On Thu, Jan 11, 2024 at 07:40:32PM -0800, Linus Torvalds wrote:
> On Thu, 11 Jan 2024 at 15:57, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> >
> > I wonder if something may be wrong with the definition and use of __m
> > for u64 accesses. The code below also fixes the build problem.
>
> Ok, that looks like the right workaround.
>
I think I'll go with the code below. It doesn't touch the MMU code
(which for some reason doesn't result in a build failure), and
it generates
! 5071 "fs/namespace.c" 1
mov.l r6,@r1
mov.l r7,@(4,r1)
which seems to be correct. It also matches the pattern used
for __put_user_asm(). Does that make sense ?
Thanks,
Guenter
---
diff --git a/arch/sh/include/asm/uaccess_32.h b/arch/sh/include/asm/uaccess_32.h
index 5d7ddc092afd..5ce46b2a95b6 100644
--- a/arch/sh/include/asm/uaccess_32.h
+++ b/arch/sh/include/asm/uaccess_32.h
@@ -176,6 +176,7 @@ do { \
} while (0)
#endif /* CONFIG_MMU */
+#ifdef CONFIG_MMU
#if defined(CONFIG_CPU_LITTLE_ENDIAN)
#define __put_user_u64(val,addr,retval) \
({ \
@@ -221,6 +222,26 @@ __asm__ __volatile__( \
: "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
: "memory"); })
#endif
+#else
+#if defined(CONFIG_CPU_LITTLE_ENDIAN)
+#define __put_user_u64(val,addr,retval) \
+({ \
+__asm__ __volatile__( \
+ "mov.l %R0,%1\n\t" \
+ "mov.l %S0,%T1\n\t" \
+ : /* no outputs */ \
+ : "r" (val), "m" (*(u64 *)(addr)) \
+ : "memory"); })
+#else
+({ \
+__asm__ __volatile__( \
+ "mov.l %S0,%1\n\t" \
+ "mov.l %R0,%T1\n\t" \
+ : /* no outputs */ \
+ : "r" (val), "m" (*(u64 *)(addr)) \
+ : "memory"); })
+#endif
+#endif /* CONFIG_MMU */
extern void __put_user_unknown(void);
