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SubjectRe: [RFC PATCH 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter
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Le 17/07/2019 à 10:06, Jason Yan a écrit :
> One may want to disable kaslr when boot, so provide a cmdline parameter
> 'nokaslr' to support this.
>
> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> Cc: Diana Craciun <diana.craciun@nxp.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Kees Cook <keescook@chromium.org>
> ---
> arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
> index 00339c05879f..e65a5d9d2ff1 100644
> --- a/arch/powerpc/kernel/kaslr_booke.c
> +++ b/arch/powerpc/kernel/kaslr_booke.c
> @@ -373,6 +373,18 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
> return kaslr_offset;
> }
>
> +static inline __init bool kaslr_disabled(void)
> +{
> + char *str;
> +
> + str = strstr(early_command_line, "nokaslr");

Why using early_command_line instead of boot_command_line ?


> + if ((str == early_command_line) ||
> + (str > early_command_line && *(str - 1) == ' '))

Is that stuff really needed ?

Why not just:

return strstr(early_command_line, "nokaslr") != NULL;

> + return true;
> +
> + return false;
> +}


> +
> /*
> * To see if we need to relocate the kernel to a random offset
> * void *dt_ptr - address of the device tree
> @@ -388,6 +400,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
> kernel_sz = (unsigned long)_end - KERNELBASE;
>
> kaslr_get_cmdline(dt_ptr);
> + if (kaslr_disabled())
> + return;
>
> offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
>
>

Christophe

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