Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> SVN-Revision: 43095master
parent
cea2b5299b
commit
a76ee3b1d5
@ -1,160 +1,105 @@ |
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MIPS: allow disabling the kernel FPU emulator
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From: Manuel Lauss <manuel.lauss@gmail.com>
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Subject: [RFC PATCH v4 2/2] MIPS: make FPU emulator optional
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Date: Mon, 7 Apr 2014 12:57:04 +0200
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Message-Id: <1396868224-252888-2-git-send-email-manuel.lauss@gmail.com>
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This patch allows turning off the in-kernel Algorithmics
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FPU emulator support, which allows one to save a couple of
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precious blocks on an embedded system.
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This small patch makes the MIPS FPU emulator optional. The kernel
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kills float-users on systems without a hardware FPU by sending a SIGILL.
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Disabling the emulator shrinks vmlinux by about 54kBytes (32bit,
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optimizing for size).
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Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
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---
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v4: rediffed because of patch 1/2, should now work with micromips as well
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v3: updated patch description with size savings.
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v2: incorporated changes suggested by Jonas Gorski
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force the fpu emulator on for micromips: relocating the parts
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of the mmips code in the emulator to other areas would be a
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much larger change; I went the cheap route instead with this.
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arch/mips/Kbuild | 2 +-
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arch/mips/Kconfig | 14 ++++++++++++++
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arch/mips/include/asm/fpu.h | 5 +++--
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arch/mips/include/asm/fpu_emulator.h | 15 +++++++++++++++
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4 files changed, 33 insertions(+), 3 deletions(-)
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Signed-off-by: Florian Fainelli <florian@openwrt.org>
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--
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -934,6 +934,17 @@ config I8259
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config MIPS_BONITO64
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bool
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@@ -2484,6 +2484,20 @@ config MIPS_O32_FP64_SUPPORT
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If unsure, say N.
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+config MIPS_FPU_EMU
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+ bool "Enable FPU emulation"
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+config MIPS_FPU_EMULATOR
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+ bool "MIPS FPU Emulator"
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+ default y
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+ help
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+ This option allows building a kernel with or without the Algorithmics
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+ FPU emulator enabled. Turning off this option results in a kernel which
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+ does not catch floating operations exceptions. Make sure that your toolchain
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+ is configured to enable software floating point emulation in that case.
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+ This option lets you disable the built-in MIPS FPU (Coprocessor 1)
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+ emulator, which handles floating-point instructions on processors
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+ without a hardware FPU. It is generally a good idea to keep the
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+ emulator built-in, unless you are perfectly sure you have a
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+ complete soft-float environment. With the emulator disabled, all
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+ users of float operations will be killed with an illegal instr-
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+ uction exception.
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+
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+ If unsure say Y here.
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+ Say Y, please.
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+
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config MIPS_MSC
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config USE_OF
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bool
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select OF
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--- a/arch/mips/Makefile
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+++ b/arch/mips/Makefile
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@@ -266,7 +266,7 @@ OBJCOPYFLAGS += --remove-section=.regin
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head-y := arch/mips/kernel/head.o
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--- a/arch/mips/math-emu/Makefile
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+++ b/arch/mips/math-emu/Makefile
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@@ -2,10 +2,12 @@
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# Makefile for the Linux/MIPS kernel FPU emulation.
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#
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-obj-y := cp1emu.o ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
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+obj-y := kernel_linkage.o
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+
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+obj-$(CONFIG_MIPS_FPU_EMU) += ieee754m.o ieee754d.o ieee754dp.o ieee754sp.o ieee754.o \
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ieee754xcpt.o dp_frexp.o dp_modf.o dp_div.o dp_mul.o dp_sub.o \
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dp_add.o dp_fsp.o dp_cmp.o dp_logb.o dp_scalb.o dp_simple.o \
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dp_tint.o dp_fint.o dp_tlong.o dp_flong.o sp_frexp.o sp_modf.o \
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sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_logb.o \
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sp_scalb.o sp_simple.o sp_tint.o sp_fint.o sp_tlong.o sp_flong.o \
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- dp_sqrt.o sp_sqrt.o kernel_linkage.o dsemul.o
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+ dp_sqrt.o sp_sqrt.o dsemul.o cp1emu.o
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--- a/arch/mips/math-emu/kernel_linkage.c
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+++ b/arch/mips/math-emu/kernel_linkage.c
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@@ -29,6 +29,7 @@
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libs-y += arch/mips/lib/
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-libs-y += arch/mips/math-emu/
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+libs-$(CONFIG_MIPS_FPU_EMULATOR) += arch/mips/math-emu/
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#define SIGNALLING_NAN 0x7ff800007ff80000LL
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# See arch/mips/Kbuild for content of core part of the kernel
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core-y += arch/mips/
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--- a/arch/mips/include/asm/fpu.h
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+++ b/arch/mips/include/asm/fpu.h
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@@ -168,8 +168,10 @@ static inline int init_fpu(void)
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ret = __own_fpu();
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if (!ret)
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_init_fpu();
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- } else
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+ } else if (IS_ENABLED(CONFIG_MIPS_FPU_EMULATOR))
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fpu_emulator_init_fpu();
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+ else
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+ ret = SIGILL;
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+#ifdef CONFIG_MIPS_FPU_EMU
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void fpu_emulator_init_fpu(void)
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{
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static int first = 1;
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@@ -115,3 +116,36 @@ int fpu_emulator_restore_context32(struc
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return err;
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return ret;
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}
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#endif
