From 426f5abcaa15d0e59475fdb33b2a4a5fdf492d05 Mon Sep 17 00:00:00 2001 From: Paul Brook Date: Sun, 22 Nov 2009 21:35:13 +0000 Subject: [PATCH] ARM atomic ops rewrite Implement ARMv6 atomic ops (ldrex/strex) using the same trick as PPC. Signed-off-by: Paul Brook --- linux-user/main.c | 80 ++++++++++++++++ target-arm/cpu.h | 9 +- target-arm/helper.c | 84 ----------------- target-arm/helpers.h | 4 - target-arm/translate.c | 250 ++++++++++++++++++++++++++++++++----------------- 5 files changed, 251 insertions(+), 176 deletions(-) diff --git a/linux-user/main.c b/linux-user/main.c index 67336d7..2b8bab1 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -524,6 +524,81 @@ do_kernel_trap(CPUARMState *env) return 0; } +static int do_strex(CPUARMState *env) +{ + uint32_t val; + int size; + int rc = 1; + int segv = 0; + uint32_t addr; + start_exclusive(); + addr = env->exclusive_addr; + if (addr != env->exclusive_test) { + goto fail; + } + size = env->exclusive_info & 0xf; + switch (size) { + case 0: + segv = get_user_u8(val, addr); + break; + case 1: + segv = get_user_u16(val, addr); + break; + case 2: + case 3: + segv = get_user_u32(val, addr); + break; + } + if (segv) { + env->cp15.c6_data = addr; + goto done; + } + if (val != env->exclusive_val) { + goto fail; + } + if (size == 3) { + segv = get_user_u32(val, addr + 4); + if (segv) { + env->cp15.c6_data = addr + 4; + goto done; + } + if (val != env->exclusive_high) { + goto fail; + } + } + val = env->regs[(env->exclusive_info >> 8) & 0xf]; + switch (size) { + case 0: + segv = put_user_u8(val, addr); + break; + case 1: + segv = put_user_u16(val, addr); + break; + case 2: + case 3: + segv = put_user_u32(val, addr); + break; + } + if (segv) { + env->cp15.c6_data = addr; + goto done; + } + if (size == 3) { + val = env->regs[(env->exclusive_info >> 12) & 0xf]; + segv = put_user_u32(val, addr); + if (segv) { + env->cp15.c6_data = addr + 4; + goto done; + } + } + rc = 0; +fail: + env->regs[(env->exclusive_info >> 4) & 0xf] = rc; +done: + end_exclusive(); + return segv; +} + void cpu_loop(CPUARMState *env) { int trapnr; @@ -717,6 +792,11 @@ void cpu_loop(CPUARMState *env) if (do_kernel_trap(env)) goto error; break; + case EXCP_STREX: + if (do_strex(env)) { + addr = env->cp15.c6_data; + goto do_segv; + } default: error: fprintf(stderr, "qemu: unhandled CPU exception 0x%x - aborting\n", diff --git a/target-arm/cpu.h b/target-arm/cpu.h index a83ce48..4a1c53f 100644 --- a/target-arm/cpu.h +++ b/target-arm/cpu.h @@ -40,6 +40,7 @@ #define EXCP_BKPT 7 #define EXCP_EXCEPTION_EXIT 8 /* Return from v7M exception. */ #define EXCP_KERNEL_TRAP 9 /* Jumped to kernel code page. */ +#define EXCP_STREX 10 #define ARMV7M_EXCP_RESET 1 #define ARMV7M_EXCP_NMI 2 @@ -180,10 +181,12 @@ typedef struct CPUARMState { float_status fp_status; } vfp; + uint32_t exclusive_addr; + uint32_t exclusive_val; + uint32_t exclusive_high; #if defined(CONFIG_USER_ONLY) - struct mmon_state *mmon_entry; -#else - uint32_t mmon_addr; + uint32_t exclusive_test; + uint32_t exclusive_info; #endif /* iwMMXt coprocessor state. */ diff --git