,27 @@ void arch_remove_kprobe(struct kprobe *); > > >>>> int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr); > > >>>> int kprobe_exceptions_notify(struct notifier_block *self, > > >>>> unsigned long val, void *data); > > >>>> + > > >>>> +struct arch_optimized_insn { > > >>>> + kprobe_opcode_t orig_insn[1]; > > >>>> + kprobe_opcode_t *trampoline; > > >>>> +}; > > >>>> + > > >>>> +#define MAX_OPTIMIZED_LENGTH sizeof(kprobe_opcode_t) > > >>>> +#define MAX_OPTINSN_SIZE \ > > >>>> + ((unsigned long)optprobe_template_restore_end - (unsigned long)optprobe_template_entry) > > >>>> + > > >>>> +extern __visible kprobe_opcode_t optprobe_template_entry[]; > > >>>> +extern __visible kprobe_opcode_t optprobe_template_val[]; > > >>>> +extern __visible kprobe_opcode_t optprobe_template_common[]; > > >>>> +extern __visible kprobe_opcode_t optprobe_template_end[]; > > >>>> +extern __visible kprobe_opcode_t optprobe_template_restore_begin[]; > > >>>> +extern __visible kprobe_opcode_t optprobe_template_restore_orig_insn[]; > > >>>> +extern __visible kprobe_opcode_t optprobe_template_restore_end[]; > > >>>> +extern __visible kprobe_opcode_t optinsn_slot[]; > > >>>> + > > >>>> +void optprobe_common(void); > > >>>> + > > >>>> void __kretprobe_trampoline(void); > > >>>> void __kprobes *trampoline_probe_handler(struct pt_regs *regs); > > >>>> > > >>>> diff --git a/arch/arm64/kernel/probes/Makefile b/arch/arm64/kernel/probes/Makefile > > >>>> index 8e4be92e25b1..07105fd3261d 100644 > > >>>> --- a/arch/arm64/kernel/probes/Makefile > > >>>> +++ b/arch/arm64/kernel/probes/Makefile > > >>>> @@ -4,3 +4,5 @@ obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o \ > > >>>> simulate-insn.o > > >>>> obj-$(CONFIG_UPROBES) += uprobes.o decode-insn.o \ > > >>>> simulate-insn.o > > >>>> +obj-$(CONFIG_OPTPROBES) += opt_arm64.o \ > > >>>> + optprobe_trampoline.o > > >>>> diff --git a/arch/arm64/kernel/probes/opt_arm64.c b/arch/arm64/kernel/probes/opt_arm64.c > > >>>> new file mode 100644 > > >>>> index 000000000000..1bad5cddcdf2 > > >>>> --- /dev/null > > >>>> +++ b/arch/arm64/kernel/probes/opt_arm64.c > > >>>> @@ -0,0 +1,199 @@ > > >>>> +// SPDX-License-Identifier: GPL-2.0-only > > >>>> +/* > > >>>> + * Code for Kernel probes Jump optimization. > > >>>> + * > > >>>> + * Copyright (C) 2021 Hisilicon Limited > > >>>> + */ > > >>>> + > > >>>> +#include <linux/jump_label.h> > > >>>> +#include <linux/kprobes.h> > > >>>> + > > >>>> +#include <asm/cacheflush.h> > > >>>> +#include <asm/compiler.h> > > >>>> +#include <asm/insn.h> > > >>>> +#include <asm/kprobes.h> > > >>>> +#include <asm/patching.h> > > >>>> + > > >>>> +#define OPTPROBE_BATCH_SIZE 64 > > >>>> +#define GET_LO_VAL(val) FIELD_GET(GENMASK(31, 0), val) > > >>>> +#define GET_HI_VAL(val) FIELD_GET(GENMASK(63, 32), val) > > >>>> + > > >>>> +#define TMPL_VAL_IDX \ > > >>>> + (optprobe_template_val - optprobe_template_entry) > > >>>> +#define TMPL_CALL_COMMON \ > > >>>> + (optprobe_template_common - optprobe_template_entry) > > >>>> +#define TMPL_RESTORE_ORIGN_INSN \ > > >>>> + (optprobe_template_restore_orig_insn - optprobe_template_entry) > > >>>> +#define TMPL_RESTORE_END \ > > >>>> + (optprobe_template_restore_end - optprobe_template_entry) > > >>>> +#define TMPL_END_IDX \ > > >>>> + (optprobe_template_end - optprobe_template_entry) > > >>>> + > > >>>> +static bool insn_page_in_use; > > >>>> + > > >>>> +void *alloc_optinsn_page(void) > > >>>> +{ > > >>>> + if (insn_page_in_use) > > >>>> + return NULL; > > >>>> + insn_page_in_use = true; > > >>>> + return &optinsn_slot; > > >>>> +} > > >>>> + > > >>>> +void free_optinsn_page(void *page) > > >>>> +{ > > >>>> + insn_page_in_use = false; > > >>>> +} > > >>>> + > > >>>> +int arch_check_optimized_kprobe(struct optimized_kprobe *op) > > >>>> +{ > > >>>> + return 0; > > >>>> +} > > >>>> + > > >>>> +int arch_prepared_optinsn(struct arch_optimized_insn *optinsn) > > >>>> +{ > > >>>> + return optinsn->trampoline != NULL; > > >>>> +} > > >>>> + > > >>>> +int arch_within_optimized_kprobe(struct optimized_kprobe *op, kprobe_opcode_t *addr) > > >>>> +{ > > >>>> + return op->kp.addr == addr; > > >>>> +} > > >>>> + > > >>>> +static void optprobe_set_pc_value(struct optimized_kprobe *op, struct pt_regs *regs) > > >>>> +{ > > >>>> + regs->pc = (unsigned long)op->kp.addr; > > >>>> +} > > >>>> + > > >>>> +static int optprobe_check_branch_limit(unsigned long pc, unsigned long addr) > > >>>> +{ > > >>>> + long offset; > > >>>> + > > >>>> + if ((pc & 0x3) || (addr & 0x3)) > > >>>> + return -ERANGE; > > >>>> + > > >>>> + offset = (long)addr - (long)pc; > > >>>> + if (offset < -SZ_128M || offset >= SZ_128M) > > >>>> + return -ERANGE; > > >>>> + > > >>>> + return 0; > > >>>> +} > > >>>> + > > >>>> +int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *orig) > > >>>> +{ > > >>>> + kprobe_opcode_t *code, *buf; > > >>>> + u32 insn; > > >>>> + int ret = -ENOMEM; > > >>>> + int i; > > >>>> + > > >>>> + buf = kcalloc(MAX_OPTINSN_SIZE, sizeof(kprobe_opcode_t), GFP_KERNEL); > > >>>> + if (!buf) > > >>>> + return ret; > > >>>> + > > >>>> + code = get_optinsn_slot(); > > >>>> + if (!code) > > >>>> + goto out; > > >>>> + > > >>>> + if (optprobe_check_branch_limit((unsigned long)code, (unsigned long)orig->addr + 8)) { > > >>>> + ret = -ERANGE; > > >>>> + goto error; > > >>>> + } > > >>>> + > > >>>> + op->set_pc = optprobe_set_pc_value; > > >>>> + memcpy(buf, optprobe_template_entry, MAX_OPTINSN_SIZE * sizeof(kprobe_opcode_t)); > > >>>> + > > >>>> + insn = aarch64_insn_gen_branch_imm((unsigned long)&code[TMPL_CALL_COMMON], > > >>>> + (unsigned long)&optprobe_common, > > >>>> + AARCH64_INSN_BRANCH_LINK); > > >>>> + buf[TMPL_CALL_COMMON] = insn; > > >>>> + > > >>>> + insn = aarch64_insn_gen_branch_imm((unsigned long)&code[TMPL_RESTORE_END], > > >>>> + (unsigned long)op->kp.addr + 