smt_astt
smt_convt::overflow_arith(const expr2tc &expr)
{
// If in integer mode, this is completely pointless. Return false.
if (int_encoding)
return mk_smt_bool(false);
const overflow2t &overflow = to_overflow2t(expr);
const arith_2ops &opers = static_cast<const arith_2ops &>(*overflow.operand);
assert(opers.side_1->type == opers.side_2->type);
constant_int2tc zero(opers.side_1->type, BigInt(0));
lessthan2tc op1neg(opers.side_1, zero);
lessthan2tc op2neg(opers.side_2, zero);
equality2tc op1iszero(opers.side_1, zero);
equality2tc op2iszero(opers.side_2, zero);
or2tc containszero(op1iszero, op2iszero);
// Guess whether we're performing a signed or unsigned comparison.
bool is_signed = (is_signedbv_type(opers.side_1) ||
is_signedbv_type(opers.side_2));
if (is_add2t(overflow.operand)) {
if (is_signed) {
// Two cases: pos/pos, and neg/neg, which can over and underflow resp.
// In pos/neg cases, no overflow or underflow is possible, for any value.
constant_int2tc zero(opers.side_1->type, BigInt(0));
lessthan2tc op1pos(zero, opers.side_1);
lessthan2tc op2pos(zero, opers.side_2);
and2tc both_pos(op1pos, op2pos);
not2tc negop1(op1pos);
not2tc negop2(op2pos);
and2tc both_neg(negop1, negop2);
implies2tc nooverflow(both_pos,
greaterthanequal2tc(overflow.operand, zero));
implies2tc nounderflow(both_neg,
lessthanequal2tc(overflow.operand, zero));
return convert_ast(not2tc(and2tc(nooverflow, nounderflow)));
} else {
// Just ensure the result is >= both operands.
greaterthanequal2tc ge1(overflow.operand, opers.side_1);
greaterthanequal2tc ge2(overflow.operand, opers.side_2);
and2tc res(ge1, ge2);
not2tc inv(res);
return convert_ast(inv);
}
} else if (is_sub2t(overflow.operand)) {
if (is_signed) {
// Convert to be an addition
neg2tc negop2(opers.side_2->type, opers.side_2);
add2tc anadd(opers.side_1->type, opers.side_1, negop2);
expr2tc add_overflows(new overflow2t(anadd));
// Corner case: subtracting MIN_INT from many things overflows. The result
// should always be positive.
constant_int2tc zero(opers.side_1->type, BigInt(0));
uint64_t topbit = 1ULL << (opers.side_1->type->get_width() - 1);
constant_int2tc min_int(opers.side_1->type, BigInt(topbit));
equality2tc is_min_int(min_int, opers.side_2);
implies2tc imp(is_min_int, greaterthan2tc(overflow.operand, zero));
return convert_ast(or2tc(add_overflows, is_min_int));
} else {
// Just ensure the result is >= the operands.
lessthanequal2tc le1(overflow.operand, opers.side_1);
lessthanequal2tc le2(overflow.operand, opers.side_2);
and2tc res(le1, le2);
not2tc inv(res);
return convert_ast(inv);
}
} else {
assert(is_mul2t(overflow.operand) && "unexpected overflow_arith operand");
// Zero extend; multiply; Make a decision based on the top half.
unsigned int sz = zero->type->get_width();
smt_sortt boolsort = boolean_sort;
smt_sortt normalsort = mk_sort(SMT_SORT_BV, sz, false);
smt_sortt bigsort = mk_sort(SMT_SORT_BV, sz * 2, false);
// All one bit vector is tricky, might be 64 bits wide for all we know.
constant_int2tc allonesexpr(zero->type, BigInt((sz == 64)
? 0xFFFFFFFFFFFFFFFFULL
: ((1ULL << sz) - 1)));
smt_astt allonesvector = convert_ast(allonesexpr);
smt_astt arg1_ext, arg2_ext;
if (is_signed) {
// sign extend top bits.
arg1_ext = convert_ast(opers.side_1);
arg1_ext = convert_sign_ext(arg1_ext, bigsort, sz - 1, sz);
arg2_ext = convert_ast(opers.side_2);
arg2_ext = convert_sign_ext(arg2_ext, bigsort, sz - 1, sz);
} else {
// Zero extend the top parts
arg1_ext = convert_ast(opers.side_1);
arg1_ext = convert_zero_ext(arg1_ext, bigsort, sz);
arg2_ext = convert_ast(opers.side_2);
arg2_ext = convert_zero_ext(arg2_ext, bigsort, sz);
}
smt_astt result = mk_func_app(bigsort, SMT_FUNC_BVMUL, arg1_ext, arg2_ext);
// Extract top half.
smt_astt toppart = mk_extract(result, (sz * 2) - 1, sz, normalsort);
if (is_signed) {
// It should either be zero or all one's; which depends on what
// configuration of signs it had. If both pos / both neg, then the top
// should all be zeros, otherwise all ones. Implement with xor.
