Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM updates from Russell King:
 "The main item in this pull request are the Spectre variant 1.1 fixes
  from Julien Thierry.

  A few other patches to improve various areas, and removal of some
  obsolete mcount bits and a redundant kbuild conditional"

* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8802/1: Call syscall_trace_exit even when system call skipped
  ARM: 8797/1: spectre-v1.1: harden __copy_to_user
  ARM: 8796/1: spectre-v1,v1.1: provide helpers for address sanitization
  ARM: 8795/1: spectre-v1.1: use put_user() for __put_user()
  ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit
  ARM: 8793/1: signal: replace __put_user_error with __put_user
  ARM: 8792/1: oabi-compat: copy oabi events using __copy_to_user()
  ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state
  ARM: 8790/1: signal: always use __copy_to_user to save iwmmxt context
  ARM: 8789/1: signal: copy registers using __copy_to_user()
  ARM: 8801/1: makefile: use ARMv3M mode for RiscPC
  ARM: 8800/1: use choice for kernel unwinders
  ARM: 8798/1: remove unnecessary KBUILD_SRC ifeq conditional
  ARM: 8788/1: ftrace: remove old mcount support
  ARM: 8786/1: Debug kernel copy by printing

6 files changed, 58 insertions, 168 deletions

diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index 783fbb4de5f9..8fa2dc21d332 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -167,9 +167,6 @@ EXPORT_SYMBOL(_find_next_bit_be);
 #endif
 
 #ifdef CONFIG_FUNCTION_TRACER
-#ifdef CONFIG_OLD_MCOUNT
-EXPORT_SYMBOL(mcount);
-#endif
 EXPORT_SYMBOL(__gnu_mcount_nc);
 #endif
 
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 746565a876dc..0465d65d23de 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -296,16 +296,15 @@ __sys_trace:
 	cmp	scno, #-1			@ skip the syscall?
 	bne	2b
 	add	sp, sp, #S_OFF			@ restore stack
-	b	ret_slow_syscall
 
-__sys_trace_return:
-	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
+__sys_trace_return_nosave:
+	enable_irq_notrace
 	mov	r0, sp
 	bl	syscall_trace_exit
 	b	ret_slow_syscall
 
-__sys_trace_return_nosave:
-	enable_irq_notrace
+__sys_trace_return:
+	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
 	mov	r0, sp
 	bl	syscall_trace_exit
 	b	ret_slow_syscall
diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S
index efcd9f25a14b..0be69e551a64 100644
--- a/arch/arm/kernel/entry-ftrace.S
+++ b/arch/arm/kernel/entry-ftrace.S
@@ -15,23 +15,8 @@
  * start of every function.  In mcount, apart from the function's address (in
  * lr), we need to get hold of the function's caller's address.
  *
- * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
- *
- *	bl	mcount
- *
- * These versions have the limitation that in order for the mcount routine to
- * be able to determine the function's caller's address, an APCS-style frame
- * pointer (which is set up with something like the code below) is required.
- *
- *	mov     ip, sp
- *	push    {fp, ip, lr, pc}
- *	sub     fp, ip, #4
- *
- * With EABI, these frame pointers are not available unless -mapcs-frame is
- * specified, and if building as Thumb-2, not even then.
- *
- * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
- * with call sites like:
+ * Newer GCCs (4.4+) solve this problem by using a version of mcount with call
+ * sites like:
  *
  *	push	{lr}
  *	bl	__gnu_mcount_nc
@@ -46,17 +31,10 @@
  * allows it to be clobbered in subroutines and doesn't use it to hold
  * parameters.)
  *
- * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
- * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
- * arch/arm/kernel/ftrace.c).
+ * When using dynamic ftrace, we patch out the mcount call by a "pop {lr}"
+ * instead of the __gnu_mcount_nc call (see arch/arm/kernel/ftrace.c).
  */
 
-#ifndef CONFIG_OLD_MCOUNT
-#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
-#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
-#endif
-#endif
-
 .macro mcount_adjust_addr rd, rn
 	bic	\rd, \rn, #1		@ clear the Thumb bit if present
 	sub	\rd, \rd, #MCOUNT_INSN_SIZE
@@ -209,51 +187,6 @@ ftrace_graph_call\suffix:
 	mcount_exit
 .endm
 
