Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze.git

12 files changed, 240 insertions, 171 deletions

diff --git a/arch/microblaze/Makefile b/arch/microblaze/Makefile
index 02e6be9c5b0d..56a161147606 100644
--- a/arch/microblaze/Makefile
+++ b/arch/microblaze/Makefile
@@ -16,7 +16,7 @@ export CPU_VER CPU_MAJOR CPU_MINOR CPU_REV
 # The various CONFIG_XILINX cpu features options are integers 0/1/2...
 # rather than bools y/n
 
-# Work out HW multipler support. This is tricky.
+# Work out HW multiplier support. This is tricky.
 # 1. Spartan2 has no HW multipliers.
 # 2. MicroBlaze v3.x always uses them, except in Spartan 2
 # 3. All other FPGa/CPU ver combos, we can trust the CONFIG_ settings
diff --git a/arch/microblaze/include/asm/entry.h b/arch/microblaze/include/asm/entry.h
index 9efadf12397c..05acf4d7bc4b 100644
--- a/arch/microblaze/include/asm/entry.h
+++ b/arch/microblaze/include/asm/entry.h
@@ -21,6 +21,19 @@
 
 #define PER_CPU(var) var
 
+/*
+ * The MicroBlaze ABI has the caller reserve an argument home area:
+ * REG_PARM_STACK_SPACE is 24 and OUTGOING_REG_PARM_STACK_SPACE is 1, so a
+ * callee may write to [caller_sp + 4, caller_sp + 28).  The kernel calls C
+ * with r1 at the frame base, so reserve that area below pt_regs and reach
+ * the saved registers through PTO.  This restores what 6e83557c38b4
+ * ("microblaze: Remove r0_ram pointer and PTO alignment") removed; the old
+ * value of 24 was one word short and left the last argument slot
+ * overlapping pt_regs' r0.
+ */
+#define PTO			28
+#define STATE_SAVE_SIZE		(PT_SIZE + PTO)
+
 # ifndef __ASSEMBLER__
 DECLARE_PER_CPU(unsigned int, KSP); /* Saved kernel stack pointer */
 DECLARE_PER_CPU(unsigned int, KM); /* Kernel/user mode */
diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
index d59bdfffca7c..595c24db2728 100644
--- a/arch/microblaze/include/asm/processor.h
+++ b/arch/microblaze/include/asm/processor.h
@@ -73,7 +73,7 @@ unsigned long __get_wchan(struct task_struct *p);
 #  define task_regs(task) ((struct pt_regs *)task_tos(task) - 1)
 
 #  define task_pt_regs_plus_args(tsk) \
-	((void *)task_pt_regs(tsk))
+	(((void *)task_pt_regs(tsk)) - PTO)
 
 #  define task_sp(task)	(task_regs(task)->r1)
 #  define task_pc(task)	(task_regs(task)->pc)
diff --git a/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c b/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
index c7ee51b0900e..1cc3fd9846ad 100644
--- a/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
+++ b/arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c
@@ -23,7 +23,7 @@
 #define CI(c, p) { ci->c = PVR_##p(pvr); }
 
 #define err_printk(x) \
-	pr_err("ERROR: Microblaze " x "-different for PVR and DTS\n");
+	pr_err("ERROR: Microblaze " x "-different for PVR and DTS\n")
 
 void set_cpuinfo_pvr_full(struct cpuinfo *ci, struct device_node *cpu)
 {
diff --git a/arch/microblaze/kernel/cpu/cpuinfo-static.c b/arch/microblaze/kernel/cpu/cpuinfo-static.c
index 03da36dc6d9c..1e4d30b6cb01 100644
--- a/arch/microblaze/kernel/cpu/cpuinfo-static.c
+++ b/arch/microblaze/kernel/cpu/cpuinfo-static.c
@@ -18,7 +18,7 @@ static const char family_string[] = CONFIG_XILINX_MICROBLAZE0_FAMILY;
 static const char cpu_ver_string[] = CONFIG_XILINX_MICROBLAZE0_HW_VER;
 
 #define err_printk(x) \
-	pr_err("ERROR: Microblaze " x "-different for kernel and DTS\n");
+	pr_err("ERROR: Microblaze " x "-different for kernel and DTS\n")
 
 void __init set_cpuinfo_static(struct cpuinfo *ci, struct device_node *cpu)
 {
diff --git a/arch/microblaze/kernel/cpu/cpuinfo.c b/arch/microblaze/kernel/cpu/cpuinfo.c
index cd9b4450763b..32c508e85408 100644
--- a/arch/microblaze/kernel/cpu/cpuinfo.c
+++ b/arch/microblaze/kernel/cpu/cpuinfo.c
@@ -133,6 +133,7 @@ void __init setup_cpuinfo_clk(void)
 		cpuinfo.cpu_clock_freq = fcpu(cpu, "timebase-frequency");
 	} else {
 		cpuinfo.cpu_clock_freq = clk_get_rate(clk);
+		clk_put(clk);
 	}
 
 	if (!cpuinfo.cpu_clock_freq) {
diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 582d7256d815..ebc8bcb98c52 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -177,78 +177,78 @@ syscall_debug_table:
 1:
 
