mark_rodata_ro is only called by the function mark_readonly when
CONFIG_STRICT_KERNEL_RWX=y,
if CONFIG_STRICT_KERNEL_RWX is not set
a compile warning may be triggered: unused function
Signed-off-by: nixiaoming <[email protected]>
---
arch/arm64/mm/mmu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 2dbb2c9..849f326 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -491,6 +491,7 @@ static void __init map_mem(pgd_t *pgdp)
#endif
}
+#ifdef CONFIG_STRICT_KERNEL_RWX
void mark_rodata_ro(void)
{
unsigned long section_size;
@@ -505,6 +506,7 @@ void mark_rodata_ro(void)
debug_checkwx();
}
+#endif
static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
pgprot_t prot, struct vm_struct *vma,
--
2.10.1
On Tue, May 29, 2018 at 09:36:15PM +0800, nixiaoming wrote:
> mark_rodata_ro is only called by the function mark_readonly when
> CONFIG_STRICT_KERNEL_RWX=y,
> if CONFIG_STRICT_KERNEL_RWX is not set
> a compile warning may be triggered: unused function
How are you achieving this configuration? In our Kconfig we select this
unconditionally.
Will
Unable to set CONFIG_STRICT_KERNEL_RWX=n by make menuconfig ARCH=arm64
When reading the code, I feel it is more appropriate to add macro control here.
-----Original Message-----
From: Will Deacon [mailto:[email protected]]
Sent: Tuesday, May 29, 2018 11:45 PM
To: Nixiaoming <[email protected]>
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH 1/3] arm64:add missing CONFIG_STRICT_KERNEL_RWX for mark_rodata_ro
On Tue, May 29, 2018 at 09:36:15PM +0800, nixiaoming wrote:
> mark_rodata_ro is only called by the function mark_readonly when
> CONFIG_STRICT_KERNEL_RWX=y,
> if CONFIG_STRICT_KERNEL_RWX is not set
> a compile warning may be triggered: unused function
How are you achieving this configuration? In our Kconfig we select this
unconditionally.
Will
On Wed, May 30, 2018 at 03:31:38AM +0000, Nixiaoming wrote:
> Unable to set CONFIG_STRICT_KERNEL_RWX=n by make menuconfig ARCH=arm64
Indeed. Making this mandatory was a deliberate decision, in part because this
allows simplification of code (e.g. removal of #ifdef guards).
> When reading the code, I feel it is more appropriate to add macro control
> here.
I must disagree. I do not think it makes sense to add an #ifdef for a
configuration option that is mandatory.
There are other places in the kernel that should behave differently if
CONFIG_STRICT_KERNEL_RWX were disabled, so this wouldn't be sufficient even if
we were to make CONFIG_STRICT_KERNEL_RWX optional. i.e. the #ifdef would give
the misleading impression that STRICT_KERNEL_RWX *could* be made optional, even
though this might not function correctly.
Having an #ifdef here makes the code more complicated and confusing, for the
benefit of a case which cannot occur.
Thanks,
Mark.
> -----Original Message-----
> From: Will Deacon [mailto:[email protected]]
> Sent: Tuesday, May 29, 2018 11:45 PM
> To: Nixiaoming <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
> Subject: Re: [PATCH 1/3] arm64:add missing CONFIG_STRICT_KERNEL_RWX for mark_rodata_ro
>
> On Tue, May 29, 2018 at 09:36:15PM +0800, nixiaoming wrote:
> > mark_rodata_ro is only called by the function mark_readonly when
> > CONFIG_STRICT_KERNEL_RWX=y,
> > if CONFIG_STRICT_KERNEL_RWX is not set
> > a compile warning may be triggered: unused function
>
> How are you achieving this configuration? In our Kconfig we select this
> unconditionally.
>
> Will
Because CONFIG_STRICT_KERNEL_RWX=n cannot be set by make menuconfig on arm64/x86/s390 architecture
So, these three patches should not be necessary
Sorry to disturb everyone
Thank you for your guidance
Thanks
-----Original Message-----
From: Mark Rutland [mailto:[email protected]]
Sent: Wednesday, May 30, 2018 4:08 PM
To: Nixiaoming <[email protected]>
Cc: Will Deacon <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH 1/3] arm64:add missing CONFIG_STRICT_KERNEL_RWX for mark_rodata_ro
On Wed, May 30, 2018 at 03:31:38AM +0000, Nixiaoming wrote:
> Unable to set CONFIG_STRICT_KERNEL_RWX=n by make menuconfig ARCH=arm64
Indeed. Making this mandatory was a deliberate decision, in part because this
allows simplification of code (e.g. removal of #ifdef guards).
> When reading the code, I feel it is more appropriate to add macro control
> here.
I must disagree. I do not think it makes sense to add an #ifdef for a
configuration option that is mandatory.
There are other places in the kernel that should behave differently if
CONFIG_STRICT_KERNEL_RWX were disabled, so this wouldn't be sufficient even if
we were to make CONFIG_STRICT_KERNEL_RWX optional. i.e. the #ifdef would give
the misleading impression that STRICT_KERNEL_RWX *could* be made optional, even
though this might not function correctly.
Having an #ifdef here makes the code more complicated and confusing, for the
benefit of a case which cannot occur.
Thanks,
Mark.
> -----Original Message-----
> From: Will Deacon [mailto:[email protected]]
> Sent: Tuesday, May 29, 2018 11:45 PM
> To: Nixiaoming <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
> Subject: Re: [PATCH 1/3] arm64:add missing CONFIG_STRICT_KERNEL_RWX for mark_rodata_ro
>
> On Tue, May 29, 2018 at 09:36:15PM +0800, nixiaoming wrote:
> > mark_rodata_ro is only called by the function mark_readonly when
> > CONFIG_STRICT_KERNEL_RWX=y,
> > if CONFIG_STRICT_KERNEL_RWX is not set
> > a compile warning may be triggered: unused function
>
> How are you achieving this configuration? In our Kconfig we select this
> unconditionally.
>
> Will