subject:"\[PATCH 2\/2\] arm64\: don't load 32\-bit binaries if platform has no aarch32

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Yury

On Tue, Sep 01, 2015 at 05:04:26PM +0100, Mark Rutland wrote:
> On Tue, Sep 01, 2015 at 03:41:12PM +0100, Yury Norov wrote:
> > Kernel option COMPAT defines the ability of executing aarch32 binaries.
> > Some platforms does not support aarch32 mode, and so cannot execute that
> > binaries. But we cannot just disable COMPAT for them because the same
> > kernel binary may be used by multiple platforms.
> > 
> > In this patch, system_supports_aarch32_el0() is introduced to detect
> > aarch32 support at run-time.
> > 
> > Signed-off-by: Yury Norov 
> > ---
> >  arch/arm64/include/asm/cpufeature.h | 1 +
> >  arch/arm64/include/asm/elf.h| 6 --
> >  arch/arm64/kernel/cpuinfo.c | 9 +
> >  3 files changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/cpufeature.h 
> > b/arch/arm64/include/asm/cpufeature.h
> > index 20cdc26..d24ea15 100644
> > --- a/arch/arm64/include/asm/cpufeature.h
> > +++ b/arch/arm64/include/asm/cpufeature.h
> > @@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
> >  void check_local_cpu_features(void);
> >  bool cpu_supports_mixed_endian_el0(void);
> >  bool system_supports_mixed_endian_el0(void);
> > +bool system_supports_aarch32_el0(void);
> >  
> >  #endif /* __ASSEMBLY__ */
> >  
> > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
> > index faad6df..461897b 100644
> > --- a/arch/arm64/include/asm/elf.h
> > +++ b/arch/arm64/include/asm/elf.h
> > @@ -21,6 +21,7 @@
> >  /*
> >   * ELF register definitions..
> >   */
> > +#include 
> >  #include 
> >  #include 
> >  
> > @@ -173,8 +174,9 @@ typedef compat_elf_greg_t   
> > compat_elf_gregset_t[COMPAT_ELF_NGREG];
> >  
> >  /* AArch32 EABI. */
> >  #define EF_ARM_EABI_MASK   0xff00
> > -#define compat_elf_check_arch(x)   (((x)->e_machine == EM_ARM) && \
> > -((x)->e_flags & EF_ARM_EABI_MASK))
> > +#define compat_elf_check_arch(x)   (system_supports_aarch32_el0()  \
> > +   && ((x)->e_machine == EM_ARM)   \
> > +   && ((x)->e_flags & EF_ARM_EABI_MASK))
> >  
> >  #define compat_start_threadcompat_start_thread
> >  #define COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT);
> > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
> > index 75d5a86..95d953f 100644
> > --- a/arch/arm64/kernel/cpuinfo.c
> > +++ b/arch/arm64/kernel/cpuinfo.c
> > @@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
> > return mixed_endian_el0;
> >  }
> >  
> > +#define AARCH641
> > +#define AARCH32_64 2
> 
> These should be better namespaced. Perhaps ID_AA64PFR0_EL1_EL0_64 and
> ID_AA64PFR0_EL1_EL0_6432 ?
> 
> > +bool system_supports_aarch32_el0(void)
> > +{
> > +   struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
> > +   u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
> > +   return arm64_el0 == AARCH32_64;
> > +}
> 
> We should handle this the same way as we do for endianness support and
> check that all CPUs support AArch32, and set a global flag, rather than
> assuming that all CPUs are symmetric. Likewise for any other feature we
> have to dynamically detect.
> 

OK. Will do in V2

> Thanks,
> Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Suzuki K. Poulose


On 01/09/15 17:04, Mark Rutland wrote:

On Tue, Sep 01, 2015 at 03:41:12PM +0100, Yury Norov wrote:

Kernel option COMPAT defines the ability of executing aarch32 binaries.
Some platforms does not support aarch32 mode, and so cannot execute that
binaries. But we cannot just disable COMPAT for them because the same
kernel binary may be used by multiple platforms.