 #define SAVE_REGS \
-	swi	r2, r1, PT_R2;	/* Save SDA */			\
-	swi	r3, r1, PT_R3;					\
-	swi	r4, r1, PT_R4;					\
-	swi	r5, r1, PT_R5;					\
-	swi	r6, r1, PT_R6;					\
-	swi	r7, r1, PT_R7;					\
-	swi	r8, r1, PT_R8;					\
-	swi	r9, r1, PT_R9;					\
-	swi	r10, r1, PT_R10;					\
-	swi	r11, r1, PT_R11;	/* save clobbered regs after rval */\
-	swi	r12, r1, PT_R12;					\
-	swi	r13, r1, PT_R13;	/* Save SDA2 */			\
-	swi	r14, r1, PT_PC;	/* PC, before IRQ/trap */	\
-	swi	r15, r1, PT_R15;	/* Save LP */			\
-	swi	r16, r1, PT_R16;					\
-	swi	r17, r1, PT_R17;					\
-	swi	r18, r1, PT_R18;	/* Save asm scratch reg */	\
-	swi	r19, r1, PT_R19;					\
-	swi	r20, r1, PT_R20;					\
-	swi	r21, r1, PT_R21;					\
-	swi	r22, r1, PT_R22;					\
-	swi	r23, r1, PT_R23;					\
-	swi	r24, r1, PT_R24;					\
-	swi	r25, r1, PT_R25;					\
-	swi	r26, r1, PT_R26;					\
-	swi	r27, r1, PT_R27;					\
-	swi	r28, r1, PT_R28;					\
-	swi	r29, r1, PT_R29;					\
-	swi	r30, r1, PT_R30;					\
-	swi	r31, r1, PT_R31;	/* Save current task reg */	\
+	swi	r2, r1, PTO+PT_R2;	/* Save SDA */			\
+	swi	r3, r1, PTO+PT_R3;					\
+	swi	r4, r1, PTO+PT_R4;					\
+	swi	r5, r1, PTO+PT_R5;					\
+	swi	r6, r1, PTO+PT_R6;					\
+	swi	r7, r1, PTO+PT_R7;					\
+	swi	r8, r1, PTO+PT_R8;					\
+	swi	r9, r1, PTO+PT_R9;					\
+	swi	r10, r1, PTO+PT_R10;					\
+	swi	r11, r1, PTO+PT_R11;	/* save clobbered regs after rval */\
+	swi	r12, r1, PTO+PT_R12;					\
+	swi	r13, r1, PTO+PT_R13;	/* Save SDA2 */			\
+	swi	r14, r1, PTO+PT_PC;	/* PC, before IRQ/trap */	\
+	swi	r15, r1, PTO+PT_R15;	/* Save LP */			\
+	swi	r16, r1, PTO+PT_R16;					\
+	swi	r17, r1, PTO+PT_R17;					\
+	swi	r18, r1, PTO+PT_R18;	/* Save asm scratch reg */	\
+	swi	r19, r1, PTO+PT_R19;					\
+	swi	r20, r1, PTO+PT_R20;					\
+	swi	r21, r1, PTO+PT_R21;					\
+	swi	r22, r1, PTO+PT_R22;					\
+	swi	r23, r1, PTO+PT_R23;					\
+	swi	r24, r1, PTO+PT_R24;					\
+	swi	r25, r1, PTO+PT_R25;					\
+	swi	r26, r1, PTO+PT_R26;					\
+	swi	r27, r1, PTO+PT_R27;					\
+	swi	r28, r1, PTO+PT_R28;					\
+	swi	r29, r1, PTO+PT_R29;					\
+	swi	r30, r1, PTO+PT_R30;					\
+	swi	r31, r1, PTO+PT_R31;	/* Save current task reg */	\
 	mfs	r11, rmsr;		/* save MSR */			\
-	swi	r11, r1, PT_MSR;
+	swi	r11, r1, PTO+PT_MSR;
 
 #define RESTORE_REGS_GP \
-	lwi	r2, r1, PT_R2;	/* restore SDA */		\
-	lwi	r3, r1, PT_R3;					\
-	lwi	r4, r1, PT_R4;					\
-	lwi	r5, r1, PT_R5;					\
-	lwi	r6, r1, PT_R6;					\
-	lwi	r7, r1, PT_R7;					\
-	lwi	r8, r1, PT_R8;					\
-	lwi	r9, r1, PT_R9;					\
-	lwi	r10, r1, PT_R10;					\
-	lwi	r11, r1, PT_R11;	/* restore clobbered regs after rval */\
-	lwi	r12, r1, PT_R12;					\
-	lwi	r13, r1, PT_R13;	/* restore SDA2 */		\
-	lwi	r14, r1, PT_PC;	/* RESTORE_LINK PC, before IRQ/trap */\
-	lwi	r15, r1, PT_R15;	/* restore LP */		\
-	lwi	r16, r1, PT_R16;					\
-	lwi	r17, r1, PT_R17;					\
-	lwi	r18, r1, PT_R18;	/* restore asm scratch reg */	\
-	lwi	r19, r1, PT_R19;					\
-	lwi	r20, r1, PT_R20;					\
-	lwi	r21, r1, PT_R21;					\
-	lwi	r22, r1, PT_R22;					\
-	lwi	r23, r1, PT_R23;					\
-	lwi	r24, r1, PT_R24;					\
-	lwi	r25, r1, PT_R25;					\
-	lwi	r26, r1, PT_R26;					\
-	lwi	r27, r1, PT_R27;					\
-	lwi	r28, r1, PT_R28;					\
-	lwi	r29, r1, PT_R29;					\
-	lwi	r30, r1, PT_R30;					\
-	lwi	r31, r1, PT_R31;	/* Restore cur task reg */
+	lwi	r2, r1, PTO+PT_R2;	/* restore SDA */		\
+	lwi	r3, r1, PTO+PT_R3;					\
+	lwi	r4, r1, PTO+PT_R4;					\
+	lwi	r5, r1, PTO+PT_R5;					\
+	lwi	r6, r1, PTO+PT_R6;					\
+	lwi	r7, r1, PTO+PT_R7;					\
+	lwi	r8, r1, PTO+PT_R8;					\
+	lwi	r9, r1, PTO+PT_R9;					\
+	lwi	r10, r1, PTO+PT_R10;					\
+	lwi	r11, r1, PTO+PT_R11;	/* restore clobbered regs after rval */\
+	lwi	r12, r1, PTO+PT_R12;					\
+	lwi	r13, r1, PTO+PT_R13;	/* restore SDA2 */		\
+	lwi	r14, r1, PTO+PT_PC;	/* RESTORE_LINK PC, before IRQ/trap */\
+	lwi	r15, r1, PTO+PT_R15;	/* restore LP */		\
+	lwi	r16, r1, PTO+PT_R16;					\
+	lwi	r17, r1, PTO+PT_R17;					\
+	lwi	r18, r1, PTO+PT_R18;	/* restore asm scratch reg */	\
+	lwi	r19, r1, PTO+PT_R19;					\
+	lwi	r20, r1, PTO+PT_R20;					\
+	lwi	r21, r1, PTO+PT_R21;					\
+	lwi	r22, r1, PTO+PT_R22;					\
+	lwi	r23, r1, PTO+PT_R23;					\
+	lwi	r24, r1, PTO+PT_R24;					\
+	lwi	r25, r1, PTO+PT_R25;					\
+	lwi	r26, r1, PTO+PT_R26;					\
+	lwi	r27, r1, PTO+PT_R27;					\
+	lwi	r28, r1, PTO+PT_R28;					\
+	lwi	r29, r1, PTO+PT_R29;					\
+	lwi	r30, r1, PTO+PT_R30;					\
+	lwi	r31, r1, PTO+PT_R31;	/* Restore cur task reg */
 
