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tcg: Support arbitrary size + alignment

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Previously we allowed fully unaligned operations, but not operations
that are aligned but with less alignment than the operation size.

In addition, arm32, ia64, mips, and sparc had been omitted from the
previous overalignment patch, which would have led to that alignment
being enforced.

Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2016-07-14 12:43:06 -07:00
parent ebc231d7da
commit 85aa80813d
10 changed files with 128 additions and 112 deletions
Download patch file Download diff file Expand all files Collapse all files

19
tcg/i386/tcg-target.inc.c
View file

@ -1202,7 +1202,10 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
TCGType ttype = TCG_TYPE_I32;
TCGType tlbtype = TCG_TYPE_I32;
int trexw = 0, hrexw = 0, tlbrexw = 0;
int a_bits = get_alignment_bits(opc);
unsigned a_bits = get_alignment_bits(opc);
unsigned s_bits = opc & MO_SIZE;
unsigned a_mask = (1 << a_bits) - 1;
unsigned s_mask = (1 << s_bits) - 1;
target_ulong tlb_mask;
if (TCG_TARGET_REG_BITS == 64) {
@ -1220,17 +1223,15 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
}
tcg_out_mov(s, tlbtype, r0, addrlo);
if (a_bits >= 0) {
/* A byte access or an alignment check required */
/* If the required alignment is at least as large as the access, simply
copy the address and mask. For lesser alignments, check that we don't
cross pages for the complete access. */
if (a_bits >= s_bits) {
tcg_out_mov(s, ttype, r1, addrlo);
tlb_mask = TARGET_PAGE_MASK | ((1 << a_bits) - 1);
} else {
/* For unaligned access check that we don't cross pages using
the page address of the last byte. */
tcg_out_modrm_offset(s, OPC_LEA + trexw, r1, addrlo,
(1 << (opc & MO_SIZE)) - 1);
tlb_mask = TARGET_PAGE_MASK;
tcg_out_modrm_offset(s, OPC_LEA + trexw, r1, addrlo, s_mask - a_mask);
}
tlb_mask = TARGET_PAGE_MASK | a_mask;
tcg_out_shifti(s, SHIFT_SHR + tlbrexw, r0,
TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS);