Commit 01af50af authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 

Pull arm64 fixes from Catalin Marinas:

 - arm64 stacktrace: address some fallout from the recent changes to
   unwinding across exception boundaries

 - Ensure the arm64 signal delivery failure is recoverable - only
   override the return registers after all the user accesses took place

 - Fix the arm64 kselftest access to SVCR - only when SME is detected

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  kselftest/arm64: abi: fix SVCR detection
  arm64: signal: Ensure signal delivery failure is recoverable
  arm64: stacktrace: Don't WARN when unwinding other tasks
  arm64: stacktrace: Skip reporting LR at exception boundaries
parents a5b3d5df ce03573a

arch/arm64/kernel/signal.c

+33 −15
Original line number Diff line number Diff line
@@ -1462,10 +1462,33 @@ static int setup_return(struct pt_regs *regs, struct ksignal *ksig, 
			 struct rt_sigframe_user_layout *user, int usig)

{

	__sigrestore_t sigtramp;

	int err;



	if (ksig->ka.sa.sa_flags & SA_RESTORER)

		sigtramp = ksig->ka.sa.sa_restorer;

	else

		sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);



	err = gcs_signal_entry(sigtramp, ksig);

	if (err)

		return err;



	/*

	 * We must not fail from this point onwards. We are going to update

	 * registers, including SP, in order to invoke the signal handler. If

	 * we failed and attempted to deliver a nested SIGSEGV to a handler

	 * after that point, the subsequent sigreturn would end up restoring

	 * the (partial) state for the original signal handler.

	 */



	regs->regs[0] = usig;

	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {

		regs->regs[1] = (unsigned long)&user->sigframe->info;

		regs->regs[2] = (unsigned long)&user->sigframe->uc;

	}

	regs->sp = (unsigned long)user->sigframe;

	regs->regs[29] = (unsigned long)&user->next_frame->fp;

	regs->regs[30] = (unsigned long)sigtramp;

	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;



	/*
@@ -1506,14 +1529,7 @@ static int setup_return(struct pt_regs *regs, struct ksignal *ksig, 
		sme_smstop();

	}



	if (ksig->ka.sa.sa_flags & SA_RESTORER)

		sigtramp = ksig->ka.sa.sa_restorer;

	else

		sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);



	regs->regs[30] = (unsigned long)sigtramp;



	return gcs_signal_entry(sigtramp, ksig);

	return 0;

}



static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
@@ -1537,14 +1553,16 @@ static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set, 


	err |= __save_altstack(&frame->uc.uc_stack, regs->sp);

	err |= setup_sigframe(&user, regs, set, &ua_state);

	if (err == 0) {

		err = setup_return(regs, ksig, &user, usig);

		if (ksig->ka.sa.sa_flags & SA_SIGINFO) {

	if (ksig->ka.sa.sa_flags & SA_SIGINFO)

		err |= copy_siginfo_to_user(&frame->info, &ksig->info);

			regs->regs[1] = (unsigned long)&frame->info;

			regs->regs[2] = (unsigned long)&frame->uc;

		}

	}



	if (err == 0)

		err = setup_return(regs, ksig, &user, usig);



	/*

	 * We must not fail if setup_return() succeeded - see comment at the

	 * beginning of setup_return().

	 */



	if (err == 0)

		set_handler_user_access_state();

arch/arm64/kernel/stacktrace.c

+7 −25
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ enum kunwind_source { 
	KUNWIND_SOURCE_CALLER,

	KUNWIND_SOURCE_TASK,

	KUNWIND_SOURCE_REGS_PC,

	KUNWIND_SOURCE_REGS_LR,

};



union unwind_flags {
@@ -138,8 +137,10 @@ kunwind_recover_return_address(struct kunwind_state *state) 
		orig_pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,

						state->common.pc,

						(void *)state->common.fp);

		if (WARN_ON_ONCE(state->common.pc == orig_pc))

		if (state->common.pc == orig_pc) {

			WARN_ON_ONCE(state->task == current);

			return -EINVAL;

		}

		state->common.pc = orig_pc;

		state->flags.fgraph = 1;

	}
@@ -178,23 +179,8 @@ int kunwind_next_regs_pc(struct kunwind_state *state) 
	state->regs = regs;

	state->common.pc = regs->pc;

	state->common.fp = regs->regs[29];

	state->source = KUNWIND_SOURCE_REGS_PC;

	return 0;

}



static __always_inline int

kunwind_next_regs_lr(struct kunwind_state *state)

{

	/*

	 * The stack for the regs was consumed by kunwind_next_regs_pc(), so we

	 * cannot consume that again here, but we know the regs are safe to

	 * access.

