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Commit 44b53f67 authored by Pratyush Anand's avatar Pratyush Anand Committed by Catalin Marinas
Browse files

arm64: Blacklist non-kprobe-able symbol 



Add all function symbols which are called from do_debug_exception under
NOKPROBE_SYMBOL, as they can not kprobed.

Signed-off-by: default avatarPratyush Anand <panand@redhat.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 2dd0e8d2

arch/arm64/kernel/arm64ksyms.c

+2 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/uaccess.h>

#include <linux/io.h>

#include <linux/arm-smccc.h>

#include <linux/kprobes.h>



#include <asm/checksum.h>
@@ -68,6 +69,7 @@ EXPORT_SYMBOL(test_and_change_bit); 


#ifdef CONFIG_FUNCTION_TRACER

EXPORT_SYMBOL(_mcount);

NOKPROBE_SYMBOL(_mcount);

#endif



	/* arm-smccc */

arch/arm64/kernel/debug-monitors.c

+17 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ static void mdscr_write(u32 mdscr) 
	asm volatile("msr mdscr_el1, %0" :: "r" (mdscr));

	local_dbg_restore(flags);

}

NOKPROBE_SYMBOL(mdscr_write);



static u32 mdscr_read(void)

{
@@ -56,6 +57,7 @@ static u32 mdscr_read(void) 
	asm volatile("mrs %0, mdscr_el1" : "=r" (mdscr));

	return mdscr;

}

NOKPROBE_SYMBOL(mdscr_read);



/*

 * Allow root to disable self-hosted debug from userspace.
@@ -104,6 +106,7 @@ void enable_debug_monitors(enum dbg_active_el el) 
		mdscr_write(mdscr);

	}

}

NOKPROBE_SYMBOL(enable_debug_monitors);



void disable_debug_monitors(enum dbg_active_el el)

{
@@ -124,6 +127,7 @@ void disable_debug_monitors(enum dbg_active_el el) 
		mdscr_write(mdscr);

	}

}

NOKPROBE_SYMBOL(disable_debug_monitors);



/*

 * OS lock clearing.
@@ -174,6 +178,7 @@ static void set_regs_spsr_ss(struct pt_regs *regs) 
	spsr |= DBG_SPSR_SS;

	regs->pstate = spsr;

}

NOKPROBE_SYMBOL(set_regs_spsr_ss);



static void clear_regs_spsr_ss(struct pt_regs *regs)

{
@@ -183,6 +188,7 @@ static void clear_regs_spsr_ss(struct pt_regs *regs) 
	spsr &= ~DBG_SPSR_SS;

	regs->pstate = spsr;

}

NOKPROBE_SYMBOL(clear_regs_spsr_ss);



/* EL1 Single Step Handler hooks */

static LIST_HEAD(step_hook);
@@ -226,6 +232,7 @@ static int call_step_hook(struct pt_regs *regs, unsigned int esr) 


	return retval;

}

NOKPROBE_SYMBOL(call_step_hook);



static void send_user_sigtrap(int si_code)

{
@@ -284,6 +291,7 @@ static int single_step_handler(unsigned long addr, unsigned int esr, 


	return 0;

}

NOKPROBE_SYMBOL(single_step_handler);



/*

 * Breakpoint handler is re-entrant as another breakpoint can
@@ -321,6 +329,7 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr) 


	return fn ? fn(regs, esr) : DBG_HOOK_ERROR;

}

NOKPROBE_SYMBOL(call_break_hook);



static int brk_handler(unsigned long addr, unsigned int esr,

		       struct pt_regs *regs)
@@ -341,6 +350,7 @@ static int brk_handler(unsigned long addr, unsigned int esr, 


	return 0;

}

NOKPROBE_SYMBOL(brk_handler);



int aarch32_break_handler(struct pt_regs *regs)

{
@@ -377,6 +387,7 @@ int aarch32_break_handler(struct pt_regs *regs) 
	send_user_sigtrap(TRAP_BRKPT);

	return 0;

}

NOKPROBE_SYMBOL(aarch32_break_handler);



static int __init debug_traps_init(void)

{
@@ -398,6 +409,7 @@ void user_rewind_single_step(struct task_struct *task) 
	if (test_ti_thread_flag(task_thread_info(task), TIF_SINGLESTEP))

		set_regs_spsr_ss(task_pt_regs(task));

}

NOKPROBE_SYMBOL(user_rewind_single_step);



void user_fastforward_single_step(struct task_struct *task)

