Before the CRT was (fully) set up in kernel_entry (bss cleared before in
_start, but also not before jump to panic() in no_tag_table case).
This patch fixes this up to have a fully working CRT when branching to panic()
in no_tag_table.
Signed-off-by: Andreas Bießmann <[email protected]>
Cc: Haavard Skinnemoen <[email protected]>
Cc: Hans-Christian Egtvedt <[email protected]>
---
arch/avr32/boot/u-boot/head.S | 30 +++++++++++++++++++++++++-----
arch/avr32/kernel/head.S | 20 --------------------
2 files changed, 25 insertions(+), 25 deletions(-)
diff --git a/arch/avr32/boot/u-boot/head.S b/arch/avr32/boot/u-boot/head.S
index 4488fa2..d36d865 100644
--- a/arch/avr32/boot/u-boot/head.S
+++ b/arch/avr32/boot/u-boot/head.S
@@ -8,6 +8,8 @@
* published by the Free Software Foundation.
*/
#include <asm/setup.h>
+#include <asm/thread_info.h>
+#include <asm/sysreg.h>
/*
* The kernel is loaded where we want it to be and all caches
@@ -20,11 +22,6 @@
.section .init.text,"ax"
.global _start
_start:
- /* Check if the boot loader actually provided a tag table */
- lddpc r0, magic_number
- cp.w r12, r0
- brne no_tag_table
-
/* Initialize .bss */
lddpc r2, bss_start_addr
lddpc r3, end_addr
@@ -34,6 +31,25 @@ _start:
cp r2, r3
brlo 1b
+ /* Initialize status register */
+ lddpc r0, init_sr
+ mtsr SYSREG_SR, r0
+
+ /* Set initial stack pointer */
+ lddpc sp, stack_addr
+ sub sp, -THREAD_SIZE
+
+#ifdef CONFIG_FRAME_POINTER
+ /* Mark last stack frame */
+ mov lr, 0
+ mov r7, 0
+#endif
+
+ /* Check if the boot loader actually provided a tag table */
+ lddpc r0, magic_number
+ cp.w r12, r0
+ brne no_tag_table
+
/*
* Save the tag table address for later use. This must be done
* _after_ .bss has been initialized...
@@ -53,6 +69,10 @@ bss_start_addr:
.long __bss_start
end_addr:
.long _end
+init_sr:
+ .long 0x007f0000 /* Supervisor mode, everything masked */
+stack_addr:
+ .long init_thread_union
no_tag_table:
sub r12, pc, (. - 2f)
diff --git a/arch/avr32/kernel/head.S b/arch/avr32/kernel/head.S
index 6163bd0..59eae6d 100644
--- a/arch/avr32/kernel/head.S
+++ b/arch/avr32/kernel/head.S
@@ -10,33 +10,13 @@
#include <linux/linkage.h>
#include <asm/page.h>
-#include <asm/thread_info.h>
-#include <asm/sysreg.h>
.section .init.text,"ax"
.global kernel_entry
kernel_entry:
- /* Initialize status register */
- lddpc r0, init_sr
- mtsr SYSREG_SR, r0
-
- /* Set initial stack pointer */
- lddpc sp, stack_addr
- sub sp, -THREAD_SIZE
-
-#ifdef CONFIG_FRAME_POINTER
- /* Mark last stack frame */
- mov lr, 0
- mov r7, 0
-#endif
-
/* Start the show */
lddpc pc, kernel_start_addr
.align 2
-init_sr:
- .long 0x007f0000 /* Supervisor mode, everything masked */
-stack_addr:
- .long init_thread_union
kernel_start_addr:
.long start_kernel
--
1.7.10.4
This patch fixes following error (for big kernels):
---8<---
arch/avr32/boot/u-boot/head.o: In function `no_tag_table':
(.init.text+0x44): relocation truncated to fit: R_AVR32_22H_PCREL against symbol `panic' defined in .text.unlikely section in kernel/built-in.o
arch/avr32/kernel/built-in.o: In function `bad_return':
(.ex.text+0x236): relocation truncated to fit: R_AVR32_22H_PCREL against symbol `panic' defined in .text.unlikely section in kernel/built-in.o
--->8---
It comes up when the kernel increases and 'panic()' is too far away to fit in
the +/- 2MiB range. Which in turn issues from the 21-bit displacement in
'br{cond4}' mnemonic which is one of the two ways to do jumps (rjmp has just
10-bit displacement and therefore a way smaller range). This fact was stated
before in 8d29b7b9f81d6b83d869ff054e6c189d6da73f1f.
One solution to solve this is to add a local storage for the symbol address
and just load the $pc with that value.
Signed-off-by: Andreas Bießmann <[email protected]>
Cc: Haavard Skinnemoen <[email protected]>
Cc: Hans-Christian Egtvedt <[email protected]>
---
arch/avr32/boot/u-boot/head.S | 5 ++++-
arch/avr32/kernel/entry-avr32b.S | 3 ++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/avr32/boot/u-boot/head.S b/arch/avr32/boot/u-boot/head.S
index d36d865..2ffc298 100644
--- a/arch/avr32/boot/u-boot/head.S
+++ b/arch/avr32/boot/u-boot/head.S
@@ -73,8 +73,11 @@ init_sr:
.long 0x007f0000 /* Supervisor mode, everything masked */
stack_addr:
.long init_thread_union
+panic_addr:
+ .long panic
no_tag_table:
sub r12, pc, (. - 2f)
- bral panic
+ /* branch to panic() which can be far away with that construct */
+ lddpc pc, panic_addr
2: .asciz "Boot loader didn't provide correct magic number\n"
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S
index 9899d3c..7301f48 100644
--- a/arch/avr32/kernel/entry-avr32b.S
+++ b/arch/avr32/kernel/entry-avr32b.S
@@ -401,9 +401,10 @@ handle_critical:
/* We should never get here... */
bad_return:
sub r12, pc, (. - 1f)
- bral panic
+ lddpc pc, 2f
.align 2
1: .asciz "Return from critical exception!"
+2: .long panic
.align 1
do_bus_error_write:
--
1.7.10.4