2017-04-03 22:43:24

by Jessica Yu

Subject: [PATCH] vmlinux.lds: add missing VMLINUX_SYMBOL macros

From: Jessica Yu <[email protected]>

When __{start,end}_ro_after_init is referenced from C code, we run into the
following build errors on blackfin:

kernel/extable.c:169: undefined reference to `__start_ro_after_init'
kernel/extable.c:169: undefined reference to `__end_ro_after_init'

The build error is due to the fact that blackfin is one of the few arches
that prepends an underscore '_' to all symbols defined in C. Fix this by
wrapping __{start,end}_ro_after_init in vmlinux.lds.h with VMLINUX_SYMBOL(),
which adds the necessary prefix for arches that have HAVE_UNDERSCORE_SYMBOL_PREFIX.

Signed-off-by: Jessica Yu <[email protected]>
---
This patch is based on next-20170403.

include/asm-generic/vmlinux.lds.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 979b573..54918ae 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -261,9 +261,9 @@
*/
#ifndef RO_AFTER_INIT_DATA
#define RO_AFTER_INIT_DATA \
- __start_ro_after_init = .; \
+ VMLINUX_SYMBOL(__start_ro_after_init) = .; \
*(.data..ro_after_init) \
- __end_ro_after_init = .;
+ VMLINUX_SYMBOL(__end_ro_after_init) = .;
#endif

/*
--
2.5.5

2017-04-03 23:30:27

by Kees Cook

Subject: Re: [PATCH] vmlinux.lds: add missing VMLINUX_SYMBOL macros

On Mon, Apr 3, 2017 at 3:43 PM, Jessica <[email protected]> wrote:
> From: Jessica Yu <[email protected]>
>
> When __{start,end}_ro_after_init is referenced from C code, we run into the
> following build errors on blackfin:
>
> kernel/extable.c:169: undefined reference to `__start_ro_after_init'
> kernel/extable.c:169: undefined reference to `__end_ro_after_init'
>
> The build error is due to the fact that blackfin is one of the few arches
> that prepends an underscore '_' to all symbols defined in C. Fix this by
> wrapping __{start,end}_ro_after_init in vmlinux.lds.h with VMLINUX_SYMBOL(),
> which adds the necessary prefix for arches that have HAVE_UNDERSCORE_SYMBOL_PREFIX.
>
> Signed-off-by: Jessica Yu <[email protected]>

Thanks!

Acked-by: Kees Cook <[email protected]>

-Kees

> ---
> This patch is based on next-20170403.
>
> include/asm-generic/vmlinux.lds.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index 979b573..54918ae 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -261,9 +261,9 @@
> */
> #ifndef RO_AFTER_INIT_DATA
> #define RO_AFTER_INIT_DATA \
> - __start_ro_after_init = .; \
> + VMLINUX_SYMBOL(__start_ro_after_init) = .; \
> *(.data..ro_after_init) \
> - __end_ro_after_init = .;
> + VMLINUX_SYMBOL(__end_ro_after_init) = .;
> #endif
>
> /*
> --
> 2.5.5
>



--
Kees Cook
Pixel Security