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SubjectRe: [PATCH] x86: Execute WP test after interrupts are enabled
On 08/25/09 12:16, Pekka Enberg wrote:
> Commit 83b519e8b9572c319c8e0c615ee5dd7272856090 ("slab: setup allocators
> earlier in the boot sequence") changed the boot sequence to call
> mem_init() early. Unfortunately Xen is not prepared to handle the WP test at
> that point so we need to make the test run later.
>
> This patch fixes the Xen boot failures reported by Arnd Hannemann.
>

I don't think this is the real fix, and it seems a bit ugly. I'm OK
with it as a workaround, but I think it will end up getting reverted if
applied.

J

> Reported-by: Arnd Hannemann <hannemann@nets.rwth-aachen.de>
> Tested-by: Arnd Hannemann <hannemann@nets.rwth-aachen.de>
> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
> ---
> arch/x86/Kconfig | 5 +++++
> arch/x86/mm/init_32.c | 10 +++++++---
> include/linux/mm.h | 8 ++++++++
> init/main.c | 1 +
> 4 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 13ffa5d..b6ff185 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -50,6 +50,7 @@ config X86
> select HAVE_KERNEL_BZIP2
> select HAVE_KERNEL_LZMA
> select HAVE_ARCH_KMEMCHECK
> + select HAVE_ARCH_MEM_INIT_LATE if X86_32
>
> config OUTPUT_FORMAT
> string
> @@ -86,6 +87,10 @@ config STACKTRACE_SUPPORT
> config HAVE_LATENCYTOP_SUPPORT
> def_bool y
>
> +config HAVE_ARCH_MEM_INIT_LATE
> + def_bool y
> + depends on X86_32
> +
> config FAST_CMPXCHG_LOCAL
> bool
> default y
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index 3cd7711..488ed4b 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -956,13 +956,17 @@ void __init mem_init(void)
> BUG_ON(VMALLOC_START >= VMALLOC_END);
> BUG_ON((unsigned long)high_memory > VMALLOC_START);
>
> - if (boot_cpu_data.wp_works_ok < 0)
> - test_wp_bit();
> -
> save_pg_dir();
> zap_low_mappings(true);
> }
>
> +void __init mem_init_late(void)
> +{
> + /* Interrupts are enabled at this point. */
> + if (boot_cpu_data.wp_works_ok < 0)
> + test_wp_bit();
> +}
> +
> #ifdef CONFIG_MEMORY_HOTPLUG
> int arch_add_memory(int nid, u64 start, u64 size)
> {
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 9a72cc7..eefcfbe 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1052,6 +1052,14 @@ extern void si_meminfo(struct sysinfo * val);
> extern void si_meminfo_node(struct sysinfo *val, int nid);
> extern int after_bootmem;
>
> +#ifdef CONFIG_HAVE_ARCH_MEM_INIT_LATE
> +extern void mem_init_late(void);
> +#else
> +static inline void mem_init_late(void)
> +{
> +}
> +#endif
> +
> #ifdef CONFIG_NUMA
> extern void setup_per_cpu_pageset(void);
> #else
> diff --git a/init/main.c b/init/main.c
> index 2d9d6bd..45d8dbd 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -643,6 +643,7 @@ asmlinkage void __init start_kernel(void)
> set_gfp_allowed_mask(__GFP_BITS_MASK);
>
> kmem_cache_init_late();
> + mem_init_late();
>
> /*
> * HACK ALERT! This is early. We're enabling the console before
>



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