From: Ard Biesheuvel <ardb+git@google.com>
To: linux-efi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Vincent Mailhol <mailhol@kernel.org>,
x86@kernel.org
Subject: [PATCH v2 09/10] efi/libstub: Add efi_snprintf() to construct wide strings
Date: Wed, 9 Sep 2026 13:55:40 +0200 [thread overview]
Message-ID: <20260909115530.1924665-21-ardb+git@google.com> (raw)
In-Reply-To: <20260909115530.1924665-12-ardb+git@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
The native EFI character set is UTF-16 (or in practice, UCS-2).
Implement efi_snprintf() to construct UTF-16 strings using printf style
templates. This will be used in a subsequent patch to set the
LoaderDevicePartUUID EFI variable.
Link: https://lore.kernel.org/all/20260903-efi_stub_bli-v2-1-dbf7ba915117@kernel.org/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
drivers/firmware/efi/libstub/efistub.h | 1 +
drivers/firmware/efi/libstub/vsprintf.c | 11 +++++++++++
2 files changed, 12 insertions(+)
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 36056c624782..880c1d0c464b 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -1084,6 +1084,7 @@ int efi_vsnprintf(efi_char16_t *buf, size_t size, const char *fmt, va_list ap,
bool crlf);
__printf(1, 2) int efi_printk(char const *fmt, ...);
+__printf(3, 4) int efi_snprintf(efi_char16_t *buf, size_t size, const char *fmt, ...);
void efi_free(unsigned long size, unsigned long addr);
DEFINE_FREE(efi_pool, void *, if (_T) efi_bs_call(free_pool, _T));
diff --git a/drivers/firmware/efi/libstub/vsprintf.c b/drivers/firmware/efi/libstub/vsprintf.c
index 7f6b891a338a..34a19495dace 100644
--- a/drivers/firmware/efi/libstub/vsprintf.c
+++ b/drivers/firmware/efi/libstub/vsprintf.c
@@ -509,3 +509,14 @@ int efi_vsnprintf(efi_char16_t *buf, size_t size, const char *fmt, va_list ap,
return pos;
}
+
+int efi_snprintf(efi_char16_t *buf, size_t size, const char *fmt, ...)
+{
+ va_list args;
+ int i;
+
+ va_start(args, fmt);
+ i = efi_vsnprintf(buf, size, fmt, args, false);
+ va_end(args);
+ return i;
+}
--
2.55.0.1003.g10538fe699-goog
next prev parent reply other threads:[~2026-09-09 11:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 11:55 [PATCH v2 00/10] efi/libstub: Avoid UTF-16 conversion busywork Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 01/10] x86/boot: Drop pointless re-implementation of panic() Ard Biesheuvel
2026-09-09 19:14 ` Borislav Petkov
2026-09-09 20:43 ` Ard Biesheuvel
2026-09-10 13:12 ` Kiryl Shutsemau
2026-09-11 7:32 ` Ard Biesheuvel
2026-09-12 6:10 ` Borislav Petkov
2026-09-12 8:41 ` Ard Biesheuvel
2026-09-12 17:54 ` Borislav Petkov
2026-09-13 16:35 ` Ard Biesheuvel
2026-09-13 18:11 ` Borislav Petkov
2026-09-09 11:55 ` [PATCH v2 02/10] lib/ucs2_string: Drop arbitrary input size limit and associated WARN() Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 03/10] lib/ucs2_string: Suppress modinfo when __DISABLE_EXPORTS is set Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 04/10] lib/ucs2_string: Split out ucs2_as_utf8_l() taking a separate limit Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 05/10] efi/libstub: Use ucs2_string library for UTF-16 to UTF-8 conversion Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 06/10] efi/libstub: Avoid efi_puts() for compile time constant strings Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 07/10] efi/libstub: Output UTF-16 directly from vsnprintf() Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 08/10] efi/libstub: Add support for printing human readable GUIDs Ard Biesheuvel
2026-09-09 11:55 ` Ard Biesheuvel [this message]
2026-09-09 11:55 ` [PATCH v2 10/10] efi/libstub: add initial Boot Loader Interface support Ard Biesheuvel
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