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Subject[PATCH v2 1/3] efi: Add a generic helper to convert strings to unicode
Date
Currently both efi-pstore and efibc rely in simple for-loops to convert
from regular char pointers to u16/unicode strings; so let's export this
functionality as a helper to common EFI code to prevent code duplication.
This helper will also be used in a subsequent patch (adding a new module).

Notice that efi-pstore didn't write the end NULL char in the unicode
string before this patch, but this should not change anything in a
relevant way for this module - other than that, no functional change is
expected.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
---
drivers/firmware/efi/efi-pstore.c | 4 +---
drivers/firmware/efi/efibc.c | 9 ++++-----
include/linux/efi.h | 17 +++++++++++++++++
3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 3bddc152fcd4..965a4c0d6e60 100644
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -167,7 +167,6 @@ static int efi_pstore_write(struct pstore_record *record)
char name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
efi_status_t status;
- int i;

record->id = generic_id(record->time.tv_sec, record->part,
record->count);
@@ -180,8 +179,7 @@ static int efi_pstore_write(struct pstore_record *record)
(long long)record->time.tv_sec,
record->compressed ? 'C' : 'D');

- for (i = 0; i < DUMP_NAME_LEN; i++)
- efi_name[i] = name[i];
+ efi_str8_to_str16(efi_name, name, DUMP_NAME_LEN - 1);

if (efivar_trylock())
return -EBUSY;
diff --git a/drivers/firmware/efi/efibc.c b/drivers/firmware/efi/efibc.c
index 8ced7af8e56d..7e3bf60d24e0 100644
--- a/drivers/firmware/efi/efibc.c
+++ b/drivers/firmware/efi/efibc.c
@@ -39,7 +39,7 @@ static int efibc_reboot_notifier_call(struct notifier_block *notifier,
: L"shutdown";
const u8 *str = data;
efi_char16_t *wdata;
- unsigned long l;
+ size_t len;
int ret;

ret = efibc_set_variable(L"LoaderEntryRebootReason", reason,
@@ -48,11 +48,10 @@ static int efibc_reboot_notifier_call(struct notifier_block *notifier,
return NOTIFY_DONE;

wdata = kmalloc(MAX_DATA_LEN * sizeof(efi_char16_t), GFP_KERNEL);
- for (l = 0; l < MAX_DATA_LEN - 1 && str[l] != '\0'; l++)
- wdata[l] = str[l];
- wdata[l] = L'\0';

- efibc_set_variable(L"LoaderEntryOneShot", wdata, l);
+ len = efi_str8_to_str16(wdata, str, MAX_DATA_LEN - 1);
+
+ efibc_set_variable(L"LoaderEntryOneShot", wdata, len);

kfree(wdata);
return NOTIFY_DONE;
diff --git a/include/linux/efi.h b/include/linux/efi.h
index d2b84c2fec39..c0ea01be3772 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1030,6 +1030,23 @@ struct efivars {

#define EFI_VAR_NAME_LEN 1024

+/*
+ * Helper that converts regular char buffer to u16 unicode-like strings;
+ * notice that the unicode buffer requires to be at least len+1 in size.
+ */
+static inline size_t
+efi_str8_to_str16(efi_char16_t *str16, const char *str8, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len && str8[i] != '\0'; i++)
+ str16[i] = str8[i];
+
+ str16[i] = L'\0';
+
+ return i;
+}
+
int efivars_register(struct efivars *efivars,
const struct efivar_operations *ops,
struct kobject *kobject);
--
2.37.1
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