 #define RESTORE_REGS \
-	lwi	r11, r1, PT_MSR;					\
+	lwi	r11, r1, PTO+PT_MSR;					\
 	mts	rmsr , r11;						\
 	RESTORE_REGS_GP
 
 #define RESTORE_REGS_RTBD \
-	lwi	r11, r1, PT_MSR;					\
+	lwi	r11, r1, PTO+PT_MSR;					\
 	andni	r11, r11, MSR_EIP;          /* clear EIP */             \
 	ori	r11, r11, MSR_EE | MSR_BIP; /* set EE and BIP */        \
 	mts	rmsr , r11;						\
@@ -265,11 +265,11 @@ syscall_debug_table:
 	lwi	r1, r0, TOPHYS(PER_CPU(ENTRY_SP));			\
 	/* FIXME: I can add these two lines to one */			\
 	/* tophys(r1,r1); */						\
-	/* addik	r1, r1, -PT_SIZE; */				\
-	addik	r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
+	/* addik	r1, r1, -STATE_SAVE_SIZE; */				\
+	addik	r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE; \
 	SAVE_REGS							\
 	brid	2f;							\
-	swi	r1, r1, PT_MODE; 	 				\
+	swi	r1, r1, PTO+PT_MODE; 	 				\
 1:	/* User-mode state save.  */					\
 	lwi	r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */\
 	tophys(r1,r1);							\
@@ -277,12 +277,13 @@ syscall_debug_table:
 	/* MS these three instructions can be added to one */		\
 	/* addik	r1, r1, THREAD_SIZE; */				\
 	/* tophys(r1,r1); */						\
-	/* addik	r1, r1, -PT_SIZE; */			\
-	addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE; \
+	/* addik	r1, r1, -STATE_SAVE_SIZE; */			\
+	addik r1, r1, THREAD_SIZE + CONFIG_KERNEL_BASE_ADDR		\
+		- CONFIG_KERNEL_START - STATE_SAVE_SIZE;		\
 	SAVE_REGS							\
 	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));			\
-	swi	r11, r1, PT_R1; /* Store user SP.  */		\
-	swi	r0, r1, PT_MODE; /* Was in user-mode.  */		\
+	swi	r11, r1, PTO+PT_R1; /* Store user SP.  */		\
+	swi	r0, r1, PTO+PT_MODE; /* Was in user-mode.  */		\
 	/* MS: I am clearing UMS even in case when I come from kernel space */ \
 	clear_ums; 							\
 2:	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
@@ -292,7 +293,7 @@ syscall_debug_table:
 .extern cpuinfo
 
 C_ENTRY(mb_flush_dcache):
-	addik	r1, r1, -PT_SIZE
+	addik	r1, r1, -STATE_SAVE_SIZE
 	SAVE_REGS
 
 	addik	r3, r0, cpuinfo
@@ -305,12 +306,12 @@ C_ENTRY(mb_flush_dcache):
 	addk	r9, r9, r8
 
 	RESTORE_REGS
-	addik	r1, r1, PT_SIZE
+	addik	r1, r1, STATE_SAVE_SIZE
 	rtsd	r15, 8
 	nop
 
 C_ENTRY(mb_invalidate_icache):
-	addik	r1, r1, -PT_SIZE
+	addik	r1, r1, -STATE_SAVE_SIZE
 	SAVE_REGS
 
 	addik	r3, r0, cpuinfo
@@ -323,7 +324,7 @@ C_ENTRY(mb_invalidate_icache):
 	addk	r9, r9, r8
 
 	RESTORE_REGS
-	addik	r1, r1, PT_SIZE
+	addik	r1, r1, STATE_SAVE_SIZE
 	rtsd	r15, 8
 	nop
 
@@ -350,18 +351,18 @@ C_ENTRY(_user_exception):
 	addik	r1, r1, THREAD_SIZE;
 	tophys(r1,r1);
 
-	addik	r1, r1, -PT_SIZE; /* Make room on the stack.  */
+	addik	r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */
 	SAVE_REGS
-	swi	r0, r1, PT_R3
-	swi	r0, r1, PT_R4
+	swi	r0, r1, PTO+PT_R3
+	swi	r0, r1, PTO+PT_R4
 
-	swi	r0, r1, PT_MODE;			/* Was in user-mode. */
+	swi	r0, r1, PTO+PT_MODE;			/* Was in user-mode. */
 	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
-	swi	r11, r1, PT_R1;		/* Store user SP.  */
+	swi	r11, r1, PTO+PT_R1;		/* Store user SP.  */
 	clear_ums;
 2:	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
 	/* Save away the syscall number.  */
-	swi	r12, r1, PT_R0;
+	swi	r12, r1, PTO+PT_R0;
 	tovirt(r1,r1)
 