a/target-arm/helper.c b/target-arm/helper.c index ffc14f0..b3aec99 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -470,16 +470,6 @@ void do_interrupt (CPUState *env) env->exception_index = -1; } -/* Structure used to record exclusive memory locations. */ -typedef struct mmon_state { - struct mmon_state *next; - CPUARMState *cpu_env; - uint32_t addr; -} mmon_state; - -/* Chain of current locks. */ -static mmon_state* mmon_head = NULL; - int cpu_arm_handle_mmu_fault (CPUState *env, target_ulong address, int rw, int mmu_idx, int is_softmmu) { @@ -493,62 +483,6 @@ int cpu_arm_handle_mmu_fault (CPUState *env, target_ulong address, int rw, return 1; } -static void allocate_mmon_state(CPUState *env) -{ - env->mmon_entry = malloc(sizeof (mmon_state)); - memset (env->mmon_entry, 0, sizeof (mmon_state)); - env->mmon_entry->cpu_env = env; - mmon_head = env->mmon_entry; -} - -/* Flush any monitor locks for the specified address. */ -static void flush_mmon(uint32_t addr) -{ - mmon_state *mon; - - for (mon = mmon_head; mon; mon = mon->next) - { - if (mon->addr != addr) - continue; - - mon->addr = 0; - break; - } -} - -/* Mark an address for exclusive access. */ -void HELPER(mark_exclusive)(CPUState *env, uint32_t addr) -{ - if (!env->mmon_entry) - allocate_mmon_state(env); - /* Clear any previous locks. */ - flush_mmon(addr); - env->mmon_entry->addr = addr; -} - -/* Test if an exclusive address is still exclusive. Returns zero - if the address is still exclusive. */ -uint32_t HELPER(test_exclusive)(CPUState *env, uint32_t addr) -{ - int res; - - if (!env->mmon_entry) - return 1; - if (env->mmon_entry->addr == addr) - res = 0; - else - res = 1; - flush_mmon(addr); - return res; -} - -void HELPER(clrex)(CPUState *env) -{ - if (!(env->mmon_entry && env->mmon_entry->addr)) - return; - flush_mmon(env->mmon_entry->addr); -} - target_phys_addr_t cpu_get_phys_page_debug(CPUState *env, target_ulong addr) { return addr; @@ -1273,24 +1207,6 @@ target_phys_addr_t cpu_get_phys_page_debug(CPUState *env, target_ulong addr) return phys_addr; } -/* Not really implemented. Need to figure out a sane way of doing this. - Maybe add generic watchpoint support and use that. */ - -void HELPER(mark_exclusive)(CPUState *env, uint32_t addr) -{ - env->mmon_addr = addr; -} - -uint32_t HELPER(test_exclusive)(CPUState *env, uint32_t addr) -{ - return (env->mmon_addr != addr); -} - -void HELPER(clrex)(CPUState *env) -{ - env->mmon_addr = -1; -} - void HELPER(set_cp)(CPUState *env, uint32_t insn, uint32_t val) { int cp_num = (insn >> 8) & 0xf; diff --git a/target-arm/helpers.h b/target-arm/helpers.h index dc25f18..0d1bc47 100644 --- a/target-arm/helpers.h +++ b/target-arm/helpers.h @@ -68,10 +68,6 @@ DEF_HELPER_2(get_cp, i32, env, i32) DEF_HELPER_2(get_r13_banked, i32, env, i32) DEF_HELPER_3(set_r13_banked, void, env, i32, i32) -DEF_HELPER_2(mark_exclusive, void, env, i32) -DEF_HELPER_2(test_exclusive, i32, env, i32) -DEF_HELPER_1(clrex, void, env) - DEF_HELPER_1(get_user_reg, i32, i32) DEF_HELPER_2(set_user_reg, void, i32, i32) diff --git a/target-arm/translate.c