[PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[Arnd Bergmann]

In order to avoid needless #ifdef CONFIG_COMPAT checks,
move the compat_ptr() definition to linux/compat.h
where it can be seen by any file regardless of the
architecture.

Only s390 needs a special definition, this can use the
self-#define trick we have elsewhere.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm64/include/asm/compat.h   | 17 -----------------
 arch/mips/include/asm/compat.h    | 18 ------------------
 arch/parisc/include/asm/compat.h  | 17 -----------------
 arch/powerpc/include/asm/compat.h | 17 -----------------
 arch/powerpc/oprofile/backtrace.c |  2 +-
 arch/s390/include/asm/compat.h    |  6 +-----
 arch/sparc/include/asm/compat.h   | 17 -----------------
 arch/x86/include/asm/compat.h     | 17 -----------------
 include/linux/compat.h            | 18 ++++++++++++++++++
 9 files changed, 20 insertions(+), 109 deletions(-)

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index 7b4172ce497c..935d2aa231bf 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -114,23 +114,6 @@ typedef u32		compat_sigset_word;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
-/*
- * A pointer passed in from user mode. This should not
- * be used for syscall parameters, just declare them
- * as pointers because the syscall entry code will have
- * appropriately converted them already.
- */
-
-static inline void __user *compat_ptr(compat_uptr_t uptr)
-{
-	return (void __user *)(unsigned long)uptr;
-}
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
-
 #define compat_user_stack_pointer() (user_stack_pointer(task_pt_regs(current)))
 #define COMPAT_MINSIGSTKSZ	2048
 
diff --git a/arch/mips/include/asm/compat.h b/arch/mips/include/asm/compat.h
index c99166eadbde..255afcdd79c9 100644
--- a/arch/mips/include/asm/compat.h
+++ b/arch/mips/include/asm/compat.h
@@ -100,24 +100,6 @@ typedef u32		compat_sigset_word;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
-/*
- * A pointer passed in from user mode. This should not
- * be used for syscall parameters, just declare them
- * as pointers because the syscall entry code will have
- * appropriately converted them already.
- */
-
-static inline void __user *compat_ptr(compat_uptr_t uptr)
-{
-	/* cast to a __user pointer via "unsigned long" makes sparse happy */
-	return (void __user *)(unsigned long)(long)uptr;
-}
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
-
 static inline void __user *arch_compat_alloc_user_space(long len)
 {
 	struct pt_regs *regs = (struct pt_regs *)
diff --git a/arch/parisc/include/asm/compat.h b/arch/parisc/include/asm/compat.h
index e03e3c849f40..2f4f66a3bac0 100644
--- a/arch/parisc/include/asm/compat.h
+++ b/arch/parisc/include/asm/compat.h
@@ -173,23 +173,6 @@ struct compat_shmid64_ds {
 #define COMPAT_ELF_NGREG 80
 typedef compat_ulong_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
 
-/*
- * A pointer passed in from user mode. This should not
- * be used for syscall parameters, just declare them
- * as pointers because the syscall entry code will have
- * appropriately converted them already.
- */
-
-static inline void __user *compat_ptr(compat_uptr_t uptr)
-{
-	return (void __user *)(unsigned long)uptr;
-}
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
-
 static __inline__ void __user *arch_compat_alloc_user_space(long len)
 {
 	struct pt_regs *regs = &current->thread.regs;
diff --git a/arch/powerpc/include/asm/compat.h b/arch/powerpc/include/asm/compat.h
index 74d0db511099..3e3cdfaa76c6 100644
--- a/arch/powerpc/include/asm/compat.h
+++ b/arch/powerpc/include/asm/compat.h
@@ -96,23 +96,6 @@ typedef u32		compat_sigset_word;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
-/*
- * A pointer passed in from user mode. This should not
- * be used for syscall parameters, just declare them
- * as pointers because the syscall entry code will have
- * appropriately converted them already.
- */
-
-static inline void __user *compat_ptr(compat_uptr_t uptr)
-{
-	return (void __user *)(unsigned long)uptr;
-}
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
-
 static inline void __user *arch_compat_alloc_user_space(long len)
 {
 	struct pt_regs *regs = current->thread.regs;
diff --git a/arch/powerpc/oprofile/backtrace.c b/arch/powerpc/oprofile/backtrace.c
index 43245f4a9bcb..6ffcb80cf844 100644
--- a/arch/powerpc/oprofile/backtrace.c
+++ b/arch/powerpc/oprofile/backtrace.c
@@ -9,7 +9,7 @@
 #include <linux/sched.h>
 #include <asm/processor.h>
 #include <linux/uaccess.h>
-#include <asm/compat.h>
+#include <linux/compat.h>
 #include <asm/oprofile_impl.h>
 
