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unicorn/qemu/target/riscv/pmp.c

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target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
/*
* QEMU RISC-V PMP (Physical Memory Protection)
*
* Author: Daire McNamara, daire.mcnamara@emdalo.com
* Ivan Griffin, ivan.griffin@emdalo.com
*
* This provides a RISC-V Physical Memory Protection implementation
*
* 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/>.
*/
/*
* PMP (Physical Memory Protection) is as-of-yet unused and needs testing.
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qapi/error.h"
#include "cpu.h"
#include "qemu-common.h"
#ifndef CONFIG_USER_ONLY
#define RISCV_DEBUG_PMP 0
#define PMP_DEBUG(fmt, ...) \
do { \
if (RISCV_DEBUG_PMP) { \
qemu_log_mask(LOG_TRACE, "%s: " fmt "\n", __func__, ##__VA_ARGS__);\
} \
} while (0)
static void pmp_write_cfg(CPURISCVState *env, uint32_t addr_index,
uint8_t val);
static uint8_t pmp_read_cfg(CPURISCVState *env, uint32_t addr_index);
static void pmp_update_rule(CPURISCVState *env, uint32_t pmp_index);
/*
* Accessor method to extract address matching type 'a field' from cfg reg
*/
static inline uint8_t pmp_get_a_field(uint8_t cfg)
{
uint8_t a = cfg >> 3;
return a & 0x3;
}
/*
* Check whether a PMP is locked or not.
*/
static inline int pmp_is_locked(CPURISCVState *env, uint32_t pmp_index)
{
if (env->pmp_state.pmp[pmp_index].cfg_reg & PMP_LOCK) {
return 1;
}
/* Top PMP has no 'next' to check */
if ((pmp_index + 1u) >= MAX_RISCV_PMPS) {
return 0;
}
/* In TOR mode, need to check the lock bit of the next pmp
* (if there is a next)
*/
const uint8_t a_field =
pmp_get_a_field(env->pmp_state.pmp[pmp_index + 1].cfg_reg);
if ((env->pmp_state.pmp[pmp_index + 1u].cfg_reg & PMP_LOCK) &&
(PMP_AMATCH_TOR == a_field)) {
return 1;
}
return 0;
}
/*
* Count the number of active rules.
*/
static inline uint32_t pmp_get_num_rules(CPURISCVState *env)
{
return env->pmp_state.num_rules;
}
/*
* Accessor to get the cfg reg for a specific PMP/HART
*/
static inline uint8_t pmp_read_cfg(CPURISCVState *env, uint32_t pmp_index)
{
if (pmp_index < MAX_RISCV_PMPS) {
return env->pmp_state.pmp[pmp_index].cfg_reg;
}
return 0;
}
/*
* Accessor to set the cfg reg for a specific PMP/HART
* Bounds checks and relevant lock bit.
*/
static void pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
{
if (pmp_index < MAX_RISCV_PMPS) {
if (!pmp_is_locked(env, pmp_index)) {
env->pmp_state.pmp[pmp_index].cfg_reg = val;
pmp_update_rule(env, pmp_index);
} else {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR, "ignoring pmpcfg write - locked\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
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}
} else {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR,
"ignoring pmpcfg write - out of bounds\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
}
}
static void pmp_decode_napot(target_ulong a, target_ulong *sa, target_ulong *ea)
{
/*
aaaa...aaa0 8-byte NAPOT range
aaaa...aa01 16-byte NAPOT range
aaaa...a011 32-byte NAPOT range
...
aa01...1111 2^XLEN-byte NAPOT range
a011...1111 2^(XLEN+1)-byte NAPOT range
0111...1111 2^(XLEN+2)-byte NAPOT range
1111...1111 Reserved
*/
if (a == -1) {
*sa = 0u;
*ea = -1;
return;
} else {
target_ulong t1 = ctz64(~a);
target_ulong base = (a & ~(((target_ulong)1 << t1) - 1)) << 2;
target_ulong range = ((target_ulong)1 << (t1 + 3)) - 1;
*sa = base;
*ea = base + range;
}
}
/* Convert cfg/addr reg values here into simple 'sa' --> start address and 'ea'
* end address values.
