arch: arc: bug fixes and add user space support in secure mode

* bug fixes
* add user space support in secure mode

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>

arch/arc/core/isr_wrapper.S

@@ -232,8 +232,12 @@ SECTION_FUNC(TEXT, _isr_wrapper)
 #if CONFIG_USERSPACE
 /* utilize the fact that Z bit is set if interrupt taken in U mode*/
 	bnz _isr_from_privilege
+#ifdef CONFIG_ARC_HAS_SECURE
+	lr sp, [_ARC_V2_SEC_U_SP]
+#else
 /* get the correct stack pointer, don't touch _ARC_V2_USER_SP in the future */
 	aex sp, [_ARC_V2_USER_SP]
+#endif
 _isr_from_privilege:
 #endif
 #if CONFIG_ARC_FIRQ

arch/arc/core/mpu/arc_mpu.c

@@ -356,18 +356,21 @@ void arc_core_mpu_configure(u8_t type, u32_t base, u32_t size)
 	 */
 	index = _mpu_probe(base);
 
-	/* ARC MPU version doesn't support region overlap.
+	/* ARC MPU version 3 doesn't support region overlap.
 	 * So it can not be directly used for stack/stack guard protect
 	 * One way to do this is splitting the ram region as follow:
 	 *
 	 *  Take THREAD_STACK_GUARD_REGION as example:
 	 *  RAM region 0: the ram region before THREAD_STACK_GUARD_REGION, rw
 	 *  RAM THREAD_STACK_GUARD_REGION: RO
-	 *  RAM region 1: the region after THREAD_STACK_GUARD_REGIO, same
+	 *  RAM region 1: the region after THREAD_STACK_GUARD_REGION, same
 	 *                as region 0
+	 *  if region_index == index, it means the same thread comes back,
+	 *  no need to split
 	 */
 
-	if (index >= 0) {  /* need to split, only 1 split is allowed */
+	if (index >= 0 && region_index != index) {
+		/* need to split, only 1 split is allowed */
 		/* find the correct region to mpu_config.mpu_regions */
 		if (index == last_region) {
 			/* already split */

arch/arc/core/offsets/offsets.c

@@ -80,7 +80,12 @@ GEN_OFFSET_SYM(_callee_saved_stack_t, r25);
 GEN_OFFSET_SYM(_callee_saved_stack_t, r26);
 GEN_OFFSET_SYM(_callee_saved_stack_t, fp);
 #ifdef CONFIG_USERSPACE
+#ifdef CONFIG_ARC_HAS_SECURE
+GEN_OFFSET_SYM(_callee_saved_stack_t, kernel_sp);
 GEN_OFFSET_SYM(_callee_saved_stack_t, user_sp);
+#else
+GEN_OFFSET_SYM(_callee_saved_stack_t, user_sp);
+#endif
 #endif
 GEN_OFFSET_SYM(_callee_saved_stack_t, r30);
 #ifdef CONFIG_FP_SHARING

arch/arc/core/swap.S

@@ -90,6 +90,11 @@ SECTION_FUNC(TEXT, __swap)
 	bclr r3, r3, _ARC_V2_STATUS32_SC_BIT
 	kflag r3
 #endif
+
+#ifdef CONFIG_ARC_HAS_SECURE
+	lr r3, [_ARC_V2_SEC_STAT]
+	push_s r3
+#endif
 	push_s blink
 
 	_save_callee_saved_regs
@@ -137,6 +142,12 @@ _swap_return_from_coop:
 	bbit1 ilink, _ARC_V2_STATUS32_AE_BIT, _return_from_exc
 
 	pop_s blink /* pc into blink */
+#ifdef CONFIG_ARC_HAS_SECURE
+	pop_s r3    /* pop SEC_STAT */
+	/* sflag r3 */
+	/* sflag instruction is not supported in current ARC GNU */
+	.long 0x00ff302f
+#endif
 	pop_s r3    /* status32 into r3 */
 	kflag r3    /* write status32 */
 
@@ -172,6 +183,8 @@ _return_from_exc:
 	ld ilink, [sp] /* pc into ilink */
 	sr ilink, [_ARC_V2_ERET]
 
+	/* SEC_STAT is bypassed when CONFIG_ARC_HAS_SECURE */
+
 	/* put status32 into estatus */
 	ld ilink, [sp, ___isf_t_status32_OFFSET - ___isf_t_pc_OFFSET]
 	sr ilink, [_ARC_V2_ERSTATUS]

arch/arc/core/thread.c

@@ -22,6 +22,9 @@
 /*  initial stack frame */
 struct init_stack_frame {
 	u32_t pc;
+#ifdef CONFIG_ARC_HAS_SECURE
+	u32_t sec_stat;
+#endif
 	u32_t status32;
 	u32_t r3;
 	u32_t r2;
@@ -99,6 +102,11 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 #else
 	pInitCtx->pc = ((u32_t)_thread_entry_wrapper);
 #endif
+
+#ifdef CONFIG_ARC_HAS_SECURE
+	pInitCtx->sec_stat = _arc_v2_aux_reg_read(_ARC_V2_SEC_STAT);
+#endif
+
 	pInitCtx->r0 = (u32_t)pEntry;
 	pInitCtx->r1 = (u32_t)parameter1;
 	pInitCtx->r2 = (u32_t)parameter2;

arch/arc/core/userspace.S

@@ -56,12 +56,19 @@ _clear_user_stack:
 	sr r0, [_ARC_V2_ERSTATUS]
 	sr r1, [_ARC_V2_ERET]
 