 #define STACK_SP(STACK)		*(STACK)
diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index 63b46e30b2c3..9547cd5d6cdc 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -177,11 +177,7 @@ static inline void __user *compat_ptr(compat_uptr_t uptr)
 {
 	return (void __user *)(unsigned long)(uptr & 0x7fffffffUL);
 }
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
+#define compat_ptr(uptr) compat_ptr(uptr)
 
 #ifdef CONFIG_COMPAT
 
diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h
index 30b1763580b1..40a267b3bd52 100644
--- a/arch/sparc/include/asm/compat.h
+++ b/arch/sparc/include/asm/compat.h
@@ -125,23 +125,6 @@ typedef u32		compat_sigset_word;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
-/*
- * A pointer passed in from user mode. This should not
- * be used for syscall parameters, just declare them
- * as pointers because the syscall entry code will have
- * appropriately converted them already.
- */
-
-static inline void __user *compat_ptr(compat_uptr_t uptr)
-{
-	return (void __user *)(unsigned long)uptr;
-}
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
-
 #ifdef CONFIG_COMPAT
 static inline void __user *arch_compat_alloc_user_space(long len)
 {
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index 22c4dfe65992..52e9f3480f69 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -177,23 +177,6 @@ typedef struct user_regs_struct compat_elf_gregset_t;
 	(!!(task_pt_regs(current)->orig_ax & __X32_SYSCALL_BIT))
 #endif
 
-/*
- * A pointer passed in from user mode. This should not
- * be used for syscall parameters, just declare them
- * as pointers because the syscall entry code will have
- * appropriately converted them already.
- */
-
-static inline void __user *compat_ptr(compat_uptr_t uptr)
-{
-	return (void __user *)(unsigned long)uptr;
-}
-
-static inline compat_uptr_t ptr_to_compat(void __user *uptr)
-{
-	return (u32)(unsigned long)uptr;
-}
-
 static inline void __user *arch_compat_alloc_user_space(long len)
 {
 	compat_uptr_t sp;
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 68f79d855c3d..11083d84eb23 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -958,4 +958,22 @@ static inline bool in_compat_syscall(void) { return false; }
 
 #endif /* CONFIG_COMPAT */
 
+/*
+ * A pointer passed in from user mode. This should not
+ * be used for syscall parameters, just declare them
+ * as pointers because the syscall entry code will have
+ * appropriately converted them already.
+ */
+#ifndef compat_ptr
+static inline void __user *compat_ptr(compat_uptr_t uptr)
+{
+	return (void __user *)(unsigned long)uptr;
+}
+#endif
+
+static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+{
+	return (u32)(unsigned long)uptr;
+}
+
 #endif /* _LINUX_COMPAT_H */
-- 
2.20.0

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[Will Deacon]

On Thu, Jan 02, 2020 at 03:55:20PM +0100, Arnd Bergmann wrote:
> In order to avoid needless #ifdef CONFIG_COMPAT checks,
> move the compat_ptr() definition to linux/compat.h
> where it can be seen by any file regardless of the
> architecture.
> 
> Only s390 needs a special definition, this can use the
> self-#define trick we have elsewhere.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm64/include/asm/compat.h   | 17 -----------------
>  arch/mips/include/asm/compat.h    | 18 ------------------
>  arch/parisc/include/asm/compat.h  | 17 -----------------
>  arch/powerpc/include/asm/compat.h | 17 -----------------
>  arch/powerpc/oprofile/backtrace.c |  2 +-
>  arch/s390/include/asm/compat.h    |  6 +-----
>  arch/sparc/include/asm/compat.h   | 17 -----------------
>  arch/x86/include/asm/compat.h     | 17 -----------------
>  include/linux/compat.h            | 18 ++++++++++++++++++
>  9 files changed, 20 insertions(+), 109 deletions(-)

For arm64:

Acked-by: Will Deacon <will@kernel.org>

Will

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[H. Peter Anvin]

On 2020-01-02 06:55, Arnd Bergmann wrote:
> In order to avoid needless #ifdef CONFIG_COMPAT checks,
> move the compat_ptr() definition to linux/compat.h
> where it can be seen by any file regardless of the
> architecture.
> 
> Only s390 needs a special definition, this can use the
> self-#define trick we have elsewhere.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm64/include/asm/compat.h   | 17 -----------------
>  arch/mips/include/asm/compat.h    | 18 ------------------
>  arch/parisc/include/asm/compat.h  | 17 -----------------
>  arch/powerpc/include/asm/compat.h | 17 -----------------
>  arch/powerpc/oprofile/backtrace.c |  2 +-
>  arch/s390/include/asm/compat.h    |  6 +-----
>  arch/sparc/include/asm/compat.h   | 17 -----------------
>  arch/x86/include/asm/compat.h     | 17 -----------------
>  include/linux/compat.h            | 18 ++++++++++++++++++
>  9 files changed, 20 insertions(+), 109 deletions(-)
> 

