Commit 83acdce6 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Alexei Starovoitov
Browse files

arm64: rethook: Add arm64 rethook implementation 



Add rethook arm64 implementation. Most of the code has been copied from
kretprobes on arm64.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735287344.1084943.9787335632585653418.stgit@devnote2
parent 75caf33e

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -201,6 +201,7 @@ config ARM64 
	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_KPROBES

	select HAVE_KRETPROBES

	select HAVE_RETHOOK

	select HAVE_GENERIC_VDSO

	select IOMMU_DMA if IOMMU_SUPPORT

	select IRQ_DOMAIN

arch/arm64/include/asm/stacktrace.h

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ struct stackframe { 
	DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);

	unsigned long prev_fp;

	enum stack_type prev_type;

#ifdef CONFIG_KRETPROBES

#if defined(CONFIG_KRETPROBES) || defined(CONFIG_RETHOOK)

	struct llist_node *kr_cur;

#endif

};

arch/arm64/kernel/probes/Makefile

+1 −0
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@@ -4,3 +4,4 @@ obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o \ 
				   simulate-insn.o

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

				   simulate-insn.o

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

arch/arm64/kernel/probes/rethook.c

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// SPDX-License-Identifier: GPL-2.0-only

/*

 * Generic return hook for arm64.

 * Most of the code is copied from arch/arm64/kernel/probes/kprobes.c

 */



#include <linux/kprobes.h>

#include <linux/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->regs[29]);

}

NOKPROBE_SYMBOL(arch_rethook_trampoline_callback);



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

{

	rhn->ret_addr = regs->regs[30];

	rhn->frame = regs->regs[29];



	/* replace return addr (x30) with trampoline */

	regs->regs[30] = (u64)arch_rethook_trampoline;

}

NOKPROBE_SYMBOL(arch_rethook_prepare);

arch/arm64/kernel/probes/rethook_trampoline.S

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/* SPDX-License-Identifier: GPL-2.0 */

/*

 * trampoline entry and return code for rethook.

 * Copied from arch/arm64/kernel/probes/kprobes_trampoline.S

 */



#include <linux/linkage.h>

#include <asm/asm-offsets.h>

#include <asm/assembler.h>



	.text



	.macro	save_all_base_regs

	stp x0, x1, [sp, #S_X0]

	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 x0, sp, #PT_REGS_SIZE

	stp lr, x0, [sp, #S_LR]

	/*

	 * Construct a useful saved PSTATE

	 */

	mrs x0, nzcv

	mrs x1, daif

	orr x0, x0, x1

	mrs x1, CurrentEL

	orr x0, x0, x1

	mrs x1, SPSel

	orr x0, x0, x1

	stp xzr, x0, [sp, #S_PC]

	.endm



	.macro	restore_all_base_regs

	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]

	.endm



SYM_CODE_START(arch_rethook_trampoline)

	sub sp, sp, #PT_REGS_SIZE



	save_all_base_regs



	/* Setup a frame pointer. */

	add x29, sp, #S_FP



	mov x0, sp

	bl arch_rethook_trampoline_callback

	/*

	 * Replace trampoline address in lr with actual orig_ret_addr return

	 * address.

	 */

	mov lr, x0



	/* The frame pointer (x29) is restored with other registers. */

	restore_all_base_regs



	add sp, sp, #PT_REGS_SIZE

	ret



SYM_CODE_END(arch_rethook_trampoline)