-#ifdef CONFIG_OLD_MCOUNT
-/*
- * mcount
- */
-
-.macro mcount_enter
-	stmdb	sp!, {r0-r3, lr}
-.endm
-
-.macro mcount_get_lr reg
-	ldr	\reg, [fp, #-4]
-.endm
-
-.macro mcount_exit
-	ldr	lr, [fp, #-4]
-	ldmia	sp!, {r0-r3, pc}
-.endm
-
-ENTRY(mcount)
-#ifdef CONFIG_DYNAMIC_FTRACE
-	stmdb	sp!, {lr}
-	ldr	lr, [fp, #-4]
-	ldmia	sp!, {pc}
-#else
-	__mcount _old
-#endif
-ENDPROC(mcount)
-
-#ifdef CONFIG_DYNAMIC_FTRACE
-ENTRY(ftrace_caller_old)
-	__ftrace_caller _old
-ENDPROC(ftrace_caller_old)
-#endif
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-ENTRY(ftrace_graph_caller_old)
-	__ftrace_graph_caller
-ENDPROC(ftrace_graph_caller_old)
-#endif
-
-.purgem mcount_enter
-.purgem mcount_get_lr
-.purgem mcount_exit
-#endif
-
 /*
  * __gnu_mcount_nc
  */
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 5617932a83df..0142fcfcc3d3 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -47,30 +47,6 @@ void arch_ftrace_update_code(int command)
 	stop_machine(__ftrace_modify_code, &command, NULL);
 }
 
-#ifdef CONFIG_OLD_MCOUNT
-#define OLD_MCOUNT_ADDR	((unsigned long) mcount)
-#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
-
-#define	OLD_NOP		0xe1a00000	/* mov r0, r0 */
-
-static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
-{
-	return rec->arch.old_mcount ? OLD_NOP : NOP;
-}
-
-static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
-{
-	if (!rec->arch.old_mcount)
-		return addr;
-
-	if (addr == MCOUNT_ADDR)
-		addr = OLD_MCOUNT_ADDR;
-	else if (addr == FTRACE_ADDR)
-		addr = OLD_FTRACE_ADDR;
-
-	return addr;
-}
-#else
 static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
 {
 	return NOP;
@@ -80,7 +56,6 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
 {
 	return addr;
 }
-#endif
 
 int ftrace_arch_code_modify_prepare(void)
 {
@@ -150,15 +125,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	}
 #endif
 
-#ifdef CONFIG_OLD_MCOUNT
-	if (!ret) {
-		pc = (unsigned long)&ftrace_call_old;
-		new = ftrace_call_replace(pc, (unsigned long)func);
-
-		ret = ftrace_modify_code(pc, 0, new, false);
-	}
-#endif
-
 	return ret;
 }
 
@@ -203,16 +169,6 @@ int ftrace_make_nop(struct module *mod,
 	new = ftrace_nop_replace(rec);
 	ret = ftrace_modify_code(ip, old, new, true);
 
-#ifdef CONFIG_OLD_MCOUNT
-	if (ret == -EINVAL && addr == MCOUNT_ADDR) {
-		rec->arch.old_mcount = true;
-
-		old = ftrace_call_replace(ip, adjust_address(rec, addr));
-		new = ftrace_nop_replace(rec);
-		ret = ftrace_modify_code(ip, old, new, true);
-	}
-#endif
-
 	return ret;
 }
 
@@ -290,13 +246,6 @@ static int ftrace_modify_graph_caller(bool enable)
 #endif
 
 
-#ifdef CONFIG_OLD_MCOUNT
-	if (!ret)
-		ret = __ftrace_modify_caller(&ftrace_graph_call_old,
-					     ftrace_graph_caller_old,
-					     enable);
-#endif
-
 	return ret;
 }
 
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index b8f766cf3a90..b908382b69ff 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -77,8 +77,6 @@ static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
 		kframe->magic = IWMMXT_MAGIC;
 		kframe->size = IWMMXT_STORAGE_SIZE;
 		iwmmxt_task_copy(current_thread_info(), &kframe->storage);
-
-		err = __copy_to_user(frame, kframe, sizeof(*frame));
 	} else {
 		/*
 		 * For bug-compatibility with older kernels, some space
@@ -86,10 +84,14 @@ static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
 		 * Set the magic and size appropriately so that properly
 		 * written userspace can skip it reliably:
 		 */
-		__put_user_error(DUMMY_MAGIC, &frame->magic, err);
-		__put_user_error(IWMMXT_STORAGE_SIZE, &frame->size, err);
+		*kframe = (struct iwmmxt_sigframe) {
+			.magic = DUMMY_MAGIC,
+			.size  = IWMMXT_STORAGE_SIZE,
+		};
 	}
 
