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path: root/drivers/char/tpm/tpm_ppi.c
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Diffstat (limited to 'drivers/char/tpm/tpm_ppi.c')
-rw-r--r--drivers/char/tpm/tpm_ppi.c137
1 files changed, 89 insertions, 48 deletions
diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index bc7b1b4501b3..c9793a3d986d 100644
--- a/drivers/char/tpm/tpm_ppi.c
+++ b/drivers/char/tpm/tpm_ppi.c
@@ -33,6 +33,20 @@ static const guid_t tpm_ppi_guid =
GUID_INIT(0x3DDDFAA6, 0x361B, 0x4EB4,
0xA4, 0x24, 0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53);
+static const char * const tpm_ppi_info[] = {
+ "Not implemented",
+ "BIOS only",
+ "Blocked for OS by system firmware",
+ "User required",
+ "User not required",
+};
+
+/* A spinlock to protect access to the cache from concurrent reads */
+static DEFINE_MUTEX(tpm_ppi_lock);
+
+static u32 ppi_operations_cache[PPI_VS_REQ_END + 1];
+static bool ppi_cache_populated;
+
static bool tpm_ppi_req_has_parameter(u64 req)
{
return req == 23;
@@ -52,7 +66,7 @@ static ssize_t tpm_show_ppi_version(struct device *dev,
{
struct tpm_chip *chip = to_tpm_chip(dev);
- return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
+ return sysfs_emit(buf, "%s\n", chip->ppi_version);
}
static ssize_t tpm_show_ppi_request(struct device *dev,
@@ -87,12 +101,10 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
else {
req = obj->package.elements[1].integer.value;
if (tpm_ppi_req_has_parameter(req))
- size = scnprintf(buf, PAGE_SIZE,
- "%llu %llu\n", req,
- obj->package.elements[2].integer.value);
+ size = sysfs_emit(buf, "%llu %llu\n", req,
+ obj->package.elements[2].integer.value);
else
- size = scnprintf(buf, PAGE_SIZE,
- "%llu\n", req);
+ size = sysfs_emit(buf, "%llu\n", req);
}
} else if (obj->package.count == 2 &&
obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
@@ -100,8 +112,8 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
if (obj->package.elements[0].integer.value)
size = -EFAULT;
else
- size = scnprintf(buf, PAGE_SIZE, "%llu\n",
- obj->package.elements[1].integer.value);
+ size = sysfs_emit(buf, "%llu\n",
+ obj->package.elements[1].integer.value);
}
ACPI_FREE(obj);
@@ -211,10 +223,10 @@ static ssize_t tpm_show_ppi_transition_action(struct device *dev,
}
if (ret < ARRAY_SIZE(info) - 1)
- status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
+ status = sysfs_emit(buf, "%d: %s\n", ret, info[ret]);
else
- status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
- info[ARRAY_SIZE(info)-1]);
+ status = sysfs_emit(buf, "%d: %s\n", ret,
+ info[ARRAY_SIZE(info) - 1]);
return status;
}
@@ -255,23 +267,23 @@ static ssize_t tpm_show_ppi_response(struct device *dev,
res = ret_obj[2].integer.value;
if (req) {
if (res == 0)
- status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
- "0: Success");
+ status = sysfs_emit(buf, "%llu %s\n", req,
+ "0: Success");
else if (res == 0xFFFFFFF0)
- status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
- "0xFFFFFFF0: User Abort");
+ status = sysfs_emit(buf, "%llu %s\n", req,
+ "0xFFFFFFF0: User Abort");
else if (res == 0xFFFFFFF1)
- status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
- "0xFFFFFFF1: BIOS Failure");
+ status = sysfs_emit(buf, "%llu %s\n", req,
+ "0xFFFFFFF1: BIOS Failure");
else if (res >= 1 && res <= 0x00000FFF)
- status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
