From: Ard Biesheuvel <ardb@kernel.org>
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 0/7] efi/libstub: Avoid UTF-16 conversion busywork
Date: Sun, 6 Sep 2026 15:08:18 +0200 [thread overview]
Message-ID: <20260906130817.1151961-9-ardb@kernel.org> (raw)
The EFI libstub performs some redundant conversions between UTF-16 and
UTF-8 and back again, which includes dealing with surrogate pairs, which
UEFI implementations themselves simply ignore.
So drop all the homegrown code, and use the existing UCS-2 (== UTF-16
without surrogate pairs) library code where conversion to UTF-8 is
actually needed (the kernel command line).
The remaining handling involves the EFI console, which supports wide
characters natively, so just use those directly.
Cc: Vincent Mailhol <mailhol@kernel.org>
Cc: x86@kernel.org
Ard Biesheuvel (7):
x86/boot: Drop pointless re-implementation of panic()
lib/ucs2_string: Avoid WARN in library code
efi/libstub: Use ucs2_string library for UTF-16 to UTF-8 conversion
efi/libstub: Avoid efi_puts() for compile time constant strings
efi/libstub: Output UTF-16 directly from vsnprintf()
efi/libstub: Add support for printing human readable GUIDs
efi/libstub: Add efi_snprintf() to construct wide strings
arch/x86/boot/compressed/error.c | 19 ---
arch/x86/boot/compressed/error.h | 1 -
arch/x86/boot/compressed/mem.c | 2 +-
drivers/firmware/efi/libstub/Makefile | 3 +-
drivers/firmware/efi/libstub/efi-stub-helper.c | 59 +++-----
drivers/firmware/efi/libstub/efistub.h | 6 +-
drivers/firmware/efi/libstub/gop.c | 6 +-
drivers/firmware/efi/libstub/printk.c | 93 ++----------
drivers/firmware/efi/libstub/vsprintf.c | 148 +++++++-------------
lib/ucs2_string.c | 2 +-
10 files changed, 87 insertions(+), 252 deletions(-)
--
2.47.3
next reply other threads:[~2026-09-06 13:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-06 13:08 Ard Biesheuvel [this message]
2026-09-06 13:08 ` [PATCH 1/7] x86/boot: Drop pointless re-implementation of panic() Ard Biesheuvel
2026-09-06 13:08 ` [PATCH 2/7] lib/ucs2_string: Avoid WARN in library code Ard Biesheuvel
2026-09-06 13:08 ` [PATCH 3/7] efi/libstub: Use ucs2_string library for UTF-16 to UTF-8 conversion Ard Biesheuvel
2026-09-06 13:08 ` [PATCH 4/7] efi/libstub: Avoid efi_puts() for compile time constant strings Ard Biesheuvel
2026-09-06 13:08 ` [PATCH 5/7] efi/libstub: Output UTF-16 directly from vsnprintf() Ard Biesheuvel
2026-09-09 12:46 ` David Laight
2026-09-06 13:08 ` [PATCH 6/7] efi/libstub: Add support for printing human readable GUIDs Ard Biesheuvel
2026-09-06 13:08 ` [PATCH 7/7] efi/libstub: Add efi_snprintf() to construct wide strings Ard Biesheuvel
2026-09-06 22:14 ` [PATCH 0/7] efi/libstub: Avoid UTF-16 conversion busywork Vincent Mailhol
2026-09-08 17:24 ` [PATCH] efi: pass NUL-inclusive sizes to ucs2_as_utf8() Vincent Mailhol
2026-09-09 11:38 ` Ard Biesheuvel
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