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SubjectRe: [PATCH] arm64: fix build error when use rodata_enabled
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Hello,

On 1/5/22 8:37 AM, AliOS system security wrote:
> rodata_enabled should be used when CONFIG_STRICT_KERNEL_RWX
> or CONFIG_STRICT_MODULE_RWX is selected

Both these configs get selected invariably with CONFIG_ARM64 in the
platform config file (arch/arm64/Kconfig). I guess there can not be
any such situation, where both configs will be missing/not selected
given ARCH_OPTIONAL_KERNEL_RWX[or _DEFAULT] is not enabled on arm64.

config ARM64
def_bool y
select ACPI_CCA_REQUIRED if ACPI
.....
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
.....

Hence for all practical purpose, rodata_enabled could be considered
always available. I am sure there other similar situations as well,
where code elements are not wrapped around if the config option is
always present.

>
> Signed-off-by: AliOS system security <alios_sys_security@linux.alibaba.com>

Also please refer Documentation/process/submitting-patches.rst for
the rules regarding names, that can be used for a commit sign off.

------------------------------------------------------------------------
then you just add a line saying::

Signed-off-by: Random J Developer <random@developer.example.org>

using your real name (sorry, no pseudonyms or anonymous contributions.)
------------------------------------------------------------------------

- Anshuman

> ---
> arch/arm64/mm/mmu.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index acfae9b..47f8754 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -596,6 +596,7 @@ static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
> vm_area_add_early(vma);
> }
>
> +#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
> static int __init parse_rodata(char *arg)
> {
> int ret = strtobool(arg, &rodata_enabled);
> @@ -613,11 +614,16 @@ static int __init parse_rodata(char *arg)
> return 0;
> }
> early_param("rodata", parse_rodata);
> +#endif
>
> #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
> static int __init map_entry_trampoline(void)
> {
> - pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
> + pgprot_t prot = PAGE_KERNEL_EXEC;
> +#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
> + if (rodata_enabled)
> + prot = PAGE_KERNEL_ROX;
> +#endif
> phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
>
> /* The trampoline is always mapped and can therefore be global */
> @@ -672,7 +678,11 @@ static void __init map_kernel(pgd_t *pgdp)
> * mapping to install SW breakpoints. Allow this (only) when
> * explicitly requested with rodata=off.
> */
> - pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
> + pgprot_t text_prot = PAGE_KERNEL_EXEC;
> +#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
> + if (rodata_enabled)
> + text_prot = PAGE_KERNEL_ROX;
> +#endif
>
> /*
> * If we have a CPU that supports BTI and a kernel built for
>

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