b/target-arm/translate.c index a002f7e..45bf772 100644 --- a/target-arm/translate.c +++ b/target-arm/translate.c @@ -76,6 +76,13 @@ static TCGv_ptr cpu_env; /* We reuse the same 64-bit temporaries for efficiency. */ static TCGv_i64 cpu_V0, cpu_V1, cpu_M0; static TCGv_i32 cpu_R[16]; +static TCGv_i32 cpu_exclusive_addr; +static TCGv_i32 cpu_exclusive_val; +static TCGv_i32 cpu_exclusive_high; +#ifdef CONFIG_USER_ONLY +static TCGv_i32 cpu_exclusive_test; +static TCGv_i32 cpu_exclusive_info; +#endif /* FIXME: These should be removed. */ static TCGv cpu_F0s, cpu_F1s; @@ -99,6 +106,18 @@ void arm_translate_init(void) offsetof(CPUState, regs[i]), regnames[i]); } + cpu_exclusive_addr = tcg_global_mem_new_i32(TCG_AREG0, + offsetof(CPUState, exclusive_addr), "exclusive_addr"); + cpu_exclusive_val = tcg_global_mem_new_i32(TCG_AREG0, + offsetof(CPUState, exclusive_val), "exclusive_val"); + cpu_exclusive_high = tcg_global_mem_new_i32(TCG_AREG0, + offsetof(CPUState, exclusive_high), "exclusive_high"); +#ifdef CONFIG_USER_ONLY + cpu_exclusive_test = tcg_global_mem_new_i32(TCG_AREG0, + offsetof(CPUState, exclusive_test), "exclusive_test"); + cpu_exclusive_info = tcg_global_mem_new_i32(TCG_AREG0, + offsetof(CPUState, exclusive_info), "exclusive_info"); +#endif #define GEN_HELPER 2 #include "helpers.h" @@ -5819,6 +5838,132 @@ static void gen_logicq_cc(TCGv_i64 val) dead_tmp(tmp); } +/* Load/Store exclusive instructions are implemented by remembering + the value/address loaded, and seeing if these are the same + when the store is performed. This should be is sufficient to implement + the architecturally mandated semantics, and avoids having to monitor + regular stores. + + In system emulation mode only one CPU will be running at once, so + this sequence is effectively atomic. In user emulation mode we + throw an exception and handle the atomic operation elsewhere. */ +static void gen_load_exclusive(DisasContext *s, int rt, int rt2, + TCGv addr, int size) +{ + TCGv tmp; + + switch (size) { + case 0: + tmp = gen_ld8u(addr, IS_USER(s)); + break; + case 1: + tmp = gen_ld16u(addr, IS_USER(s)); + break; + case 2: + case 3: + tmp = gen_ld32(addr, IS_USER(s)); + break; + default: + abort(); + } + tcg_gen_mov_i32(cpu_exclusive_val, tmp); + store_reg(s, rt, tmp); + if (size == 3) { + tcg_gen_addi_i32(addr, addr, 4); + tmp = gen_ld32(addr, IS_USER(s)); + tcg_gen_mov_i32(cpu_exclusive_high, tmp); + store_reg(s, rt2, tmp); + } + tcg_gen_mov_i32(cpu_exclusive_addr, addr); +} + +static void gen_clrex(DisasContext *s) +{ + tcg_gen_movi_i32(cpu_exclusive_addr, -1); +} + +#ifdef CONFIG_USER_ONLY +static void gen_store_exclusive(DisasContext *s, int rd, int rt, int rt2, + TCGv addr, int size) +{ + tcg_gen_mov_i32(cpu_exclusive_test, addr); + tcg_gen_movi_i32(cpu_exclusive_info, + size | (rd << 4) | (rt << 8) | (rt2 << 12)); + gen_set_condexec(s); + gen_set_pc_im(s->pc - 4); + gen_exception(EXCP_STREX); + s->is_jmp = DISAS_JUMP; +} +#else +static void gen_store_exclusive(DisasContext *s, int rd, int rt, int rt2, + TCGv addr, int size) +{ + TCGv tmp; + int done_label; + int