arc: introduce separate section for interrupt vector table

Even though existing implementation works fine in preparation to submission of ARCv2 architecture we need this change. In case of ARCv2 interrupt vector table consists of just addresses of corresponding handlers. And if those addresses will be in .text section then assembler will encode them as everything in .text section as middle-endian and then on real execution CPU will read swapped addresses and will jump into the wild. Once introduced new section is situated so .text section remains the first which allows us to use common linker option for linking everything to a specified CONFIG_SYS_TEXT_BASE. Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Signed-off-by: Igor Guryanov <guryanov@synopsys.com>

arc: introduce separate section for interrupt vector table
Even though existing implementation works fine in preparation to submission of ARCv2 architecture we need this change. In case of ARCv2 interrupt vector table consists of just addresses of corresponding handlers. And if those addresses will be in .text section then assembler will encode them as everything in .text section as middle-endian and then on real execution CPU will read swapped addresses and will jump into the wild. Once introduced new section is situated so .text section remains the first which allows us to use common linker option for linking everything to a specified CONFIG_SYS_TEXT_BASE. Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Signed-off-by: Igor Guryanov <guryanov@synopsys.com>
Igor Guryanov · Alexey Brodkin
1 parent dcb431e723
Showing 7 changed files with 46 additions and 31 deletions Side-by-side Diff
arch/arc/Makefile
arch/arc/cpu/arc700/Makefile
arch/arc/cpu/arc700/start.S
arch/arc/cpu/arc700/u-boot.lds
arch/arc/include/asm/sections.h
arch/arc/lib/relocate.c
arch/arc/lib/sections.c
@@ -2,8 +2,6 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
  
-head-y := arch/arc/cpu/$(CPU)/start.o
-
 libs-y += arch/arc/cpu/$(CPU)/
 libs-y += arch/arc/lib/
  
@@ -4,11 +4,10 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
  
-extra-y	+= start.o
-
 obj-y	+= cache.o
 obj-y	+= cpu.o
 obj-y	+= interrupts.o
 obj-y	+= reset.o
+obj-y	+= start.o
 obj-y	+= timer.o
@@ -88,11 +88,11 @@
 #endif
 .endm
  
+.section .ivt, "ax",@progbits
 .align 4
-.globl _start
-_start:
+_ivt:
 	/* Critical system events */
-	j	reset			/* 0 - 0x000 */
+	j	_start			/* 0 - 0x000 */
 	j	memory_error		/* 1 - 0x008 */
 	j	instruction_error	/* 2 - 0x010 */
  
@@ -110,6 +110,28 @@
 	j	EV_Trap			/* 0x128, Trap exception       (0x25) */
 	j	EV_Extension		/* 0x130, Extn Intruction Excp (0x26) */
  
+.text
+.globl _start
+_start:
+	/* Setup interrupt vector base that matches "__text_start" */
+	sr	__ivt_start, [ARC_AUX_INTR_VEC_BASE]
+
+	/* Setup stack pointer */
+	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
+	mov	%fp, %sp
+
+	/* Clear bss */
+	mov	%r0, __bss_start
+	mov	%r1, __bss_end
+
+clear_bss:
+	st.ab	0, [%r0, 4]
+	brlt	%r0, %r1, clear_bss
+
+	/* Zero the one and only argument of "board_init_f" */
+	mov_s	%r0, 0
+	j	board_init_f
+
 memory_error:
 	SAVE_ALL_SYS
 	SAVE_EXCEPTION_SOURCE
@@ -163,27 +185,6 @@
 	SAVE_ALL_SYS
 	mov	%r0, %sp
 	j	do_extension
-
-
-reset:
-	/* Setup interrupt vector base that matches "__text_start" */
-	sr	__text_start, [ARC_AUX_INTR_VEC_BASE]
-
-	/* Setup stack pointer */
-	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
-	mov	%fp, %sp
-
-	/* Clear bss */
-	mov	%r0, __bss_start
-	mov	%r1, __bss_end
-
-clear_bss:
-	st.ab	0, [%r0, 4]
-	brlt	%r0, %r1, clear_bss
-
-	/* Zero the one and only argument of "board_init_f" */
-	mov_s	%r0, 0
-	j	board_init_f
  
