Unverified Commit b57c2f12 authored by Binglei Wang's avatar Binglei Wang Committed by Palmer Dabbelt
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riscv: add riscv rethook implementation 



Implement the kretprobes on riscv arch by using rethook machenism
which abstracts general kretprobe info into a struct rethook_node
to be embedded in the struct kretprobe_instance.

Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarBinglei Wang <l3b2w1@gmail.com>
Signed-off-by: default avatarConor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221025151831.1097417-1-conor@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent d8bf77a1

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ config RISCV 
	select HAVE_KPROBES if !XIP_KERNEL

	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL

	select HAVE_KRETPROBES if !XIP_KERNEL

	select HAVE_RETHOOK if !XIP_KERNEL

	select HAVE_MOVE_PMD

	select HAVE_MOVE_PUD

	select HAVE_PCI

arch/riscv/include/asm/kprobes.h

+0 −2
Original line number Diff line number Diff line
@@ -40,8 +40,6 @@ void arch_remove_kprobe(struct kprobe *p); 
int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);

bool kprobe_breakpoint_handler(struct pt_regs *regs);

bool kprobe_single_step_handler(struct pt_regs *regs);

void __kretprobe_trampoline(void);

void __kprobes *trampoline_probe_handler(struct pt_regs *regs);



#endif /* CONFIG_KPROBES */

#endif /* _ASM_RISCV_KPROBES_H */

arch/riscv/kernel/probes/Makefile

+1 −1
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_KPROBES)		+= kprobes_trampoline.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)

arch/riscv/kernel/probes/kprobes.c

+0 −13
Original line number Diff line number Diff line
@@ -345,19 +345,6 @@ int __init arch_populate_kprobe_blacklist(void) 
	return ret;

}



void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)

{

	return (void *)kretprobe_trampoline_handler(regs, NULL);

}



void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,

				      struct pt_regs *regs)

{

	ri->ret_addr = (kprobe_opcode_t *)regs->ra;

	ri->fp = NULL;

	regs->ra = (unsigned long) &__kretprobe_trampoline;

}



int __kprobes arch_trampoline_kprobe(struct kprobe *p)

{

	return 0;

arch/riscv/kernel/probes/rethook.c

0 → 100644
+27 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Generic return hook for riscv.

 */



#include <linux/kprobes.h>

#include <linux/rethook.h>

#include "rethook.h"



/* This is called from arch_rethook_trampoline() */

unsigned long __used arch_rethook_trampoline_callback(struct pt_regs *regs)

{

	return rethook_trampoline_handler(regs, regs->s0);

}



NOKPROBE_SYMBOL(arch_rethook_trampoline_callback);



void arch_rethook_prepare(struct rethook_node *rhn, struct pt_regs *regs, bool mcount)

{

	rhn->ret_addr = regs->ra;

	rhn->frame = regs->s0;



	/* replace return addr with trampoline */

	regs->ra = (unsigned long)arch_rethook_trampoline;

}



NOKPROBE_SYMBOL(arch_rethook_prepare);