riscv: uaccess should be used in nommu mode

It might have the unaligned access exception when trying to exchange data
with user space program. In this case, it failed in tty_ioctl(). Therefore
we should enable uaccess.S for NOMMU mode since the generic code doesn't
handle the unaligned access cases.

   0x8013a212 <tty_ioctl+462>:  ld      a5,460(s1)

[    0.115279] Oops - load address misaligned [#1]
[    0.115284] CPU: 0 PID: 29 Comm: sh Not tainted 5.4.0-rc5-00020-gb4c27160d562-dirty #36
[    0.115294] epc: 000000008013a212 ra : 000000008013a212 sp : 000000008f48dd50
[    0.115303]  gp : 00000000801cac28 tp : 000000008fb80000 t0 : 00000000000000e8
[    0.115312]  t1 : 000000008f58f108 t2 : 0000000000000009 s0 : 000000008f48ddf0
[    0.115321]  s1 : 000000008f8c6220 a0 : 0000000000000001 a1 : 000000008f48dd28
[    0.115330]  a2 : 000000008fb80000 a3 : 00000000801a7398 a4 : 0000000000000000
[    0.115339]  a5 : 0000000000000000 a6 : 000000008f58f0c6 a7 : 000000000000001d
[    0.115348]  s2 : 000000008f8c6308 s3 : 000000008f78b7c8 s4 : 000000008fb834c0
[    0.115357]  s5 : 0000000000005413 s6 : 0000000000000000 s7 : 000000008f58f2b0
[    0.115366]  s8 : 000000008f858008 s9 : 000000008f776818 s10: 000000008f776830
[    0.115375]  s11: 000000008fb840a8 t3 : 1999999999999999 t4 : 000000008f78704c
[    0.115384]  t5 : 0000000000000005 t6 : 0000000000000002
[    0.115391] status: 0000000200001880 badaddr: 000000008f8c63ec cause: 0000000000000004
[    0.115401] ---[ end trace 00d490c6a8b6c9ac ]---

This failure could be fixed after this patch applied.

[    0.002282] Run /init as init process
Initializing random number generator... [    0.005573] random: dd: uninitialized urandom read (512 bytes read)
done.

Welcome to Buildroot
buildroot login: root
Password:
Jan  1 00:00:00 login[62]: root login on 'ttySIF0'
~ #

Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1a3b5a5276be26cdc052eca8d997864735802316..cd5db57bfd41de99b08d7eace62bce0086c42bb3 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -50,7 +50,6 @@ config RISCV
        select PCI_DOMAINS_GENERIC if PCI
        select PCI_MSI if PCI
        select RISCV_TIMER
-       select UACCESS_MEMCPY if !MMU
        select GENERIC_IRQ_MULTI_HANDLER
        select GENERIC_ARCH_TOPOLOGY if SMP
        select ARCH_HAS_PTE_SPECIAL

diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index f462a183a9c2343415ce933ce34d996f0ae0b4d0..8ce9d607b53dceb8f115d4ebf7a43657270ed56a 100644 (file)
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -11,6 +11,24 @@
 /*
  * User space memory access functions
  */
+
+extern unsigned long __must_check __asm_copy_to_user(void __user *to,
+       const void *from, unsigned long n);
+extern unsigned long __must_check __asm_copy_from_user(void *to,
+       const void __user *from, unsigned long n);
+
+static inline unsigned long
+raw_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+       return __asm_copy_from_user(to, from, n);
+}
+
+static inline unsigned long
+raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+       return __asm_copy_to_user(to, from, n);
+}
+
 #ifdef CONFIG_MMU
 #include <linux/errno.h>
 #include <linux/compiler.h>
@@ -367,24 +385,6 @@ do {                                                               \
                -EFAULT;                                        \
 })
 
-
-extern unsigned long __must_check __asm_copy_to_user(void __user *to,
-       const void *from, unsigned long n);
-extern unsigned long __must_check __asm_copy_from_user(void *to,
-       const void __user *from, unsigned long n);
-
-static inline unsigned long
-raw_copy_from_user(void *to, const void __user *from, unsigned long n)
-{
-       return __asm_copy_from_user(to, from, n);
-}
-
-static inline unsigned long
-raw_copy_to_user(void __user *to, const void *from, unsigned long n)
-{
-       return __asm_copy_to_user(to, from, n);
-}
-
 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 
 extern long __must_check strlen_user(const char __user *str);

diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 47e7a82044608d1b1b81a981b1511ee3406cf68a..0d0db80800c4ed32f8b9a39a6a60a2aa9f9886aa 100644 (file)
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -2,5 +2,5 @@
 lib-y                  += delay.o
 lib-y                  += memcpy.o
 lib-y                  += memset.o
-lib-$(CONFIG_MMU)      += uaccess.o
+lib-y                  += uaccess.o
 lib-$(CONFIG_64BIT)    += tishift.o