summaryrefslogtreecommitdiffstats
path: root/arch/xtensa/kernel/head.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/xtensa/kernel/head.S')
-rw-r--r--arch/xtensa/kernel/head.S130
1 files changed, 87 insertions, 43 deletions
diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index 7d740ebbe198..74ec62c892bc 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S
@@ -19,6 +19,7 @@
#include <asm/page.h>
#include <asm/cacheasm.h>
#include <asm/initialize_mmu.h>
+#include <asm/mxregs.h>
#include <linux/init.h>
#include <linux/linkage.h>
@@ -54,7 +55,7 @@ ENTRY(_start)
/* Preserve the pointer to the boot parameter list in EXCSAVE_1 */
wsr a2, excsave1
- _j _SetupMMU
+ _j _SetupOCD
.align 4
.literal_position
@@ -62,6 +63,23 @@ ENTRY(_start)
.word _startup
.align 4
+_SetupOCD:
+ /*
+ * Initialize WB, WS, and clear PS.EXCM (to allow loop instructions).
+ * Set Interrupt Level just below XCHAL_DEBUGLEVEL to allow
+ * xt-gdb to single step via DEBUG exceptions received directly
+ * by ocd.
+ */
+ movi a1, 1
+ movi a0, 0
+ wsr a1, windowstart
+ wsr a0, windowbase
+ rsync
+
+ movi a1, LOCKLEVEL
+ wsr a1, ps
+ rsync
+
.global _SetupMMU
_SetupMMU:
Offset = _SetupMMU - _start
@@ -90,19 +108,6 @@ ENDPROC(_start)
ENTRY(_startup)
- /* Disable interrupts and exceptions. */
-
- movi a0, LOCKLEVEL
- wsr a0, ps
-
- /* Start with a fresh windowbase and windowstart. */
-
- movi a1, 1
- movi a0, 0
- wsr a1, windowstart
- wsr a0, windowbase
- rsync
-
/* Set a0 to 0 for the remaining initialization. */
movi a0, 0
@@ -154,17 +159,6 @@ ENTRY(_startup)
wsr a0, cpenable
#endif
- /* Set PS.INTLEVEL=LOCKLEVEL, PS.WOE=0, kernel stack, PS.EXCM=0
- *
- * Note: PS.EXCM must be cleared before using any loop
- * instructions; otherwise, they are silently disabled, and
- * at most one iteration of the loop is executed.
- */
-
- movi a1, LOCKLEVEL
- wsr a1, ps
- rsync
-
/* Initialize the caches.
* a2, a3 are just working registers (clobbered).
*/
@@ -182,6 +176,37 @@ ENTRY(_startup)
isync
+#ifdef CONFIG_HAVE_SMP
+ movi a2, CCON # MX External Register to Configure Cache
+ movi a3, 1
+ wer a3, a2
+#endif
+
+ /* Setup stack and enable window exceptions (keep irqs disabled) */
+
+ movi a1, start_info
+ l32i a1, a1, 0
+
+ movi a2, (1 << PS_WOE_BIT) | LOCKLEVEL
+ # WOE=1, INTLEVEL=LOCKLEVEL, UM=0
+ wsr a2, ps # (enable reg-windows; progmode stack)
+ rsync
+
+ /* Set up EXCSAVE[DEBUGLEVEL] to point to the Debug Exception Handler.*/
+
+ movi a2, debug_exception
+ wsr a2, SREG_EXCSAVE + XCHAL_DEBUGLEVEL
+
+#ifdef CONFIG_SMP
+ /*
+ * Notice that we assume with SMP that cores have PRID
+ * supported by the cores.
+ */
+ rsr a2, prid
+ bnez a2, .Lboot_secondary
+
+#endif /* CONFIG_SMP */
+
/* Unpack data sections
*
* The linker script used to build the Linux kernel image
@@ -234,24 +259,7 @@ ENTRY(_startup)
___invalidate_icache_all a2 a3
isync
- /* Setup stack and enable window exceptions (keep irqs disabled) */
-
- movi a1, init_thread_union
- addi a1, a1, KERNEL_STACK_SIZE
-
- movi a2, (1 << PS_WOE_BIT) | LOCKLEVEL
- # WOE=1, INTLEVEL=LOCKLEVEL, UM=0
- wsr a2, ps # (enable reg-windows; progmode stack)
- rsync
-
- /* Set up EXCSAVE[DEBUGLEVEL] to point to the Debug Exception Handler.*/
-
- movi a2, debug_exception
- wsr a2, SREG_EXCSAVE + XCHAL_DEBUGLEVEL
-
- /* Set up EXCSAVE[1] to point to the exc_table. */
-
- movi a6, exc_table
+ movi a6, 0
xsr a6, excsave1
/* init_arch kick-starts the linux kernel */
@@ -265,9 +273,45 @@ ENTRY(_startup)
should_never_return:
j should_never_return
+#ifdef CONFIG_SMP
+.Lboot_secondary:
+
+ movi a2, cpu_start_ccount
+1:
+ l32i a3, a2, 0
+ beqi a3, 0, 1b
+ movi a3, 0
+ s32i a3, a2, 0
+ memw
+1:
+ l32i a3, a2, 0
+ beqi a3, 0, 1b
+ wsr a3, ccount
+ movi a3, 0
+ s32i a3, a2, 0
+ memw
+
+ movi a6, 0
+ wsr a6, excsave1
+
+ movi a4, secondary_start_kernel
+ callx4 a4
+ j should_never_return
+
+#endif /* CONFIG_SMP */
+
ENDPROC(_startup)
/*
+ * DATA section
+ */
+
+ .section ".data.init.refok"
+ .align 4
+ENTRY(start_info)
+ .long init_thread_union + KERNEL_STACK_SIZE
+
+/*
* BSS section
*/
OpenPOWER on IntegriCloud