From 0ae2d26ffe70c32d4a7fe77593f0a55ce416c09e Mon Sep 17 00:00:00 2001 From: Babu Moger Date: Fri, 17 Mar 2017 14:52:21 -0600 Subject: [PATCH] arch/sparc: Avoid DCTI Couples MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Rob Gardner Signed-off-by: David S. Miller --- arch/sparc/kernel/head_64.S | 4 ++++ arch/sparc/kernel/misctrap.S | 1 + arch/sparc/kernel/rtrap_64.S | 1 + arch/sparc/kernel/spiterrs.S | 1 + arch/sparc/kernel/sun4v_tlb_miss.S | 1 + arch/sparc/kernel/urtt_fill.S | 1 + arch/sparc/kernel/winfixup.S | 2 ++ arch/sparc/lib/NG2memcpy.S | 4 ++++ arch/sparc/lib/NG4memcpy.S | 1 + arch/sparc/lib/NG4memset.S | 1 + arch/sparc/lib/NGmemcpy.S | 1 + 11 files changed, 18 insertions(+) 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 */ -- 2.20.1