[U-Boot] [PATCH] armv7: do not relocate _start twice
The _start symbol is already relocated, so do not add the relocation the second time in c_runtime_cpu_setup.
This fixes e.g. the abort exception handling path, which ended in double fault due to bad address in VBAR.
Signed-off-by: Vincent Stehlé v-stehle@ti.com Reported-by: Lubomir Popov lpopov@mm-sol.com ---
Hello,
Here is a fix for a bug reported by Lubomir. He noticed that exceptions were not handled correctly anymore. This can be seen with e.g. the 'dhcp' command on some OMAP platforms.
Looking at the code, I would says the fix applies to all armv7 platforms except Tegra but I did only test on OMAP5. On this platform at least the abort is now handled:
OMAP5430 EVM # dhcp data abort
MAYBE you should read doc/README.arm-unaligned-accesses
pc : [<fef9bd78>] lr : [<fefa1790>] sp : feef9dc4 ip : fefed0f8 fp : 00000000 r10: 00000001 r9 : 00000001 r8 : feef9f48 r7 : feef9fe0 r6 : 00000000 r5 : 00000000 r4 : 00000014 r3 : 00000000 r2 : 00000002 r1 : 00000014 r0 : fefed0f4 Flags: Nzcv IRQs off FIQs off Mode SVC_32 Resetting CPU ...
resetting ...
It would be appreciated if folks could verify on other ARMv7 platforms, when running from flash for example (where relocation may differ?)
arch/arm/cpu/armv7/start.S | 1 - 1 file changed, 1 deletion(-)
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 6b59529d..d06b35f 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -254,7 +254,6 @@ ENTRY(c_runtime_cpu_setup) #if !defined(CONFIG_TEGRA) /* Set vector address in CP15 VBAR register */ ldr r0, =_start - add r0, r0, r9 mcr p15, 0, r0, c12, c0, 0 @Set VBAR #endif /* !Tegra */
Hi Vincent,
On Fri, 15 Mar 2013 17:54:00 +0100, Vincent Stehlé v-stehle@ti.com wrote:
The _start symbol is already relocated, so do not add the relocation the second time in c_runtime_cpu_setup.
This fixes e.g. the abort exception handling path, which ended in double fault due to bad address in VBAR.
Signed-off-by: Vincent Stehlé v-stehle@ti.com Reported-by: Lubomir Popov lpopov@mm-sol.com
Hello,
Here is a fix for a bug reported by Lubomir. He noticed that exceptions were not handled correctly anymore. This can be seen with e.g. the 'dhcp' command on some OMAP platforms.
Looking at the code, I would says the fix applies to all armv7 platforms except Tegra but I did only test on OMAP5. On this platform at least the abort is now handled:
OMAP5430 EVM # dhcp data abort
MAYBE you should read doc/README.arm-unaligned-accessespc : [<fef9bd78>] lr : [<fefa1790>] sp : feef9dc4 ip : fefed0f8 fp : 00000000 r10: 00000001 r9 : 00000001 r8 : feef9f48 r7 : feef9fe0 r6 : 00000000 r5 : 00000000 r4 : 00000014 r3 : 00000000 r2 : 00000002 r1 : 00000014 r0 : fefed0f4 Flags: Nzcv IRQs off FIQs off Mode SVC_32 Resetting CPU ...
resetting ...
It would be appreciated if folks could verify on other ARMv7 platforms, when running from flash for example (where relocation may differ?)
arch/arm/cpu/armv7/start.S | 1 - 1 file changed, 1 deletion(-)
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 6b59529d..d06b35f 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -254,7 +254,6 @@ ENTRY(c_runtime_cpu_setup) #if !defined(CONFIG_TEGRA) /* Set vector address in CP15 VBAR register */ ldr r0, =_start
- add r0, r0, r9 mcr p15, 0, r0, c12, c0, 0 @Set VBAR
#endif /* !Tegra */
That's a very good catch!
For the record, the issue crept in when I applied the patch set to remove all R_ARM_ABS32 relocation record types; after that, the only manual relocations that should have remained were the three ones in each relocate_code() routine, yet in armv7 there was this fourth one which had totally escaped my attention.
I have verified in the ELF dump of omap5_evm that the "=_start" reference is indeed relocated as part of relocate_code() execution.
As this is a bugfix, applied to u-boot-arm/master,
thanks!
Amicalement,
participants (2)
-
Albert ARIBAUD -
Vincent Stehlé