In this patch, system_supports_aarch32_el0() is introduced to detect
aarch32 support at run-time.

Signed-off-by: Yury Norov 
---
  arch/arm64/include/asm/cpufeature.h | 1 +
  arch/arm64/include/asm/elf.h| 6 --
  arch/arm64/kernel/cpuinfo.c | 9 +
  3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h 
b/arch/arm64/include/asm/cpufeature.h
index 20cdc26..d24ea15 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
  void check_local_cpu_features(void);
  bool cpu_supports_mixed_endian_el0(void);
  bool system_supports_mixed_endian_el0(void);
+bool system_supports_aarch32_el0(void);

  #endif /* __ASSEMBLY__ */

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index faad6df..461897b 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -21,6 +21,7 @@
  /*
   * ELF register definitions..
   */
+#include 
  #include 
  #include 

@@ -173,8 +174,9 @@ typedef compat_elf_greg_t   
compat_elf_gregset_t[COMPAT_ELF_NGREG];

  /* AArch32 EABI. */
  #define EF_ARM_EABI_MASK  0xff00
-#define compat_elf_check_arch(x)   (((x)->e_machine == EM_ARM) && \
-((x)->e_flags & EF_ARM_EABI_MASK))
+#define compat_elf_check_arch(x)   (system_supports_aarch32_el0()  \
+   && ((x)->e_machine == EM_ARM)\
+   && ((x)->e_flags & EF_ARM_EABI_MASK))

  #define compat_start_thread   compat_start_thread
  #define COMPAT_SET_PERSONALITY(ex)set_thread_flag(TIF_32BIT);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 75d5a86..95d953f 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
return mixed_endian_el0;
  }

+#define AARCH641
+#define AARCH32_64 2


These should be better namespaced. Perhaps ID_AA64PFR0_EL1_EL0_64 and
ID_AA64PFR0_EL1_EL0_6432 ?


+bool system_supports_aarch32_el0(void)
+{
+   struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
+   u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
+   return arm64_el0 == AARCH32_64;
+}


We should handle this the same way as we do for endianness support and
check that all CPUs support AArch32, and set a global flag, rather than
assuming that all CPUs are symmetric. Likewise for any other feature we
have to dynamically detect.


Correct. With my series, which I will post after the merge window, we should be 
able to
define this as a CPU capability and check that bit instead, which would give us 
a system
wide value.

Suzuki




Thanks,
Mark.



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Mark Rutland

On Tue, Sep 01, 2015 at 03:41:12PM +0100, Yury Norov wrote:
> Kernel option COMPAT defines the ability of executing aarch32 binaries.
> Some platforms does not support aarch32 mode, and so cannot execute that
> binaries. But we cannot just disable COMPAT for them because the same
> kernel binary may be used by multiple platforms.
> 
> In this patch, system_supports_aarch32_el0() is introduced to detect
> aarch32 support at run-time.
> 
> Signed-off-by: Yury Norov 
> ---
>  arch/arm64/include/asm/cpufeature.h | 1 +
>  arch/arm64/include/asm/elf.h| 6 --
>  arch/arm64/kernel/cpuinfo.c | 9 +
>  3 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/cpufeature.h 
> b/arch/arm64/include/asm/cpufeature.h
> index 20cdc26..d24ea15 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
>  void check_local_cpu_features(void);
>  bool cpu_supports_mixed_endian_el0(void);
>  bool system_supports_mixed_endian_el0(void);
> +bool system_supports_aarch32_el0(void);
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
> index faad6df..461897b 100644
> --- a/arch/arm64/include/asm/elf.h
> +++ b/arch/arm64/include/asm/elf.h
> @@ -21,6 +21,7 @@
>  /*
>   * ELF register definitions..
>   */
> +#include 
>  #include 
>  #include 
>  
> @@ -173,8 +174,9 @@ typedef compat_elf_greg_t 
> compat_elf_gregset_t[COMPAT_ELF_NGREG];
>  
>  /* AArch32 EABI. */
>  #define EF_ARM_EABI_MASK 0xff00
> -#define compat_elf_check_arch(x) (((x)->e_machine == EM_ARM) && \
> -  ((x)->e_flags & EF_ARM_EABI_MASK))
> +#define compat_elf_check_arch(x) (system_supports_aarch32_el0()  \
> + && ((x)->e_machine == EM_ARM)   \
> + && ((x)->e_flags & EF_ARM_EABI_MASK))
>  
>  #define compat_start_thread  compat_start_thread
>  #define COMPAT_SET_PERSONALITY(ex)   set_thread_flag(TIF_32BIT);
> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
> index 75d5a86..95d953f 100644
> --- a/arch/arm64/kernel/cpuinfo.c
> +++ b/arch/arm64/kernel/cpuinfo.c
> @@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
>   return mixed_endian_el0;
>  }
>  
> +#define AARCH64  1
> +#define AARCH32_64   2