+#ifdef CONFIG_ARC_HAS_SECURE
+	lr r0, [_ARC_V2_SEC_STAT]
+	/* the mode returns from exception return is secure mode */
+	bset r0, r0, 31
+	sr r0, [_ARC_V2_ERSEC_STAT]
+	sr r5, [_ARC_V2_SEC_U_SP]
+#else
 	/* when exception returns from kernel to user, sp and _ARC_V2_USER_SP
 	 * will be switched
 	 */
 	sr r5, [_ARC_V2_USER_SP]
+#endif
 	mov sp, r2
-
 	rtie
 
 /**
@@ -94,6 +101,12 @@ SECTION_FUNC(TEXT, _arc_do_syscall)
 	/* through fake exception return, go back to the caller */
 	kflag _ARC_V2_STATUS32_AE
 
+#ifdef CONFIG_ARC_HAS_SECURE
+	lr r6, [_ARC_V2_SEC_STAT]
+	/* the mode returns from exception return is secure mode */
+	bset r6, r6, 31
+	sr r6, [_ARC_V2_ERSEC_STAT]
+#endif
 	/* the status and return addesss are saved in trap_s handler */
 	pop r6
 	sr r6, [_ARC_V2_ERSTATUS]

arch/arc/include/kernel_arch_data.h

@@ -131,7 +131,12 @@ struct _callee_saved_stack {
 	u32_t fp; /* r27 */
 
 #ifdef CONFIG_USERSPACE
+#ifdef CONFIG_ARC_HAS_SECURE
 	u32_t user_sp;
+	u32_t kernel_sp;
+#else
+	u32_t user_sp;
+#endif
 #endif
 	/* r28 is the stack pointer and saved separately */
 	/* r29 is ILINK and does not need to be saved */

arch/arc/include/swap_macros.h

@@ -43,8 +43,15 @@ extern "C" {
 	st fp,  [sp, ___callee_saved_stack_t_fp_OFFSET]
 
 #ifdef CONFIG_USERSPACE
+#ifdef CONFIG_ARC_HAS_SECURE
+	lr r13, [_ARC_V2_SEC_U_SP]
+	st r13, [sp, ___callee_saved_stack_t_user_sp_OFFSET]
+	lr r13, [_ARC_V2_SEC_K_SP]
+	st r13, [sp, ___callee_saved_stack_t_kernel_sp_OFFSET]
+#else
 	lr r13, [_ARC_V2_USER_SP]
 	st r13, [sp, ___callee_saved_stack_t_user_sp_OFFSET]
+#endif
 #endif
 	st r30, [sp, ___callee_saved_stack_t_r30_OFFSET]
 
@@ -101,8 +108,15 @@ extern "C" {
 #endif
 
 #ifdef CONFIG_USERSPACE
+#ifdef CONFIG_ARC_HAS_SECURE
+	ld r13, [sp, ___callee_saved_stack_t_user_sp_OFFSET]
+	sr r13, [_ARC_V2_SEC_U_SP]
+	ld r13, [sp, ___callee_saved_stack_t_kernel_sp_OFFSET]
+	sr r13, [_ARC_V2_SEC_K_SP]
+#else
 	ld_s r13, [sp, ___callee_saved_stack_t_user_sp_OFFSET]
 	sr r13, [_ARC_V2_USER_SP]
+#endif
 #endif
 
 	ld_s r13, [sp, ___callee_saved_stack_t_r13_OFFSET]

boards/arc/em_starterkit/arc_mpu_regions.c

@@ -13,16 +13,16 @@ static struct arc_mpu_region mpu_regions[] = {
 #if CONFIG_ARC_MPU_VER == 3 && defined(CONFIG_APPLICATION_MEMORY)
 	/* Region ICCM */
 	MPU_REGION_ENTRY("IMAGE ROM",
-			 _image_rom_start,
+			 (u32_t) _image_rom_start,
-			 _image_rom_end,
+			 (u32_t) _image_rom_end,
 			 REGION_FLASH_ATTR),
 	MPU_REGION_ENTRY("APP MEMORY",
-			 __app_ram_start,
+			 (u32_t) __app_ram_start,
-			 __app_ram_size,
+			 (u32_t) __app_ram_size,
 			 REGION_RAM_ATTR),
 	MPU_REGION_ENTRY("KERNEL MEMORY",
-			 __kernel_ram_start,
+			 (u32_t) __kernel_ram_start,
-			 __kernel_ram_size,
+			 (u32_t) __kernel_ram_size,
 			 AUX_MPU_RDP_KW | AUX_MPU_RDP_KR),
 
 #else

include/arch/arc/v2/aux_regs.h

@@ -37,6 +37,8 @@ extern "C" {
 #define _ARC_V2_TMR0_LIMIT 0x023
 #define _ARC_V2_IRQ_VECT_BASE    0x025
 #define _ARC_V2_IRQ_VECT_BASE_S 0x26
+#define _ARC_V2_SEC_U_SP 0x39
+#define _ARC_V2_SEC_K_SP 0x3a
 #define _ARC_V2_AUX_IRQ_ACT 0x043
 #define _ARC_V2_DC_IVDC 0x047
 #define _ARC_V2_DC_CTRL 0x048
@@ -83,6 +85,7 @@ extern "C" {
 #define _ARC_V2_ERSTATUS 0x402
 #define _ARC_V2_ECR 0x403
 #define _ARC_V2_EFA 0x404
+#define _ARC_V2_ERSEC_STAT 0x406
 #define _ARC_V2_ICAUSE 0x40a
 #define _ARC_V2_IRQ_SELECT 0x40b
 #define _ARC_V2_IRQ_ENABLE 0x40c