+	err = __copy_to_user(frame, kframe, sizeof(*kframe));
+
 	return err;
 }
 
@@ -135,17 +137,18 @@ static int restore_iwmmxt_context(char __user **auxp)
 
 static int preserve_vfp_context(struct vfp_sigframe __user *frame)
 {
-	const unsigned long magic = VFP_MAGIC;
-	const unsigned long size = VFP_STORAGE_SIZE;
+	struct vfp_sigframe kframe;
 	int err = 0;
 
-	__put_user_error(magic, &frame->magic, err);
-	__put_user_error(size, &frame->size, err);
+	memset(&kframe, 0, sizeof(kframe));
+	kframe.magic = VFP_MAGIC;
+	kframe.size = VFP_STORAGE_SIZE;
 
+	err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
 	if (err)
-		return -EFAULT;
+		return err;
 
-	return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
+	return __copy_to_user(frame, &kframe, sizeof(kframe));
 }
 
 static int restore_vfp_context(char __user **auxp)
@@ -288,30 +291,35 @@ static int
 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 {
 	struct aux_sigframe __user *aux;
+	struct sigcontext context;
 	int err = 0;
 
-	__put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
-	__put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
-	__put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
-	__put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
-	__put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
-	__put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
-	__put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
-	__put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
-	__put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
-	__put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
-	__put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
-	__put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
-	__put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
-	__put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
-	__put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
-	__put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
-	__put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
-
-	__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
-	__put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
-	__put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
-	__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
+	context = (struct sigcontext) {
+		.arm_r0        = regs->ARM_r0,
+		.arm_r1        = regs->ARM_r1,
+		.arm_r2        = regs->ARM_r2,
+		.arm_r3        = regs->ARM_r3,
+		.arm_r4        = regs->ARM_r4,
+		.arm_r5        = regs->ARM_r5,
+		.arm_r6        = regs->ARM_r6,
+		.arm_r7        = regs->ARM_r7,
+		.arm_r8        = regs->ARM_r8,
+		.arm_r9        = regs->ARM_r9,
+		.arm_r10       = regs->ARM_r10,
+		.arm_fp        = regs->ARM_fp,
+		.arm_ip        = regs->ARM_ip,
+		.arm_sp        = regs->ARM_sp,
+		.arm_lr        = regs->ARM_lr,
+		.arm_pc        = regs->ARM_pc,
+		.arm_cpsr      = regs->ARM_cpsr,
+
+		.trap_no       = current->thread.trap_no,
+		.error_code    = current->thread.error_code,
+		.fault_address = current->thread.address,
+		.oldmask       = set->sig[0],
+	};
+
+	err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));
 
 	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 
@@ -328,7 +336,7 @@ setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 	if (err == 0)
 		err |= preserve_vfp_context(&aux->vfp);
 #endif
-	__put_user_error(0, &aux->end_magic, err);
+	err |= __put_user(0, &aux->end_magic);
 
 	return err;
 }
@@ -491,7 +499,7 @@ setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
 	/*
 	 * Set uc.uc_flags to a value which sc.trap_no would never have.
 	 */
-	__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
+	err = __put_user(0x5ac3c35a, &frame->uc.uc_flags);
 
 	err |= setup_sigframe(frame, regs, set);
 	if (err == 0)
@@ -511,8 +519,8 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
 
 	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 
-	__put_user_error(0, &frame->sig.uc.uc_flags, err);
-	__put_user_error(NULL, &frame->sig.uc.uc_link, err);
+	err |= __put_user(0, &frame->sig.uc.uc_flags);
+	err |= __put_user(NULL, &frame->sig.uc.uc_link);
 
 	err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
 	err |= setup_sigframe(&frame->sig, regs, set);
diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c
index f0dd4b6ebb63..40da0872170f 100644
--- a/arch/arm/kernel/sys_oabi-compat.c
+++ b/arch/arm/kernel/sys_oabi-compat.c
@@ -277,6 +277,7 @@ asmlinkage long sys_oabi_epoll_wait(int epfd,
 				    int maxevents, int timeout)
 {
 	struct epoll_event *kbuf;
+	struct oabi_epoll_event e;
 	mm_segment_t fs;
 	long ret, err, i;
 
@@ -295,8 +296,11 @@ asmlinkage long sys_oabi_epoll_wait(int epfd,
 	set_fs(fs);
 	err = 0;
 	for (i = 0; i < ret; i++) {
-		__put_user_error(kbuf[i].events, &events->events, err);
-		__put_user_error(kbuf[i].data,   &events->data,   err);
+		e.events = kbuf[i].events;
+		e.data = kbuf[i].data;
+		err = __copy_to_user(events, &e, sizeof(e));
+		if (err)
+			break;
 		events++;
 	}
 	kfree(kbuf);