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target/riscv: fix read/write virtual memory across page boundaries 

When read/write virtual addresses cross page boundaries,
the physical addresses are not necessarily contiguous and
need to call virt2phys again.
This commit is contained in:
Mark Zhuang 2024-10-11 16:57:48 +08:00
parent a4020f1a02
commit 593b377073
2 changed files with 68 additions and 12 deletions
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69
src/target/riscv/riscv.c
View File

@ -3061,6 +3061,27 @@ static int riscv_virt2phys(struct target *target, target_addr_t virtual, target_
virtual, physical);
}
static int check_access_request(struct target *target, target_addr_t address,
uint32_t size, uint32_t count, bool is_write)
{
const bool is_misaligned = address % size != 0;
// TODO: This assumes that size of each page is 4 KiB, which is not necessarily the case.
const bool crosses_page_boundary = RISCV_PGBASE(address + size * count - 1) != RISCV_PGBASE(address);
if (is_misaligned && crosses_page_boundary) {
int mmu_enabled;
int result = riscv_mmu(target, &mmu_enabled);
if (result != ERROR_OK)
return result;
if (mmu_enabled) {
LOG_TARGET_ERROR(target, "Mis-aligned memory %s (address=0x%" TARGET_PRIxADDR ", size=%d, count=%d)"
" would access an element across page boundary. This is not supported.",
is_write ? "write" : "read", address, size, count);
return ERROR_FAIL;
}
}
return ERROR_OK;
}
static int riscv_read_phys_memory(struct target *target, target_addr_t phys_address,
uint32_t size, uint32_t count, uint8_t *buffer)
{
@ -3076,15 +3097,32 @@ static int riscv_read_memory(struct target *target, target_addr_t address,
return ERROR_OK;
}
int result = check_access_request(target, address, size, count, false);
if (result != ERROR_OK)
return result;
RISCV_INFO(r);
uint32_t current_count = 0;
while (current_count < count) {
target_addr_t physical_addr;
int result = target->type->virt2phys(target, address, &physical_addr);
result = target->type->virt2phys(target, address, &physical_addr);
if (result != ERROR_OK) {
LOG_TARGET_ERROR(target, "Address translation failed.");
return result;
}
RISCV_INFO(r);
return r->read_memory(target, physical_addr, size, count, buffer, size);
/* TODO: For simplicity, this algorithm assumes the worst case - the smallest possible page size,
* which is 4 KiB. The algorithm can be improved to detect the real page size, and allow to use larger
* memory transfers and avoid extra unnecessary virt2phys address translations. */
uint32_t chunk_count = MIN(count - current_count, (RISCV_PGSIZE - RISCV_PGOFFSET(address)) / size);
result = r->read_memory(target, physical_addr, size, chunk_count, buffer + current_count * size, size);
if (result != ERROR_OK)
return result;
current_count += chunk_count;
address += chunk_count * size;
}
return ERROR_OK;
}
static int riscv_write_phys_memory(struct target *target, target_addr_t phys_address,
@ -3104,17 +3142,32 @@ static int riscv_write_memory(struct target *target, target_addr_t address,
return ERROR_OK;
}
int result = check_access_request(target, address, size, count, true);
if (result != ERROR_OK)
return result;
struct target_type *tt = get_target_type(target);
if (!tt)
return ERROR_FAIL;
uint32_t current_count = 0;
while (current_count < count) {
target_addr_t physical_addr;
int result = target->type->virt2phys(target, address, &physical_addr);
result = target->type->virt2phys(target, address, &physical_addr);
if (result != ERROR_OK) {
LOG_TARGET_ERROR(target, "Address translation failed.");
return result;
}
struct target_type *tt = get_target_type(target);
if (!tt)
return ERROR_FAIL;
return tt->write_memory(target, physical_addr, size, count, buffer);
uint32_t chunk_count = MIN(count - current_count, (RISCV_PGSIZE - RISCV_PGOFFSET(address)) / size);
result = tt->write_memory(target, physical_addr, size, chunk_count, buffer + current_count * size);
if (result != ERROR_OK)
return result;
current_count += chunk_count;
address += chunk_count * size;
}
return ERROR_OK;
}
static const char *riscv_get_gdb_arch(const struct target *target)

3
src/target/riscv/riscv.h
View File

@ -29,6 +29,9 @@ struct riscv_program;
#define RISCV_HGATP_MODE(xlen) ((xlen) == 32 ? HGATP32_MODE : HGATP64_MODE)
#define RISCV_HGATP_PPN(xlen) ((xlen) == 32 ? HGATP32_PPN : HGATP64_PPN)
#define RISCV_PGSHIFT 12
#define RISCV_PGSIZE BIT(RISCV_PGSHIFT)
#define RISCV_PGBASE(addr) ((addr) & ~(RISCV_PGSIZE - 1))
#define RISCV_PGOFFSET(addr) ((addr) & (RISCV_PGSIZE - 1))
#define PG_MAX_LEVEL 5