| Message ID | 20180529133622.26982-1-nixiaoming@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* nixiaoming <nixiaoming@huawei.com> 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 > > Signed-off-by: nixiaoming <nixiaoming@huawei.com> > --- > arch/x86/mm/init_32.c | 2 ++ > arch/x86/mm/init_64.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c > index c893c6a..121c567 100644 > --- a/arch/x86/mm/init_32.c > +++ b/arch/x86/mm/init_32.c > @@ -920,6 +920,7 @@ static void mark_nxdata_nx(void) > set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); > } > > +#ifdef CONFIG_STRICT_KERNEL_RWX > void mark_rodata_ro(void) > { > unsigned long start = PFN_ALIGN(_text); > @@ -957,3 +958,4 @@ void mark_rodata_ro(void) > if (__supported_pte_mask & _PAGE_NX) > debug_checkwx(); > } > +#endif /*end of CONFIG_STRICT_KERNEL_RWX*/ > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 0a40060..1b7a1a7 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -1245,6 +1245,7 @@ void set_kernel_text_ro(void) > set_memory_ro(start, (end - start) >> PAGE_SHIFT); > } > > +#ifdef CONFIG_STRICT_KERNEL_RWX > void mark_rodata_ro(void) > { > unsigned long start = PFN_ALIGN(_text); > @@ -1298,6 +1299,7 @@ void mark_rodata_ro(void) > */ > pti_clone_kernel_text(); > } > +#endif NAK, this is very ugly and the changelog doesn't appear to be true: the build warning does not trigger in the default build, correct? Thanks, Ingo
On 30 May 2018 at 07:58, Ingo Molnar <mingo@kernel.org> wrote: > > * nixiaoming <nixiaoming@huawei.com> 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 >> >> Signed-off-by: nixiaoming <nixiaoming@huawei.com> >> --- >> arch/x86/mm/init_32.c | 2 ++ >> arch/x86/mm/init_64.c | 2 ++ >> 2 files changed, 4 insertions(+) >> >> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c >> index c893c6a..121c567 100644 >> --- a/arch/x86/mm/init_32.c >> +++ b/arch/x86/mm/init_32.c >> @@ -920,6 +920,7 @@ static void mark_nxdata_nx(void) >> set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); >> } >> >> +#ifdef CONFIG_STRICT_KERNEL_RWX >> void mark_rodata_ro(void) >> { >> unsigned long start = PFN_ALIGN(_text); >> @@ -957,3 +958,4 @@ void mark_rodata_ro(void) >> if (__supported_pte_mask & _PAGE_NX) >> debug_checkwx(); >> } >> +#endif /*end of CONFIG_STRICT_KERNEL_RWX*/ >> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c >> index 0a40060..1b7a1a7 100644 >> --- a/arch/x86/mm/init_64.c >> +++ b/arch/x86/mm/init_64.c >> @@ -1245,6 +1245,7 @@ void set_kernel_text_ro(void) >> set_memory_ro(start, (end - start) >> PAGE_SHIFT); >> } >> >> +#ifdef CONFIG_STRICT_KERNEL_RWX >> void mark_rodata_ro(void) >> { >> unsigned long start = PFN_ALIGN(_text); >> @@ -1298,6 +1299,7 @@ void mark_rodata_ro(void) >> */ >> pti_clone_kernel_text(); >> } >> +#endif > > NAK, this is very ugly and the changelog doesn't appear to be true: the build > warning does not trigger in the default build, correct? > I don't see how the build warning could trigger at all, given that mark_rodata_ro() has external linkage.
On 30 May 2018 at 2:07PM Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org] wrote: >On 30 May 2018 at 07:58, Ingo Molnar <mingo@kernel.org> wrote: >> >> * nixiaoming <nixiaoming@huawei.com> 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 >.... >> >> NAK, this is very ugly and the changelog doesn't appear to be true: the build >> warning does not trigger in the default build, correct? >> > >I don't see how the build warning could trigger at all, given that >mark_rodata_ro() has external linkage. > Unable to set CONFIG_STRICT_KERNEL_RWX=n by make menuconfig ARCH=x86_64 the build warning does not trigger in the default build, but it should be more appropriate to add CONFIG control to the code.
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index c893c6a..121c567 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -920,6 +920,7 @@ static void mark_nxdata_nx(void) set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); } +#ifdef CONFIG_STRICT_KERNEL_RWX void mark_rodata_ro(void) { unsigned long start = PFN_ALIGN(_text); @@ -957,3 +958,4 @@ void mark_rodata_ro(void) if (__supported_pte_mask & _PAGE_NX) debug_checkwx(); } +#endif /*end of CONFIG_STRICT_KERNEL_RWX*/ diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 0a40060..1b7a1a7 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1245,6 +1245,7 @@ void set_kernel_text_ro(void) set_memory_ro(start, (end - start) >> PAGE_SHIFT); } +#ifdef CONFIG_STRICT_KERNEL_RWX void mark_rodata_ro(void) { unsigned long start = PFN_ALIGN(_text); @@ -1298,6 +1299,7 @@ void mark_rodata_ro(void) */ pti_clone_kernel_text(); } +#endif int kern_addr_valid(unsigned long addr) {
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 <nixiaoming@huawei.com> --- arch/x86/mm/init_32.c | 2 ++ arch/x86/mm/init_64.c | 2 ++ 2 files changed, 4 insertions(+)