[PATCH 2/9] lpc2k: Exception vector handling
Uwe Kleine-König
u.kleine-koenig at pengutronix.de
Thu Mar 17 12:18:25 EDT 2011
On Thu, Mar 17, 2011 at 04:54:17PM +0100, Ithamar R. Adema wrote:
> Since the LPC2K does not have an MMU (ARM7TDMI based), it expects the vectors to be
> stored in on-chip SRAM. However, this moves the vectors too far away from the stubs
> page, requiring the vector jumps to be indirect.
>
> Since now VECTOR_BASE is below PHYS_OFFSET, do not try to reserve the vector
> page, as it will fail (and prevent the kernel from booting).
>
> Also, commit 247055aa (6384/1: Remove the domain switching on ARMv6k/v7 CPUs) broke
> the placement of vectors in the !MMU case, so fix this too.
>
> Signed-off-by: Ithamar R. Adema <ithamar.adema at team-embedded.nl>
> ---
> arch/arm/Kconfig | 1 +
> arch/arm/kernel/entry-armv.S | 18 ++++++++++++++++++
> arch/arm/kernel/traps.c | 2 +-
> arch/arm/mm/nommu.c | 2 ++
> 4 files changed, 22 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 331540d..9c12d71 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -186,6 +186,7 @@ config VECTORS_BASE
> hex
> default 0xffff0000 if MMU || CPU_HIGH_VECTOR
> default DRAM_BASE if REMAP_VECTORS_TO_RAM
> + default 0x40000000 if ARCH_LPC2K
> default 0x00000000
> help
> The base address of exception vectors.
> diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
> index e8d8856..618a971 100644
> --- a/arch/arm/kernel/entry-armv.S
> +++ b/arch/arm/kernel/entry-armv.S
> @@ -1208,6 +1208,7 @@ __stubs_end:
>
> .globl __vectors_start
> __vectors_start:
> +#ifndef CONFIG_ARCH_LPC2K
> ARM( swi SYS_ERROR0 )
> THUMB( svc #0 )
> THUMB( nop )
> @@ -1218,6 +1219,23 @@ __vectors_start:
> W(b) vector_addrexcptn + stubs_offset
> W(b) vector_irq + stubs_offset
> W(b) vector_fiq + stubs_offset
> +#else /* CONFIG_ARCH_LPC2K */
The description from the commit log should be repeated here.
And I wonder if this shouldn't depend on CONFIG_ARCH_LPC2K but
CONFIG_MMU.
> + swi SYS_ERROR0
I think arm7tdmi doesn't have thumb2, does it? If it has you need to do
ARM(swi SYS_ERROR0)
THUMB(svc ..)
...
as above
> + ldr pc, .vector_und
> + ldr pc, .vector_swi
> + ldr pc, .vector_pabt
> + ldr pc, .vector_dabt
> + ldr pc, .vector_addrexcptn
> + ldr pc, .vector_irq
> + ldr pc, .vector_fiq
> +.vector_und: .word vector_und
> +.vector_swi: .word vector_swi
> +.vector_pabt: .word vector_pabt
> +.vector_dabt: .word vector_dabt
> +.vector_addrexcptn: .word vector_addrexcptn
> +.vector_irq: .word vector_irq
> +.vector_fiq: .word vector_fiq
> +#endif
>
> .globl __vectors_end
> __vectors_end:
> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
> index 21ac43f..639c4c8 100644
> --- a/arch/arm/kernel/traps.c
> +++ b/arch/arm/kernel/traps.c
> @@ -758,7 +758,7 @@ static void __init kuser_get_tls_init(unsigned long vectors)
>
> void __init early_trap_init(void)
> {
> -#if defined(CONFIG_CPU_USE_DOMAINS)
> +#if defined(CONFIG_CPU_USE_DOMAINS) || !defined(CONFIG_MMU)
> unsigned long vectors = CONFIG_VECTORS_BASE;
> #else
> unsigned long vectors = (unsigned long)vectors_page;
> diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
> index 687d023..e3bec02 100644
> --- a/arch/arm/mm/nommu.c
> +++ b/arch/arm/mm/nommu.c
> @@ -24,7 +24,9 @@ void __init arm_mm_memblock_reserve(void)
> * some architectures which the DRAM is the exception vector to trap,
> * alloc_page breaks with error, although it is not NULL, but "0."
> */
> +#if PHYS_OFFSET <= CONFIG_VECTORS_BASE
> memblock_reserve(CONFIG_VECTORS_BASE, PAGE_SIZE);
> +#endif
> }
>
> /*
> --
> 1.7.1
>
>
> _______________________________________________
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> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
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