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RISC-V: Check for the effective memory privilege mode during PMP checks

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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).

Suggested-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Hesham Almatary <Hesham.Almatary@cl.cam.ac.uk>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This commit is contained in:
Hesham Almatary 2019-05-30 14:51:32 +01:00 committed by Palmer Dabbelt
parent 635b0b0ea3
commit cc0fdb2985
No known key found for this signature in database
GPG key ID: EF4CA1502CCBAB41
3 changed files with 13 additions and 5 deletions
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10
target/riscv/cpu_helper.c
View file

@ -427,19 +427,27 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
int prot;
bool pmp_violation = false;
int ret = TRANSLATE_FAIL;
int mode = mmu_idx;
qemu_log_mask(CPU_LOG_MMU, "%s ad %" VADDR_PRIx " rw %d mmu_idx %d\n",
__func__, address, access_type, mmu_idx);
ret = get_physical_address(env, &pa, &prot, address, access_type, mmu_idx);
if (mode == PRV_M && access_type != MMU_INST_FETCH) {
if (get_field(env->mstatus, MSTATUS_MPRV)) {
mode = get_field(env->mstatus, MSTATUS_MPP);
}
}
qemu_log_mask(CPU_LOG_MMU,
"%s address=%" VADDR_PRIx " ret %d physical " TARGET_FMT_plx
" prot %d\n", __func__, address, ret, pa, prot);
if (riscv_feature(env, RISCV_FEATURE_PMP) &&
(ret == TRANSLATE_SUCCESS) &&
!pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type)) {
!pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type,
mode)) {
pmp_violation = true;
ret = TRANSLATE_FAIL;
}

6
target/riscv/pmp.c
View file

@ -228,7 +228,7 @@ static int pmp_is_in_range(CPURISCVState *env, int pmp_index, target_ulong addr)
* Check if the address has required RWX privs to complete desired operation
*/
bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
target_ulong size, pmp_priv_t privs)
target_ulong size, pmp_priv_t privs, target_ulong mode)
{
int i = 0;
int ret = -1;
@ -264,7 +264,7 @@ bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
}
allowed_privs = PMP_READ | PMP_WRITE | PMP_EXEC;
if ((env->priv != PRV_M) || pmp_is_locked(env, i)) {
if ((mode != PRV_M) || pmp_is_locked(env, i)) {
allowed_privs &= env->pmp_state.pmp[i].cfg_reg;
}
@ -280,7 +280,7 @@ bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
/* No rule matched */
if (ret == -1) {
if (env->priv == PRV_M) {
if (mode == PRV_M) {
ret = 1; /* Privileged spec v1.10 states if no PMP entry matches an
* M-Mode access, the access succeeds */
} else {

2
target/riscv/pmp.h
View file

@ -59,6 +59,6 @@ void pmpaddr_csr_write(CPURISCVState *env, uint32_t addr_index,
target_ulong val);
target_ulong pmpaddr_csr_read(CPURISCVState *env, uint32_t addr_index);
bool pmp_hart_has_privs(CPURISCVState *env, target_ulong addr,
target_ulong size, pmp_priv_t priv);
target_ulong size, pmp_priv_t priv, target_ulong mode);
#endif