linux-kernel - [PATCH v8 0/5] riscv: Add support to no-FPU systems

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 9 Oct 2018 10:18:29 +0800
From:   Alan Kao <alankao@...estech.com>
To:     Palmer Dabbelt <palmer@...ive.com>,
        <linux-riscv@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        Christoph Hellwig <hch@....de>
CC:     Greentime Hu <greentime@...estech.com>,
        Vincent Chen <vincentc@...estech.com>,
        Zong Li <zong@...estech.com>, Nick Hu <nickhu@...estech.com>,
        Alan Kao <alankao@...estech.com>
Subject: [PATCH v8 0/5] riscv: Add support to no-FPU systems

This patchset adds an option, CONFIG_FPU, to enable/disable floating-
point procedures.

Kernel's new behavior will be as follows:

* with CONFIG_FPU=y
  All FPU codes are reserved.  If no FPU is found during booting, a
  global flag will be set, and those functions will be bypassed with
  condition check to that flag.

* with CONFIG_FPU=n
  No floating-point instructions in kernel and all related settings
  are excluded.

Changes in v8:
 - Fix a build fail introduced in v7.

Changes in v7:
 - Remove "fd" attribute from KBUILD_CFLAGS.

Changes in v6 (PATCH 0005 only):
 - Make the flag checking neater.

Changes in v5:
 - Invert the polarity of checking flag from no_fpu to has_fpu.

Changes in v4:
 - Append a new patch to detect existence of FPU and followups.
 - Add SPDX header to newly created fpu.S.
 - Fix a build error, sorry for that.
 - Fix wording, style, etc.

Changes in v3:
 - Refactor the whole patch into independent ones.

Changes in v2:
 - Various code cleanups and style fixes.

Alan Kao (5):
  Extract FPU context operations from entry.S
  Refactor FPU code in signal setup/return procedures
  Cleanup ISA string setting
  Allow to disable FPU support
  Auto-detect whether a FPU exists

 arch/riscv/Kconfig                 |   9 ++++
 arch/riscv/Makefile                |  19 +++----
 arch/riscv/include/asm/switch_to.h |  12 ++++-
 arch/riscv/kernel/Makefile         |   1 +
 arch/riscv/kernel/cpufeature.c     |   8 +++
 arch/riscv/kernel/entry.S          |  87 ------------------------------
 arch/riscv/kernel/fpu.S            | 106 +++++++++++++++++++++++++++++++++++++
 arch/riscv/kernel/process.c        |   6 ++-
 arch/riscv/kernel/signal.c         |  75 ++++++++++++++++----------
 9 files changed, 196 insertions(+), 127 deletions(-)
 create mode 100644 arch/riscv/kernel/fpu.S

-- 
2.7.4