qemu/target/riscv/internals.h
Deepak Gupta 669b486749 target/riscv: mmu changes for zicfiss shadow stack protection
zicfiss protects shadow stack using new page table encodings PTE.W=1,
PTE.R=0 and PTE.X=0. This encoding is reserved if zicfiss is not
implemented or if shadow stack are not enabled.
Loads on shadow stack memory are allowed while stores to shadow stack
memory leads to access faults. Shadow stack accesses to RO memory
leads to store page fault.

To implement special nature of shadow stack memory where only selected
stores (shadow stack stores from sspush) have to be allowed while rest
of regular stores disallowed, new MMU TLB index is created for shadow
stack.

Furthermore, `check_zicbom_access` (`cbo.clean/flush/inval`) may probe
shadow stack memory and must always raise store/AMO access fault because
it has store semantics. For non-shadow stack memory even though
`cbo.clean/flush/inval` have store semantics, it will not fault if read
is allowed (probably to follow `clflush` on x86). Although if read is not
allowed, eventually `probe_write` will do store page (or access) fault (if
permissions don't allow it). cbo operations on shadow stack memory must
always raise store access fault. Thus extending `get_physical_address` to
recieve `probe` parameter as well.

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20241008225010.1861630-14-debug@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2024-10-30 11:22:08 +10:00

146 lines
3.8 KiB
C

/*
* QEMU RISC-V CPU -- internal functions and types
*
* Copyright (c) 2020 T-Head Semiconductor Co., Ltd. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2 or later, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef RISCV_CPU_INTERNALS_H
#define RISCV_CPU_INTERNALS_H
#include "hw/registerfields.h"
/*
* The current MMU Modes are:
* - U 0b000
* - S 0b001
* - S+SUM 0b010
* - M 0b011
* - U+2STAGE 0b100
* - S+2STAGE 0b101
* - S+SUM+2STAGE 0b110
* - Shadow stack+U 0b1000
* - Shadow stack+S 0b1001
*/
#define MMUIdx_U 0
#define MMUIdx_S 1
#define MMUIdx_S_SUM 2
#define MMUIdx_M 3
#define MMU_2STAGE_BIT (1 << 2)
#define MMU_IDX_SS_WRITE (1 << 3)
static inline int mmuidx_priv(int mmu_idx)
{
int ret = mmu_idx & 3;
if (ret == MMUIdx_S_SUM) {
ret = PRV_S;
}
return ret;
}
static inline bool mmuidx_sum(int mmu_idx)
{
return (mmu_idx & 3) == MMUIdx_S_SUM;
}
static inline bool mmuidx_2stage(int mmu_idx)
{
return mmu_idx & MMU_2STAGE_BIT;
}
/* share data between vector helpers and decode code */
FIELD(VDATA, VM, 0, 1)
FIELD(VDATA, LMUL, 1, 3)
FIELD(VDATA, VTA, 4, 1)
FIELD(VDATA, VTA_ALL_1S, 5, 1)
FIELD(VDATA, VMA, 6, 1)
FIELD(VDATA, NF, 7, 4)
FIELD(VDATA, WD, 7, 1)
/* float point classify helpers */
target_ulong fclass_h(uint64_t frs1);
target_ulong fclass_s(uint64_t frs1);
target_ulong fclass_d(uint64_t frs1);
#ifndef CONFIG_USER_ONLY
extern const VMStateDescription vmstate_riscv_cpu;
#endif
enum {
RISCV_FRM_RNE = 0, /* Round to Nearest, ties to Even */
RISCV_FRM_RTZ = 1, /* Round towards Zero */
RISCV_FRM_RDN = 2, /* Round Down */
RISCV_FRM_RUP = 3, /* Round Up */
RISCV_FRM_RMM = 4, /* Round to Nearest, ties to Max Magnitude */
RISCV_FRM_DYN = 7, /* Dynamic rounding mode */
RISCV_FRM_ROD = 8, /* Round to Odd */
};
static inline uint64_t nanbox_s(CPURISCVState *env, float32 f)
{
/* the value is sign-extended instead of NaN-boxing for zfinx */
if (env_archcpu(env)->cfg.ext_zfinx) {
return (int32_t)f;
} else {
return f | MAKE_64BIT_MASK(32, 32);
}
}
static inline float32 check_nanbox_s(CPURISCVState *env, uint64_t f)
{
/* Disable NaN-boxing check when enable zfinx */
if (env_archcpu(env)->cfg.ext_zfinx) {
return (uint32_t)f;
}
uint64_t mask = MAKE_64BIT_MASK(32, 32);
if (likely((f & mask) == mask)) {
return (uint32_t)f;
} else {
return 0x7fc00000u; /* default qnan */
}
}
static inline uint64_t nanbox_h(CPURISCVState *env, float16 f)
{
/* the value is sign-extended instead of NaN-boxing for zfinx */
if (env_archcpu(env)->cfg.ext_zfinx) {
return (int16_t)f;
} else {
return f | MAKE_64BIT_MASK(16, 48);
}
}
static inline float16 check_nanbox_h(CPURISCVState *env, uint64_t f)
{
/* Disable nanbox check when enable zfinx */
if (env_archcpu(env)->cfg.ext_zfinx) {
return (uint16_t)f;
}
uint64_t mask = MAKE_64BIT_MASK(16, 48);
if (likely((f & mask) == mask)) {
return (uint16_t)f;
} else {
return 0x7E00u; /* default qnan */
}
}
/* Our implementation of CPUClass::has_work */
bool riscv_cpu_has_work(CPUState *cs);
#endif