- req, res, "Corresponding TPM error");
+ status = sysfs_emit(buf, "%llu %llu: %s\n",
+ req, res, "Corresponding TPM error");
else
- status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
- req, res, "Error");
+ status = sysfs_emit(buf, "%llu %llu: %s\n",
+ req, res, "Error");
} else {
- status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
- req, "No Recent Request");
+ status = sysfs_emit(buf, "%llu: %s\n",
+ req, "No Recent Request");
}
cleanup:
@@ -279,46 +291,33 @@ cleanup:
return status;
}
-static ssize_t show_ppi_operations(acpi_handle dev_handle, char *buf, u32 start,
- u32 end)
+static ssize_t cache_ppi_operations(acpi_handle dev_handle, char *buf)
{
int i;
u32 ret;
- char *str = buf;
+ int len = 0;
union acpi_object *obj, tmp;
union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
- static char *info[] = {
- "Not implemented",
- "BIOS only",
- "Blocked for OS by BIOS",
- "User required",
- "User not required",
- };
-
if (!acpi_check_dsm(dev_handle, &tpm_ppi_guid, TPM_PPI_REVISION_ID_1,
1 << TPM_PPI_FN_GETOPR))
return -EPERM;
tmp.integer.type = ACPI_TYPE_INTEGER;
- for (i = start; i <= end; i++) {
+ for (i = 0; i <= PPI_VS_REQ_END; i++) {
tmp.integer.value = i;
obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
ACPI_TYPE_INTEGER, &argv,
TPM_PPI_REVISION_ID_1);
- if (!obj) {
+ if (!obj)
return -ENOMEM;
- } else {
- ret = obj->integer.value;
- ACPI_FREE(obj);
- }
- if (ret > 0 && ret < ARRAY_SIZE(info))
- str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
- i, ret, info[ret]);
+ ret = obj->integer.value;
+ ppi_operations_cache[i] = ret;
+ ACPI_FREE(obj);
}
- return str - buf;
+ return len;
}
static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
@@ -326,9 +325,30 @@ static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
char *buf)
{
struct tpm_chip *chip = to_tpm_chip(dev);
+ ssize_t len = 0;
+ u32 ret;
+ int i;
+
+ mutex_lock(&tpm_ppi_lock);
+ if (!ppi_cache_populated) {
+ len = cache_ppi_operations(chip->acpi_dev_handle, buf);
+ if (len < 0) {
+ mutex_unlock(&tpm_ppi_lock);
+ return len;
+ }
+
+ ppi_cache_populated = true;
+ }
- return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
- PPI_TPM_REQ_MAX);
+ for (i = 0; i <= PPI_TPM_REQ_MAX; i++) {
+ ret = ppi_operations_cache[i];
+ if (ret >= 0 && ret < ARRAY_SIZE(tpm_ppi_info))
+ len += sysfs_emit_at(buf, len, "%d %d: %s\n",
+ i, ret, tpm_ppi_info[ret]);
+ }
+ mutex_unlock(&tpm_ppi_lock);
+
+ return len;
}
static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
@@ -336,9 +356,30 @@ static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
char *buf)
{
struct tpm_chip *chip = to_tpm_chip(dev);
+ ssize_t len = 0;
+ u32 ret;
+ int i;
+
+ mutex_lock(&tpm_ppi_lock);
+ if (!ppi_cache_populated) {
+ len = cache_ppi_operations(chip->acpi_dev_handle, buf);
+ if (len < 0) {
+ mutex_unlock(&tpm_ppi_lock);
+ return len;
+ }
+
+ ppi_cache_populated = true;
+ }
+
+ for (i = PPI_VS_REQ_START; i <= PPI_VS_REQ_END; i++) {
+ ret = ppi_operations_cache[i];
+ if (ret >= 0 && ret < ARRAY_SIZE(tpm_ppi_info))
+ len += sysfs_emit_at(buf, len, "%d %d: %s\n",
+ i, ret, tpm_ppi_info[ret]);
+ }
+ mutex_unlock(&tpm_ppi_lock);
- return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
- PPI_VS_REQ_END);
+ return len;
}
static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
generated by cgit (git 2.34.1) at 2025-12-25 06:30:25 +0000