 /* where the trap should return need -8 to adjust for rtsd r15, 8*/
@@ -380,18 +381,18 @@ C_ENTRY(_user_exception):
 	beqi	r11, 4f
 
 	addik	r3, r0, -ENOSYS
-	swi	r3, r1, PT_R3
+	swi	r3, r1, PTO+PT_R3
 	brlid	r15, do_syscall_trace_enter
-	addik	r5, r1, PT_R0
+	addik	r5, r1, PTO+PT_R0
 
 	# do_syscall_trace_enter returns the new syscall nr.
 	addk	r12, r0, r3
-	lwi	r5, r1, PT_R5;
-	lwi	r6, r1, PT_R6;
-	lwi	r7, r1, PT_R7;
-	lwi	r8, r1, PT_R8;
-	lwi	r9, r1, PT_R9;
-	lwi	r10, r1, PT_R10;
+	lwi	r5, r1, PTO+PT_R5;
+	lwi	r6, r1, PTO+PT_R6;
+	lwi	r7, r1, PTO+PT_R7;
+	lwi	r8, r1, PTO+PT_R8;
+	lwi	r9, r1, PTO+PT_R9;
+	lwi	r10, r1, PTO+PT_R10;
 4:
 /* Jump to the appropriate function for the system call number in r12
  * (r12 is not preserved), or return an error if r12 is not valid.
@@ -432,10 +433,16 @@ C_ENTRY(_user_exception):
 /* Entry point used to return from a syscall/trap */
 /* We re-enable BIP bit before state restore */
 C_ENTRY(ret_from_trap):
-	swi	r3, r1, PT_R3
-	swi	r4, r1, PT_R4
-
-	lwi	r11, r1, PT_MODE;
+	swi	r3, r1, PTO+PT_R3
+	swi	r4, r1, PTO+PT_R4
+/*
+ * Entry point for returns that must not store r3/r4 back into pt_regs,
+ * i.e. rt_sigreturn, which has already restored them from the signal
+ * context.  Reached as "rtsd r15, 8" with r15 set to this label minus 8,
+ * so it stays correct if the number of stores above ever changes.
+ */
+ret_from_trap_no_rval:
+	lwi	r11, r1, PTO+PT_MODE;
 /* See if returning to kernel mode, if so, skip resched &c.  */
 	bnei	r11, 2f;
 	/* We're returning to user mode, so check for various conditions that
@@ -447,7 +454,7 @@ C_ENTRY(ret_from_trap):
 	beqi	r11, 1f
 
 	brlid	r15, do_syscall_trace_leave
-	addik	r5, r1, PT_R0
+	addik	r5, r1, PTO+PT_R0
 1:
 	/* We're returning to user mode, so check for various conditions that
 	 * trigger rescheduling. */
@@ -466,7 +473,7 @@ C_ENTRY(ret_from_trap):
 	andi	r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
 	beqi	r11, 4f;		/* Signals to handle, handle them */
 
-	addik	r5, r1, 0;		/* Arg 1: struct pt_regs *regs */
+	addik	r5, r1, PTO;		/* Arg 1: struct pt_regs *regs */
 	bralid	r15, do_notify_resume;	/* Handle any signals */
 	add	r6, r30, r0;		/* Arg 2: int in_syscall */
 	add	r30, r0, r0		/* no more restarts */
@@ -478,7 +485,11 @@ C_ENTRY(ret_from_trap):
 	VM_OFF;
 	tophys(r1,r1);
 	RESTORE_REGS_RTBD;
-	addik	r1, r1, PT_SIZE		/* Clean up stack space.  */
+	addik	r1, r1, STATE_SAVE_SIZE		/* Clean up stack space.  */
+	/*
+	 * Deliberately PT_SIZE, not STATE_SAVE_SIZE: r1 is back at the stack
+	 * top, so PTO cancels and the saved SP sits at PT_R1 - PT_SIZE.
+	 */
 	lwi	r1, r1, PT_R1 - PT_SIZE;/* Restore user stack pointer. */
 	bri	6f;
 
@@ -487,7 +498,7 @@ C_ENTRY(ret_from_trap):
 	VM_OFF;
 	tophys(r1,r1);
 	RESTORE_REGS_RTBD;
-	addik	r1, r1, PT_SIZE		/* Clean up stack space.  */
+	addik	r1, r1, STATE_SAVE_SIZE		/* Clean up stack space.  */
 	tovirt(r1,r1);
 6:
 TRAP_return:		/* Make global symbol for debugging */
@@ -518,8 +529,17 @@ C_ENTRY(ret_from_kernel_thread):
 
 C_ENTRY(sys_rt_sigreturn_wrapper):
 	addik	r30, r0, 0		/* no restarts */
+	/*
+	 * rt_sigreturn restores the full register set from the signal
+	 * context, so it must skip the r3/r4 syscall-return stores at the
+	 * head of ret_from_trap which would otherwise overwrite the
+	 * just-restored r3/r4.  Every C function returns with "rtsd r15, 8"
+	 * -- the ABI return, where the 8 skips the caller's branch and its
+	 * delay slot -- so bias r15 by -8 to land on ret_from_trap_no_rval.
+	 */
+	addik	r15, r0, ret_from_trap_no_rval - 8
 	brid	sys_rt_sigreturn	/* Do real work */
-	addik	r5, r1, 0;		/* add user context as 1st arg */
+	addik	r5, r1, PTO;		/* add user context as 1st arg */
 
 /*
  * HW EXCEPTION rutine start
@@ -530,7 +550,7 @@ C_ENTRY(full_exception_trap):
 	addik	r17, r17, -4
 	SAVE_STATE /* Save registers */
 	/* PC, before IRQ/trap - this is one instruction above */
-	swi	r17, r1, PT_PC;
+	swi	r17, r1, PTO+PT_PC;
 	tovirt(r1,r1)
 	/* FIXME this can be store directly in PT_ESR reg.
 	 * I tested it but there is a fault */
@@ -540,7 +560,7 @@ C_ENTRY(full_exception_trap):
 	mfs	r7, rfsr;		/* save FSR */
 	mts	rfsr, r0;	/* Clear sticky fsr */
 	rted	r0, full_exception
-	addik	r5, r1, 0		 /* parameter struct pt_regs * regs */
+	addik	r5, r1, PTO		 /* parameter struct pt_regs * regs */
 
