From b1ee3c67253a40f8e62a799eb5b5a0d2954769f4 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 27 Jul 2021 19:42:35 -1000 Subject: [PATCH] tcg/i386: Support raising sigbus for user-only Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- tcg/i386/tcg-target.c.inc | 103 +++++++++++++++++++++++++++++++++++++++++++--- tcg/i386/tcg-target.h | 2 - 2 files changed, 98 insertions(+), 7 deletions(-) diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc index 4dab09f265..faa15eecab 100644 --- a/tcg/i386/tcg-target.c.inc +++ b/tcg/i386/tcg-target.c.inc @@ -22,6 +22,7 @@ * THE SOFTWARE. */ +#include "../tcg-ldst.c.inc" #include "../tcg-pool.c.inc" #ifdef CONFIG_DEBUG_TCG @@ -421,8 +422,9 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct) #define OPC_VZEROUPPER (0x77 | P_EXT) #define OPC_XCHG_ax_r32 (0x90) -#define OPC_GRP3_Ev (0xf7) -#define OPC_GRP5 (0xff) +#define OPC_GRP3_Eb (0xf6) +#define OPC_GRP3_Ev (0xf7) +#define OPC_GRP5 (0xff) #define OPC_GRP14 (0x73 | P_EXT | P_DATA16) /* Group 1 opcode extensions for 0x80-0x83. @@ -444,6 +446,7 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct) #define SHIFT_SAR 7 /* Group 3 opcode extensions for 0xf6, 0xf7. To be used with OPC_GRP3. */ +#define EXT3_TESTi 0 #define EXT3_NOT 2 #define EXT3_NEG 3 #define EXT3_MUL 4 @@ -1606,8 +1609,6 @@ static void tcg_out_nopn(TCGContext *s, int n) } #if defined(CONFIG_SOFTMMU) -#include "../tcg-ldst.c.inc" - /* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr, * int mmu_idx, uintptr_t ra) */ @@ -1916,7 +1917,84 @@ static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l) tcg_out_jmp(s, qemu_st_helpers[opc & (MO_BSWAP | MO_SIZE)]); return true; } -#elif TCG_TARGET_REG_BITS == 32 +#else + +static void tcg_out_test_alignment(TCGContext *s, bool is_ld, TCGReg addrlo, + TCGReg addrhi, unsigned a_bits) +{ + unsigned a_mask = (1 << a_bits) - 1; + TCGLabelQemuLdst *label; + + /* + * We are expecting a_bits to max out at 7, so we can usually use testb. + * For i686, we have to use testl for %esi/%edi. + */ + if (a_mask <= 0xff && (TCG_TARGET_REG_BITS == 64 || addrlo < 4)) { + tcg_out_modrm(s, OPC_GRP3_Eb | P_REXB_RM, EXT3_TESTi, addrlo); + tcg_out8(s, a_mask); + } else { + tcg_out_modrm(s, OPC_GRP3_Ev, EXT3_TESTi, addrlo); + tcg_out32(s, a_mask); + } + + /* jne slow_path */ + tcg_out_opc(s, OPC_JCC_long + JCC_JNE, 0, 0, 0); + + label = new_ldst_label(s); + label->is_ld = is_ld; + label->addrlo_reg = addrlo; + label->addrhi_reg = addrhi; + label->raddr = tcg_splitwx_to_rx(s->code_ptr + 4); + label->label_ptr[0] = s->code_ptr; + + s->code_ptr += 4; +} + +static bool tcg_out_fail_alignment(TCGContext *s, TCGLabelQemuLdst *l) +{ + /* resolve label address */ + tcg_patch32(l->label_ptr[0], s->code_ptr - l->label_ptr[0] - 4); + + if (TCG_TARGET_REG_BITS == 32) { + int ofs = 0; + + tcg_out_st(s, TCG_TYPE_PTR, TCG_AREG0, TCG_REG_ESP, ofs); + ofs += 4; + + tcg_out_st(s, TCG_TYPE_I32, l->addrlo_reg, TCG_REG_ESP, ofs); + ofs += 4; + if (TARGET_LONG_BITS == 64) { + tcg_out_st(s, TCG_TYPE_I32, l->addrhi_reg, TCG_REG_ESP, ofs); + ofs += 4; + } + + tcg_out_pushi(s, (uintptr_t)l->raddr); + } else { + tcg_out_mov(s, TCG_TYPE_TL, tcg_target_call_iarg_regs[1], + l->addrlo_reg); + tcg_out_mov(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[0], TCG_AREG0); + + tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_RAX, (uintptr_t)l->raddr); + tcg_out_push(s, TCG_REG_RAX); + } + + /* "Tail call" to the helper, with the return address back inline. */ + tcg_out_jmp(s, (const void *)(l->is_ld ? helper_unaligned_ld + : helper_unaligned_st)); + return true; +} + +static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l) +{ + return tcg_out_fail_alignment(s, l); +} + +static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l) +{ + return tcg_out_fail_alignment(s, l); +} + +#if TCG_TARGET_REG_BITS == 32 # define x86_guest_base_seg 0 # define x86_guest_base_index -1 # define x86_guest_base_offset guest_base @@ -1950,6 +2028,7 @@ static inline int setup_guest_base_seg(void) return 0; } # endif +#endif #endif /* SOFTMMU */ static void tcg_out_qemu_ld_direct(TCGContext *s, TCGReg datalo, TCGReg datahi, @@ -2059,6 +2138,8 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, bool is64) #if defined(CONFIG_SOFTMMU) int mem_index; tcg_insn_unit *label_ptr[2]; +#else + unsigned a_bits; #endif datalo = *args++; @@ -2081,6 +2162,11 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, bool is64) add_qemu_ldst_label(s, true, is64, oi, datalo, datahi, addrlo, addrhi, s->code_ptr, label_ptr); #else + a_bits = get_alignment_bits(opc); + if (a_bits) { + tcg_out_test_alignment(s, true, addrlo, addrhi, a_bits); + } + tcg_out_qemu_ld_direct(s, datalo, datahi, addrlo, x86_guest_base_index, x86_guest_base_offset, x86_guest_base_seg, is64, opc); @@ -2148,6 +2234,8 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, bool is64) #if defined(CONFIG_SOFTMMU) int mem_index; tcg_insn_unit *label_ptr[2]; +#else + unsigned a_bits; #endif datalo = *args++; @@ -2170,6 +2258,11 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, bool is64) add_qemu_ldst_label(s, false, is64, oi, datalo, datahi, addrlo, addrhi, s->code_ptr, label_ptr); #else + a_bits = get_alignment_bits(opc); + if (a_bits) { + tcg_out_test_alignment(s, false, addrlo, addrhi, a_bits); + } + tcg_out_qemu_st_direct(s, datalo, datahi, addrlo, x86_guest_base_index, x86_guest_base_offset, x86_guest_base_seg, opc); #endif diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h index b00a6da293..3b2c9437a0 100644 --- a/tcg/i386/tcg-target.h +++ b/tcg/i386/tcg-target.h @@ -232,9 +232,7 @@ static inline void tb_target_set_jmp_target(uintptr_t tc_ptr, uintptr_t jmp_rx, #define TCG_TARGET_HAS_MEMORY_BSWAP have_movbe -#ifdef CONFIG_SOFTMMU #define TCG_TARGET_NEED_LDST_LABELS -#endif #define TCG_TARGET_NEED_POOL_LABELS #endif -- 2.11.0