fail_label; + + /* if (env->exclusive_addr == addr && env->exclusive_val == [addr]) { + [addr] = {Rt}; + {Rd} = 0; + } else { + {Rd} = 1; + } */ + fail_label = gen_new_label(); + done_label = gen_new_label(); + tcg_gen_brcond_i32(TCG_COND_NE, addr, cpu_exclusive_addr, fail_label); + switch (size) { + case 0: + tmp = gen_ld8u(addr, IS_USER(s)); + break; + case 1: + tmp = gen_ld16u(addr, IS_USER(s)); + break; + case 2: + case 3: + tmp = gen_ld32(addr, IS_USER(s)); + break; + default: + abort(); + } + tcg_gen_brcond_i32(TCG_COND_NE, tmp, cpu_exclusive_val, fail_label); + dead_tmp(tmp); + if (size == 3) { + TCGv tmp2 = new_tmp(); + tcg_gen_addi_i32(tmp2, addr, 4); + tmp = gen_ld32(addr, IS_USER(s)); + dead_tmp(tmp2); + tcg_gen_brcond_i32(TCG_COND_NE, tmp, cpu_exclusive_high, fail_label); + dead_tmp(tmp); + } + tmp = load_reg(s, rt); + switch (size) { + case 0: + gen_st8(tmp, addr, IS_USER(s)); + break; + case 1: + gen_st16(tmp, addr, IS_USER(s)); + break; + case 2: + case 3: + gen_st32(tmp, addr, IS_USER(s)); + break; + default: + abort(); + } + if (size == 3) { + tcg_gen_addi_i32(addr, addr, 4); + tmp = load_reg(s, rt2); + gen_st32(tmp, addr, IS_USER(s)); + } + tcg_gen_movi_i32(cpu_R[rd], 0); + tcg_gen_br(done_label); + gen_set_label(fail_label); + tcg_gen_movi_i32(cpu_R[rd], 1); + gen_set_label(done_label); + tcg_gen_movi_i32(cpu_exclusive_addr, -1); +} +#endif + static void disas_arm_insn(CPUState * env, DisasContext *s) { unsigned int cond, insn, val, op1, i, shift, rm, rs, rn, rd, sh; @@ -5869,7 +6014,7 @@ static void disas_arm_insn(CPUState * env, DisasContext *s) switch ((insn >> 4) & 0xf) { case 1: /* clrex */ ARCH(6K); - gen_helper_clrex(cpu_env); + gen_clrex(s); return; case 4: /* dsb */ case 5: /* dmb */ @@ -6454,57 +6599,40 @@ static void disas_arm_insn(CPUState * env, DisasContext *s) addr = tcg_temp_local_new_i32(); load_reg_var(s, addr, rn); if (insn & (1 << 20)) { - gen_helper_mark_exclusive(cpu_env, addr); switch (op1) { case 0: /* ldrex */ - tmp = gen_ld32(addr, IS_USER(s)); + gen_load_exclusive(s, rd, 15, addr, 2); break; case 1: /* ldrexd */ - tmp = gen_ld32(addr, IS_USER(s)); - store_reg(s, rd, tmp); - tcg_gen_addi_i32(addr, addr, 4); - tmp = gen_ld32(addr, IS_USER(s)); - rd++; + gen_load_exclusive(s, rd, rd + 1, addr, 3); break; case 2: /* ldrexb */ - tmp = gen_ld8u(addr, IS_USER(s)); + gen_load_exclusive(s, rd, 15, addr, 0); break; case 3: /* ldrexh */ - tmp = gen_ld16u(addr, IS_USER(s)); + gen_load_exclusive(s, rd, 15, addr, 1); break; default: abort(); } - store_reg(s, rd, tmp); } else { - int label = gen_new_label(); rm = insn & 0xf; - tmp2 = tcg_temp_local_new_i32(); - gen_helper_test_exclusive(tmp2, cpu_env, addr); - tcg_gen_brcondi_i32(TCG_COND_NE, tmp2, 0, label); - tmp = load_reg(s,rm); switch (op1) { case 0: /* strex */ - gen_st32(tmp, addr, IS_USER(s)); + gen_store_exclusive(s, rd, rm, 15, addr, 2); break; case 1: /* strexd */ - gen_st32(tmp, addr, IS_USER(s)); - tcg_gen_addi_i32(addr, addr, 4); - tmp = load_reg(s, rm + 1); - gen_st32(tmp, addr, IS_USER(s)); + gen_store_exclusive(s, rd, rm, rm + 1, addr, 