Commit 390bf177 authored by Andre Przywara's avatar Andre Przywara Committed by Catalin Marinas
Browse files

arm64: consolidate signal injection on emulation errors 



The code for injecting a signal into userland if a trapped instruction
fails emulation due to a _userland_ error (like an illegal address)
will be used more often with the next patch.
Factor out the core functionality into a separate function and use
that both for the existing trap handler and for the deprecated
instructions emulation.

Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
[catalin.marinas@arm.com: s/set_segfault/arm64_notify_segfault/]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 8e231852

arch/arm64/include/asm/traps.h

+2 −0
Original line number Diff line number Diff line
@@ -34,6 +34,8 @@ struct undef_hook { 
void register_undef_hook(struct undef_hook *hook);

void unregister_undef_hook(struct undef_hook *hook);



void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr);



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

static inline int __in_irqentry_text(unsigned long ptr)

{

arch/arm64/kernel/armv8_deprecated.c

+2 −23
Original line number Diff line number Diff line
@@ -316,28 +316,6 @@ static void __init register_insn_emulation_sysctl(struct ctl_table *table) 
 */

#define TYPE_SWPB (1 << 22)



/*

 * Set up process info to signal segmentation fault - called on access error.

 */

static void set_segfault(struct pt_regs *regs, unsigned long addr)

{

	siginfo_t info;



	down_read(&current->mm->mmap_sem);

	if (find_vma(current->mm, addr) == NULL)

		info.si_code = SEGV_MAPERR;

	else

		info.si_code = SEGV_ACCERR;

	up_read(&current->mm->mmap_sem);



	info.si_signo = SIGSEGV;

	info.si_errno = 0;

	info.si_addr  = (void *) instruction_pointer(regs);



	pr_debug("SWP{B} emulation: access caused memory abort!\n");

	arm64_notify_die("Illegal memory access", regs, &info, 0);

}



static int emulate_swpX(unsigned int address, unsigned int *data,

			unsigned int type)

{
@@ -430,7 +408,8 @@ ret: 
	return 0;



fault:

	set_segfault(regs, address);

	pr_debug("SWP{B} emulation: access caused memory abort!\n");

	arm64_notify_segfault(regs, address);



	return 0;

}

arch/arm64/kernel/traps.c

+50 −13
Original line number Diff line number Diff line
@@ -364,30 +364,67 @@ exit: 
	return fn ? fn(regs, instr) : 1;

}



asmlinkage void __exception do_undefinstr(struct pt_regs *regs)

static void force_signal_inject(int signal, int code, struct pt_regs *regs,

				unsigned long address)

{

	siginfo_t info;

	void __user *pc = (void __user *)instruction_pointer(regs);

	const char *desc;



	/* check for AArch32 breakpoint instructions */

	if (!aarch32_break_handler(regs))

		return;



	if (call_undef_hook(regs) == 0)

		return;

	switch (signal) {

	case SIGILL:

		desc = "undefined instruction";

		break;

	case SIGSEGV:

		desc = "illegal memory access";

		break;

	default:

		desc = "bad mode";

		break;

	}



	if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) {

		pr_info("%s[%d]: undefined instruction: pc=%p\n",

			current->comm, task_pid_nr(current), pc);

	if (unhandled_signal(current, signal) &&

	    show_unhandled_signals_ratelimited()) {

		pr_info("%s[%d]: %s: pc=%p\n",

			current->comm, task_pid_nr(current), desc, pc);

		dump_instr(KERN_INFO, regs);

	}



	info.si_signo = SIGILL;

	info.si_signo = signal;

	info.si_errno = 0;

	info.si_code  = ILL_ILLOPC;

	info.si_code  = code;

	info.si_addr  = pc;



	arm64_notify_die("Oops - undefined instruction", regs, &info, 0);

	arm64_notify_die(desc, regs, &info, 0);

}



/*

 * Set up process info to signal segmentation fault - called on access error.

 */

void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)

{

	int code;



	down_read(&current->mm->mmap_sem);

	if (find_vma(current->mm, addr) == NULL)

		code = SEGV_MAPERR;

	else

		code = SEGV_ACCERR;

	up_read(&current->mm->mmap_sem);



	force_signal_inject(SIGSEGV, code, regs, addr);

}



asmlinkage void __exception do_undefinstr(struct pt_regs *regs)

{

	/* check for AArch32 breakpoint instructions */

	if (!aarch32_break_handler(regs))

		return;



	if (call_undef_hook(regs) == 0)

		return;



	force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);

}



long compat_arm_syscall(struct pt_regs *regs);

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