4, > > >>>> + AARCH64_INSN_BRANCH_NOLINK); > > >>>> + buf[TMPL_RESTORE_END] = insn; > > >>>> + > > >>>> + buf[TMPL_VAL_IDX] = cpu_to_le32(GET_LO_VAL((unsigned long)op)); > > >>>> + buf[TMPL_VAL_IDX + 1] = cpu_to_le32(GET_HI_VAL((unsigned long)op)); > > >>>> + buf[TMPL_RESTORE_ORIGN_INSN] = orig->opcode; > > >>>> + > > >>>> + /* Setup template */ > > >>>> + for (i = 0; i < MAX_OPTINSN_SIZE; i++) > > >>>> + aarch64_insn_patch_text_nosync(code + i, buf[i]); > > >>>> + > > >>>> + flush_icache_range((unsigned long)code, (unsigned long)(&code[TMPL_VAL_IDX])); > > >>>> + /* Set op->optinsn.trampoline means prepared. */ > > >>>> + op->optinsn.trampoline = code; > > >>>> + > > >>>> +out: > > >>>> + kfree(buf); > > >>>> + return ret; > > >>>> + > > >>>> +error: > > >>>> + free_optinsn_slot(code, 0); > > >>>> + goto out; > > >>>> +} > > >>>> + > > >>>> +void arch_optimize_kprobes(struct list_head *oplist) > > >>>> +{ > > >>>> + struct optimized_kprobe *op, *tmp; > > >>>> + kprobe_opcode_t insns[OPTPROBE_BATCH_SIZE]; > > >>>> + void *addrs[OPTPROBE_BATCH_SIZE]; > > >>>> + int i = 0; > > >>>> + > > >>>> + list_for_each_entry_safe(op, tmp, oplist, list) { > > >>>> + WARN_ON(kprobe_disabled(&op->kp)); > > >>>> + > > >>>> + /* > > >>>> + * Backup instructions which will be replaced > > >>>> + * by jump address > > >>>> + */ > > >>>> + memcpy(op->optinsn.orig_insn, op->kp.addr, AARCH64_INSN_SIZE); > > >>>> + > > >>>> + addrs[i] = (void *)op->kp.addr; > > >>>> + insns[i] = aarch64_insn_gen_branch_imm((unsigned long)op->kp.addr, > > >>>> + (unsigned long)op->optinsn.trampoline, > > >>>> + AARCH64_INSN_BRANCH_NOLINK); > > >>>> + > > >>>> + list_del_init(&op->list); > > >>>> + if (++i == OPTPROBE_BATCH_SIZE) > > >>>> + break; > > >>>> + } > > >>>> + > > >>>> + aarch64_insn_patch_text(addrs, insns, i); > > >>>> +} > > >>>> + > > >>>> +void arch_unoptimize_kprobe(struct optimized_kprobe *op) > > >>>> +{ > > >>>> + arch_arm_kprobe(&op->kp); > > >>>> +} > > >>>> + > > >>>> +/* > > >>>> + * Recover original instructions and breakpoints from relative jumps. > > >>>> + * Caller must call with locking kprobe_mutex. > > >>>> + */ > > >>>> +void arch_unoptimize_kprobes(struct list_head *oplist, > > >>>> + struct list_head *done_list) > > >>>> +{ > > >>>> + struct optimized_kprobe *op, *tmp; > > >>>> + kprobe_opcode_t insns[OPTPROBE_BATCH_SIZE]; > > >>>> + void *addrs[OPTPROBE_BATCH_SIZE]; > > >>>> + int i = 0; > > >>>> + > > >>>> + list_for_each_entry_safe(op, tmp, oplist, list) { > > >>>> + addrs[i] = (void *)op->kp.addr; > > >>>> + insns[i] = BRK64_OPCODE_KPROBES; > > >>>> + list_move(&op->list, done_list); > > >>>> + > > >>>> + if (++i == OPTPROBE_BATCH_SIZE) > > >>>> + break; > > >>>> + } > > >>>> + > > >>>> + aarch64_insn_patch_text(addrs, insns, i); > > >>>> +} > > >>>> + > > >>>> +void arch_remove_optimized_kprobe(struct optimized_kprobe *op) > > >>>> +{ > > >>>> + if (op->optinsn.trampoline) { > > >>>> + free_optinsn_slot(op->optinsn.trampoline, 