 /*
  * Unaligned data trap.
@@ -566,14 +586,14 @@ C_ENTRY(unaligned_data_trap):
 	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
 	SAVE_STATE		/* Save registers.*/
 	/* PC, before IRQ/trap - this is one instruction above */
-	swi	r17, r1, PT_PC;
+	swi	r17, r1, PTO+PT_PC;
 	tovirt(r1,r1)
 	/* where the trap should return need -8 to adjust for rtsd r15, 8 */
 	addik	r15, r0, ret_from_exc-8
 	mfs	r3, resr		/* ESR */
 	mfs	r4, rear		/* EAR */
 	rtbd	r0, _unaligned_data_exception
-	addik	r7, r1, 0		/* parameter struct pt_regs * regs */
+	addik	r7, r1, PTO		/* parameter struct pt_regs * regs */
 
 /*
  * Page fault traps.
@@ -596,30 +616,30 @@ C_ENTRY(unaligned_data_trap):
 C_ENTRY(page_fault_data_trap):
 	SAVE_STATE		/* Save registers.*/
 	/* PC, before IRQ/trap - this is one instruction above */
-	swi	r17, r1, PT_PC;
+	swi	r17, r1, PTO+PT_PC;
 	tovirt(r1,r1)
 	/* where the trap should return need -8 to adjust for rtsd r15, 8 */
 	addik	r15, r0, ret_from_exc-8
 	mfs	r6, rear		/* parameter unsigned long address */
 	mfs	r7, resr		/* parameter unsigned long error_code */
 	rted	r0, do_page_fault
-	addik	r5, r1, 0		/* parameter struct pt_regs * regs */
+	addik	r5, r1, PTO		/* parameter struct pt_regs * regs */
 
 C_ENTRY(page_fault_instr_trap):
 	SAVE_STATE		/* Save registers.*/
 	/* PC, before IRQ/trap - this is one instruction above */
-	swi	r17, r1, PT_PC;
+	swi	r17, r1, PTO+PT_PC;
 	tovirt(r1,r1)
 	/* where the trap should return need -8 to adjust for rtsd r15, 8 */
 	addik	r15, r0, ret_from_exc-8
 	mfs	r6, rear		/* parameter unsigned long address */
 	ori	r7, r0, 0		/* parameter unsigned long error_code */
 	rted	r0, do_page_fault
-	addik	r5, r1, 0		/* parameter struct pt_regs * regs */
+	addik	r5, r1, PTO		/* parameter struct pt_regs * regs */
 
 /* Entry point used to return from an exception.  */
 C_ENTRY(ret_from_exc):
-	lwi	r11, r1, PT_MODE;
+	lwi	r11, r1, PTO+PT_MODE;
 	bnei	r11, 2f;		/* See if returning to kernel mode, */
 					/* ... if so, skip resched &c.  */
 
@@ -651,7 +671,7 @@ C_ENTRY(ret_from_exc):
 	 * complete register state.  Here we save anything not saved by
 	 * the normal entry sequence, so that it may be safely restored
 	 * (in a possibly modified form) after do_notify_resume returns. */
-	addik	r5, r1, 0;		/* Arg 1: struct pt_regs *regs */
+	addik	r5, r1, PTO;		/* Arg 1: struct pt_regs *regs */
 	bralid	r15, do_notify_resume;	/* Handle any signals */
 	addi	r6, r0, 0;		/* Arg 2: int in_syscall */
 	bri	1b
@@ -663,7 +683,7 @@ C_ENTRY(ret_from_exc):
 	tophys(r1,r1);
 
 	RESTORE_REGS_RTBD;
-	addik	r1, r1, PT_SIZE		/* Clean up stack space.  */
+	addik	r1, r1, STATE_SAVE_SIZE		/* Clean up stack space.  */
 
 	lwi	r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer. */
 	bri	6f;
@@ -672,7 +692,7 @@ C_ENTRY(ret_from_exc):
 	VM_OFF;
 	tophys(r1,r1);
 	RESTORE_REGS_RTBD;
-	addik	r1, r1, PT_SIZE		/* Clean up stack space.  */
+	addik	r1, r1, STATE_SAVE_SIZE		/* Clean up stack space.  */
 
 	tovirt(r1,r1);
 6:
@@ -705,10 +725,10 @@ C_ENTRY(_interrupt):
 	tophys(r1,r1); /* MS: I have in r1 physical address where stack is */
 	/* save registers */
 /* MS: Make room on the stack -> activation record */
-	addik	r1, r1, -PT_SIZE;
+	addik	r1, r1, -STATE_SAVE_SIZE;
 	SAVE_REGS
 	brid	2f;
-	swi	r1, r1, PT_MODE; /* 0 - user mode, 1 - kernel mode */
+	swi	r1, r1, PTO+PT_MODE; /* 0 - user mode, 1 - kernel mode */
 1:
 /* User-mode state save. */
  /* MS: get the saved current */
@@ -718,23 +738,23 @@ C_ENTRY(_interrupt):
 	addik	r1, r1, THREAD_SIZE;
 	tophys(r1,r1);
 	/* save registers */
-	addik	r1, r1, -PT_SIZE;
+	addik	r1, r1, -STATE_SAVE_SIZE;
 	SAVE_REGS
 	/* calculate mode */
-	swi	r0, r1, PT_MODE;
+	swi	r0, r1, PTO+PT_MODE;
 	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
-	swi	r11, r1, PT_R1;
+	swi	r11, r1, PTO+PT_R1;
 	clear_ums;
 2:
 	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
 	tovirt(r1,r1)
 	addik	r15, r0, irq_call;
 irq_call:rtbd	r0, do_IRQ;
-	addik	r5, r1, 0;
+	addik	r5, r1, PTO;
 