* This function is called relatively infrequently whereas the check that
* an address is within a pmp rule is called often, so optimise that one
*/
static void pmp_update_rule(CPURISCVState *env, uint32_t pmp_index)
{
int i;
env->pmp_state.num_rules = 0;
uint8_t this_cfg = env->pmp_state.pmp[pmp_index].cfg_reg;
target_ulong this_addr = env->pmp_state.pmp[pmp_index].addr_reg;
target_ulong prev_addr = 0u;
target_ulong sa = 0u;
target_ulong ea = 0u;
if (pmp_index >= 1u) {
prev_addr = env->pmp_state.pmp[pmp_index - 1].addr_reg;
}
switch (pmp_get_a_field(this_cfg)) {
case PMP_AMATCH_OFF:
sa = 0u;
ea = -1;
break;
case PMP_AMATCH_TOR:
sa = prev_addr << 2; /* shift up from [xx:0] to [xx+2:2] */
ea = (this_addr << 2) - 1u;
break;
case PMP_AMATCH_NA4:
sa = this_addr << 2; /* shift up from [xx:0] to [xx+2:2] */
ea = (this_addr + 4u) - 1u;
break;
case PMP_AMATCH_NAPOT:
pmp_decode_napot(this_addr, &sa, &ea);
break;
default:
sa = 0u;
ea = 0u;
break;
}
env->pmp_state.addr[pmp_index].sa = sa;
env->pmp_state.addr[pmp_index].ea = ea;
for (i = 0; i < MAX_RISCV_PMPS; i++) {
const uint8_t a_field =
pmp_get_a_field(env->pmp_state.pmp[i].cfg_reg);
if (PMP_AMATCH_OFF != a_field) {
env->pmp_state.num_rules++;
}
}
}
static int pmp_is_in_range(CPURISCVState *env, int pmp_index, target_ulong addr)
{
int result = 0;
if ((addr >= env->pmp_state.addr[pmp_index].sa)
&& (addr <= env->pmp_state.addr[pmp_index].ea)) {
result = 1;
} else {
result = 0;
}
return result;
}
/*
* Public Interface
*/
/*
* Check if the address has required RWX privs to complete desired operation
*/
bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
RISC-V: Check for the effective memory privilege mode during PMP checks The current PMP check function checks for env->priv which is not the effective memory privilege mode. For example, mstatus.MPRV could be set while executing in M-Mode, and in that case the privilege mode for the PMP check should be S-Mode rather than M-Mode (in env->priv) if mstatus.MPP == PRV_S. This patch passes the effective memory privilege mode to the PMP check. Functions that call the PMP check should pass the correct memory privilege mode after reading mstatus' MPRV/MPP or hstatus.SPRV (if Hypervisor mode exists). Backports commit cc0fdb298517ce56c770803447f8b02a90271152 from qemu
2019-08-08 20:52:56 +00:00
target_ulong size, pmp_priv_t privs, target_ulong mode)
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
{
int i = 0;
int ret = -1;
target_ulong s = 0;
target_ulong e = 0;
pmp_priv_t allowed_privs = 0;
/* Short cut if no rules */
if (0 == pmp_get_num_rules(env)) {
return true;
}
/* 1.10 draft priv spec states there is an implicit order
from low to high */
for (i = 0; i < MAX_RISCV_PMPS; i++) {
s = pmp_is_in_range(env, i, addr);
target/riscv: Fix PMP range boundary address bug A wrong address is passed to `pmp_is_in_range` while checking if a memory access is within a PMP range. Since the ending address of the pmp range (i.e., pmp_state.addr[i].ea) is set to the last address in the range (i.e., pmp base + pmp size - 1), memory accesses containg the last address in the range will always fail. For example, assume that a PMP range is 4KB from 0x87654000 such that the last address within the range is 0x87654fff. 1-byte access to 0x87654fff should be considered to be fully inside the PMP range. However the access now fails and complains partial inclusion because pmp_is_in_range(env, i, addr + size) returns 0 whereas pmp_is_in_range(env, i, addr) returns 1. Backports commit 49db9fa1fd7c252596b53cf80876e06f407d09ed from qemu
2019-08-08 20:42:08 +00:00
e = pmp_is_in_range(env, i, addr + size - 1);
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
/* partially inside */
if ((s + e) == 1) {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR,
"pmp violation - access is partially inside\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
ret = 0;
break;
}
/* fully inside */
const uint8_t a_field =
pmp_get_a_field(env->pmp_state.pmp[i].cfg_reg);
RISC-V: Fix a PMP bug where it succeeds even if PMP entry is off The current implementation returns 1 (PMP check success) if the address is in range even if the PMP entry is off. This is a bug. For example, if there is a PMP check in S-Mode which is in range, but its PMP entry is off, this will succeed, which it should not. The patch fixes this bug by only checking the PMP permissions if the address is in range and its corresponding PMP entry it not off. Otherwise, it will keep the ret = -1 which will be checked and handled correctly at the end of the function. Backports commit f8162068f18f2f264a0355938784f54089234211 from qemu
2019-08-08 20:55:50 +00:00
/*
* If the PMP entry is not off and the address is in range, do the priv
* check
*/
if (((s + e) == 2) && (PMP_AMATCH_OFF != a_field)) {
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC;
