libpayload arm64: Make exceptions work

BUG=chrome-os-partner:31634
BRANCH=None
TEST=test_exc generates and handles exceptions properly

Change-Id: If3ecab93be6d02942b52960ec97edc687bedf64b
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: bba2caae0bd436ba9e5215f5d8606ce8c4987c98
Original-Change-Id: I4abe8a0e426eab2532852179dbb32505353cd0a1
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/214609
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/8783
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

4 files changed, 73 insertions, 56 deletions

diff --git a/payloads/libpayload/arch/arm64/exception.c b/payloads/libpayload/arch/arm64/exception.c
index 226f5ca27d..2330a98456 100644
--- a/payloads/libpayload/arch/arm64/exception.c
+++ b/payloads/libpayload/arch/arm64/exception.c
@@ -40,22 +40,34 @@ struct exception_handler_info
 
 static exception_hook hook;
 struct exception_state *exception_state;
+
 static struct exception_handler_info exceptions[EXC_COUNT] = {
-	[EXC_INV]  = { "_invalid_exception" },
-	[EXC_SYNC] = { "_sync" },
-	[EXC_IRQ]  = { "_irq" },
-	[EXC_FIQ]  = { "_fiq" },
-	[EXC_SERROR] = {"_serror"}
+	[EXC_SYNC_SP0] = { "_sync_sp_el0" },
+	[EXC_IRQ_SP0]  = { "_irq_sp_el0" },
+	[EXC_FIQ_SP0]  = { "_fiq_sp_el0" },
+	[EXC_SERROR_SP0] = {"_serror_sp_el0"},
+	[EXC_SYNC_SPX] = { "_sync_spx" },
+	[EXC_IRQ_SPX]  = { "_irq_spx" },
+	[EXC_FIQ_SPX]  = { "_fiq_spx" },
+	[EXC_SERROR_SPX] = {"_serror_spx"},
+	[EXC_SYNC_ELX_64] = { "_sync_elx_64" },
+	[EXC_IRQ_ELX_64]  = { "_irq_elx_64" },
+	[EXC_FIQ_ELX_64]  = { "_fiq_elx_64" },
+	[EXC_SERROR_ELX_64] = {"_serror_elx_64"},
+	[EXC_SYNC_ELX_32] = { "_sync_elx_32" },
+	[EXC_IRQ_ELX_32]  = { "_irq_elx_32" },
+	[EXC_FIQ_ELX_32]  = { "_fiq_elx_32" },
+	[EXC_SERROR_ELX_32] = {"_serror_elx_32"},
 };
 
 static void print_regs(struct exception_state *state)
 {
 	int i;
 
-	printf("ELR = 0x%016llx        ",state->elr);
-	printf("ESR = 0x%08llx         ",state->esr);
+	printf("ELR = 0x%016llx\n",state->elr);
+	printf("ESR = 0x%08llx\n",state->esr);
 	for (i = 0; i < 31; i++) {
-		printf("X%02d = 0x%016llx        ", i, state->regs[i]);
+		printf("X%02d = 0x%016llx\n", i, state->regs[i]);
 	}
 }
 
@@ -78,8 +90,11 @@ void exception_dispatch(struct exception_state *state, int idx)
 	}
 	print_regs(state);
 
-	if (test_exc)
+	if (test_exc) {
+		state->elr += 4;
 		test_exc = 0;
+		printf("returning back now\n");
+	}
 	else
 		halt();
 }
@@ -87,7 +102,7 @@ void exception_dispatch(struct exception_state *state, int idx)
 void exception_init(void)
 {
 	extern void* exception_table;
-	set_vbar(exception_table);
+	set_vbar(&exception_table);
 }
 
 void exception_install_hook(exception_hook h)
diff --git a/payloads/libpayload/arch/arm64/exception_asm.S b/payloads/libpayload/arch/arm64/exception_asm.S
index c68ba5a7c6..8e69ddad86 100644
--- a/payloads/libpayload/arch/arm64/exception_asm.S
+++ b/payloads/libpayload/arch/arm64/exception_asm.S
@@ -35,11 +35,13 @@
 	 * Move exception id into x1
 	 * Branch to exception_handler
 	 */
-.macro eentry id
-	stp     x30, xzr, [sp, #-16]!
-	bl      exception_prologue
-	mov     x1, \id
-	bl      exception_handler
+.macro eentry lbl id
+	.align 7
+\lbl:
+	stp	x30, xzr, [sp, #-16]!
+	bl	exception_prologue
+	mov	x1, \id
+	bl	exception_handler
 .endm
 
