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authorBabu Moger <babu.moger@oracle.com>2017-03-17 14:52:21 -0600
committerDavid S. Miller <davem@davemloft.net>2017-03-27 21:51:40 -0700
commit0ae2d26ffe70c32d4a7fe77593f0a55ce416c09e (patch)
tree56fd33ac22298ef2ae162366727ada11c719323e
parentadfae8a5d833fa2b46577a8081f350e408851f5b (diff)
arch/sparc: Avoid DCTI Couples
Avoid un-intended DCTI Couples. Use of DCTI couples is deprecated. Also address the "Programming Note" for optimal performance. Here is the complete text from Oracle SPARC Architecture Specs. 6.3.4.7 DCTI Couples "A delayed control transfer instruction (DCTI) in the delay slot of another DCTI is referred to as a “DCTI couple”. The use of DCTI couples is deprecated in the Oracle SPARC Architecture; no new software should place a DCTI in the delay slot of another DCTI, because on future Oracle SPARC Architecture implementations DCTI couples may execute either slowly or differently than the programmer assumes it will. SPARC V8 and SPARC V9 Compatibility Note The SPARC V8 architecture left behavior undefined for a DCTI couple. The SPARC V9 architecture defined behavior in that case, but as of UltraSPARC Architecture 2005, use of DCTI couples was deprecated. Software should not expect high performance from DCTI couples, and performance of DCTI couples should be expected to decline further in future processors. Programming Note As noted in TABLE 6-5 on page 115, an annulled branch-always (branch-always with a = 1) instruction is not architecturally a DCTI. However, since not all implementations make that distinction, for optimal performance, a DCTI should not be placed in the instruction word immediately following an annulled branch-always instruction (BA,A or BPA,A)." Signed-off-by: Babu Moger <babu.moger@oracle.com> Reviewed-by: Rob Gardner <rob.gardner@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/sparc/kernel/head_64.S4
-rw-r--r--arch/sparc/kernel/misctrap.S1
-rw-r--r--arch/sparc/kernel/rtrap_64.S1
-rw-r--r--arch/sparc/kernel/spiterrs.S1
-rw-r--r--arch/sparc/kernel/sun4v_tlb_miss.S1
-rw-r--r--arch/sparc/kernel/urtt_fill.S1
-rw-r--r--arch/sparc/kernel/winfixup.S2
-rw-r--r--arch/sparc/lib/NG2memcpy.S4
-rw-r--r--arch/sparc/lib/NG4memcpy.S1
-rw-r--r--arch/sparc/lib/NG4memset.S1
-rw-r--r--arch/sparc/lib/NGmemcpy.S1
11 files changed, 18 insertions, 0 deletions
diff --git a/arch/sparc/kernel/head_64.S b/arch/sparc/kernel/head_64.S
index 6aa3da152c20..44101196d02b 100644
--- a/arch/sparc/kernel/head_64.S
+++ b/arch/sparc/kernel/head_64.S
@@ -96,6 +96,7 @@ sparc64_boot:
andn %g1, PSTATE_AM, %g1
wrpr %g1, 0x0, %pstate
ba,a,pt %xcc, 1f
+ nop
.globl prom_finddev_name, prom_chosen_path, prom_root_node
.globl prom_getprop_name, prom_mmu_name, prom_peer_name
@@ -613,6 +614,7 @@ niagara_tlb_fixup:
nop
ba,a,pt %xcc, 80f
+ nop
niagara4_patch:
call niagara4_patch_copyops
nop
@@ -622,6 +624,7 @@ niagara4_patch:
nop
ba,a,pt %xcc, 80f
+ nop
niagara2_patch:
call niagara2_patch_copyops
@@ -632,6 +635,7 @@ niagara2_patch:
nop
ba,a,pt %xcc, 80f
+ nop
niagara_patch:
call niagara_patch_copyops
diff --git a/arch/sparc/kernel/misctrap.S b/arch/sparc/kernel/misctrap.S
index 34b4933900bf..9276d2f0dd86 100644
--- a/arch/sparc/kernel/misctrap.S
+++ b/arch/sparc/kernel/misctrap.S
@@ -82,6 +82,7 @@ do_stdfmna:
call handle_stdfmna
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
+ nop
.size do_stdfmna,.-do_stdfmna
.type breakpoint_trap,#function