For x86:

Reviewed-by: H. Peter Anvin <hpa@zytor.com>

It still suffers from the zero-one-infinity rule failure of the compat
architecture as a whole, but that is a very different problem. In this case
"compat" is obviously meaning "a 32-on-64 ABI" and simply centralizes a common
API, which is a Good Thing[TM].

	-hpa

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[Michael Ellerman]

Arnd Bergmann <arnd@arndb.de> writes:
> In order to avoid needless #ifdef CONFIG_COMPAT checks,
> move the compat_ptr() definition to linux/compat.h
> where it can be seen by any file regardless of the
> architecture.
>
> Only s390 needs a special definition, this can use the
> self-#define trick we have elsewhere.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm64/include/asm/compat.h   | 17 -----------------
>  arch/mips/include/asm/compat.h    | 18 ------------------
>  arch/parisc/include/asm/compat.h  | 17 -----------------
>  arch/powerpc/include/asm/compat.h | 17 -----------------
>  arch/powerpc/oprofile/backtrace.c |  2 +-

LGTM.

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

One minor comment:

> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index 68f79d855c3d..11083d84eb23 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -958,4 +958,22 @@ static inline bool in_compat_syscall(void) { return false; }
>  
>  #endif /* CONFIG_COMPAT */
>  
> +/*
> + * A pointer passed in from user mode. This should not
> + * be used for syscall parameters, just declare them
> + * as pointers because the syscall entry code will have
> + * appropriately converted them already.
> + */
> +#ifndef compat_ptr
> +static inline void __user *compat_ptr(compat_uptr_t uptr)
> +{
> +	return (void __user *)(unsigned long)uptr;
> +}
> +#endif
> +
> +static inline compat_uptr_t ptr_to_compat(void __user *uptr)
> +{
> +	return (u32)(unsigned long)uptr;
> +}

Is there a reason we cast to u32 directly instead of using compat_uptr_t?

cheers

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[Arnd Bergmann]

On Tue, Jan 7, 2020 at 3:05 AM Michael Ellerman <mpe@ellerman.id.au> wrote:
> Arnd Bergmann <arnd@arndb.de> writes:
> > +
> > +static inline compat_uptr_t ptr_to_compat(void __user *uptr)
> > +{
> > +     return (u32)(unsigned long)uptr;
> > +}
>
> Is there a reason we cast to u32 directly instead of using compat_uptr_t?

Probably Al found this to be more explicit at the time when he introduced
it on all the architectures in 2005. I just moved it here and kept the
definition.

       Arnd

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[H. Peter Anvin]

<linuxppc-dev@lists.ozlabs.org>,oprofile-list@lists.sf.net,linux-s390 <linux-s390@vger.kernel.org>,sparclinux <sparclinux@vger.kernel.org>
From: hpa@zytor.com
Message-ID: <41625F06-D755-4C82-86DF-A9415FEEE13D@zytor.com>

On January 7, 2020 12:08:31 AM PST, Arnd Bergmann <arnd@arndb.de> wrote:
>On Tue, Jan 7, 2020 at 3:05 AM Michael Ellerman <mpe@ellerman.id.au>
>wrote:
>> Arnd Bergmann <arnd@arndb.de> writes:
>> > +
>> > +static inline compat_uptr_t ptr_to_compat(void __user *uptr)
>> > +{
>> > +     return (u32)(unsigned long)uptr;
>> > +}
>>
>> Is there a reason we cast to u32 directly instead of using
>compat_uptr_t?
>
>Probably Al found this to be more explicit at the time when he
>introduced
>it on all the architectures in 2005. I just moved it here and kept the
>definition.
>
>       Arnd

Did compat_uptr_t exist back then?
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[Arnd Bergmann]

