2019-12-22 09:34:50

by Luc Van Oostenryck

Subject: [PATCH] riscv: fix compile failure with EXPORT_SYMBOL() & !MMU

When support for !MMU was added, the declaration of
__asm_copy_to_user() & __asm_copy_from_user() were #ifdefed
out hence their EXPORT_SYMBOL() give an error message like:
.../riscv_ksyms.c:13:15: error: '__asm_copy_to_user' undeclared here
.../riscv_ksyms.c:14:15: error: '__asm_copy_from_user' undeclared here

Since these symbols are not defined with !MMU it's wrong to export them.
Same for __clear_user() (even though this one is also declared in
include/asm-generic/uaccess.h and thus doesn't give an error message).

Fix this by doing the EXPORT_SYMBOL() directly where these symbols
are defined: inside lib/uaccess.S itself.

Fixes 6bd33e1ece528f67646db33bf97406b747dafda0
Reported-by: kbuild test robot <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Signed-off-by: Luc Van Oostenryck <[email protected]>

---

Note: this is only compile tested, not link tested, because the
config given in the bot's report gives me several other
unrelared failure.

arch/riscv/kernel/riscv_ksyms.c | 3 ---
arch/riscv/lib/uaccess.S | 4 ++++
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
index 4800cf703186..2a02b7eebee0 100644
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ b/arch/riscv/kernel/riscv_ksyms.c
@@ -9,8 +9,5 @@
/*
* Assembly functions that may be used (directly or indirectly) by modules
*/
-EXPORT_SYMBOL(__clear_user);
-EXPORT_SYMBOL(__asm_copy_to_user);
-EXPORT_SYMBOL(__asm_copy_from_user);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memcpy);
diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S
index fecd65657a6f..f29d2ba2c0a6 100644
--- a/arch/riscv/lib/uaccess.S
+++ b/arch/riscv/lib/uaccess.S
@@ -1,4 +1,5 @@
#include <linux/linkage.h>
+#include <asm-generic/export.h>
#include <asm/asm.h>
#include <asm/csr.h>

@@ -66,6 +67,8 @@ ENTRY(__asm_copy_from_user)
j 3b
ENDPROC(__asm_copy_to_user)
ENDPROC(__asm_copy_from_user)
+EXPORT_SYMBOL(__asm_copy_to_user)
+EXPORT_SYMBOL(__asm_copy_from_user)


ENTRY(__clear_user)
@@ -108,6 +111,7 @@ ENTRY(__clear_user)
bltu a0, a3, 5b
j 3b
ENDPROC(__clear_user)
+EXPORT_SYMBOL(__clear_user)

.section .fixup,"ax"
.balign 4
--
2.24.0

2019-12-28 06:06:01

by Paul Walmsley

Subject: Re: [PATCH] riscv: fix compile failure with EXPORT_SYMBOL() & !MMU

On Sun, 22 Dec 2019, Luc Van Oostenryck wrote:

> When support for !MMU was added, the declaration of
> __asm_copy_to_user() & __asm_copy_from_user() were #ifdefed
> out hence their EXPORT_SYMBOL() give an error message like:
> .../riscv_ksyms.c:13:15: error: '__asm_copy_to_user' undeclared here
> .../riscv_ksyms.c:14:15: error: '__asm_copy_from_user' undeclared here
>
> Since these symbols are not defined with !MMU it's wrong to export them.
> Same for __clear_user() (even though this one is also declared in
> include/asm-generic/uaccess.h and thus doesn't give an error message).
>
> Fix this by doing the EXPORT_SYMBOL() directly where these symbols
> are defined: inside lib/uaccess.S itself.
>
> Fixes 6bd33e1ece528f67646db33bf97406b747dafda0
> Reported-by: kbuild test robot <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Paul Walmsley <[email protected]>
> Signed-off-by: Luc Van Oostenryck <[email protected]>

Thanks Luc; queued for v5.5-rc.


- Paul