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sparc64: fix fault handling in NGbzero.S and GENbzero.S

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commit 3c7f62212018b904ae17f5636ead18a4dca3a88f upstream.

When any of the functions contained in NGbzero.S and GENbzero.S
vector through *bzero_from_clear_user, we may end up taking a
fault when executing one of the store alternate address space
instructions. If this happens, the exception handler does not
restore the %asi register.

This commit fixes the issue by introducing a new exception
handler that ensures the %asi register is restored when
a fault is handled.

Orabug: 25577560

Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Reviewed-by: Rob Gardner <rob.gardner@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dave Aldridge 2017-05-09 02:57:35 -06:00 committed by Greg Kroah-Hartman
parent c98f47c1f6
commit e2b8851f1f
3 changed files with 8 additions and 2 deletions
arch/sparc
kernel
head_64.S
lib
GENbzero.SNGbzero.S

6
arch/sparc/kernel/head_64.S

@ -939,3 +939,9 @@ ENTRY(__retl_o1)
retl
mov %o1, %o0
ENDPROC(__retl_o1)
ENTRY(__retl_o1_asi)
wr %o5, 0x0, %asi
retl
mov %o1, %o0
ENDPROC(__retl_o1_asi)

2
arch/sparc/lib/GENbzero.S

@ -8,7 +8,7 @@
98: x,y; \
.section __ex_table,"a";\
.align 4; \
.word 98b, __retl_o1; \
.word 98b, __retl_o1_asi;\
.text; \
.align 4;

2
arch/sparc/lib/NGbzero.S

@ -8,7 +8,7 @@
98: x,y; \
.section __ex_table,"a";\
.align 4; \
.word 98b, __retl_o1; \
.word 98b, __retl_o1_asi;\
.text; \
.align 4;