Unverified Commit 33081722 authored by Jinjie Ruan's avatar Jinjie Ruan Committed by Palmer Dabbelt
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trace: riscv: Remove deprecated kprobe on ftrace support 



Since commit 7caa9765 ("ftrace: riscv: move from REGS to ARGS"),
kprobe on ftrace is not supported by riscv, because riscv's support for
FTRACE_WITH_REGS has been replaced with support for FTRACE_WITH_ARGS, and
KPROBES_ON_FTRACE will be supplanted by FPROBES. So remove the deprecated
kprobe on ftrace support, which is misunderstood.

Signed-off-by: default avatarJinjie Ruan <ruanjinjie@huawei.com>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240613111347.1745379-1-ruanjinjie@huawei.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent b9a603da

arch/riscv/Kconfig

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Original line number Diff line number Diff line
@@ -154,7 +154,6 @@ config RISCV 
	select HAVE_KERNEL_UNCOMPRESSED if !XIP_KERNEL && !EFI_ZBOOT

	select HAVE_KERNEL_ZSTD if !XIP_KERNEL && !EFI_ZBOOT

	select HAVE_KPROBES if !XIP_KERNEL

	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL

	select HAVE_KRETPROBES if !XIP_KERNEL

	# https://github.com/ClangBuiltLinux/linux/issues/1881

	select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD

arch/riscv/kernel/probes/Makefile

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Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

obj-$(CONFIG_KPROBES)		+= kprobes.o decode-insn.o simulate-insn.o

obj-$(CONFIG_RETHOOK)		+= rethook.o rethook_trampoline.o

obj-$(CONFIG_KPROBES_ON_FTRACE)	+= ftrace.o

obj-$(CONFIG_UPROBES)		+= uprobes.o decode-insn.o simulate-insn.o

CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_rethook.o = $(CC_FLAGS_FTRACE)

arch/riscv/kernel/probes/ftrace.c

deleted100644 → 0
+0 −65
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <linux/kprobes.h>



/* Ftrace callback handler for kprobes -- called under preepmt disabled */

void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,

			   struct ftrace_ops *ops, struct ftrace_regs *fregs)

{

	struct kprobe *p;

	struct pt_regs *regs;

	struct kprobe_ctlblk *kcb;

	int bit;



	if (unlikely(kprobe_ftrace_disabled))

		return;



	bit = ftrace_test_recursion_trylock(ip, parent_ip);

	if (bit < 0)

		return;



	p = get_kprobe((kprobe_opcode_t *)ip);

	if (unlikely(!p) || kprobe_disabled(p))

		goto out;



	regs = ftrace_get_regs(fregs);

	kcb = get_kprobe_ctlblk();

	if (kprobe_running()) {

		kprobes_inc_nmissed_count(p);

	} else {

		unsigned long orig_ip = instruction_pointer(regs);



		instruction_pointer_set(regs, ip);



		__this_cpu_write(current_kprobe, p);

		kcb->kprobe_status = KPROBE_HIT_ACTIVE;

		if (!p->pre_handler || !p->pre_handler(p, regs)) {

			/*

			 * Emulate singlestep (and also recover regs->pc)

			 * as if there is a nop

			 */

			instruction_pointer_set(regs,

				(unsigned long)p->addr + MCOUNT_INSN_SIZE);

			if (unlikely(p->post_handler)) {

				kcb->kprobe_status = KPROBE_HIT_SSDONE;

				p->post_handler(p, regs, 0);

			}

			instruction_pointer_set(regs, orig_ip);

		}



		/*

		 * If pre_handler returns !0, it changes regs->pc. We have to

		 * skip emulating post_handler.

		 */

		__this_cpu_write(current_kprobe, NULL);

	}

out:

	ftrace_test_recursion_unlock(bit);

}

NOKPROBE_SYMBOL(kprobe_ftrace_handler);



int arch_prepare_kprobe_ftrace(struct kprobe *p)

{

	p->ainsn.api.insn = NULL;

	return 0;

}