On Tue, Jan 7, 2020 at 9:20 AM H. Peter Anvin <hpa@zytor.com> wrote:
>
> <linuxppc-dev@lists.ozlabs.org>,oprofile-list@lists.sf.net,linux-s390 <linux-s390@vger.kernel.org>,sparclinux <sparclinux@vger.kernel.org>
> From: hpa@zytor.com
> Message-ID: <41625F06-D755-4C82-86DF-A9415FEEE13D@zytor.com>
>
> On January 7, 2020 12:08:31 AM PST, Arnd Bergmann <arnd@arndb.de> wrote:
> >On Tue, Jan 7, 2020 at 3:05 AM Michael Ellerman <mpe@ellerman.id.au>
> >wrote:
> >> Arnd Bergmann <arnd@arndb.de> writes:
> >> > +
> >> > +static inline compat_uptr_t ptr_to_compat(void __user *uptr)
> >> > +{
> >> > +     return (u32)(unsigned long)uptr;
> >> > +}
> >>
> >> Is there a reason we cast to u32 directly instead of using
> >compat_uptr_t?
> >
> >Probably Al found this to be more explicit at the time when he
> >introduced
> >it on all the architectures in 2005. I just moved it here and kept the
> >definition.
> >
> >       Arnd
>
> Did compat_uptr_t exist back then?

Yes, compat_uptr_t (and the earlier compat_ptr_t) goes back
to at least 2003 with the introduction of compat_ptr().

These are some related commits from bitkeeper:

commit 29d04cca305a93cfa90afe1c6440ce5421837213
Author: Stephen Rothwell <sfr@canb.auug.org.au>
Date:   Sun Mar 23 04:59:16 2003 -0800

    [PATCH] compat_uptr_t and compat_ptr

    This creates compat_uptr_t (to represent a user mode pointer passed to
    the kernel other than as a syscall parameter) and compat_ptr() to
    convert it to a kernel pointer.

    This fixes a couple of bugs in s390x (where the conversion of pointers
    actually does something).

diff --git a/include/asm-s390x/compat.h b/include/asm-s390x/compat.h
index 55e23c9b36fe..d1e948ae4bff 100644
--- a/include/asm-s390x/compat.h
+++ b/include/asm-s390x/compat.h
@@ -101,4 +101,17 @@ typedef u32                compat_sigset_word;
 #define COMPAT_OFF_T_MAX       0x7fffffff
 #define COMPAT_LOFF_T_MAX      0x7fffffffffffffffL

+/*
+ * A pointer passed in from user mode. This should not
+ * be used for syscall parameters, just declare them
+ * as pointers because the syscall entry code will have
+ * appropriately comverted them already.
+ */
+typedef        u32             compat_uptr_t;
+
+static inline void *compat_ptr(compat_ptr_t uptr)
+{
+       return (void *)(uptr & 0x7fffffffUL);
+}
+
 #endif /* _ASM_S390X_COMPAT_H */


commit 9d814250b08868cb39cc5a4f43f5cbf5e517f5f4
Author: Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
Date:   Tue Feb 1 21:21:39 2005 -0800

    [PATCH] sparc64 compat annotations

    same story as for amd64 - ptr_to_compat() + normal __user annotations

    Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-sparc64/compat.h b/include/asm-sparc64/compat.h
index 874b136ded90..e26d7d85c55a 100644
--- a/include/asm-sparc64/compat.h
+++ b/include/asm-sparc64/compat.h
@@ -121,6 +121,11 @@ static inline void __user *compat_ptr(compat_uptr_t uptr)
        return (void __user *)(unsigned long)uptr;
 }

+static inline compat_uptr_t ptr_to_compat(void __user *uptr)
+{
+       return (u32)(unsigned long)uptr;
+}
+
 static __inline__ void __user *compat_alloc_user_space(long len)
 {
        struct pt_regs *regs = current_thread_info()->kregs;

Re: [PATCH v3 02/22] compat: provide compat_ptr() on all architectures

[Heiko Carstens]

On Thu, Jan 02, 2020 at 03:55:20PM +0100, Arnd Bergmann wrote:
> In order to avoid needless #ifdef CONFIG_COMPAT checks,
> move the compat_ptr() definition to linux/compat.h
> where it can be seen by any file regardless of the
> architecture.
> 
> Only s390 needs a special definition, this can use the
> self-#define trick we have elsewhere.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm64/include/asm/compat.h   | 17 -----------------
>  arch/mips/include/asm/compat.h    | 18 ------------------
>  arch/parisc/include/asm/compat.h  | 17 -----------------
>  arch/powerpc/include/asm/compat.h | 17 -----------------
>  arch/powerpc/oprofile/backtrace.c |  2 +-
>  arch/s390/include/asm/compat.h    |  6 +-----
>  arch/sparc/include/asm/compat.h   | 17 -----------------
>  arch/x86/include/asm/compat.h     | 17 -----------------
>  include/linux/compat.h            | 18 ++++++++++++++++++
>  9 files changed, 20 insertions(+), 109 deletions(-)

For s390:

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>