These should be better namespaced. Perhaps ID_AA64PFR0_EL1_EL0_64 and
ID_AA64PFR0_EL1_EL0_6432 ?

> +bool system_supports_aarch32_el0(void)
> +{
> + struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
> + u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
> + return arm64_el0 == AARCH32_64;
> +}

We should handle this the same way as we do for endianness support and
check that all CPUs support AArch32, and set a global flag, rather than
assuming that all CPUs are symmetric. Likewise for any other feature we
have to dynamically detect.

Thanks,
Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Yury Norov

Kernel option COMPAT defines the ability of executing aarch32 binaries.
Some platforms does not support aarch32 mode, and so cannot execute that
binaries. But we cannot just disable COMPAT for them because the same
kernel binary may be used by multiple platforms.

In this patch, system_supports_aarch32_el0() is introduced to detect
aarch32 support at run-time.

Signed-off-by: Yury Norov 
---
 arch/arm64/include/asm/cpufeature.h | 1 +
 arch/arm64/include/asm/elf.h| 6 --
 arch/arm64/kernel/cpuinfo.c | 9 +
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h 
b/arch/arm64/include/asm/cpufeature.h
index 20cdc26..d24ea15 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
 void check_local_cpu_features(void);
 bool cpu_supports_mixed_endian_el0(void);
 bool system_supports_mixed_endian_el0(void);
+bool system_supports_aarch32_el0(void);
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index faad6df..461897b 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -21,6 +21,7 @@
 /*
  * ELF register definitions..
  */
+#include 
 #include 
 #include 
 
@@ -173,8 +174,9 @@ typedef compat_elf_greg_t   
compat_elf_gregset_t[COMPAT_ELF_NGREG];
 
 /* AArch32 EABI. */
 #define EF_ARM_EABI_MASK   0xff00
-#define compat_elf_check_arch(x)   (((x)->e_machine == EM_ARM) && \
-((x)->e_flags & EF_ARM_EABI_MASK))
+#define compat_elf_check_arch(x)   (system_supports_aarch32_el0()  \
+   && ((x)->e_machine == EM_ARM)   \
+   && ((x)->e_flags & EF_ARM_EABI_MASK))
 
 #define compat_start_threadcompat_start_thread
 #define COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 75d5a86..95d953f 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
return mixed_endian_el0;
 }
 
+#define AARCH641
+#define AARCH32_64 2
+bool system_supports_aarch32_el0(void)
+{
+   struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
+   u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
+   return arm64_el0 == AARCH32_64;
+}
+
 static void update_mixed_endian_el0_support(struct cpuinfo_arm64 *info)
 {
mixed_endian_el0 &= 
id_aa64mmfr0_mixed_endian_el0(info->reg_id_aa64mmfr0);
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Suzuki K. Poulose


On 01/09/15 17:04, Mark Rutland wrote:

On Tue, Sep 01, 2015 at 03:41:12PM +0100, Yury Norov wrote:

Kernel option COMPAT defines the ability of executing aarch32 binaries.
Some platforms does not support aarch32 mode, and so cannot execute that
binaries. But we cannot just disable COMPAT for them because the same
kernel binary may be used by multiple platforms.