 /*
  * void relocate_code (addr_sp, gd, addr_moni)
@@ -13,7 +13,6 @@
 	.text :	{
 		*(.__text_start)
 		*(.__image_copy_start)
-		CPUDIR/start.o (.text*)
 		*(.text*)
 	}
  
@@ -21,6 +20,20 @@
 	.text_end :
 	{
 		*(.__text_end)
+	}
+
+	. = ALIGN(1024);
+	.ivt_start : {
+		*(.__ivt_start)
+	}
+
+	.ivt :
+	{
+		*(.ivt)
+	}
+
+	.ivt_end : {
+		*(.__ivt_end)
 	}
  
 	. = ALIGN(4);
@@ -10,6 +10,8 @@
 #include <asm-generic/sections.h>
  
 extern ulong __text_end;
+extern ulong __ivt_start;
+extern ulong __ivt_end;
  
 #endif /* __ASM_ARC_SECTIONS_H */
@@ -44,7 +44,7 @@
 #ifdef __LITTLE_ENDIAN__
 			/* If location in ".text" section swap value */
 			if ((unsigned int)offset_ptr_rom <
-			    (unsigned int)&__text_end)
+			    (unsigned int)&__ivt_end)
 				val = (val << 16) | (val >> 16);
 #endif
  
@@ -55,7 +55,7 @@
 #ifdef __LITTLE_ENDIAN__
 				/* If location in ".text" section swap value */
 				if ((unsigned int)offset_ptr_rom <
-				    (unsigned int)&__text_end)
+				    (unsigned int)&__ivt_end)
 					val = (val << 16) | (val >> 16);
 #endif
 				memcpy(offset_ptr_ram, &val, sizeof(int));
@@ -19,4 +19,6 @@
 char __text_start[0] __attribute__((section(".__text_start")));
 char __text_end[0] __attribute__((section(".__text_end")));
 char __init_end[0] __attribute__((section(".__init_end")));
+char __ivt_start[0] __attribute__((section(".__ivt_start")));
+char __ivt_end[0] __attribute__((section(".__ivt_end")));
...	...	@@ -2,8 +2,6 @@
2	2	# SPDX-License-Identifier: GPL-2.0+
3	3	#
4	4
5		-head-y := arch/arc/cpu/$(CPU)/start.o
6		-
7	5	libs-y += arch/arc/cpu/$(CPU)/
8	6	libs-y += arch/arc/lib/
9	7
...	...	@@ -4,11 +4,10 @@
4	4	# SPDX-License-Identifier: GPL-2.0+
5	5	#
6	6
7		-extra-y += start.o
8		-
9	7	obj-y += cache.o
10	8	obj-y += cpu.o
11	9	obj-y += interrupts.o
12	10	obj-y += reset.o
	11	+obj-y += start.o
13	12	obj-y += timer.o
...	...	@@ -88,11 +88,11 @@
88	88	#endif
89	89	.endm
90	90
	91	+.section .ivt, "ax",@progbits
91	92	.align 4
92		-.globl _start
93		-_start:
	93	+_ivt:
94	94	/* Critical system events */
95		- j reset /* 0 - 0x000 */
	95	+ j _start /* 0 - 0x000 */
96	96	j memory_error /* 1 - 0x008 */
97	97	j instruction_error /* 2 - 0x010 */
98	98
...	...	@@ -110,6 +110,28 @@
110	110	j EV_Trap /* 0x128, Trap exception (0x25) */
111	111	j EV_Extension /* 0x130, Extn Intruction Excp (0x26) */
112	112
	113	+.text
	114	+.globl _start
	115	+_start:
	116	+ /* Setup interrupt vector base that matches "__text_start" */
	117	+ sr __ivt_start, [ARC_AUX_INTR_VEC_BASE]
	118	+
	119	+ /* Setup stack pointer */
	120	+ mov %sp, CONFIG_SYS_INIT_SP_ADDR
	121	+ mov %fp, %sp
	122	+
