[v2] sh: Implement __get_user_u64() required for 64-bit get_user()
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Message ID 20200531104715.2512247-1-glaubitz@physik.fu-berlin.de
State New
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Series
  • [v2] sh: Implement __get_user_u64() required for 64-bit get_user()
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Commit Message

John Paul Adrian Glaubitz May 31, 2020, 10:47 a.m. UTC
Trying to build the kernel with CONFIG_INFINIBAND_USER_ACCESS enabled fails

     ERROR: "__get_user_unknown" [drivers/infiniband/core/ib_uverbs.ko] undefined!

with on SH since the kernel misses a 64-bit implementation of get_user().

Implement the missing 64-bit get_user() as __get_user_u64(), matching the
already existing __put_user_u64() which implements the 64-bit put_user().

Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
---
 arch/sh/include/asm/uaccess_32.h | 51 ++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

 Changes since v1:
 - Replace single mov instruction for exception handling
   in case of invalid load

Comments

John Paul Adrian Glaubitz June 3, 2020, 7:20 a.m. UTC | #1
Hi!

On 5/31/20 12:47 PM, John Paul Adrian Glaubitz wrote:
>  Changes since v1:
>  - Replace single mov instruction for exception handling
>    in case of invalid load

Yutaka Niibe has had a look at my patch and he says, we might have to add
an entry for the fault handling of the upper word.

Quote:

> (1) I think that there is possibility that the second access to user
> space fails (while the first access succeeds).  IIUC, it's good have
> an entry in __ex_tables for the second access too, like:
>     ".long 1b+2, 3b\n\t"
> I don't know if the expression "1b+2" is correct, my intention is
> detecting the failure in the seccond access.

Comments?

@Sato-san: Can you comment on the patch as well?

Thanks,
Adrian
Geert Uytterhoeven June 3, 2020, 7:35 a.m. UTC | #2
Hi Adrian,

On Wed, Jun 3, 2020 at 9:20 AM John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On 5/31/20 12:47 PM, John Paul Adrian Glaubitz wrote:
> >  Changes since v1:
> >  - Replace single mov instruction for exception handling
> >    in case of invalid load
>
> Yutaka Niibe has had a look at my patch and he says, we might have to add
> an entry for the fault handling of the upper word.
>
> Quote:
>
> > (1) I think that there is possibility that the second access to user
> > space fails (while the first access succeeds).  IIUC, it's good have
> > an entry in __ex_tables for the second access too, like:
> >     ".long 1b+2, 3b\n\t"
> > I don't know if the expression "1b+2" is correct, my intention is
> > detecting the failure in the seccond access.

So just add another numeric label, like is done on m68k.

Gr{oetje,eeting}s,

                        Geert

Patch
diff mbox series

diff --git a/arch/sh/include/asm/uaccess_32.h b/arch/sh/include/asm/uaccess_32.h
index 624cf55acc27..35f6c1e40ec3 100644
--- a/arch/sh/include/asm/uaccess_32.h
+++ b/arch/sh/include/asm/uaccess_32.h
@@ -26,6 +26,9 @@  do {								\
 	case 4:							\
 		__get_user_asm(x, ptr, retval, "l");		\
 		break;						\
+	case 8:							\
+		__get_user_u64(x, ptr, retval);			\
+		break;						\
 	default:						\
 		__get_user_unknown();				\
 		break;						\
@@ -66,6 +69,54 @@  do {							\
 
 extern void __get_user_unknown(void);
 
+#if defined(CONFIG_CPU_LITTLE_ENDIAN)
+#define __get_user_u64(x, addr, err) \
+({ \
+__asm__ __volatile__( \
+	"1:\n\t" \
+	"mov.l	%2,%R1\n\t" \
+	"mov.l	%T2,%S1\n\t" \
+	"2:\n" \
+	".section	.fixup,\"ax\"\n" \
+	"3:\n\t" \
+	"mov  #0,%R1\n\t"   \
+	"mov  #0,%S1\n\t"   \
+	"mov.l	4f, %0\n\t" \
+	"jmp	@%0\n\t" \
+	" mov	%3, %0\n\t" \
+	".balign	4\n" \
+	"4:	.long	2b\n\t" \
+	".previous\n" \
+	".section	__ex_table,\"a\"\n\t" \
+	".long	1b, 3b\n\t" \
+	".previous" \
+	:"=&r" (err), "=&r" (x) \
+	:"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
+#else
+#define __get_user_u64(x, addr, err) \
+({ \
+__asm__ __volatile__( \
+	"1:\n\t" \
+	"mov.l	%2,%S1\n\t" \
+	"mov.l	%T2,%R1\n\t" \
+	"2:\n" \
+	".section	.fixup,\"ax\"\n" \
+	"3:\n\t" \
+	"mov  #0,%S1\n\t"   \
+	"mov  #0,%R1\n\t"   \
+	"mov.l	4f, %0\n\t" \
+	"jmp	@%0\n\t" \
+	" mov	%3, %0\n\t" \
+	".balign	4\n" \
+	"4:	.long	2b\n\t" \
+	".previous\n" \
+	".section	__ex_table,\"a\"\n\t" \
+	".long	1b, 3b\n\t" \
+	".previous" \
+	:"=&r" (err), "=&r" (x) \
+	:"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
+#endif
+
 #define __put_user_size(x,ptr,size,retval)		\
 do {							\
 	retval = 0;					\