In this patch, system_supports_aarch32_el0() is introduced to detect
aarch32 support at run-time.

Signed-off-by: Yury Norov 
---
  arch/arm64/include/asm/cpufeature.h | 1 +
  arch/arm64/include/asm/elf.h| 6 --
  arch/arm64/kernel/cpuinfo.c | 9 +
  3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h 
b/arch/arm64/include/asm/cpufeature.h
index 20cdc26..d24ea15 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
  void check_local_cpu_features(void);
  bool cpu_supports_mixed_endian_el0(void);
  bool system_supports_mixed_endian_el0(void);
+bool system_supports_aarch32_el0(void);

  #endif /* __ASSEMBLY__ */

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index faad6df..461897b 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -21,6 +21,7 @@
  /*
   * ELF register definitions..
   */
+#include 
  #include 
  #include 

@@ -173,8 +174,9 @@ typedef compat_elf_greg_t   
compat_elf_gregset_t[COMPAT_ELF_NGREG];

  /* AArch32 EABI. */
  #define EF_ARM_EABI_MASK  0xff00
-#define compat_elf_check_arch(x)   (((x)->e_machine == EM_ARM) && \
-((x)->e_flags & EF_ARM_EABI_MASK))
+#define compat_elf_check_arch(x)   (system_supports_aarch32_el0()  \
+   && ((x)->e_machine == EM_ARM)\
+   && ((x)->e_flags & EF_ARM_EABI_MASK))

  #define compat_start_thread   compat_start_thread
  #define COMPAT_SET_PERSONALITY(ex)set_thread_flag(TIF_32BIT);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 75d5a86..95d953f 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
return mixed_endian_el0;
  }

+#define AARCH641
+#define AARCH32_64 2


These should be better namespaced. Perhaps ID_AA64PFR0_EL1_EL0_64 and
ID_AA64PFR0_EL1_EL0_6432 ?


+bool system_supports_aarch32_el0(void)
+{
+   struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
+   u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
+   return arm64_el0 == AARCH32_64;
+}


We should handle this the same way as we do for endianness support and
check that all CPUs support AArch32, and set a global flag, rather than
assuming that all CPUs are symmetric. Likewise for any other feature we
have to dynamically detect.


Correct. With my series, which I will post after the merge window, we should be 
able to
define this as a CPU capability and check that bit instead, which would give us 
a system
wide value.

Suzuki




Thanks,
Mark.