RISC-V: Check for the effective memory privilege mode during PMP checks The current PMP check function checks for env->priv which is not the effective memory privilege mode. For example, mstatus.MPRV could be set while executing in M-Mode, and in that case the privilege mode for the PMP check should be S-Mode rather than M-Mode (in env->priv) if mstatus.MPP == PRV_S. This patch passes the effective memory privilege mode to the PMP check. Functions that call the PMP check should pass the correct memory privilege mode after reading mstatus' MPRV/MPP or hstatus.SPRV (if Hypervisor mode exists). Backports commit cc0fdb298517ce56c770803447f8b02a90271152 from qemu
2019-08-08 20:52:56 +00:00
if ((mode != PRV_M) || pmp_is_locked(env, i)) {
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
allowed_privs &= env->pmp_state.pmp[i].cfg_reg;
}
if ((privs & allowed_privs) == privs) {
ret = 1;
break;
} else {
ret = 0;
break;
}
}
}
/* No rule matched */
if (ret == -1) {
RISC-V: Check for the effective memory privilege mode during PMP checks The current PMP check function checks for env->priv which is not the effective memory privilege mode. For example, mstatus.MPRV could be set while executing in M-Mode, and in that case the privilege mode for the PMP check should be S-Mode rather than M-Mode (in env->priv) if mstatus.MPP == PRV_S. This patch passes the effective memory privilege mode to the PMP check. Functions that call the PMP check should pass the correct memory privilege mode after reading mstatus' MPRV/MPP or hstatus.SPRV (if Hypervisor mode exists). Backports commit cc0fdb298517ce56c770803447f8b02a90271152 from qemu
2019-08-08 20:52:56 +00:00
if (mode == PRV_M) {
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
ret = 1; /* Privileged spec v1.10 states if no PMP entry matches an
* M-Mode access, the access succeeds */
} else {
ret = 0; /* Other modes are not allowed to succeed if they don't
* match a rule, but there are rules. We've checked for
* no rule earlier in this function. */
}
}
return ret == 1 ? true : false;
}
/*
* Handle a write to a pmpcfg CSP
*/
void pmpcfg_csr_write(CPURISCVState *env, uint32_t reg_index,
target_ulong val)
{
int i;
uint8_t cfg_val;
PMP_DEBUG("hart " TARGET_FMT_ld ": reg%d, val: 0x" TARGET_FMT_lx,
env->mhartid, reg_index, val);
if ((reg_index & 1) && (sizeof(target_ulong) == 8)) {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR,
"ignoring pmpcfg write - incorrect address\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
return;
}
for (i = 0; i < sizeof(target_ulong); i++) {
cfg_val = (val >> 8 * i) & 0xff;
pmp_write_cfg(env, (reg_index * sizeof(target_ulong)) + i,
cfg_val);
}
}
/*
* Handle a read from a pmpcfg CSP
*/
target_ulong pmpcfg_csr_read(CPURISCVState *env, uint32_t reg_index)
{
int i;
target_ulong cfg_val = 0;
target_ulong val = 0;
for (i = 0; i < sizeof(target_ulong); i++) {
val = pmp_read_cfg(env, (reg_index * sizeof(target_ulong)) + i);
cfg_val |= (val << (i * 8));
}
PMP_DEBUG("hart " TARGET_FMT_ld ": reg%d, val: 0x" TARGET_FMT_lx,
env->mhartid, reg_index, cfg_val);
return cfg_val;
}
/*
* Handle a write to a pmpaddr CSP
*/
void pmpaddr_csr_write(CPURISCVState *env, uint32_t addr_index,
target_ulong val)
{
PMP_DEBUG("hart " TARGET_FMT_ld ": addr%d, val: 0x" TARGET_FMT_lx,
env->mhartid, addr_index, val);
if (addr_index < MAX_RISCV_PMPS) {
if (!pmp_is_locked(env, addr_index)) {
env->pmp_state.pmp[addr_index].addr_reg = val;
pmp_update_rule(env, addr_index);
} else {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR,
"ignoring pmpaddr write - locked\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
}
} else {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR,
"ignoring pmpaddr write - out of bounds\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
}
}
/*
* Handle a read from a pmpaddr CSP
*/
target_ulong pmpaddr_csr_read(CPURISCVState *env, uint32_t addr_index)
{
PMP_DEBUG("hart " TARGET_FMT_ld ": addr%d, val: 0x" TARGET_FMT_lx,
env->mhartid, addr_index,
env->pmp_state.pmp[addr_index].addr_reg);
if (addr_index < MAX_RISCV_PMPS) {
return env->pmp_state.pmp[addr_index].addr_reg;
} else {
riscv: pmp: Log pmp access errors as guest errors Backports commit aad5ac2311f3ad2c0be12d0eaaf4ef4398438fc2 from qemu
2019-03-20 03:44:55 +00:00
qemu_log_mask(LOG_GUEST_ERROR,
"ignoring pmpaddr read - out of bounds\n");
target/riscv: Initial introduction of the RISC-V target This ports over the RISC-V architecture from Qemu. This is currently a very barebones transition. No code hooking or any fancy stuff. Currently, you can feed it instructions and query the CPU state itself. This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit is desirable through Unicorn's interface as well. Extremely basic examples of executing a single instruction have been added to the samples directory to help demonstrate how to use the basic functionality.
2019-03-08 18:06:28 +00:00
return 0;
}
}
#endif
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