 /* MS: we are in virtual mode */
 ret_from_irq:
-	lwi	r11, r1, PT_MODE;
+	lwi	r11, r1, PTO+PT_MODE;
 	bnei	r11, 2f;
 
 1:
@@ -750,7 +770,7 @@ ret_from_irq:
 5:	andi	r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
 	beqid	r11, no_intr_resched
 /* Handle a signal return; Pending signals should be in r18. */
-	addik	r5, r1, 0; /* Arg 1: struct pt_regs *regs */
+	addik	r5, r1, PTO; /* Arg 1: struct pt_regs *regs */
 	bralid	r15, do_notify_resume;	/* Handle any signals */
 	addi	r6, r0, 0; /* Arg 2: int in_syscall */
 	bri	1b
@@ -763,7 +783,7 @@ no_intr_resched:
 	VM_OFF;
 	tophys(r1,r1);
 	RESTORE_REGS
-	addik	r1, r1, PT_SIZE /* MS: Clean up stack space. */
+	addik	r1, r1, STATE_SAVE_SIZE /* MS: Clean up stack space. */
 	lwi	r1, r1, PT_R1 - PT_SIZE;
 	bri	6f;
 /* MS: Return to kernel state. */
@@ -786,7 +806,7 @@ restore:
 	VM_OFF /* MS: turn off MMU */
 	tophys(r1,r1)
 	RESTORE_REGS
-	addik	r1, r1, PT_SIZE	/* MS: Clean up stack space. */
+	addik	r1, r1, STATE_SAVE_SIZE	/* MS: Clean up stack space. */
 	tovirt(r1,r1);
 6:
 IRQ_return: /* MS: Make global symbol for debugging */
@@ -805,29 +825,29 @@ C_ENTRY(_xtmr_manager_reset):
 	lwi	r1, r0, xmb_manager_stackpointer
 
 	/* Restore MSR */
-	lwi	r2, r1, PT_MSR
+	lwi	r2, r1, PTO+PT_MSR
 	mts	rmsr, r2
 	bri	4
 
 	/* restore Special purpose registers */
-	lwi	r2, r1, PT_PID
+	lwi	r2, r1, PTO+PT_PID
 	mts	rpid, r2
 
-	lwi	r2, r1, PT_TLBI
+	lwi	r2, r1, PTO+PT_TLBI
 	mts	rtlbx, r2
 
-	lwi	r2, r1, PT_ZPR
+	lwi	r2, r1, PTO+PT_ZPR
 	mts	rzpr, r2
 
 #if CONFIG_XILINX_MICROBLAZE0_USE_FPU
-	lwi	r2, r1, PT_FSR
+	lwi	r2, r1, PTO+PT_FSR
 	mts	rfsr, r2
 #endif
 
 	/* restore all the tlb's */
 	addik	r3, r0, TOPHYS(tlb_skip)
-	addik	r6, r0, PT_TLBL0
-	addik	r7, r0, PT_TLBH0
+	addik	r6, r0, PTO+PT_TLBL0
+	addik	r7, r0, PTO+PT_TLBH0
 restore_tlb:
 	add	r6, r6, r1
 	add	r7, r7, r1
@@ -853,9 +873,9 @@ ret_from_reset:
 	VM_OFF
 	/* MS: Restore all regs */
 	RESTORE_REGS
-	lwi	r14, r1, PT_R14
-	lwi	r16, r1, PT_PC
-	addik	r1, r1, PT_SIZE + 36
+	lwi	r14, r1, PTO+PT_R14
+	lwi	r16, r1, PTO+PT_PC
+	addik	r1, r1, STATE_SAVE_SIZE + 36
 	rtbd	r16, 0
 	nop
 
@@ -870,11 +890,11 @@ C_ENTRY(_xmb_manager_break):
 	 * Reserve memory in the stack for context store/restore
 	 * (which includes memory for storing tlbs (max two tlbs))
 	 */
-	addik	r1, r1, -PT_SIZE - 36
+	addik	r1, r1, -STATE_SAVE_SIZE - 36
 	swi	r1, r0, xmb_manager_stackpointer
 	SAVE_REGS
-	swi	r14, r1, PT_R14	/* rewrite saved R14 value */
-	swi	r16, r1, PT_PC; /* PC and r16 are the same */
+	swi	r14, r1, PTO+PT_R14	/* rewrite saved R14 value */
+	swi	r16, r1, PTO+PT_PC; /* PC and r16 are the same */
 
 	lwi	r6, r0, TOPHYS(xmb_manager_baseaddr)
 	lwi	r7, r0, TOPHYS(xmb_manager_crval)
@@ -888,25 +908,25 @@ C_ENTRY(_xmb_manager_break):
 
 	/* Save the special purpose registers  */
 	mfs	r2, rpid
-	swi	r2, r1, PT_PID
+	swi	r2, r1, PTO+PT_PID
 
 	mfs	r2, rtlbx
-	swi	r2, r1, PT_TLBI
+	swi	r2, r1, PTO+PT_TLBI
 
 	mfs	r2, rzpr
-	swi	r2, r1, PT_ZPR
+	swi	r2, r1, PTO+PT_ZPR
 
 #if CONFIG_XILINX_MICROBLAZE0_USE_FPU
 	mfs	r2, rfsr
-	swi	r2, r1, PT_FSR
+	swi	r2, r1, PTO+PT_FSR
 #endif
 	mfs	r2, rmsr
-	swi	r2, r1, PT_MSR
+	swi	r2, r1, PTO+PT_MSR
 
 	/* Save all the tlb's */
 	addik	r3, r0, TOPHYS(tlb_skip)
-	addik	r6, r0, PT_TLBL0
-	addik	r7, r0, PT_TLBH0
+	addik	r6, r0, PTO+PT_TLBL0
+	addik	r7, r0, PTO+PT_TLBH0
 save_tlb:
 	add	r6, r6, r1
 	add	r7, r7, r1
@@ -943,7 +963,7 @@ ret_from_break:
 	mbar	1
 	mbar	2
 	bri	4
-	suspend
+	mbar	24 /* suspend */
 	nop
 #endif
 
