linux/arch/sparc64/lib/NGbzero.S
David S. Miller 24d559cac4 [SPARC64]: store-init needs trailing membar.
The manual says that it is required and we actually have crash reports
where loads see stale data due to not having membars here.

In one case the networking does:

	memset(skb, 0, offsetof(struct sk_buff, truesize));

and then some code later checks skb->nohdr for zero, but it's still
the value that was there before the memset().

Note that arch/sparc64/lib/xor.S already got this right.

Signed-off-by: David S. Miller <davem@davemloft.net>
2007-03-19 13:27:33 -07:00

165 lines
3.4 KiB
ArmAsm

/* NGbzero.S: Niagara optimized memset/clear_user.
*
* Copyright (C) 2006 David S. Miller (davem@davemloft.net)
*/
#include <asm/asi.h>
#define EX_ST(x,y) \
98: x,y; \
.section .fixup; \
.align 4; \
99: retl; \
mov %o1, %o0; \
.section __ex_table; \
.align 4; \
.word 98b, 99b; \
.text; \
.align 4;
.text
.globl NGmemset
.type NGmemset, #function
NGmemset: /* %o0=buf, %o1=pat, %o2=len */
and %o1, 0xff, %o3
mov %o2, %o1
sllx %o3, 8, %g1
or %g1, %o3, %o2
sllx %o2, 16, %g1
or %g1, %o2, %o2
sllx %o2, 32, %g1
ba,pt %xcc, 1f
or %g1, %o2, %o2
.globl NGbzero
.type NGbzero, #function
NGbzero:
clr %o2
1: brz,pn %o1, NGbzero_return
mov %o0, %o3
/* %o5: saved %asi, restored at NGbzero_done
* %g7: store-init %asi to use
* %o4: non-store-init %asi to use
*/
rd %asi, %o5
mov ASI_BLK_INIT_QUAD_LDD_P, %g7
mov ASI_P, %o4
wr %o4, 0x0, %asi
NGbzero_from_clear_user:
cmp %o1, 15
bl,pn %icc, NGbzero_tiny
andcc %o0, 0x7, %g1
be,pt %xcc, 2f
mov 8, %g2
sub %g2, %g1, %g1
sub %o1, %g1, %o1
1: EX_ST(stba %o2, [%o0 + 0x00] %asi)
subcc %g1, 1, %g1
bne,pt %xcc, 1b
add %o0, 1, %o0
2: cmp %o1, 128
bl,pn %icc, NGbzero_medium
andcc %o0, (64 - 1), %g1
be,pt %xcc, NGbzero_pre_loop
mov 64, %g2
sub %g2, %g1, %g1
sub %o1, %g1, %o1
1: EX_ST(stxa %o2, [%o0 + 0x00] %asi)
subcc %g1, 8, %g1
bne,pt %xcc, 1b
add %o0, 8, %o0
NGbzero_pre_loop:
wr %g7, 0x0, %asi
andn %o1, (64 - 1), %g1
sub %o1, %g1, %o1
NGbzero_loop:
EX_ST(stxa %o2, [%o0 + 0x00] %asi)
EX_ST(stxa %o2, [%o0 + 0x08] %asi)
EX_ST(stxa %o2, [%o0 + 0x10] %asi)
EX_ST(stxa %o2, [%o0 + 0x18] %asi)
EX_ST(stxa %o2, [%o0 + 0x20] %asi)
EX_ST(stxa %o2, [%o0 + 0x28] %asi)
EX_ST(stxa %o2, [%o0 + 0x30] %asi)
EX_ST(stxa %o2, [%o0 + 0x38] %asi)
subcc %g1, 64, %g1
bne,pt %xcc, NGbzero_loop
add %o0, 64, %o0
membar #Sync
wr %o4, 0x0, %asi
brz,pn %o1, NGbzero_done
NGbzero_medium:
andncc %o1, 0x7, %g1
be,pn %xcc, 2f
sub %o1, %g1, %o1
1: EX_ST(stxa %o2, [%o0 + 0x00] %asi)
subcc %g1, 8, %g1
bne,pt %xcc, 1b
add %o0, 8, %o0
2: brz,pt %o1, NGbzero_done
nop
NGbzero_tiny:
1: EX_ST(stba %o2, [%o0 + 0x00] %asi)
subcc %o1, 1, %o1
bne,pt %icc, 1b
add %o0, 1, %o0
/* fallthrough */
NGbzero_done:
wr %o5, 0x0, %asi
NGbzero_return:
retl
mov %o3, %o0
.size NGbzero, .-NGbzero
.size NGmemset, .-NGmemset
.globl NGclear_user
.type NGclear_user, #function
NGclear_user: /* %o0=buf, %o1=len */
rd %asi, %o5
brz,pn %o1, NGbzero_done
clr %o3
cmp %o5, ASI_AIUS
bne,pn %icc, NGbzero
clr %o2
mov ASI_BLK_INIT_QUAD_LDD_AIUS, %g7
ba,pt %xcc, NGbzero_from_clear_user
mov ASI_AIUS, %o4
.size NGclear_user, .-NGclear_user
#define BRANCH_ALWAYS 0x10680000
#define NOP 0x01000000
#define NG_DO_PATCH(OLD, NEW) \
sethi %hi(NEW), %g1; \
or %g1, %lo(NEW), %g1; \
sethi %hi(OLD), %g2; \
or %g2, %lo(OLD), %g2; \
sub %g1, %g2, %g1; \
sethi %hi(BRANCH_ALWAYS), %g3; \
sll %g1, 11, %g1; \
srl %g1, 11 + 2, %g1; \
or %g3, %lo(BRANCH_ALWAYS), %g3; \
or %g3, %g1, %g3; \
stw %g3, [%g2]; \
sethi %hi(NOP), %g3; \
or %g3, %lo(NOP), %g3; \
stw %g3, [%g2 + 0x4]; \
flush %g2;
.globl niagara_patch_bzero
.type niagara_patch_bzero,#function
niagara_patch_bzero:
NG_DO_PATCH(memset, NGmemset)
NG_DO_PATCH(__bzero, NGbzero)
NG_DO_PATCH(__clear_user, NGclear_user)
NG_DO_PATCH(tsb_init, NGtsb_init)
retl
nop
.size niagara_patch_bzero,.-niagara_patch_bzero