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+
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+#else
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+
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+void fpu_emulator_init_fpu(void)
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+{
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+ printk(KERN_INFO "FPU emulator disabled, make sure your toolchain"
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+ "was compiled with software floating point support (soft-float)\n");
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+ return;
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+}
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+
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+int fpu_emulator_save_context(struct sigcontext __user *sc)
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+{
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+ return 0;
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+}
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+
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+int fpu_emulator_restore_context(struct sigcontext __user *sc)
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+{
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+ return 0;
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+}
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+
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+#ifdef CONFIG_64BIT
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+int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
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+{
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+ return 0;
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+}
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+
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+int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
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+{
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+ return 0;
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+}
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+#endif /* CONFIG_64BIT */
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+
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+#endif /* CONFIG_MIPS_FPU_EMU */
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--- a/arch/mips/include/asm/fpu_emulator.h
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+++ b/arch/mips/include/asm/fpu_emulator.h
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@@ -27,6 +27,8 @@
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#include <asm/inst.h>
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@@ -30,6 +30,7 @@
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#include <asm/local.h>
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#include <asm/processor.h>
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+#ifdef CONFIG_MIPS_FPU_EMU
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+
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+#ifdef CONFIG_MIPS_FPU_EMULATOR
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#ifdef CONFIG_DEBUG_FS
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struct mips_fpu_emulator_stats {
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@@ -60,6 +62,38 @@ extern int fpu_emulator_cop1Handler(stru
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int process_fpemu_return(int sig, void __user *fault_addr);
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int mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
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unsigned long *contpc);
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+#else
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+static inline int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
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+ unsigned long cpc)
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+{
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+ return 0;
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+}
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+
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@@ -65,6 +66,20 @@ extern int do_dsemulret(struct pt_regs *
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extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
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struct mips_fpu_struct *ctx, int has_fpu,
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void *__user *fault_addr);
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+#else /* no CONFIG_MIPS_FPU_EMULATOR */
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+static inline int do_dsemulret(struct pt_regs *xcp)
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+{
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+ return 0;
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+ return 0; /* 0 means error, should never get here anyway */
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+}
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+
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+static inline int fpu_emulator_cop1Handler(struct pt_regs *xcp,
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+ struct mips_fpu_struct *ctx,
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+ int has_fpu,
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+ struct mips_fpu_struct *ctx, int has_fpu,
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+ void *__user *fault_addr)
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+{
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+ return 0;
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+}
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+
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+static inline int process_fpemu_return(int sig, void __user *fault_addr)
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+{
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+ return -EINVAL;
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+ return SIGILL; /* we don't speak MIPS FPU */
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+}
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+#endif /* CONFIG_MIPS_FPU_EMULATOR */
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+
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+static inline int mm_isBranchInstr(struct pt_regs *regs,
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+ struct mm_decoded_insn dec_insn,
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+ unsigned long *contpc)
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+{
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+ return 0;
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+}
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+#endif /* CONFIG_MIPS_FPU_EMU */
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/*
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* Instruction inserted following the badinst to further tag the sequence
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--- a/arch/mips/kernel/traps.c
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+++ b/arch/mips/kernel/traps.c
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@@ -701,6 +701,7 @@ asmlinkage void do_ov(struct pt_regs *re
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exception_exit(prev_state);
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}
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+#ifdef CONFIG_MIPS_FPU_EMU
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int process_fpemu_return(int sig, void __user *fault_addr)
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{
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if (sig == SIGSEGV || sig == SIGBUS) {
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@@ -724,6 +725,7 @@ int process_fpemu_return(int sig, void _
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return 0;
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}
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}
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+#endif /* CONFIG_MIPS_FPU_EMU */
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/*
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* XXX Delayed fp exceptions when doing a lazy ctx switch XXX
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int process_fpemu_return(int sig, void __user *fault_addr);
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int mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
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unsigned long *contpc);
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@ -1,122 +0,0 @@ |
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From 90bea5a3f0bf680b87b90516f3c231997f4b8f3b Mon Sep 17 00:00:00 2001
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From: Daniel Golle <daniel@makrotopia.org>
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Date: Mon, 2 Jun 2014 15:51:10 +0200
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X-Git-Url: http://git.infradead.org/linux-ubifs.git/commitdiff_plain/90bea5a3f0bf680b87b90516f3c231997f4b8f3b
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X-Git-Url: https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=90bea5a3f0bf680b87b90516f3c231997f4b8f3b
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Subject: UBIFS: respect MS_SILENT mount flag
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When attempting to mount a non-ubifs formatted volume, lots of error
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messages (including a stack dump) are thrown to the kernel log even if
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the MS_SILENT mount flag is set.
