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[PATCH] arm64: fix build error when use rodata_enabled

AliOS system security posted 1 patch 4 years, 5 months ago 
arch/arm64/mm/mmu.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
[PATCH] arm64: fix build error when use rodata_enabled
Posted by AliOS system security 4 years, 5 months ago 
rodata_enabled should be used when CONFIG_STRICT_KERNEL_RWX
or CONFIG_STRICT_MODULE_RWX is selected

Signed-off-by: AliOS system security <alios_sys_security@linux.alibaba.com>
---
 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
-- 
2.7.4
Re: [PATCH] arm64: fix build error when use rodata_enabled
Posted by Anshuman Khandual 4 years, 5 months ago 
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
>
Re: [PATCH] arm64: fix build error when use rodata_enabled
Posted by Mark Rutland 4 years, 5 months ago 
On Wed, Jan 05, 2022 at 02:51:05PM +0530, Anshuman Khandual wrote:
> 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

Further to Anshuman's comments here, for a build issue, please include the
specific build error in the commit log, and describe the configuration where
this manifests.

For the reasons Anshuman gives below I do not see how this can be a problem in
mainline.

Thanks,
Mark.

> 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
> > 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Re: [PATCH] arm64: fix build error when use rodata_enabled
Posted by kernel test robot 4 years, 5 months ago 
Hi AliOS,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on arm64/for-next/core]
[also build test WARNING on v5.16-rc8 next-20220105]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/AliOS-system-security/arm64-fix-build-error-when-use-rodata_enabled/20220105-110838
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: arm64-randconfig-s032-20220105 (https://download.01.org/0day-ci/archive/20220105/202201051817.4KPMZJag-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/0day-ci/linux/commit/6af4245e93d33d4f4a79a560a707539be994f73e
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review AliOS-system-security/arm64-fix-build-error-when-use-rodata_enabled/20220105-110838
        git checkout 6af4245e93d33d4f4a79a560a707539be994f73e
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arm64 SHELL=/bin/bash arch/arm64/mm/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   arch/arm64/mm/mmu.c: In function 'map_entry_trampoline':
>> arch/arm64/mm/mmu.c:627:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
     627 |         phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
         |         ^~~~~~~~~~~


vim +627 arch/arm64/mm/mmu.c

28b066da69b937 Ard Biesheuvel        2017-03-09  618  
51a0048beb4496 Will Deacon           2017-11-14  619  #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
51a0048beb4496 Will Deacon           2017-11-14  620  static int __init map_entry_trampoline(void)
51a0048beb4496 Will Deacon           2017-11-14  621  {
6af4245e93d33d AliOS system security 2022-01-05  622  	pgprot_t prot = PAGE_KERNEL_EXEC;
6af4245e93d33d AliOS system security 2022-01-05  623  #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
6af4245e93d33d AliOS system security 2022-01-05  624  	if (rodata_enabled)
6af4245e93d33d AliOS system security 2022-01-05  625  		prot = PAGE_KERNEL_ROX;
6af4245e93d33d AliOS system security 2022-01-05  626  #endif
51a0048beb4496 Will Deacon           2017-11-14 @627  	phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
51a0048beb4496 Will Deacon           2017-11-14  628  
51a0048beb4496 Will Deacon           2017-11-14  629  	/* The trampoline is always mapped and can therefore be global */
51a0048beb4496 Will Deacon           2017-11-14  630  	pgprot_val(prot) &= ~PTE_NG;
51a0048beb4496 Will Deacon           2017-11-14  631  
51a0048beb4496 Will Deacon           2017-11-14  632  	/* Map only the text into the trampoline page table */
51a0048beb4496 Will Deacon           2017-11-14  633  	memset(tramp_pg_dir, 0, PGD_SIZE);
51a0048beb4496 Will Deacon           2017-11-14  634  	__create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
475ba3fc194b64 Will Deacon           2019-04-08  635  			     prot, __pgd_pgtable_alloc, 0);
51a0048beb4496 Will Deacon           2017-11-14  636  
6c27c4082f4f70 Will Deacon           2017-12-06  637  	/* Map both the text and data into the kernel page table */
51a0048beb4496 Will Deacon           2017-11-14  638  	__set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
6c27c4082f4f70 Will Deacon           2017-12-06  639  	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
6c27c4082f4f70 Will Deacon           2017-12-06  640  		extern char __entry_tramp_data_start[];
6c27c4082f4f70 Will Deacon           2017-12-06  641  
6c27c4082f4f70 Will Deacon           2017-12-06  642  		__set_fixmap(FIX_ENTRY_TRAMP_DATA,
6c27c4082f4f70 Will Deacon           2017-12-06  643  			     __pa_symbol(__entry_tramp_data_start),
6c27c4082f4f70 Will Deacon           2017-12-06  644  			     PAGE_KERNEL_RO);
6c27c4082f4f70 Will Deacon           2017-12-06  645  	}
6c27c4082f4f70 Will Deacon           2017-12-06  646  
51a0048beb4496 Will Deacon           2017-11-14  647  	return 0;
51a0048beb4496 Will Deacon           2017-11-14  648  }
51a0048beb4496 Will Deacon           2017-11-14  649  core_initcall(map_entry_trampoline);
51a0048beb4496 Will Deacon           2017-11-14  650  #endif
51a0048beb4496 Will Deacon           2017-11-14  651  

---
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https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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