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Yury

On Tue, Sep 01, 2015 at 05:04:26PM +0100, Mark Rutland wrote:
> On Tue, Sep 01, 2015 at 03:41:12PM +0100, Yury Norov wrote:
> > Kernel option COMPAT defines the ability of executing aarch32 binaries.
> > Some platforms does not support aarch32 mode, and so cannot execute that
> > binaries. But we cannot just disable COMPAT for them because the same
> > kernel binary may be used by multiple platforms.
> > 
> > In this patch, system_supports_aarch32_el0() is introduced to detect
> > aarch32 support at run-time.
> > 
> > Signed-off-by: Yury Norov 
> > ---
> >  arch/arm64/include/asm/cpufeature.h | 1 +
> >  arch/arm64/include/asm/elf.h| 6 --
> >  arch/arm64/kernel/cpuinfo.c | 9 +
> >  3 files changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/cpufeature.h 
> > b/arch/arm64/include/asm/cpufeature.h
> > index 20cdc26..d24ea15 100644
> > --- a/arch/arm64/include/asm/cpufeature.h
> > +++ b/arch/arm64/include/asm/cpufeature.h
> > @@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
> >  void check_local_cpu_features(void);
> >  bool cpu_supports_mixed_endian_el0(void);
> >  bool system_supports_mixed_endian_el0(void);
> > +bool system_supports_aarch32_el0(void);
> >  
> >  #endif /* __ASSEMBLY__ */
> >  
> > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
> > index faad6df..461897b 100644
> > --- a/arch/arm64/include/asm/elf.h
> > +++ b/arch/arm64/include/asm/elf.h
> > @@ -21,6 +21,7 @@
> >  /*
> >   * ELF register definitions..
> >   */
> > +#include 
> >  #include 
> >  #include 
> >  
> > @@ -173,8 +174,9 @@ typedef compat_elf_greg_t   
> > compat_elf_gregset_t[COMPAT_ELF_NGREG];
> >  
> >  /* AArch32 EABI. */
> >  #define EF_ARM_EABI_MASK   0xff00
> > -#define compat_elf_check_arch(x)   (((x)->e_machine == EM_ARM) && \
> > -((x)->e_flags & EF_ARM_EABI_MASK))
> > +#define compat_elf_check_arch(x)   (system_supports_aarch32_el0()  \
> > +   && ((x)->e_machine == EM_ARM)   \
> > +   && ((x)->e_flags & EF_ARM_EABI_MASK))
> >  
> >  #define compat_start_threadcompat_start_thread
> >  #define COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT);
> > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
> > index 75d5a86..95d953f 100644
> > --- a/arch/arm64/kernel/cpuinfo.c
> > +++ b/arch/arm64/kernel/cpuinfo.c
> > @@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
> > return mixed_endian_el0;
> >  }
> >  
> > +#define AARCH641
> > +#define AARCH32_64 2
> 
> These should be better namespaced. Perhaps ID_AA64PFR0_EL1_EL0_64 and
> ID_AA64PFR0_EL1_EL0_6432 ?
> 
> > +bool system_supports_aarch32_el0(void)
> > +{
> > +   struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
> > +   u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
> > +   return arm64_el0 == AARCH32_64;
> > +}
> 
> We should handle this the same way as we do for endianness support and
> check that all CPUs support AArch32, and set a global flag, rather than
> assuming that all CPUs are symmetric. Likewise for any other feature we
> have to dynamically detect.
> 

OK. Will do in V2

> Thanks,
> Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Yury Norov

Kernel option COMPAT defines the ability of executing aarch32 binaries.
Some platforms does not support aarch32 mode, and so cannot execute that
binaries. But we cannot just disable COMPAT for them because the same
kernel binary may be used by multiple platforms.

In this patch, system_supports_aarch32_el0() is introduced to detect
aarch32 support at run-time.

Signed-off-by: Yury Norov 
---
 arch/arm64/include/asm/cpufeature.h | 1 +
 arch/arm64/include/asm/elf.h| 6 --
 arch/arm64/kernel/cpuinfo.c | 9 +
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h 
b/arch/arm64/include/asm/cpufeature.h
index 20cdc26..d24ea15 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
 void check_local_cpu_features(void);
 bool cpu_supports_mixed_endian_el0(void);
 bool system_supports_mixed_endian_el0(void);
+bool system_supports_aarch32_el0(void);
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index faad6df..461897b 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -21,6 +21,7 @@
 /*
  * ELF register definitions..
  */
+#include 
 #include 
 #include 
 
@@ -173,8 +174,9 @@ typedef compat_elf_greg_t   
compat_elf_gregset_t[COMPAT_ELF_NGREG];
 
 /* AArch32 EABI. */
 #define EF_ARM_EABI_MASK   0xff00
-#define compat_elf_check_arch(x)   (((x)->e_machine == EM_ARM) && \
-((x)->e_flags & EF_ARM_EABI_MASK))
+#define compat_elf_check_arch(x)   (system_supports_aarch32_el0()  \
+   && ((x)->e_machine == EM_ARM)   \
+   && ((x)->e_flags & EF_ARM_EABI_MASK))
 