	 */

	state->common.pc = state->regs->regs[30];

	state->common.fp = state->regs->regs[29];

	state->regs = NULL;

	state->source = KUNWIND_SOURCE_REGS_LR;



	state->source = KUNWIND_SOURCE_REGS_PC;

	return 0;

}
@@ -215,12 +201,12 @@ kunwind_next_frame_record_meta(struct kunwind_state *state) 
	case FRAME_META_TYPE_FINAL:

		if (meta == &task_pt_regs(tsk)->stackframe)

			return -ENOENT;

		WARN_ON_ONCE(1);

		WARN_ON_ONCE(tsk == current);

		return -EINVAL;

	case FRAME_META_TYPE_PT_REGS:

		return kunwind_next_regs_pc(state);

	default:

		WARN_ON_ONCE(1);

		WARN_ON_ONCE(tsk == current);

		return -EINVAL;

	}

}
@@ -274,11 +260,8 @@ kunwind_next(struct kunwind_state *state) 
	case KUNWIND_SOURCE_FRAME:

	case KUNWIND_SOURCE_CALLER:

	case KUNWIND_SOURCE_TASK:

	case KUNWIND_SOURCE_REGS_LR:

		err = kunwind_next_frame_record(state);

		break;

	case KUNWIND_SOURCE_REGS_PC:

		err = kunwind_next_regs_lr(state);

		err = kunwind_next_frame_record(state);

		break;

	default:

		err = -EINVAL;
@@ -436,7 +419,6 @@ static const char *state_source_string(const struct kunwind_state *state) 
	case KUNWIND_SOURCE_CALLER:	return "C";

	case KUNWIND_SOURCE_TASK:	return "T";

	case KUNWIND_SOURCE_REGS_PC:	return "P";

	case KUNWIND_SOURCE_REGS_LR:	return "L";

	default:			return "U";

	}

}

tools/testing/selftests/arm64/abi/syscall-abi-asm.S

+15 −17
Original line number Diff line number Diff line
@@ -81,32 +81,31 @@ do_syscall: 
	stp	x27, x28, [sp, #96]



	// Set SVCR if we're doing SME

	cbz	x1, 1f

	cbz	x1, load_gpr

	adrp	x2, svcr_in

	ldr	x2, [x2, :lo12:svcr_in]

	msr	S3_3_C4_C2_2, x2

1:



	// Load ZA and ZT0 if enabled - uses x12 as scratch due to SME LDR

	tbz	x2, #SVCR_ZA_SHIFT, 1f

	tbz	x2, #SVCR_ZA_SHIFT, load_gpr

	mov	w12, #0

	ldr	x2, =za_in

2:	_ldr_za 12, 2

1:	_ldr_za 12, 2

	add	x2, x2, x1

	add	x12, x12, #1

	cmp	x1, x12

	bne	2b

	bne	1b



	// ZT0

	mrs	x2, S3_0_C0_C4_5	// ID_AA64SMFR0_EL1

	ubfx	x2, x2, #ID_AA64SMFR0_EL1_SMEver_SHIFT, \

			 #ID_AA64SMFR0_EL1_SMEver_WIDTH

	cbz	x2, 1f

	cbz	x2, load_gpr

	adrp	x2, zt_in

	add	x2, x2, :lo12:zt_in

	_ldr_zt 2

1:



load_gpr:

	// Load GPRs x8-x28, and save our SP/FP for later comparison

	ldr	x2, =gpr_in

	add	x2, x2, #64
@@ -125,9 +124,9 @@ do_syscall: 
	str	x30, [x2], #8		// LR



	// Load FPRs if we're not doing neither SVE nor streaming SVE

	cbnz	x0, 1f

	cbnz	x0, check_sve_in

	ldr	x2, =svcr_in

	tbnz	x2, #SVCR_SM_SHIFT, 1f

	tbnz	x2, #SVCR_SM_SHIFT, check_sve_in



	ldr	x2, =fpr_in

	ldp	q0, q1, [x2]
@@ -148,8 +147,8 @@ do_syscall: 
	ldp	q30, q31, [x2, #16 * 30]



	b	2f

1:



check_sve_in:

	// Load the SVE registers if we're doing SVE/SME



	ldr	x2, =z_in
@@ -256,32 +255,31 @@ do_syscall: 
	stp	q30, q31, [x2, #16 * 30]



	// Save SVCR if we're doing SME

	cbz	x1, 1f

	cbz	x1, check_sve_out

	mrs	x2, S3_3_C4_C2_2

	adrp	x3, svcr_out

	str	x2, [x3, :lo12:svcr_out]

1:



	// Save ZA if it's enabled - uses x12 as scratch due to SME STR

	tbz	x2, #SVCR_ZA_SHIFT, 1f

	tbz	x2, #SVCR_ZA_SHIFT, check_sve_out

	mov	w12, #0

	ldr	x2, =za_out

2:	_str_za 12, 2

1:	_str_za 12, 2

	add	x2, x2, x1

	add	x12, x12, #1

	cmp	x1, x12

	bne	2b

	bne	1b



	// ZT0

	mrs	x2, S3_0_C0_C4_5	// ID_AA64SMFR0_EL1

	ubfx	x2, x2, #ID_AA64SMFR0_EL1_SMEver_SHIFT, \

			#ID_AA64SMFR0_EL1_SMEver_WIDTH

	cbz	x2, 1f

	cbz	x2, check_sve_out

	adrp	x2, zt_out

	add	x2, x2, :lo12:zt_out

	_str_zt 2

1:



check_sve_out:

	// Save the SVE state if we have some

	cbz	x0, 1f