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Subject[PATCH] nios2: __kuser_sigtramp placement fix
The address of __kuser_sigtramp is wrong by one word, due to padding
__kuser_cmpxchg to fully 64 bytes. The version word at the start of the
page displaces __kuser_sigtramp to 0x1044, instead of the intended 0x1040.

Fixed by counting the 64-byte frame from the start of the page instead
of __kuser_cmpxchg. This shortens the __kuser_cmpxchg frame to 60-bytes,
but that's likely enough.

The zero-byte padding parts of the kuser_pad macro has been removed, due
to the .if command refusing to behave properly when there are other
.word directives in between. Probably a binutils gas bug.

Thanks,
Chung-Lin

Cc: Ley Foon Tan <lftan@altera.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Chung-Lin Tang <cltang@codesourcery.com>

diff --git a/arch/nios2/kernel/entry.S b/arch/nios2/kernel/entry.S
index 0bdfd13..3224839 100644
--- a/arch/nios2/kernel/entry.S
+++ b/arch/nios2/kernel/entry.S
@@ -492,14 +492,7 @@ ENTRY(ret_from_kernel_thread)

/* Filling pads with undefined instructions. */
.macro kuser_pad sym size
- .if ((. - \sym) & 3)
- .rept (4 - (. - \sym) & 3)
- .byte 0
- .endr
- .endif
- .rept ((\size - (. - \sym)) / 4)
- .word 0xdeadbeef
- .endr
+ .fill ((\size - (. - \sym)) / 4), 4, 0xdeadbeef
.endm

.align 6
@@ -526,7 +519,10 @@ cmpxchg_stw:
cmpxchg_ret:
ret

- kuser_pad __kuser_cmpxchg, 64
+ /* The first 64-byte frame contains the version word, so note
+ that the first padding entry is based from the start of the kuser
+ page, instead of __kuser_cmpxchg. */
+ kuser_pad __kuser_helper_start, 64

.globl __kuser_sigtramp
__kuser_sigtramp:

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