Use the new LL/SC runtime helpers to handle the aarch64 atomic instructions in softmmu_llsc_template.h.
The STXP emulation required a dedicated helper to handle the paired doubleword case. Suggested-by: Jani Kokkonen <jani.kokko...@huawei.com> Suggested-by: Claudio Fontana <claudio.font...@huawei.com> Signed-off-by: Alvise Rigo <a.r...@virtualopensystems.com> --- configure | 6 +- target-arm/helper-a64.c | 55 +++++++++++++++++++ target-arm/helper-a64.h | 4 ++ target-arm/op_helper.c | 8 +++ target-arm/translate-a64.c | 134 ++++++++++++++++++++++++++++++++++++++++++++- 5 files changed, 204 insertions(+), 3 deletions(-) diff --git a/configure b/configure index 915efcc..38121ff 100755 --- a/configure +++ b/configure @@ -5873,9 +5873,11 @@ echo "QEMU_CFLAGS+=$cflags" >> $config_target_mak # Use tcg LL/SC tcg backend for exclusive instruction is arm/aarch64 # softmmus targets if test "$arm_tcg_use_llsc" = "yes" ; then - if test "$target" = "arm-softmmu" ; then + case "$target" in + arm-softmmu | aarch64-softmmu) echo "CONFIG_ARM_USE_LDST_EXCL=y" >> $config_target_mak - fi + ;; + esac fi done # for target in $targets diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c index c7bfb4d..dcee66f 100644 --- a/target-arm/helper-a64.c +++ b/target-arm/helper-a64.c @@ -26,6 +26,7 @@ #include "qemu/bitops.h" #include "internals.h" #include "qemu/crc32c.h" +#include "tcg/tcg.h" #include <zlib.h> /* For crc32 */ /* C2.4.7 Multiply and divide */ @@ -443,3 +444,57 @@ uint64_t HELPER(crc32c_64)(uint64_t acc, uint64_t val, uint32_t bytes) /* Linux crc32c converts the output to one's complement. */ return crc32c(acc, buf, bytes) ^ 0xffffffff; } + +#ifdef CONFIG_ARM_USE_LDST_EXCL +/* STXP emulation for two 64 bit doublewords. We can't use directly two + * stcond_i64 accesses, otherwise the first will conclude the LL/SC pair. + * Instead, two normal 64-bit accesses are used and the CPUState is + * updated accordingly. */ +target_ulong HELPER(stxp_i128)(CPUArchState *env, target_ulong addr, + uint64_t vall, uint64_t valh, + uint32_t mmu_idx) +{ + CPUState *cpu = ENV_GET_CPU(env); + TCGMemOpIdx op; + target_ulong ret = 0; + + if (!cpu->ll_sc_context) { + cpu->excl_succeeded = false; + ret = 1; + goto out; + } + + op = make_memop_idx(MO_BEQ, mmu_idx); + + /* According to section C6.6.191 of ARM ARM DDI 0487A.h, the access has to + * be quadword aligned. For the time being, we do not support paired STXPs + * to MMIO memory, this will become trivial when the softmmu will support + * 128bit memory accesses. */ + if (addr & 0xf) { + /* TODO: Do unaligned access */ + } + + /* Setting excl_succeeded to true will make the store exclusive. */ + cpu->excl_succeeded = true; + helper_ret_stq_mmu(env, addr, vall, op, GETRA()); + + if (!cpu->excl_succeeded) { + ret = 1; + goto out; + } + + helper_ret_stq_mmu(env, addr + 8, valh, op, GETRA()); + if (!cpu->excl_succeeded) { + ret = 1; + } else { + cpu->excl_succeeded = false; + } + +out: + /* Unset LL/SC context */ + cpu->ll_sc_context = false; + cpu->excl_protected_range.begin = EXCLUSIVE_RESET_ADDR; + + return ret; +} +#endif diff --git a/target-arm/helper-a64.h b/target-arm/helper-a64.h index 1d3d10f..c416a83 100644 --- a/target-arm/helper-a64.h +++ b/target-arm/helper-a64.h @@ -46,3 +46,7 @@ DEF_HELPER_FLAGS_2(frecpx_f32, TCG_CALL_NO_RWG, f32, f32, ptr) DEF_HELPER_FLAGS_2(fcvtx_f64_to_f32, TCG_CALL_NO_RWG, f32, f64, env) DEF_HELPER_FLAGS_3(crc32_64, TCG_CALL_NO_RWG_SE, i64, i64, i64, i32) DEF_HELPER_FLAGS_3(crc32c_64, TCG_CALL_NO_RWG_SE, i64, i64, i64, i32) +#ifdef CONFIG_ARM_USE_LDST_EXCL +/* STXP helper */ +DEF_HELPER_5(stxp_i128, i64, env, i64, i64, i64, i32) +#endif diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c index 404c13b..146fc9a 100644 --- a/target-arm/op_helper.c +++ b/target-arm/op_helper.c @@ -34,6 +34,14 @@ static void raise_exception(CPUARMState *env, uint32_t excp, cs->exception_index = excp; env->exception.syndrome = syndrome; env->exception.target_el = target_el; +#ifdef CONFIG_ARM_USE_LDST_EXCL + HELPER(atomic_clear)(env); + /* If the exception happens in the middle of a LL/SC, we need to clear + * excl_succeeded to avoid that the normal store following the exception is + * wrongly interpreted as exclusive. + * */ + cs->excl_succeeded = 0; +#endif cpu_loop_exit(cs); } diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c index 80f6c20..f34e957 100644 --- a/target-arm/translate-a64.c +++ b/target-arm/translate-a64.c @@ -37,8 +37,10 @@ static TCGv_i64 cpu_X[32]; static TCGv_i64 cpu_pc; +#if !defined(CONFIG_ARM_USE_LDST_EXCL) /* Load/store exclusive handling */ static TCGv_i64 cpu_exclusive_high; +#endif static const char *regnames[] = { "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7", @@ -94,8 +96,10 @@ void a64_translate_init(void) regnames[i]); } +#if !defined(CONFIG_ARM_USE_LDST_EXCL) cpu_exclusive_high = tcg_global_mem_new_i64(TCG_AREG0, offsetof(CPUARMState, exclusive_high), "exclusive_high"); +#endif } static inline ARMMMUIdx get_a64_user_mem_index(DisasContext *s) @@ -1219,7 +1223,11 @@ static void handle_hint(DisasContext *s, uint32_t insn, static void gen_clrex(DisasContext *s, uint32_t insn) { +#ifndef CONFIG_ARM_USE_LDST_EXCL tcg_gen_movi_i64(cpu_exclusive_addr, -1); +#else + gen_helper_atomic_clear(cpu_env); +#endif } /* CLREX, DSB, DMB, ISB */ @@ -1685,7 +1693,11 @@ static void disas_b_exc_sys(DisasContext *s, uint32_t insn) } /* - * Load/Store exclusive instructions are implemented by remembering + * If the softmmu is enabled, the translation of Load/Store exclusive + * instructions will rely on the gen_helper_{ldlink,stcond} helpers, + * offloading most of the work to the softmmu_llsc_template.h functions. + * + * Otherwise, instructions are implemented by remembering * the value/address loaded, and seeing if these are the same * when the store is performed. This is not actually the architecturally * mandated semantics, but it works for typical guest code sequences @@ -1695,6 +1707,66 @@ static void disas_b_exc_sys(DisasContext *s, uint32_t insn) * this sequence is effectively atomic. In user emulation mode we * throw an exception and handle the atomic operation elsewhere. */ +#ifdef CONFIG_ARM_USE_LDST_EXCL +static void gen_load_exclusive(DisasContext *s, int rt, int rt2, + TCGv_i64 addr, int size, bool is_pair) +{ + /* In case @is_pair is set, we have to guarantee that at least the 128 bits + * accessed by a Load Exclusive Pair (64-bit variant) are protected. Since + * we do not have 128-bit helpers, we split the access in two halves, the + * first of them will set the exclusive region to cover at least 128 bits + * (this is why aarch64 has a custom cc->cpu_set_excl_protected_range which + * covers 128 bits). + * */ + TCGv_i32 mem_idx = tcg_temp_new_i32(); + + tcg_gen_movi_i32(mem_idx, get_mem_index(s)); + + g_assert(size <= 3); + + if (size < 3) { + TCGv_i32 tmp = tcg_temp_new_i32(); + + switch (size) { + case 0: + gen_helper_ldlink_i8(tmp, cpu_env, addr, mem_idx); + break; + case 1: + gen_helper_ldlink_i16(tmp, cpu_env, addr, mem_idx); + break; + case 2: + gen_helper_ldlink_i32(tmp, cpu_env, addr, mem_idx); + break; + default: + abort(); + } + + TCGv_i64 tmp64 = tcg_temp_new_i64(); + tcg_gen_ext_i32_i64(tmp64, tmp); + tcg_gen_mov_i64(cpu_reg(s, rt), tmp64); + + tcg_temp_free_i32(tmp); + tcg_temp_free_i64(tmp64); + } else { + gen_helper_ldlink_i64(cpu_reg(s, rt), cpu_env, addr, mem_idx); + } + + if (is_pair) { + TCGMemOp memop = MO_TE + size; + TCGv_i64 addr2 = tcg_temp_new_i64(); + TCGv_i64 hitmp = tcg_temp_new_i64(); + + g_assert(size >= 2); + tcg_gen_addi_i64(addr2, addr, 1 << size); + tcg_gen_qemu_ld_i64(hitmp, addr2, get_mem_index(s), memop); + tcg_temp_free_i64(addr2); + tcg_gen_mov_i64(cpu_reg(s, rt2), hitmp); + tcg_temp_free_i64(hitmp); + } + + tcg_temp_free_i32(mem_idx); +} +#else static void gen_load_exclusive(DisasContext *s, int rt, int rt2, TCGv_i64 addr, int size, bool is_pair) { @@ -1723,6 +1795,7 @@ static void gen_load_exclusive(DisasContext *s, int rt, int rt2, tcg_temp_free_i64(tmp); tcg_gen_mov_i64(cpu_exclusive_addr, addr); } +#endif #ifdef CONFIG_USER_ONLY static void gen_store_exclusive(DisasContext *s, int rd, int rt, int rt2, @@ -1733,6 +1806,65 @@ static void gen_store_exclusive(DisasContext *s, int rd, int rt, int rt2, size | is_pair << 2 | (rd << 4) | (rt << 9) | (rt2 << 14)); gen_exception_internal_insn(s, 4, EXCP_STREX); } +#elif defined(CONFIG_ARM_USE_LDST_EXCL) +static void gen_store_exclusive(DisasContext *s, int rd, int rt, int rt2, + TCGv_i64 addr, int size, int is_pair) +{ + /* Don't bother to check if we are actually in exclusive context since the + * helpers keep care of it. */ + TCGv_i32 mem_idx = tcg_temp_new_i32(); + + tcg_gen_movi_i32(mem_idx, get_mem_index(s)); + + g_assert(size <= 3); + if (is_pair) { + if (size == 3) { + gen_helper_stxp_i128(cpu_reg(s, rd), cpu_env, addr, cpu_reg(s, rt), + cpu_reg(s, rt2), mem_idx); + } else if (size == 2) { + /* Paired single word case. After merging the two registers into + * one, we use one stcond_i64 to store the value to memory. */ + TCGv_i64 val = tcg_temp_new_i64(); + TCGv_i64 valh = tcg_temp_new_i64(); + tcg_gen_shli_i64(valh, cpu_reg(s, rt2), 32); + tcg_gen_and_i64(val, valh, cpu_reg(s, rt)); + gen_helper_stcond_i64(cpu_reg(s, rd), cpu_env, addr, val, mem_idx); + tcg_temp_free_i64(valh); + tcg_temp_free_i64(val); + } else { + abort(); + } + } else { + if (size < 3) { + TCGv_i32 val = tcg_temp_new_i32(); + + tcg_gen_extrl_i64_i32(val, cpu_reg(s, rt)); + + switch (size) { + case 0: + gen_helper_stcond_i8(cpu_reg(s, rd), cpu_env, addr, val, + mem_idx); + break; + case 1: + gen_helper_stcond_i16(cpu_reg(s, rd), cpu_env, addr, val, + mem_idx); + break; + case 2: + gen_helper_stcond_i32(cpu_reg(s, rd), cpu_env, addr, val, + mem_idx); + break; + default: + abort(); + } + tcg_temp_free_i32(val); + } else { + gen_helper_stcond_i64(cpu_reg(s, rd), cpu_env, addr, cpu_reg(s, rt), + mem_idx); + } + } + + tcg_temp_free_i32(mem_idx); +} #else static void gen_store_exclusive(DisasContext *s, int rd, int rt, int rt2, TCGv_i64 inaddr, int size, int is_pair) -- 2.7.0