 #define compat_start_threadcompat_start_thread
 #define COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 75d5a86..95d953f 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
return mixed_endian_el0;
 }
 
+#define AARCH641
+#define AARCH32_64 2
+bool system_supports_aarch32_el0(void)
+{
+   struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
+   u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
+   return arm64_el0 == AARCH32_64;
+}
+
 static void update_mixed_endian_el0_support(struct cpuinfo_arm64 *info)
 {
mixed_endian_el0 &= 
id_aa64mmfr0_mixed_endian_el0(info->reg_id_aa64mmfr0);
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

2015-09-01 Thread Mark Rutland

On Tue, Sep 01, 2015 at 03:41:12PM +0100, Yury Norov wrote:
> Kernel option COMPAT defines the ability of executing aarch32 binaries.
> Some platforms does not support aarch32 mode, and so cannot execute that
> binaries. But we cannot just disable COMPAT for them because the same
> kernel binary may be used by multiple platforms.
> 
> In this patch, system_supports_aarch32_el0() is introduced to detect
> aarch32 support at run-time.
> 
> Signed-off-by: Yury Norov 
> ---
>  arch/arm64/include/asm/cpufeature.h | 1 +
>  arch/arm64/include/asm/elf.h| 6 --
>  arch/arm64/kernel/cpuinfo.c | 9 +
>  3 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/cpufeature.h 
> b/arch/arm64/include/asm/cpufeature.h
> index 20cdc26..d24ea15 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -81,6 +81,7 @@ void check_local_cpu_errata(void);
>  void check_local_cpu_features(void);
>  bool cpu_supports_mixed_endian_el0(void);
>  bool system_supports_mixed_endian_el0(void);
> +bool system_supports_aarch32_el0(void);
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
> index faad6df..461897b 100644
> --- a/arch/arm64/include/asm/elf.h
> +++ b/arch/arm64/include/asm/elf.h
> @@ -21,6 +21,7 @@
>  /*
>   * ELF register definitions..
>   */
> +#include 
>  #include 
>  #include 
>  
> @@ -173,8 +174,9 @@ typedef compat_elf_greg_t 
> compat_elf_gregset_t[COMPAT_ELF_NGREG];
>  
>  /* AArch32 EABI. */
>  #define EF_ARM_EABI_MASK 0xff00
> -#define compat_elf_check_arch(x) (((x)->e_machine == EM_ARM) && \
> -  ((x)->e_flags & EF_ARM_EABI_MASK))
> +#define compat_elf_check_arch(x) (system_supports_aarch32_el0()  \
> + && ((x)->e_machine == EM_ARM)   \
> + && ((x)->e_flags & EF_ARM_EABI_MASK))
>  
>  #define compat_start_thread  compat_start_thread
>  #define COMPAT_SET_PERSONALITY(ex)   set_thread_flag(TIF_32BIT);
> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
> index 75d5a86..95d953f 100644
> --- a/arch/arm64/kernel/cpuinfo.c
> +++ b/arch/arm64/kernel/cpuinfo.c
> @@ -79,6 +79,15 @@ bool system_supports_mixed_endian_el0(void)
>   return mixed_endian_el0;
>  }
>  
> +#define AARCH64  1
> +#define AARCH32_64   2

These should be better namespaced. Perhaps ID_AA64PFR0_EL1_EL0_64 and
ID_AA64PFR0_EL1_EL0_6432 ?

> +bool system_supports_aarch32_el0(void)
> +{
> + struct cpuinfo_arm64 *info = this_cpu_ptr(_data);
> + u64 arm64_el0 = info->reg_id_aa64pfr0 & 0xf;
> + return arm64_el0 == AARCH32_64;
> +}

We should handle this the same way as we do for endianness support and
check that all CPUs support AArch32, and set a global flag, rather than
assuming that all CPUs are symmetric. Likewise for any other feature we
have to dynamically detect.

Thanks,
Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

[PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

[PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

Re: [PATCH 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0

8 matches

Site Navigation

Mail list logo

Footer information