@@ -963,28 +983,28 @@ C_ENTRY(_debug_exception):
 	lwi	r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
 
 	/* BIP bit is set on entry, no interrupts can occur */
-	addik   r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - PT_SIZE;
+	addik   r1, r1, CONFIG_KERNEL_BASE_ADDR - CONFIG_KERNEL_START - STATE_SAVE_SIZE;
 	SAVE_REGS;
 	/* save all regs to pt_reg structure */
-	swi	r0, r1, PT_R0;	/* R0 must be saved too */
-	swi	r14, r1, PT_R14	/* rewrite saved R14 value */
-	swi	r16, r1, PT_PC; /* PC and r16 are the same */
+	swi	r0, r1, PTO+PT_R0;	/* R0 must be saved too */
+	swi	r14, r1, PTO+PT_R14	/* rewrite saved R14 value */
+	swi	r16, r1, PTO+PT_PC; /* PC and r16 are the same */
 	/* save special purpose registers to pt_regs */
 	mfs	r11, rear;
-	swi	r11, r1, PT_EAR;
+	swi	r11, r1, PTO+PT_EAR;
 	mfs	r11, resr;
-	swi	r11, r1, PT_ESR;
+	swi	r11, r1, PTO+PT_ESR;
 	mfs	r11, rfsr;
-	swi	r11, r1, PT_FSR;
+	swi	r11, r1, PTO+PT_FSR;
 
 	/* stack pointer is in physical address at it is decrease
-	 * by PT_SIZE but we need to get correct R1 value */
-	addik   r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + PT_SIZE;
-	swi	r11, r1, PT_R1
+	 * by STATE_SAVE_SIZE but we need to get correct R1 value */
+	addik   r11, r1, CONFIG_KERNEL_START - CONFIG_KERNEL_BASE_ADDR + STATE_SAVE_SIZE;
+	swi	r11, r1, PTO+PT_R1
 	/* MS: r31 - current pointer isn't changed */
 	tovirt(r1,r1)
 #ifdef CONFIG_KGDB
-	addi	r5, r1, 0 /* pass pt_reg address as the first arg */
+	addi	r5, r1, PTO /* pass pt_reg address as the first arg */
 	addik	r15, r0, dbtrap_call; /* return address */
 	rtbd	r0, microblaze_kgdb_break
 	nop;
@@ -1000,16 +1020,16 @@ C_ENTRY(_debug_exception):
 	addik	r1, r1, THREAD_SIZE;	/* calculate kernel stack pointer */
 	tophys(r1,r1);
 
-	addik	r1, r1, -PT_SIZE; /* Make room on the stack.  */
+	addik	r1, r1, -STATE_SAVE_SIZE; /* Make room on the stack.  */
 	SAVE_REGS;
-	swi	r16, r1, PT_PC;	/* Save LP */
-	swi	r0, r1, PT_MODE; /* Was in user-mode.  */
+	swi	r16, r1, PTO+PT_PC;	/* Save LP */
+	swi	r0, r1, PTO+PT_MODE; /* Was in user-mode.  */
 	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));
-	swi	r11, r1, PT_R1; /* Store user SP.  */
+	swi	r11, r1, PTO+PT_R1; /* Store user SP.  */
 	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));
 	tovirt(r1,r1)
 	set_vms;
-	addik	r5, r1, 0;
+	addik	r5, r1, PTO;
 	addik	r15, r0, dbtrap_call;
 dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
 	rtbd	r0, sw_exception
@@ -1017,7 +1037,7 @@ dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
 
 	/* MS: The first instruction for the second part of the gdb/kgdb */
 	set_bip; /* Ints masked for state restore */
-	lwi	r11, r1, PT_MODE;
+	lwi	r11, r1, PTO+PT_MODE;
 	bnei	r11, 2f;
 /* MS: Return to user space - gdb */
 1:
@@ -1036,7 +1056,7 @@ dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
 5:	andi	r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME;
 	beqi	r11, 4f;		/* Signals to handle, handle them */
 
-	addik	r5, r1, 0;		/* Arg 1: struct pt_regs *regs */
+	addik	r5, r1, PTO;		/* Arg 1: struct pt_regs *regs */
 	bralid	r15, do_notify_resume;	/* Handle any signals */
 	addi  r6, r0, 0;	/* Arg 2: int in_syscall */
 	bri	1b
@@ -1047,7 +1067,7 @@ dbtrap_call: /* Return point for kernel/user entry + 8 because of rtsd r15, 8 */
 	tophys(r1,r1);
 	/* MS: Restore all regs */
 	RESTORE_REGS_RTBD
-	addik	r1, r1, PT_SIZE	 /* Clean up stack space */
+	addik	r1, r1, STATE_SAVE_SIZE	 /* Clean up stack space */
 	lwi	r1, r1, PT_R1 - PT_SIZE; /* Restore user stack pointer */
 DBTRAP_return_user: /* MS: Make global symbol for debugging */
 	rtbd	r16, 0; /* MS: Instructions to return from a debug trap */
@@ -1058,9 +1078,9 @@ DBTRAP_return_user: /* MS: Make global symbol for debugging */
 	tophys(r1,r1);
 	/* MS: Restore all regs */
 	RESTORE_REGS_RTBD
-	lwi	r14, r1, PT_R14;
-	lwi	r16, r1, PT_PC;
-	addik	r1, r1, PT_SIZE; /* MS: Clean up stack space */
+	lwi	r14, r1, PTO+PT_R14;
+	lwi	r16, r1, PTO+PT_PC;
+	addik	r1, r1, STATE_SAVE_SIZE; /* MS: Clean up stack space */
 	tovirt(r1,r1);
 DBTRAP_return_kernel: /* MS: Make global symbol for debugging */
 	rtbd	r16, 0; /* MS: Instructions to return from a debug trap */
@@ -1158,7 +1178,7 @@ ENTRY(_switch_to)
 .ent xmb_inject_err
 .type xmb_inject_err, @function
 xmb_inject_err:
-	addik	r1, r1, -PT_SIZE
+	addik	r1, r1, -STATE_SAVE_SIZE
 	SAVE_REGS
 
