From f2488736371ae902f345cf9270d141f0a6797731 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 28 Aug 2013 14:40:52 -0700 Subject: tcg-arm: Use QEMU_BUILD_BUG_ON to verify constraints on tlb One of the two constraints we already checked via #if, but the tlb offset distance was only checked at runtime. Signed-off-by: Richard Henderson --- tcg/arm/tcg-target.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c index f953f4e556..1f7bbe1195 100644 --- a/tcg/arm/tcg-target.c +++ b/tcg/arm/tcg-target.c @@ -1163,6 +1163,15 @@ static TCGReg tcg_out_arg_reg64(TCGContext *s, TCGReg argreg, #define TLB_SHIFT (CPU_TLB_ENTRY_BITS + CPU_TLB_BITS) +/* We're expecting to use an 8-bit immediate and to mask. */ +QEMU_BUILD_BUG_ON(CPU_TLB_BITS > 8); + +/* We're expecting to use an 8-bit immediate add + 8-bit ldrd offset. + Using the offset of the second entry in the last tlb table ensures + that we can index all of the elements of the first entry. */ +QEMU_BUILD_BUG_ON(offsetof(CPUArchState, tlb_table[NB_MMU_MODES - 1][1]) + > 0xffff); + /* Load and compare a TLB entry, leaving the flags set. Leaves R2 pointing to the tlb entry. Clobbers R1 and TMP. */ @@ -1190,14 +1199,10 @@ static void tcg_out_tlb_read(TCGContext *s, TCGReg addrlo, TCGReg addrhi, * ldr r0, [r2, r0]! (3) * cmp r0, tmp (4) */ -# if CPU_TLB_BITS > 8 -# error -# endif tcg_out_dat_reg(s, COND_AL, ARITH_MOV, TCG_REG_TMP, 0, addrlo, SHIFT_IMM_LSR(TARGET_PAGE_BITS)); - /* We assume that the offset is contained within 16 bits. */ - assert((tlb_offset & ~0xffff) == 0); + /* We checked that the offset is contained within 16 bits above. */ if (tlb_offset > 0xff) { tcg_out_dat_imm(s, COND_AL, ARITH_ADD, TCG_REG_R2, base, (24 << 7) | (tlb_offset >> 8)); -- cgit v1.2.3