diff options
| author | Pranith Kumar <bobby.prani@gmail.com> | 2017-06-30 10:36:13 -0400 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2017-07-09 21:10:23 -1000 |
| commit | b68686bd4bfeb70040b4099df993dfa0b4f37b03 (patch) | |
| tree | 7e6c83c69cffd2680b5963276eb1b8ad5394a9dc /tcg/aarch64 | |
| parent | 23b7aa1d2af04ba57cc94f74d9f0ab25dce72fa0 (diff) | |
| download | qemu-b68686bd4bfeb70040b4099df993dfa0b4f37b03.tar.gz | |
tcg/aarch64: Use ADRP+ADD to compute target address
We use ADRP+ADD to compute the target address for goto_tb. This patch
introduces the NOP instruction which is used to align the above
instruction pair so that we can use one atomic instruction to patch
the destination offsets.
CC: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Message-Id: <20170630143614.31059-2-bobby.prani@gmail.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'tcg/aarch64')
| -rw-r--r-- | tcg/aarch64/tcg-target.inc.c | 36 |
1 files changed, 30 insertions, 6 deletions
diff --git a/tcg/aarch64/tcg-target.inc.c b/tcg/aarch64/tcg-target.inc.c index 8fce11ace7..a84422d633 100644 --- a/tcg/aarch64/tcg-target.inc.c +++ b/tcg/aarch64/tcg-target.inc.c @@ -372,6 +372,7 @@ typedef enum { I3510_EON = 0x4a200000, I3510_ANDS = 0x6a000000, + NOP = 0xd503201f, /* System instructions. */ DMB_ISH = 0xd50338bf, DMB_LD = 0x00000100, @@ -865,11 +866,27 @@ static inline void tcg_out_call(TCGContext *s, tcg_insn_unit *target) void aarch64_tb_set_jmp_target(uintptr_t jmp_addr, uintptr_t addr) { - tcg_insn_unit *code_ptr = (tcg_insn_unit *)jmp_addr; - tcg_insn_unit *target = (tcg_insn_unit *)addr; + tcg_insn_unit i1, i2; + TCGType rt = TCG_TYPE_I64; + TCGReg rd = TCG_REG_TMP; + uint64_t pair; - reloc_pc26_atomic(code_ptr, target); - flush_icache_range(jmp_addr, jmp_addr + 4); + ptrdiff_t offset = addr - jmp_addr; + + if (offset == sextract64(offset, 0, 26)) { + i1 = I3206_B | ((offset >> 2) & 0x3ffffff); + i2 = NOP; + } else { + offset = (addr >> 12) - (jmp_addr >> 12); + + /* patch ADRP */ + i1 = I3406_ADRP | (offset & 3) << 29 | (offset & 0x1ffffc) << (5 - 2) | rd; + /* patch ADDI */ + i2 = I3401_ADDI | rt << 31 | (addr & 0xfff) << 10 | rd << 5 | rd; + } + pair = (uint64_t)i2 << 32 | i1; + atomic_set((uint64_t *)jmp_addr, pair); + flush_icache_range(jmp_addr, jmp_addr + 8); } static inline void tcg_out_goto_label(TCGContext *s, TCGLabel *l) @@ -1388,10 +1405,17 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, #endif /* consistency for USE_DIRECT_JUMP */ tcg_debug_assert(s->tb_jmp_insn_offset != NULL); + /* Ensure that ADRP+ADD are 8-byte aligned so that an atomic + write can be used to patch the target address. */ + if ((uintptr_t)s->code_ptr & 7) { + tcg_out32(s, NOP); + } s->tb_jmp_insn_offset[a0] = tcg_current_code_size(s); /* actual branch destination will be patched by - aarch64_tb_set_jmp_target later, beware retranslation. */ - tcg_out_goto_noaddr(s); + aarch64_tb_set_jmp_target later. */ + tcg_out_insn(s, 3406, ADRP, TCG_REG_TMP, 0); + tcg_out_insn(s, 3401, ADDI, TCG_TYPE_I64, TCG_REG_TMP, TCG_REG_TMP, 0); + tcg_out_insn(s, 3207, BR, TCG_REG_TMP); s->tb_jmp_reset_offset[a0] = tcg_current_code_size(s); break; |