{
@@ -413,6 +425,7 @@ void kernel_enable_single_step(struct pt_regs *regs) 
	mdscr_write(mdscr_read() | DBG_MDSCR_SS);

	enable_debug_monitors(DBG_ACTIVE_EL1);

}

NOKPROBE_SYMBOL(kernel_enable_single_step);



void kernel_disable_single_step(void)

{
@@ -420,12 +433,14 @@ void kernel_disable_single_step(void) 
	mdscr_write(mdscr_read() & ~DBG_MDSCR_SS);

	disable_debug_monitors(DBG_ACTIVE_EL1);

}

NOKPROBE_SYMBOL(kernel_disable_single_step);



int kernel_active_single_step(void)

{

	WARN_ON(!irqs_disabled());

	return mdscr_read() & DBG_MDSCR_SS;

}

NOKPROBE_SYMBOL(kernel_active_single_step);



/* ptrace API */

void user_enable_single_step(struct task_struct *task)
@@ -433,8 +448,10 @@ void user_enable_single_step(struct task_struct *task) 
	set_ti_thread_flag(task_thread_info(task), TIF_SINGLESTEP);

	set_regs_spsr_ss(task_pt_regs(task));

}

NOKPROBE_SYMBOL(user_enable_single_step);



void user_disable_single_step(struct task_struct *task)

{

	clear_ti_thread_flag(task_thread_info(task), TIF_SINGLESTEP);

}

NOKPROBE_SYMBOL(user_disable_single_step);

arch/arm64/kernel/hw_breakpoint.c

+8 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/cpu_pm.h>

#include <linux/errno.h>

#include <linux/hw_breakpoint.h>

#include <linux/kprobes.h>

#include <linux/perf_event.h>

#include <linux/ptrace.h>

#include <linux/smp.h>
@@ -127,6 +128,7 @@ static u64 read_wb_reg(int reg, int n) 


	return val;

}

NOKPROBE_SYMBOL(read_wb_reg);



static void write_wb_reg(int reg, int n, u64 val)

{
@@ -140,6 +142,7 @@ static void write_wb_reg(int reg, int n, u64 val) 
	}

	isb();

}

NOKPROBE_SYMBOL(write_wb_reg);



/*

 * Convert a breakpoint privilege level to the corresponding exception
@@ -157,6 +160,7 @@ static enum dbg_active_el debug_exception_level(int privilege) 
		return -EINVAL;

	}

}

NOKPROBE_SYMBOL(debug_exception_level);



enum hw_breakpoint_ops {

	HW_BREAKPOINT_INSTALL,
@@ -575,6 +579,7 @@ static void toggle_bp_registers(int reg, enum dbg_active_el el, int enable) 
		write_wb_reg(reg, i, ctrl);

	}

}

NOKPROBE_SYMBOL(toggle_bp_registers);



/*

 * Debug exception handlers.
@@ -654,6 +659,7 @@ static int breakpoint_handler(unsigned long unused, unsigned int esr, 


	return 0;

}

NOKPROBE_SYMBOL(breakpoint_handler);



static int watchpoint_handler(unsigned long addr, unsigned int esr,

			      struct pt_regs *regs)
@@ -756,6 +762,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr, 


	return 0;

}

NOKPROBE_SYMBOL(watchpoint_handler);



/*

 * Handle single-step exception.
@@ -813,6 +820,7 @@ int reinstall_suspended_bps(struct pt_regs *regs) 


	return !handled_exception;

}

NOKPROBE_SYMBOL(reinstall_suspended_bps);



/*

 * Context-switcher for restoring suspended breakpoints.

arch/arm64/kernel/kgdb.c

+4 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/irq.h>

#include <linux/kdebug.h>

#include <linux/kgdb.h>

#include <linux/kprobes.h>

#include <asm/traps.h>



struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
@@ -230,6 +231,7 @@ static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr) 
	kgdb_handle_exception(1, SIGTRAP, 0, regs);

	return 0;

}

NOKPROBE_SYMBOL(kgdb_brk_fn)



static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr)

{
@@ -238,12 +240,14 @@ static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr) 


	return 0;

}

NOKPROBE_SYMBOL(kgdb_compiled_brk_fn);



static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)

{

	kgdb_handle_exception(1, SIGTRAP, 0, regs);

	return 0;

}

NOKPROBE_SYMBOL(kgdb_step_brk_fn);



static struct break_hook kgdb_brkpt_hook = {

	.esr_mask	= 0xffffffff,