1); > > >>>> + op->optinsn.trampoline = NULL; > > >>>> + } > > >>>> +} > > >>>> diff --git a/arch/arm64/kernel/probes/optprobe_trampoline.S b/arch/arm64/kernel/probes/optprobe_trampoline.S > > >>>> new file mode 100644 > > >>>> index 000000000000..1376daeae844 > > >>>> --- /dev/null > > >>>> +++ b/arch/arm64/kernel/probes/optprobe_trampoline.S > > >>>> @@ -0,0 +1,97 @@ > > >>>> +/* SPDX-License-Identifier: GPL-2.0 */ > > >>>> +/* > > >>>> + * trampoline entry and return code for optprobes. > > >>>> + */ > > >>>> + > > >>>> +#include <linux/linkage.h> > > >>>> +#include <asm/asm-offsets.h> > > >>>> +#include <asm/assembler.h> > > >>>> + > > >>>> +#define OPT_SLOT_SIZE 65536 > > >>>> + > > >>>> + .global optinsn_slot > > >>>> +optinsn_slot: > > >>>> + .space OPT_SLOT_SIZE > > >>>> + > > >>>> +SYM_CODE_START(optprobe_common) > > >>>> + stp x2, x3, [sp, #S_X2] > > >>>> + stp x4, x5, [sp, #S_X4] > > >>>> + stp x6, x7, [sp, #S_X6] > > >>>> + stp x8, x9, [sp, #S_X8] > > >>>> + stp x10, x11, [sp, #S_X10] > > >>>> + stp x12, x13, [sp, #S_X12] > > >>>> + stp x14, x15, [sp, #S_X14] > > >>>> + stp x16, x17, [sp, #S_X16] > > >>>> + stp x18, x19, [sp, #S_X18] > > >>>> + stp x20, x21, [sp, #S_X20] > > >>>> + stp x22, x23, [sp, #S_X22] > > >>>> + stp x24, x25, [sp, #S_X24] > > >>>> + stp x26, x27, [sp, #S_X26] > > >>>> + stp x28, x29, [sp, #S_X28] > > >>>> + add x2, sp, #PT_REGS_SIZE > > >>>> + str x2, [sp, #S_SP] > > >>>> + /* Construct a useful saved PSTATE */ > > >>>> + mrs x2, nzcv > > >>>> + mrs x3, daif > > >>>> + orr x2, x2, x3 > > >>>> + mrs x3, CurrentEL > > >>>> + orr x2, x2, x3 > > >>>> + mrs x3, SPSel > > >>>> + orr x2, x2, x3 > > >>>> + stp xzr, x2, [sp, #S_PC] > > >>>> + > > >>>> + /* set the pt_regs address to x1 */ > > >>>> + mov x1, sp > > >>>> + /* store lr of optprobe_common temporary */ > > >>>> + sub sp, sp, #0x10 > > >>>> + str lr, [sp, #0x8] > > >>>> + > > >>>> + bl optprobe_optimized_callback > > >>>> + > > >>>> + ldr lr, [sp, #0x8] > > >>>> + add sp, sp, #0x10 > > >>>> + ldr x0, [sp, #S_PSTATE] > > >>>> + and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT) > > >>>> + msr nzcv, x0 > > >>>> + ldp x0, x1, [sp, #S_X0] > > >>>> + ldp x2, x3, [sp, #S_X2] > > >>>> + ldp x4, x5, [sp, #S_X4] > > >>>> + ldp x6, x7, [sp, #S_X6] > > >>>> + ldp x8, x9, [sp, #S_X8] > > >>>> + ldp x10, x11, [sp, #S_X10] > > >>>> + ldp x12, x13, [sp, #S_X12] > > >>>> + ldp x14, x15, [sp, #S_X14] > > >>>> + ldp x16, x17, [sp, #S_X16] > > >>>> + ldp x18, x19, [sp, #S_X18] > > >>>> + ldp x20, x21, [sp, #S_X20] > > >>>> + ldp x22, x23, [sp, #S_X22] > > >>>> + ldp x24, x25, [sp, #S_X24] > > >>>> + ldp x26, x27, [sp, #S_X26] > > >>>> + ldp x28, x29, [sp, #S_X28] > > >>>> + ret > > >>>> +SYM_CODE_END(optprobe_common) > > >>>> + > > >>>> + .global optprobe_template_entry > > >>>> +optprobe_template_entry: > > >>>> + sub sp, sp, #PT_REGS_SIZE > > >>>> + str