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Fix this by introducing adding an additional state-variable in
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struct ubifs_info and suppress error messages in ubifs_read_node if
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MS_SILENT is set.
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Signed-off-by: Daniel Golle <daniel@makrotopia.org>
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Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
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---
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fs/ubifs/io.c | 18 ++++++++++--------
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fs/ubifs/super.c | 5 +++++
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fs/ubifs/ubifs.h | 11 +++++++++++
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3 files changed, 26 insertions(+), 8 deletions(-)
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---
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--- a/fs/ubifs/io.c
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+++ b/fs/ubifs/io.c
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@@ -988,30 +988,32 @@ int ubifs_read_node(const struct ubifs_i
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return err;
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if (type != ch->node_type) {
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- ubifs_err("bad node type (%d but expected %d)",
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- ch->node_type, type);
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+ ubifs_errc(c, "bad node type (%d but expected %d)",
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+ ch->node_type, type);
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goto out;
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}
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err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
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if (err) {
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- ubifs_err("expected node type %d", type);
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+ ubifs_errc(c, "expected node type %d", type);
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return err;
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}
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l = le32_to_cpu(ch->len);
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if (l != len) {
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- ubifs_err("bad node length %d, expected %d", l, len);
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+ ubifs_errc(c, "bad node length %d, expected %d", l, len);
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goto out;
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}
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return 0;
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out:
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- ubifs_err("bad node at LEB %d:%d, LEB mapping status %d", lnum, offs,
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- ubi_is_mapped(c->ubi, lnum));
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- ubifs_dump_node(c, buf);
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- dump_stack();
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+ ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
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+ offs, ubi_is_mapped(c->ubi, lnum));
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+ if (!c->probing) {
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+ ubifs_dump_node(c, buf);
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+ dump_stack();
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+ }
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return -EINVAL;
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}
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--- a/fs/ubifs/super.c
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+++ b/fs/ubifs/super.c
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@@ -1149,6 +1149,9 @@ static int mount_ubifs(struct ubifs_info
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size_t sz;
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c->ro_mount = !!(c->vfs_sb->s_flags & MS_RDONLY);
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+ /* Suppress error messages while probing if MS_SILENT is set */
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+ c->probing = !!(c->vfs_sb->s_flags & MS_SILENT);
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+
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err = init_constants_early(c);
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if (err)
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return err;
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@@ -1214,6 +1217,8 @@ static int mount_ubifs(struct ubifs_info
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if (err)
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goto out_free;
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+ c->probing = 0;
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+
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/*
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* Make sure the compressor which is set as default in the superblock
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* or overridden by mount options is actually compiled in.
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--- a/fs/ubifs/ubifs.h
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+++ b/fs/ubifs/ubifs.h
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@@ -51,6 +51,15 @@
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#define ubifs_warn(fmt, ...) \
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pr_warn("UBIFS warning (pid %d): %s: " fmt "\n", \
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current->pid, __func__, ##__VA_ARGS__)
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+/*
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+ * A variant of 'ubifs_err()' which takes the UBIFS file-sytem description
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+ * object as an argument.
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+ */
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+#define ubifs_errc(c, fmt, ...) \
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+ do { \
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+ if (!(c)->probing) \
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+ ubifs_err(fmt, ##__VA_ARGS__); \
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+ } while (0)
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/* UBIFS file system VFS magic number */
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#define UBIFS_SUPER_MAGIC 0x24051905
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@@ -1209,6 +1218,7 @@ struct ubifs_debug_info;
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* @need_recovery: %1 if the file-system needs recovery
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* @replaying: %1 during journal replay
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* @mounting: %1 while mounting
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+ * @probing: %1 while attempting to mount if MS_SILENT mount flag is set
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* @remounting_rw: %1 while re-mounting from R/O mode to R/W mode
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* @replay_list: temporary list used during journal replay
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* @replay_buds: list of buds to replay
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@@ -1441,6 +1451,7 @@ struct ubifs_info {
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unsigned int replaying:1;
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unsigned int mounting:1;
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unsigned int remounting_rw:1;
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+ unsigned int probing:1;
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struct list_head replay_list;
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struct list_head replay_buds;
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unsigned long long cs_sqnum;
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Loading…
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