// SPDX-License-Identifier: GPL-2.0-only
/*
* Author: Erik Kaneda <[email protected]>
* Copyright 2020 Intel Corporation
*
* prmt.c
*
* Each PRM service is an executable that is run in a restricted environment
* that is invoked by writing to the PlatformRtMechanism OperationRegion from
* AML bytecode.
*
* init_prmt initializes the Platform Runtime Mechanism (PRM) services by
* processing data in the PRMT as well as registering an ACPI OperationRegion
* handler for the PlatformRtMechanism subtype.
*
*/
#include <linux/kernel.h>
#include <linux/efi.h>
#include <linux/acpi.h>
#include <linux/prmt.h>
#include <asm/efi.h>
#pragma pack(1)
struct prm_mmio_addr_range {
u64 phys_addr;
u64 virt_addr;
u32 length;
};
struct prm_mmio_info {
u64 mmio_count;
struct prm_mmio_addr_range addr_ranges[];
};
struct prm_buffer {
u8 prm_status;
u64 efi_status;
u8 prm_cmd;
guid_t handler_guid;
};
struct prm_context_buffer {
char signature[ACPI_NAMESEG_SIZE];
u16 revision;
u16 reserved;
guid_t identifier;
u64 static_data_buffer;
struct prm_mmio_info *mmio_ranges;
};
#pragma pack()
static LIST_HEAD(prm_module_list);
struct prm_handler_info {
guid_t guid;
efi_status_t (__efiapi *handler_addr)(u64, void *);
u64 static_data_buffer_addr;
u64 acpi_param_buffer_addr;
struct list_head handler_list;
};
struct prm_module_info {
guid_t guid;
u16 major_rev;
u16 minor_rev;
u16 handler_count;
struct prm_mmio_info *mmio_info;
bool updatable;
struct list_head module_list;
struct prm_handler_info handlers[] __counted_by(handler_count);
};
static u64 efi_pa_va_lookup(u64 pa)
{
efi_memory_desc_t *md;
u64 pa_offset = pa & ~PAGE_MASK;
u64 page = pa & PAGE_MASK;
for_each_efi_memory_desc(md) {
if (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages)
return pa_offset + md->virt_addr + page - md->phys_addr;
}
return 0;
}
#define get_first_handler(a) ((struct acpi_prmt_handler_info *) ((char *) (a) + a->handler_info_offset))
#define get_next_handler(a) ((struct acpi_prmt_handler_info *) (sizeof(struct acpi_prmt_handler_info) + (char *) a))
static int __init
acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
{
struct acpi_prmt_module_info *module_info;
struct acpi_prmt_handler_info *handler_info;
struct prm_handler_info *th;
struct prm_module_info *tm;
u64 *mmio_count;
u64 cur_handler = 0;
u32 module_info_size = 0;
u64 mmio_range_size = 0;
void *temp_mmio;
module_info = (struct acpi_prmt_module_info *) header;
module_info_size = struct_size(tm, handlers, module_info->handler_info_count);
tm = kmalloc(module_info_size, GFP_KERNEL);
if (!tm)
goto parse_prmt_out1;
guid_copy(&tm->guid, (guid_t *) module_info->module_guid);
tm->major_rev = module_info->major_rev;
tm->minor_rev = module_info->minor_rev;
tm->handler_count = module_info->handler_info_count;
tm->updatable = true;
if (module_info->mmio_list_pointer) {
/*
* Each module is associated with a list of addr
* ranges that it can use during the service
*/
mmio_count = (u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB);
if (!mmio_count)
goto parse_prmt_out2;
mmio_range_size = struct_size(tm->mmio_info, addr_ranges, *mmio_count);
tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
if (!tm->mmio_info)
goto parse_prmt_out3;
temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB);
if (!temp_mmio)
goto parse_prmt_out4;
memmove(tm->mmio_info, temp_mmio, mmio_range_size);
} else {
tm->mmio_info = kmalloc(sizeof(*tm->mmio_info), GFP_KERNEL);
if (!tm->mmio_info)
goto parse_prmt_out2;
tm->mmio_info->mmio_count = 0;
}
INIT_LIST_HEAD(&tm->module_list);
list_add(&tm->module_list, &prm_module_list);
handler_info = get_first_handler(module_info);
do {
th = &tm->handlers[cur_handler];
guid_copy(&th->guid, (guid_t *)handler_info->handler_guid);
th->handler_addr = (void *)efi_pa_va_lookup(handler_info->handler_address);
th->static_data_buffer_addr = efi_pa_va_lookup(handler_info->static_data_buffer_address);
th->acpi_param_buffer_addr = efi_pa_va_lookup(handler_info->acpi_param_buffer_address);
} while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));
return 0;
parse_prmt_out4:
kfree(tm->mmio_info);
parse_prmt_out3:
memunmap(mmio_count);
parse_prmt_out2:
kfree(tm);
parse_prmt_out1:
return -ENOMEM;
}
#define GET_MODULE 0
#define GET_HANDLER 1
static void *find_guid_info(const guid_t *guid, u8 mode)
{
struct prm_handler_info *cur_handler;
struct prm_module_info *cur_module;
int i = 0;
list_for_each_entry(cur_module, &prm_module_list, module_list) {
for (i = 0; i < cur_module->handler_count; ++i) {
cur_handler = &cur_module->handlers[i];
if (guid_equal(guid, &cur_handler->guid)) {