 	/* Switch to real mode */
@@ -1182,7 +1202,7 @@ xmb_inject_err:
 	nop;
 1:
 	RESTORE_REGS
-	addik	r1, r1, PT_SIZE
+	addik	r1, r1, STATE_SAVE_SIZE
 	rtsd	r15, 8;
 	nop;
 .end xmb_inject_err
diff --git a/arch/microblaze/kernel/hw_exception_handler.S b/arch/microblaze/kernel/hw_exception_handler.S
index 07ea23965f81..4693916be526 100644
--- a/arch/microblaze/kernel/hw_exception_handler.S
+++ b/arch/microblaze/kernel/hw_exception_handler.S
@@ -313,6 +313,11 @@ _MB_HW_ExceptionVectorTable:
 .align 4
 .ent _hw_exception_handler
 _hw_exception_handler:
+	/*
+	 * This handler saves into the static pt_pool_space buffer, not into a
+	 * stack frame, so the plain PT_* offsets are right here -- do not add
+	 * the PTO of entry.S's frames.
+	 */
 	swi	r1, r0, TOPHYS(pt_pool_space + PT_R1); /* GET_SP */
 	/* Save date to kernel memory. Here is the problem
 	 * when you came from user space */
diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 6cbf642d7b80..090e1697ea7a 100644
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -19,6 +19,7 @@
 #include <linux/bitops.h>
 #include <linux/ptrace.h>
 #include <asm/cacheflush.h>
+#include <asm/entry.h>
 
 void show_regs(struct pt_regs *regs)
 {
@@ -65,7 +66,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 		 * the registers. That's OK for a brand new thread.*/
 		memset(childregs, 0, sizeof(struct pt_regs));
 		memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
-		ti->cpu_context.r1  = (unsigned long)childregs;
+		ti->cpu_context.r1  = (unsigned long)childregs - PTO;
 		ti->cpu_context.r20 = (unsigned long)args->fn;
 		ti->cpu_context.r19 = (unsigned long)args->fn_arg;
 		childregs->pt_mode = 1;
@@ -79,7 +80,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 		childregs->r1 = usp;
 
 	memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
-	ti->cpu_context.r1 = (unsigned long)childregs;
+	ti->cpu_context.r1 = (unsigned long)childregs - PTO;
 	childregs->msr |= MSR_UMS;
 
 	/* we should consider the fact that childregs is a copy of the parent
diff --git a/arch/microblaze/kernel/ptrace.c b/arch/microblaze/kernel/ptrace.c
index 236264e932d6..ac1f0503216b 100644
--- a/arch/microblaze/kernel/ptrace.c
+++ b/arch/microblaze/kernel/ptrace.c
@@ -101,6 +101,9 @@ long arch_ptrace(struct task_struct *child, long request,
 			} else {
 				rval = -EIO;
 			}
+		} else if (request == PTRACE_POKEUSR &&
+			   (addr == PT_MSR || addr == PT_MODE)) {
+			rval = -EIO;
 		} else if (addr < PT_SIZE && (addr & 0x3) == 0) {
 			microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
 			if (request == PTRACE_PEEKUSR)
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index c78a0ff48066..6bbc16f98d5e 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -33,6 +33,7 @@
 #include <linux/linkage.h>
 #include <linux/resume_user_mode.h>
 #include <asm/entry.h>
+#include <asm/registers.h>
 #include <asm/ucontext.h>
 #include <linux/uaccess.h>
 #include <linux/syscalls.h>
@@ -49,6 +50,14 @@ struct sigframe {
 };
 
 struct rt_sigframe {
+	/*
+	 * Home area for the handler's register arguments: the MicroBlaze
+	 * ABI reserves [r1+0] for the return address and lets the callee
+	 * store r5..r10 at [r1+4]..[r1+24], and r1 points at this frame
+	 * when the handler is entered.  Without the gap those stores
+	 * corrupt frame->info.
+	 */
+	unsigned long abi_gap[7];
 	struct siginfo info;
 	struct ucontext uc;
 	unsigned long tramp[2];	/* signal trampoline */
@@ -73,6 +82,22 @@ static int restore_sigcontext(struct pt_regs *regs,
 	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
 #undef COPY
 
+	/*
+	 * The frame is user-writable, so restore only the user-writable
+	 * status flags (carry) and keep the kernel-controlled MSR bits
+	 * (UMS/VMS/IE/EE/...) from regs->msr: rtbd derives the resumed mode
+	 * from UMS/VMS, so a verbatim restore would hand userspace the
+	 * privileged return state.  Same idea as x86 masking the restored
+	 * EFLAGS to FIX_EFLAGS.
+	 */
+	{
+		unsigned long msr;
+
+		err |= __get_user(msr, &sc->regs.msr);
+		regs->msr = (regs->msr & ~(MSR_C | MSR_CC)) |
+			    (msr & (MSR_C | MSR_CC));
+	}
+
 	*rval_p = regs->r3;
 
 	return err;
@@ -132,6 +157,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
 	COPY(r30);	COPY(r31);
 	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
+	COPY(msr);	/* restore_sigcontext() accepts only carry state */
 #undef COPY
 
 	err |= __put_user(mask, &sc->oldmask);
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index c55a5c96f49b..76d7cbe2a133 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -193,7 +193,7 @@
 183	common	getcwd				sys_getcwd
 184	common	capget				sys_capget
 185	common	capset				sys_capset
-186	common	sigaltstack			sys_ni_syscall
+186	common	sigaltstack			sys_sigaltstack
 187	common	sendfile			sys_sendfile
 188	common	getpmsg				sys_ni_syscall
 189	common	putpmsg				sys_ni_syscall