2); break; case 2: /* strexb */ - gen_st8(tmp, addr, IS_USER(s)); + gen_store_exclusive(s, rd, rm, 15, addr, 0); break; case 3: /* strexh */ - gen_st16(tmp, addr, IS_USER(s)); + gen_store_exclusive(s, rd, rm, 15, addr, 1); break; default: abort(); } - gen_set_label(label); - tcg_gen_mov_i32(cpu_R[rd], tmp2); - tcg_temp_free(tmp2); } tcg_temp_free(addr); } else { @@ -7259,20 +7387,11 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1) /* Load/store exclusive word. */ addr = tcg_temp_local_new(); load_reg_var(s, addr, rn); + tcg_gen_addi_i32(addr, addr, (insn & 0xff) << 2); if (insn & (1 << 20)) { - gen_helper_mark_exclusive(cpu_env, addr); - tmp = gen_ld32(addr, IS_USER(s)); - store_reg(s, rd, tmp); + gen_load_exclusive(s, rs, 15, addr, 2); } else { - int label = gen_new_label(); - tmp2 = tcg_temp_local_new(); - gen_helper_test_exclusive(tmp2, cpu_env, addr); - tcg_gen_brcondi_i32(TCG_COND_NE, tmp2, 0, label); - tmp = load_reg(s, rs); - gen_st32(tmp, addr, IS_USER(s)); - gen_set_label(label); - tcg_gen_mov_i32(cpu_R[rd], tmp2); - tcg_temp_free(tmp2); + gen_store_exclusive(s, rd, rs, 15, addr, 2); } tcg_temp_free(addr); } else if ((insn & (1 << 6)) == 0) { @@ -7300,56 +7419,17 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1) store_reg(s, 15, tmp); } else { /* Load/store exclusive byte/halfword/doubleword. */ - /* ??? These are not really atomic. However we know - we never have multiple CPUs running in parallel, - so it is good enough. */ + ARCH(7); op = (insn >> 4) & 0x3; + if (op == 2) { + goto illegal_op; + } addr = tcg_temp_local_new(); load_reg_var(s, addr, rn); if (insn & (1 << 20)) { - gen_helper_mark_exclusive(cpu_env, addr); - switch (op) { - case 0: - tmp = gen_ld8u(addr, IS_USER(s)); - break; - case 1: - tmp = gen_ld16u(addr, IS_USER(s)); - break; - case 3: - tmp = gen_ld32(addr, IS_USER(s)); - tcg_gen_addi_i32(addr, addr, 4); - tmp2 = gen_ld32(addr, IS_USER(s)); - store_reg(s, rd, tmp2); - break; - default: - goto illegal_op; - } - store_reg(s, rs, tmp); + gen_load_exclusive(s, rs, rd, addr, op); } else { - int label = gen_new_label(); - tmp2 = tcg_temp_local_new(); - gen_helper_test_exclusive(tmp2, cpu_env, addr); - tcg_gen_brcondi_i32(TCG_COND_NE, tmp2, 0, label); - tmp = load_reg(s, rs); - switch (op) { - case 0: - gen_st8(tmp, addr, IS_USER(s)); - break; - case 1: - gen_st16(tmp, addr, IS_USER(s)); - break; - case 3: - gen_st32(tmp, addr, IS_USER(s)); - tcg_gen_addi_i32(addr, addr, 4); - tmp = load_reg(s, rd); - gen_st32(tmp, addr, IS_USER(s)); - break; - default: - goto illegal_op; - } - gen_set_label(label); - tcg_gen_mov_i32(cpu_R[rm], tmp2); - tcg_temp_free(tmp2); + gen_store_exclusive(s, rm, rs, rd, addr, op); } tcg_temp_free(addr); } @@ -7845,16 +7925,16 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1) } break; case 3: /* Special control operations. */ + ARCH(7); op = (insn >> 4) & 0xf; switch (op) { case 2: /* clrex */ - gen_helper_clrex(cpu_env); + gen_clrex(s); break; case 4: /* dsb */ case 5: /* dmb */ case 6: /* isb */ /* These execute as NOPs. */ - ARCH(7); break; default: goto illegal_op; -- 2.7.4