[PATCH] ARC: SMP failed to boot due to missing IVT setup

From: Noam Camus
Date: Thu Sep 12 2013 - 03:37:39 EST


Commit 05b016ecf5e7a "ARC: Setup Vector Table Base in early boot" moved
the Interrupt vector Table setup out of arc_init_IRQ() which is called
for all CPUs, to entry point of boot cpu only, breaking booting of others.

Fix by adding the same to entry point of non-boot CPUs too.

read_arc_build_cfg_regs() printing IVT Base Register didn't help the
casue since it prints a synthetic value if zero which is totally bogus,
so fix that to print the exact Register.

[vgupta: Remove the now stale comment from header of arc_init_IRQ and
also added the commentary for halt-on-reset]

Cc: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
Cc: Cc: <stable@xxxxxxxxxxxxxxx> #3.11
Signed-off-by: Noam Camus <noamc@xxxxxxxxxx>
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
---
arch/arc/include/asm/sections.h | 1 -
arch/arc/kernel/head.S | 5 +++++
arch/arc/kernel/irq.c | 1 -
arch/arc/kernel/setup.c | 3 ---
4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arc/include/asm/sections.h b/arch/arc/include/asm/sections.h
index 6fc1159..764f1e3 100644
--- a/arch/arc/include/asm/sections.h
+++ b/arch/arc/include/asm/sections.h
@@ -11,7 +11,6 @@

#include <asm-generic/sections.h>

-extern char _int_vec_base_lds[];
extern char __arc_dccm_base[];
extern char __dtb_start[];

diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 2a913f8..0f944f0 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -34,6 +34,9 @@ stext:
; IDENTITY Reg [ 3 2 1 0 ]
; (cpu-id) ^^^ => Zero for UP ARC700
; => #Core-ID if SMP (Master 0)
+ ; Note that non-boot CPUs might not land here if halt-on-reset and
+ ; instead breath life from @first_lines_of_secondary, but we still
+ ; need to make sure only boot cpu takes this path.
GET_CPU_ID r5
cmp r5, 0
jnz arc_platform_smp_wait_to_boot
@@ -98,6 +101,8 @@ stext:

first_lines_of_secondary:

+ sr @_int_vec_base_lds, [AUX_INTR_VEC_BASE]
+
; setup per-cpu idle task as "current" on this CPU
ld r0, [@secondary_idle_tsk]
SET_CURR_TASK_ON_CPU r0, r1
diff --git a/arch/arc/kernel/irq.c b/arch/arc/kernel/irq.c
index 305b3f8..5fc9245 100644
--- a/arch/arc/kernel/irq.c
+++ b/arch/arc/kernel/irq.c
@@ -24,7 +24,6 @@
* -Needed for each CPU (hence not foldable into init_IRQ)
*
* what it does ?
- * -setup Vector Table Base Reg - in case Linux not linked at 0x8000_0000
* -Disable all IRQs (on CPU side)
* -Optionally, setup the High priority Interrupts as Level 2 IRQs
*/
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index cd74625..d9e15f1 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -46,10 +46,7 @@ static void read_arc_build_cfg_regs(void)
READ_BCR(AUX_IDENTITY, cpu->core);

cpu->timers = read_aux_reg(ARC_REG_TIMERS_BCR);
-
cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
- if (cpu->vec_base == 0)
- cpu->vec_base = (unsigned int)_int_vec_base_lds;

READ_BCR(ARC_REG_D_UNCACH_BCR, uncached_space);
cpu->uncached_base = uncached_space.start << 24;
--
1.8.1.2
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