 	/* Exception table has 16 entries and each of 128 bytes
@@ -51,37 +53,22 @@
 	.global exception_table
 exception_table:
 
-	.align  7
-sync_el0:
-	eentry #0
-
-	.align  7
-irq_el0:
-	eentry #0
-
-	.align  7
-fiq_el0:
-	eentry #0
-
-	.align  7
-serror_el0:
-	eentry #0
-
-	.align  7
-sync_elx:
-	eentry #1
-
-	.align  7
-irq_elx:
-	eentry #2
-
-	.align  7
-fiq_elx:
-	eentry #3
-
-	.align  7
-serror_elx:
-	eentry #4
+eentry	sync_sp0,#0
+eentry	irq_sp0,#1
+eentry	fiq_sp0,#2
+eentry	serror_sp0,#3
+eentry	sync_spx,#4
+eentry	irq_spx,#5
+eentry	fiq_spx,#6
+eentry	serror_spx,#7
+eentry	sync_elx_64,#8
+eentry	irq_elx_64,#9
+eentry	fiq_elx_64,#10
+eentry	serror_elx_64,#11
+eentry	sync_elx_32,#12
+eentry	irq_elx_32,#13
+eentry	fiq_elx_32,#14
+eentry	serror_elx_32,#15
 
 exception_prologue:
 	/* Save all registers x0-x29 */
@@ -119,6 +106,8 @@ exception_handler:
 
 	/* Pop return address saved on stack */
 	ldp     x0, x1, [sp], #16
+	msr     elr_el3, x0
+	msr     esr_el3, x1
 	/* Pop exception reason saved on stack, followed by regs x0-x30 */
 	ldp     x0, x1, [sp], #16
 	ldp     x2, x3, [sp], #16
diff --git a/payloads/libpayload/arch/arm64/gdb.c b/payloads/libpayload/arch/arm64/gdb.c
index 857272f095..c976483f04 100644
--- a/payloads/libpayload/arch/arm64/gdb.c
+++ b/payloads/libpayload/arch/arm64/gdb.c
@@ -33,11 +33,22 @@ struct gdb_regs
 } __attribute__((packed));
 
 static const u8 type_to_signal[] = {
-	[EXC_INV]    = GDB_SIGILL,
-	[EXC_SYNC]   = GDB_SIGTRAP,
-	[EXC_IRQ]    = GDB_SIGSEGV,
-	[EXC_FIQ]    = GDB_SIGSEGV,
-	[EXC_SERROR] = GDB_SIGSEGV
+	[EXC_SYNC_SP0] = GDB_SIGTRAP,
+	[EXC_IRQ_SP0] = GDB_SIGSEGV,
+	[EXC_FIQ_SP0] = GDB_SIGSEGV,
+	[EXC_SERROR_SP0] = GDB_SIGSEGV,
+	[EXC_SYNC_SPX] = GDB_SIGTRAP,
+	[EXC_IRQ_SPX] = GDB_SIGSEGV,
+	[EXC_FIQ_SPX] = GDB_SIGSEGV,
+	[EXC_SERROR_SPX] = GDB_SIGSEGV,
+	[EXC_SYNC_ELX_64] = GDB_SIGTRAP,
+	[EXC_IRQ_ELX_64] = GDB_SIGSEGV,
+	[EXC_FIQ_ELX_64] = GDB_SIGSEGV,
+	[EXC_SERROR_ELX_64] = GDB_SIGSEGV,
+	[EXC_SYNC_ELX_32] = GDB_SIGTRAP,
+	[EXC_IRQ_ELX_32] = GDB_SIGSEGV,
+	[EXC_FIQ_ELX_32] = GDB_SIGSEGV,
+	[EXC_SERROR_ELX_32] = GDB_SIGSEGV
 };
 
 static int gdb_exception_hook(u32 type)
diff --git a/payloads/libpayload/arch/arm64/main.c b/payloads/libpayload/arch/arm64/main.c
index 864e3cafd1..6b45a018c2 100644
--- a/payloads/libpayload/arch/arm64/main.c
+++ b/payloads/libpayload/arch/arm64/main.c
@@ -37,13 +37,15 @@ char *main_argv[MAX_ARGC_COUNT];
 
 unsigned int test_exc;
 
-int test_exception(void);
-int test_exception(void)
+static int test_exception(void)
 {
-	int a = 1;
-	int b = 0;
+	uint64_t *a = (uint64_t *)0xfffffffff0000000ULL;
+
 	test_exc = 1;
-	return a/b;
+
+	printf("%llx\n", *a);
+
+	return 0;
 }
 
 /**