smt_astt op1neg_ast = convert_ast(op1neg);
smt_astt op2neg_ast = convert_ast(op2neg);
smt_astt allonescond =
mk_func_app(boolsort, SMT_FUNC_XOR, op1neg_ast, op2neg_ast);
smt_astt zerovector = convert_ast(zero);
smt_astt initial_switch =
mk_func_app(normalsort, SMT_FUNC_ITE, allonescond,
allonesvector, zerovector);
// either value being zero means the top must be zero.
smt_astt contains_zero_ast = convert_ast(containszero);
smt_astt second_switch = mk_func_app(normalsort, SMT_FUNC_ITE,
contains_zero_ast,
zerovector,
initial_switch);
smt_astt is_eq =
mk_func_app(boolsort, SMT_FUNC_EQ, second_switch, toppart);
return mk_func_app(boolsort, SMT_FUNC_NOT, &is_eq, 1);
} else {
// It should be zero; if not, overflow
smt_astt iseq =
mk_func_app(boolsort, SMT_FUNC_EQ, toppart, convert_ast(zero));
return mk_func_app(boolsort, SMT_FUNC_NOT, &iseq, 1);
}
}
return NULL;
}
static dma_addr_t i915_stolen_to_dma(struct drm_i915_private *dev_priv)
{
struct pci_dev *pdev = dev_priv->drm.pdev;
struct i915_ggtt *ggtt = &dev_priv->ggtt;
struct resource *r;
dma_addr_t base;
/* Almost universally we can find the Graphics Base of Stolen Memory
* at register BSM (0x5c) in the igfx configuration space. On a few
* (desktop) machines this is also mirrored in the bridge device at
* different locations, or in the MCHBAR.
*
* On 865 we just check the TOUD register.
*
* On 830/845/85x the stolen memory base isn't available in any
* register. We need to calculate it as TOM-TSEG_SIZE-stolen_size.
*
*/
base = 0;
if (INTEL_GEN(dev_priv) >= 3) {
u32 bsm;
pci_read_config_dword(pdev, INTEL_BSM, &bsm);
base = bsm & INTEL_BSM_MASK;
} else if (IS_I865G(dev_priv)) {
u32 tseg_size = 0;
u16 toud = 0;
u8 tmp;
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
I845_ESMRAMC, &tmp);
if (tmp & TSEG_ENABLE) {
switch (tmp & I845_TSEG_SIZE_MASK) {
case I845_TSEG_SIZE_512K:
tseg_size = KB(512);
break;
case I845_TSEG_SIZE_1M:
tseg_size = MB(1);
break;
}
}
pci_bus_read_config_word(pdev->bus, PCI_DEVFN(0, 0),
I865_TOUD, &toud);
base = (toud << 16) + tseg_size;
} else if (IS_I85X(dev_priv)) {
u32 tseg_size = 0;
u32 tom;
u8 tmp;
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
I85X_ESMRAMC, &tmp);
if (tmp & TSEG_ENABLE)
tseg_size = MB(1);
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 1),
I85X_DRB3, &tmp);
tom = tmp * MB(32);
base = tom - tseg_size - ggtt->stolen_size;
} else if (IS_I845G(dev_priv)) {
u32 tseg_size = 0;
u32 tom;
u8 tmp;
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
I845_ESMRAMC, &tmp);
if (tmp & TSEG_ENABLE) {
switch (tmp & I845_TSEG_SIZE_MASK) {
case I845_TSEG_SIZE_512K:
tseg_size = KB(512);
break;
case I845_TSEG_SIZE_1M:
tseg_size = MB(1);
break;
}
}
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
I830_DRB3, &tmp);
tom = tmp * MB(32);
base = tom - tseg_size - ggtt->stolen_size;
} else if (IS_I830(dev_priv)) {
u32 tseg_size = 0;
u32 tom;
u8 tmp;
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
I830_ESMRAMC, &tmp);
if (tmp & TSEG_ENABLE) {
if (tmp & I830_TSEG_SIZE_1M)
tseg_size = MB(1);
else
tseg_size = KB(512);
}
pci_bus_read_config_byte(pdev->bus, PCI_DEVFN(0, 0),
I830_DRB3, &tmp);
tom = tmp * MB(32);
base = tom - tseg_size - ggtt->stolen_size;
}
if (base == 0 || add_overflows(base, ggtt->stolen_size))
return 0;
/* make sure we don't clobber the GTT if it's within stolen memory */
if (INTEL_GEN(dev_priv) <= 4 &&
!IS_G33(dev_priv) && !IS_PINEVIEW(dev_priv) && !IS_G4X(dev_priv)) {
struct {
dma_addr_t start, end;
} stolen[2] = {
{ .start = base, .end = base + ggtt->stolen_size, },
{ .start = base, .end = base + ggtt->stolen_size, },
};
