| Message ID | 1473328861-15792-1-git-send-email-leon.alrae@imgtec.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/08/2016 03:01 AM, Leon Alrae wrote: > Make use of memory barrier TCG opcode in MIPS front end. > > Signed-off-by: Leon Alrae <leon.alrae@imgtec.com> > --- > v2: > * generate weaker barriers according to stype > --- > target-mips/translate.c | 32 ++++++++++++++++++++++++++++++-- > 1 file changed, 30 insertions(+), 2 deletions(-) Ah, even better. Reviewed-by: Richard Henderson <rth@twiddle.net> > +static void gen_sync(int stype) > +{ > + TCGOrder tcg_mo = TCG_BAR_SC; > + > + switch (stype) { > + case 0x4: /* SYNC_WMB */ > + tcg_mo |= TCG_MO_ST_ST; > + break; > + case 0x10: /* SYNC_MB */ > + tcg_mo |= TCG_MO_ALL; > + break; > + case 0x11: /* SYNC_ACQUIRE */ > + tcg_mo |= TCG_MO_LD_LD | TCG_MO_LD_ST; > + break; > + case 0x12: /* SYNC_RELEASE */ > + tcg_mo |= TCG_MO_ST_ST | TCG_MO_LD_ST; > + break; > + case 0x13: /* SYNC_RMB */ > + tcg_mo |= TCG_MO_LD_LD; > + break; > + default: > + tcg_mo |= TCG_MO_ALL; > + break; > + } See git://github.com/rth7680/qemu.git tcg-next wherein this suggests that some enhancement is desired in tcg/mips/ as well. Not that I have a mips32r6 board with which to test. Would you or James Hogan be able to improve that? r~
On Thu, Sep 08, 2016 at 10:04:05AM -0700, Richard Henderson wrote: > > +static void gen_sync(int stype) > > +{ > > + TCGOrder tcg_mo = TCG_BAR_SC; > > + > > + switch (stype) { > > + case 0x4: /* SYNC_WMB */ > > + tcg_mo |= TCG_MO_ST_ST; > > + break; > > + case 0x10: /* SYNC_MB */ > > + tcg_mo |= TCG_MO_ALL; > > + break; > > + case 0x11: /* SYNC_ACQUIRE */ > > + tcg_mo |= TCG_MO_LD_LD | TCG_MO_LD_ST; > > + break; > > + case 0x12: /* SYNC_RELEASE */ > > + tcg_mo |= TCG_MO_ST_ST | TCG_MO_LD_ST; > > + break; > > + case 0x13: /* SYNC_RMB */ > > + tcg_mo |= TCG_MO_LD_LD; > > + break; > > + default: > > + tcg_mo |= TCG_MO_ALL; > > + break; > > + } > > See git://github.com/rth7680/qemu.git tcg-next wherein this suggests that some > enhancement is desired in tcg/mips/ as well. Not that I have a mips32r6 board > with which to test. Would you or James Hogan be able to improve that? Actually the lightweight variants of SYNC exist also in earlier revisions of MIPS architecture; therefore this can be tested for example on mips32r2. According to manuals the support is optional, and if given CPU doesn't implement lightweight SYNCs (i.e. with stype != 0) then they are supposed to behave in the same way as SYNC 0. (which also means I simplified that here and always interpret the stype to take advantage of weaker ordering barriers). Thanks, Leon
On 09/09/2016 01:49 AM, Leon Alrae wrote: > Actually the lightweight variants of SYNC exist also in earlier revisions of > MIPS architecture; therefore this can be tested for example on mips32r2. > > According to manuals the support is optional, and if given CPU doesn't > implement lightweight SYNCs (i.e. with stype != 0) then they are supposed > to behave in the same way as SYNC 0. (which also means I simplified that here > and always interpret the stype to take advantage of weaker ordering barriers). Noted. I've adjusted the patch in the tcg-next tree to always generate the weaker forms of sync. r~
diff --git a/target-mips/translate.c b/target-mips/translate.c index c212e4f..1e66274 100644 --- a/target-mips/translate.c +++ b/target-mips/translate.c @@ -13109,6 +13109,34 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd, tcg_temp_free(t1); } +static void gen_sync(int stype) +{ + TCGOrder tcg_mo = TCG_BAR_SC; + + switch (stype) { + case 0x4: /* SYNC_WMB */ + tcg_mo |= TCG_MO_ST_ST; + break; + case 0x10: /* SYNC_MB */ + tcg_mo |= TCG_MO_ALL; + break; + case 0x11: /* SYNC_ACQUIRE */ + tcg_mo |= TCG_MO_LD_LD | TCG_MO_LD_ST; + break; + case 0x12: /* SYNC_RELEASE */ + tcg_mo |= TCG_MO_ST_ST | TCG_MO_LD_ST; + break; + case 0x13: /* SYNC_RMB */ + tcg_mo |= TCG_MO_LD_LD; + break; + default: + tcg_mo |= TCG_MO_ALL; + break; + } + + tcg_gen_mb(tcg_mo); +} + static void gen_pool32axf (CPUMIPSState *env, DisasContext *ctx, int rt, int rs) { int extension = (ctx->opcode >> 6) & 0x3f; @@ -13384,7 +13412,7 @@ static void gen_pool32axf (CPUMIPSState *env, DisasContext *ctx, int rt, int rs) case 0x2d: switch (minor) { case SYNC: - /* NOP */ + gen_sync(extract32(ctx->opcode, 16, 5)); break; case SYSCALL: generate_exception_end(ctx, EXCP_SYSCALL); @@ -17201,7 +17229,7 @@ static void decode_opc_special(CPUMIPSState *env, DisasContext *ctx) break; case OPC_SYNC: check_insn(ctx, ISA_MIPS2); - /* Treat as NOP. */ + gen_sync(extract32(ctx->opcode, 6, 5)); break; #if defined(TARGET_MIPS64)
Make use of memory barrier TCG opcode in MIPS front end. Signed-off-by: Leon Alrae <leon.alrae@imgtec.com> --- v2: * generate weaker barriers according to stype --- target-mips/translate.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-)