diff --git a/arch/sparc/kernel/rtrap_64.S b/arch/sparc/kernel/rtrap_64.S
index 216948ca4382..709a82ebd294 100644
--- a/arch/sparc/kernel/rtrap_64.S
+++ b/arch/sparc/kernel/rtrap_64.S
@@ -237,6 +237,7 @@ rt_continue: ldx [%sp + PTREGS_OFF + PT_V9_G1], %g1
bne,pt %xcc, user_rtt_fill_32bit
wrpr %g1, %cwp
ba,a,pt %xcc, user_rtt_fill_64bit
+ nop
user_rtt_fill_fixup_dax:
ba,pt %xcc, user_rtt_fill_fixup_common
diff --git a/arch/sparc/kernel/spiterrs.S b/arch/sparc/kernel/spiterrs.S
index 4a73009f66a5..d7e540842809 100644
--- a/arch/sparc/kernel/spiterrs.S
+++ b/arch/sparc/kernel/spiterrs.S
@@ -86,6 +86,7 @@ __spitfire_cee_trap_continue:
rd %pc, %g7
ba,a,pt %xcc, 2f
+ nop
1: ba,pt %xcc, etrap_irq
rd %pc, %g7
diff --git a/arch/sparc/kernel/sun4v_tlb_miss.S b/arch/sparc/kernel/sun4v_tlb_miss.S
index 6179e19bc9b9..c19f352f46c7 100644
--- a/arch/sparc/kernel/sun4v_tlb_miss.S
+++ b/arch/sparc/kernel/sun4v_tlb_miss.S
@@ -352,6 +352,7 @@ sun4v_mna:
call sun4v_do_mna
add %sp, PTREGS_OFF, %o0
ba,a,pt %xcc, rtrap
+ nop
/* Privileged Action. */
sun4v_privact:
diff --git a/arch/sparc/kernel/urtt_fill.S b/arch/sparc/kernel/urtt_fill.S
index 5604a2b051d4..364af3250646 100644
--- a/arch/sparc/kernel/urtt_fill.S
+++ b/arch/sparc/kernel/urtt_fill.S
@@ -92,6 +92,7 @@ user_rtt_fill_fixup_common:
call sun4v_data_access_exception
nop
ba,a,pt %xcc, rtrap
+ nop
1: call spitfire_data_access_exception
nop
diff --git a/arch/sparc/kernel/winfixup.S b/arch/sparc/kernel/winfixup.S
index 855019a8590e..1ee173cc3c39 100644
--- a/arch/sparc/kernel/winfixup.S
+++ b/arch/sparc/kernel/winfixup.S
@@ -152,6 +152,8 @@ fill_fixup_dax:
call sun4v_data_access_exception
nop
ba,a,pt %xcc, rtrap
+ nop
1: call spitfire_data_access_exception
nop
ba,a,pt %xcc, rtrap
+ nop
diff --git a/arch/sparc/lib/NG2memcpy.S b/arch/sparc/lib/NG2memcpy.S
index c629dbd121b6..64dcd6cdb606 100644
--- a/arch/sparc/lib/NG2memcpy.S
+++ b/arch/sparc/lib/NG2memcpy.S
@@ -326,11 +326,13 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */
blu 170f
nop
ba,a,pt %xcc, 180f
+ nop
4: /* 32 <= low bits < 48 */
blu 150f
nop
ba,a,pt %xcc, 160f
+ nop
5: /* 0 < low bits < 32 */
blu,a 6f
cmp %g2, 8
@@ -338,6 +340,7 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */
blu 130f
nop
ba,a,pt %xcc, 140f
+ nop
6: /* 0 < low bits < 16 */
bgeu 120f
nop
@@ -475,6 +478,7 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */
brz,pt %o2, 85f
sub %o0, %o1, GLOBAL_SPARE
ba,a,pt %XCC, 90f
+ nop
.align 64
75: /* 16 < len <= 64 */
diff --git a/arch/sparc/lib/NG4memcpy.S b/arch/sparc/lib/NG4memcpy.S
index 75bb93b1437f..78ea962edcbe 100644
--- a/arch/sparc/lib/NG4memcpy.S
+++ b/arch/sparc/lib/NG4memcpy.S
@@ -530,4 +530,5 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */
bne,pt %icc, 1b
EX_ST(STORE(stb, %g1, %o0 - 0x01), NG4_retl_o2_plus_1)
ba,a,pt %icc, .Lexit
+ nop
.size FUNC_NAME, .-FUNC_NAME
diff --git a/arch/sparc/lib/NG4memset.S b/arch/sparc/lib/NG4memset.S
index 41da4bdd95cb..7c0c81f18837 100644
--- a/arch/sparc/lib/NG4memset.S
+++ b/arch/sparc/lib/NG4memset.S
@@ -102,4 +102,5 @@ NG4bzero:
bne,pt %icc, 1b
add %o0, 0x30, %o0
ba,a,pt %icc, .Lpostloop
+ nop
.size NG4bzero,.-NG4bzero
diff --git a/arch/sparc/lib/NGmemcpy.S b/arch/sparc/lib/NGmemcpy.S
index d88c4ed50a00..cd654a719b27 100644
--- a/arch/sparc/lib/NGmemcpy.S
+++ b/arch/sparc/lib/NGmemcpy.S
@@ -394,6 +394,7 @@ FUNC_NAME: /* %i0=dst, %i1=src, %i2=len */
brz,pt %i2, 85f
sub %o0, %i1, %i3
ba,a,pt %XCC, 90f
+ nop
.align 64
70: /* 16 < len <= 64 */