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fix(mpu-regions): Fix find region function on arm-r MPU #267

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fix(mpu-regions): Fix find region function on arm-r MPU #267

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49f4791
fix(mpu-regions): make region lookup ASID-aware and merge find helpers
miguelafsilva5 Nov 4, 2025
06c615b
ref(priv): remove as->type to priv function
miguelafsilva5 Nov 4, 2025
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1 change: 1 addition & 0 deletions src/arch/armv8/armv8-r/inc/arch/mpu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
struct mpu_arch {
BITMAP_ALLOC(allocated_entries, MPU_ARCH_MAX_NUM_ENTRIES);
BITMAP_ALLOC(locked_entries, MPU_ARCH_MAX_NUM_ENTRIES);
asid_t entry_asid[MPU_ARCH_MAX_NUM_ENTRIES];
};

bool mpu_perms_compatible(unsigned long perms1, unsigned long perms2);
Expand Down
60 changes: 13 additions & 47 deletions src/arch/armv8/armv8-r/mpu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,19 +9,6 @@
#include <arch/sysregs.h>
#include <arch/fences.h>

static priv_t mpu_as_priv(struct addr_space* as)
{
priv_t priv;

if (as->type == AS_VM) {
priv = PRIV_VM;
} else {
priv = PRIV_HYP;
}

return priv;
}

static unsigned long mpu_get_region_base(mpid_t mpid)
{
unsigned long prbar = 0;
Expand All @@ -33,24 +20,14 @@ static unsigned long mpu_get_region_base(mpid_t mpid)
return PRBAR_BASE(prbar);
}

static unsigned long mpu_get_region_limit(mpid_t mpid)
{
unsigned long prlar = 0;

sysreg_prselr_el2_write(mpid);
ISB();
prlar = sysreg_prlar_el2_read();

return PRLAR_LIMIT(prlar);
}

static mpid_t mpu_find_region_base(struct mp_region* mpr)
static mpid_t mpu_find_region(struct mp_region* mpr, asid_t asid)
{
mpid_t mpid = INVALID_MPID;

for (mpid_t i = 0; i < MPU_ARCH_MAX_NUM_ENTRIES; i++) {
if (bitmap_get(cpu()->arch.profile.mpu.allocated_entries, i)) {
if (mpu_get_region_base(i) == mpr->base) {
if (mpu_get_region_base(i) == mpr->base &&
cpu()->arch.profile.mpu.entry_asid[i] == asid) {
mpid = i;
break;
}
Expand All @@ -59,33 +36,22 @@ static mpid_t mpu_find_region_base(struct mp_region* mpr)
return mpid;
}

static mpid_t mpu_find_region_exact(struct mp_region* mpr)
{
mpid_t mpid = mpu_find_region_base(mpr);

if (mpid != INVALID_MPID) {
if (mpu_get_region_limit(mpid) == PRLAR_LIMIT(mpr->base + mpr->size - 1)) {
return mpid;
}
}

return INVALID_MPID;
}

static mpid_t mpu_entry_allocate(void)
static mpid_t mpu_entry_allocate(asid_t asid)
{
mpid_t reg_num = INVALID_MPID;
reg_num = (mpid_t)bitmap_find_nth(cpu()->arch.profile.mpu.allocated_entries,
MPU_ARCH_MAX_NUM_ENTRIES, 1, 0, false);

bitmap_set(cpu()->arch.profile.mpu.allocated_entries, reg_num);
cpu()->arch.profile.mpu.entry_asid[reg_num] = asid;

return reg_num;
}

static inline void mpu_entry_deallocate(mpid_t mpid)
{
bitmap_clear(cpu()->arch.profile.mpu.allocated_entries, mpid);
cpu()->arch.profile.mpu.entry_asid[mpid] = INVALID_ASID;
}

static inline void mpu_entry_lock(mpid_t mpid)
Expand Down Expand Up @@ -132,7 +98,6 @@ static bool mpu_entry_clear(mpid_t mpid)
bool mpu_map(struct addr_space* as, struct mp_region* mpr, bool locked)
{
mpid_t mpid = INVALID_MPID;
priv_t priv = mpu_as_priv(as);

if (mpr->size == 0) {
return false;
Expand All @@ -145,14 +110,16 @@ bool mpu_map(struct addr_space* as, struct mp_region* mpr, bool locked)
*/

else {
mpid = mpu_entry_allocate();
mpid = mpu_entry_allocate(as->id);
if (mpid != INVALID_MPID) {
if (locked) {
mpu_entry_lock(mpid);
}
bitmap_set((bitmap_t*)&as->arch.mpu_entry_mask, mpid);
if (priv == PRIV_VM) {
if (as->type == AS_VM) {
mpr->mem_flags.prlar &= (uint16_t)~PRLAR_EN;
} else if (as->type == AS_HYP || as->type == AS_HYP_CPY) {
mpr->mem_flags.prlar |= (uint16_t)PRLAR_EN;
}
mpu_entry_set(mpid, mpr);
}
Expand All @@ -164,7 +131,7 @@ bool mpu_map(struct addr_space* as, struct mp_region* mpr, bool locked)
bool mpu_unmap(struct addr_space* as, struct mp_region* mpr)
{
UNUSED_ARG(as);
mpid_t mpid = mpu_find_region_exact(mpr);
mpid_t mpid = mpu_find_region(mpr, as->id);

if (mpid != INVALID_MPID) {
mpu_entry_deallocate(mpid);
Expand All @@ -180,9 +147,7 @@ bool mpu_unmap(struct addr_space* as, struct mp_region* mpr)

bool mpu_update(struct addr_space* as, struct mp_region* mpr)
{
UNUSED_ARG(as);

mpid_t mpid = mpu_find_region_base(mpr);
mpid_t mpid = mpu_find_region(mpr, as->id);

if (mpid != INVALID_MPID) {
mpu_entry_update_limit(mpid, mpr);
Expand Down Expand Up @@ -213,5 +178,6 @@ void mpu_init()
for (mpid_t mpid = 0; mpid < MPU_ARCH_MAX_NUM_ENTRIES; mpid++) {
bitmap_clear(cpu()->arch.profile.mpu.allocated_entries, mpid);
bitmap_clear(cpu()->arch.profile.mpu.locked_entries, mpid);
cpu()->arch.profile.mpu.entry_asid[mpid] = INVALID_ASID;
}
}
1 change: 1 addition & 0 deletions src/core/inc/types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
typedef signed long ssize_t;

typedef unsigned long asid_t;
#define INVALID_ASID ((asid_t)~0UL)

typedef unsigned long vmid_t;
#define INVALID_VMID ((vmid_t)~0UL)
Expand Down