lr, [sp, #S_LR] > > >>>> + stp x0, x1, [sp, #S_X0] > > >>>> + /* Get parameters to optimized_callback() */ > > >>>> + ldr x0, 1f > > >>>> + .global optprobe_template_common > > >>>> +optprobe_template_common: > > >>>> + nop > > >>>> + ldr lr, [sp, #S_LR] > > >>>> + add sp, sp, #PT_REGS_SIZE > > >>>> + .global optprobe_template_restore_orig_insn > > >>>> +optprobe_template_restore_orig_insn: > > >>>> + nop > > >>>> + .global optprobe_template_restore_end > > >>>> +optprobe_template_restore_end: > > >>>> + nop > > >>>> + .global optprobe_template_val > > >>>> +optprobe_template_val: > > >>>> + 1: .long 0 > > >>>> + .long 0 > > >>>> + .global optprobe_template_end > > >>>> +optprobe_template_end: > > >>>> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h > > >>>> index 8c8f7a4d93af..7be680155df7 100644 > > >>>> --- a/include/linux/kprobes.h > > >>>> +++ b/include/linux/kprobes.h > > >>>> @@ -329,6 +329,7 @@ struct optimized_kprobe { > > >>>> struct kprobe kp; > > >>>> struct list_head list; /* list for optimizing queue */ > > >>>> struct arch_optimized_insn optinsn; > > >>>> + void (*set_pc)(struct optimized_kprobe *op, struct pt_regs *regs); > > >>>> }; > > >>>> > > >>>> /* Architecture dependent functions for direct jump optimization */ > > >>>> @@ -345,6 +346,7 @@ extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, > > >>>> kprobe_opcode_t *addr); > > >>>> > > >>>> extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); > > >>>> +extern void optprobe_optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs); > > >>>> > > >>>> DEFINE_INSN_CACHE_OPS(optinsn); > > >>>> > > >>>> diff --git a/kernel/kprobes.c b/kernel/kprobes.c > > >>>> index 21eccc961bba..d799e562a39a 100644 > > >>>> --- a/kernel/kprobes.c > > >>>> +++ b/kernel/kprobes.c > > >>>> @@ -430,6 +430,28 @@ void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) > > >>>> } > > >>>> NOKPROBE_SYMBOL(opt_pre_handler); > > >>>> > > >>>> +void optprobe_optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs) > > >>>> +{ > > >>>> + if (kprobe_disabled(&op->kp)) > > >>>> + return; > > >>>> + > > >>>> + preempt_disable(); > > >>>> + > > >>>> + if (kprobe_running()) { > > >>>> + kprobes_inc_nmissed_count(&op->kp); > > >>>> + } else { > > >>>> + op->set_pc(op, regs); > > >>>> + __this_cpu_write(current_kprobe, &op->kp); > > >>>> + get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; > > >>>> + opt_pre_handler(&op->kp, regs); > > >>>> + __this_cpu_write(current_kprobe, NULL); > > >>>> + } > > >>>> + > > >>>> + preempt_enable(); > > >>>> +} > > >>>> +NOKPROBE_SYMBOL(optprobe_optimized_callback) > > >>>> + > > >>>> + > > >>>> /* Free optimized instructions and optimized_kprobe */ > > >>>> static void free_aggr_kprobe(struct kprobe *p) > > >>>> { > > >>>> -- > > >>>> 2.33.0 > > >>>> > > >> > > >> > > >> -- > > >> Masami Hiramatsu <mhiramat@kernel.org> > > > . > > >
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