if (mode == GET_MODULE)
return (void *)cur_module;
else
return (void *)cur_handler;
}
}
}
return NULL;
}
static struct prm_module_info *find_prm_module(const guid_t *guid)
{
return (struct prm_module_info *)find_guid_info(guid, GET_MODULE);
}
static struct prm_handler_info *find_prm_handler(const guid_t *guid)
{
return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER);
}
/* In-coming PRM commands */
#define PRM_CMD_RUN_SERVICE 0
#define PRM_CMD_START_TRANSACTION 1
#define PRM_CMD_END_TRANSACTION 2
/* statuses that can be passed back to ASL */
#define PRM_HANDLER_SUCCESS 0
#define PRM_HANDLER_ERROR 1
#define INVALID_PRM_COMMAND 2
#define PRM_HANDLER_GUID_NOT_FOUND 3
#define UPDATE_LOCK_ALREADY_HELD 4
#define UPDATE_UNLOCK_WITHOUT_LOCK 5
int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
{
struct prm_handler_info *handler = find_prm_handler(&handler_guid);
struct prm_module_info *module = find_prm_module(&handler_guid);
struct prm_context_buffer context;
efi_status_t status;
if (!module || !handler)
return -ENODEV;
memset(&context, 0, sizeof(context));
ACPI_COPY_NAMESEG(context.signature, "PRMC");
context.identifier = handler->guid;
context.static_data_buffer = handler->static_data_buffer_addr;
context.mmio_ranges = module->mmio_info;
status = efi_call_acpi_prm_handler(handler->handler_addr,
(u64)param_buffer,
&context);
return efi_status_to_err(status);
}
EXPORT_SYMBOL_GPL(acpi_call_prm_handler);
/*
* This is the PlatformRtMechanism opregion space handler.
* @function: indicates the read/write. In fact as the PlatformRtMechanism
* message is driven by command, only write is meaningful.
*
* @addr : not used
* @bits : not used.
* @value : it is an in/out parameter. It points to the PRM message buffer.
* @handler_context: not used
*/
static acpi_status acpi_platformrt_space_handler(u32 function,
acpi_physical_address addr,
u32 bits, acpi_integer *value,
void *handler_context,
void *region_context)
{
struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value);
struct prm_handler_info *handler;
struct prm_module_info *module;
efi_status_t status;
struct prm_context_buffer context;
if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
pr_err_ratelimited("PRM: EFI runtime services no longer available\n");
return AE_NO_HANDLER;
}
/*
* The returned acpi_status will always be AE_OK. Error values will be
* saved in the first byte of the PRM message buffer to be used by ASL.
*/
switch (buffer->prm_cmd) {
case PRM_CMD_RUN_SERVICE:
handler = find_prm_handler(&buffer->handler_guid);
module = find_prm_module(&buffer->handler_guid);
if (!handler || !module)
goto invalid_guid;
ACPI_COPY_NAMESEG(context.signature, "PRMC");
context.revision = 0x0;
context.reserved = 0x0;
context.identifier = handler->guid;
context.static_data_buffer = handler->static_data_buffer_addr;
context.mmio_ranges = module->mmio_info;
status = efi_call_acpi_prm_handler(handler->handler_addr,
handler->acpi_param_buffer_addr,
&context);
if (status == EFI_SUCCESS) {
buffer->prm_status = PRM_HANDLER_SUCCESS;
} else {
buffer->prm_status = PRM_HANDLER_ERROR;
buffer->efi_status = status;
}
break;
case PRM_CMD_START_TRANSACTION:
module = find_prm_module(&buffer->handler_guid);
if (!module)
goto invalid_guid;
if (module->updatable)
module->updatable = false;
else
buffer->prm_status = UPDATE_LOCK_ALREADY_HELD;
break;
case PRM_CMD_END_TRANSACTION:
module = find_prm_module(&buffer->handler_guid);
if (!module)
goto invalid_guid;
if (module->updatable)
buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
else
module->updatable = true;
break;
default:
buffer->prm_status = INVALID_PRM_COMMAND;
break;
}
return AE_OK;
invalid_guid:
buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
return AE_OK;
}
void __init init_prmt(void)
{
struct acpi_table_header *tbl;
acpi_status status;
int mc;
status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
if (ACPI_FAILURE(status))
return;
mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
sizeof (struct acpi_table_prmt_header),
0, acpi_parse_prmt, 0);
acpi_put_table(tbl);
/*
* Return immediately if PRMT table is not present or no PRM module found.
*/
if (mc <= 0)
return;
pr_info("PRM: found %u modules\n", mc);
if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
pr_err("PRM: EFI runtime services unavailable\n");
return;
}
status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
ACPI_ADR_SPACE_PLATFORM_RT,
&acpi_platformrt_space_handler,
NULL, NULL);
if (ACPI_FAILURE(status))
pr_alert("PRM: OperationRegion handler could not be installed\n");
}
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