	123	+ /* Clear bss */
	124	+ mov %r0, __bss_start
	125	+ mov %r1, __bss_end
	126	+
	127	+clear_bss:
	128	+ st.ab 0, [%r0, 4]
	129	+ brlt %r0, %r1, clear_bss
	130	+
	131	+ /* Zero the one and only argument of "board_init_f" */
	132	+ mov_s %r0, 0
	133	+ j board_init_f
	134	+
113	135	memory_error:
114	136	SAVE_ALL_SYS
115	137	SAVE_EXCEPTION_SOURCE
...	...	@@ -163,27 +185,6 @@
163	185	SAVE_ALL_SYS
164	186	mov %r0, %sp
165	187	j do_extension
166		-
167		-
168		-reset:
169		- /* Setup interrupt vector base that matches "__text_start" */
170		- sr __text_start, [ARC_AUX_INTR_VEC_BASE]
171		-
172		- /* Setup stack pointer */
173		- mov %sp, CONFIG_SYS_INIT_SP_ADDR
174		- mov %fp, %sp
175		-
176		- /* Clear bss */
177		- mov %r0, __bss_start
178		- mov %r1, __bss_end
179		-
180		-clear_bss:
181		- st.ab 0, [%r0, 4]
182		- brlt %r0, %r1, clear_bss
183		-
184		- /* Zero the one and only argument of "board_init_f" */
185		- mov_s %r0, 0
186		- j board_init_f
187	188
188	189	/*
189	190	* void relocate_code (addr_sp, gd, addr_moni)
...	...	@@ -13,7 +13,6 @@
13	13	.text : {
14	14	*(.__text_start)
15	15	*(.__image_copy_start)
16		- CPUDIR/start.o (.text*)
17	16	(.text)
18	17	}
19	18
...	...	@@ -21,6 +20,20 @@
21	20	.text_end :
22	21	{
23	22	*(.__text_end)
	23	+ }
	24	+
	25	+ . = ALIGN(1024);
	26	+ .ivt_start : {
	27	+ *(.__ivt_start)
	28	+ }
	29	+
	30	+ .ivt :
	31	+ {
	32	+ *(.ivt)
	33	+ }
	34	+
	35	+ .ivt_end : {
	36	+ *(.__ivt_end)
24	37	}
25	38
26	39	. = ALIGN(4);
...	...	@@ -10,6 +10,8 @@
10	10	#include <asm-generic/sections.h>
11	11
12	12	extern ulong __text_end;
	13	+extern ulong __ivt_start;
	14	+extern ulong __ivt_end;
13	15
14	16	#endif /* __ASM_ARC_SECTIONS_H */
...	...	@@ -44,7 +44,7 @@
44	44	#ifdef __LITTLE_ENDIAN__
45	45	/* If location in ".text" section swap value */
46	46	if ((unsigned int)offset_ptr_rom <
47		- (unsigned int)&__text_end)
	47	+ (unsigned int)&__ivt_end)
48	48	val = (val << 16) \| (val >> 16);
49	49	#endif
50	50
...	...	@@ -55,7 +55,7 @@
55	55	#ifdef __LITTLE_ENDIAN__
56	56	/* If location in ".text" section swap value */
57	57	if ((unsigned int)offset_ptr_rom <
58		- (unsigned int)&__text_end)
	58	+ (unsigned int)&__ivt_end)
59	59	val = (val << 16) \| (val >> 16);
60	60	#endif
61	61	memcpy(offset_ptr_ram, &val, sizeof(int));
...	...	@@ -19,4 +19,6 @@
19	19	char __text_start[0] __attribute__((section(".__text_start")));
20	20	char __text_end[0] __attribute__((section(".__text_end")));
21	21	char __init_end[0] __attribute__((section(".__init_end")));
	22	+char __ivt_start[0] __attribute__((section(".__ivt_start")));
	23	+char __ivt_end[0] __attribute__((section(".__ivt_end")));