linux-stable.git/arch/mips/include/asm/elf.h, branch linux-4.2.y

MIPS: Fix a preemption issue with thread's FPU defaults

2015-05-12T21:15:49+00:00

Fix "BUG: using smp_processor_id() in preemptible" reported in accesses
to thread's FPU defaults: the value to initialise FSCR to at program
startup, the FCSR r/w mask and the contents of FIR in full FPU
emulation, removing a regression introduced with 9b26616c [MIPS: Respect
the ISA level in FCSR handling] and f6843626 [MIPS: math-emu: Set FIR
feature flags for full emulation].

Use `boot_cpu_data' to obtain the data from, following the approach that
`cpu_has_*' macros take and avoiding the call to `smp_processor_id' made
in the reference to `current_cpu_data'.  The contents of FSCR have to be
consistent across processors in an SMP system, the settings there must
not change as a thread is migrated across processors.  And the contents
of FIR are guaranteed to be consistent in FPU emulation, by definition.

Signed-off-by: Maciej W. Rozycki 
Tested-by: Ezequiel Garcia 
Tested-by: Paul Martin 
Cc: Markos Chandras 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10030/
Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2015-04-17T19:50:54+00:00

Pull MIPS updates from Ralf Baechle:
 "This is the main pull request for MIPS for Linux 4.1.  Most
  noteworthy:

   - Add more Octeon-optimized crypto functions
   - Octeon crypto preemption and locking fixes
   - Little endian support for Octeon
   - Use correct CSR to soft reset Octeons
   - Support LEDs on the Octeon-based DSR-1000N
   - Fix PCI interrupt mapping for the Octeon-based DSR-1000N
   - Mark prom_free_prom_memory() as __init for a number of systems
   - Support for Imagination's Pistachio SOC.  This includes arch and
     CLK bits.  I'd like to merge pinctrl bits later
   - Improve parallelism of csum_partial for certain pipelines
   - Organize DTB files in subdirs like other architectures
   - Implement read_sched_clock for all MIPS platforms other than
     Octeon
   - Massive series of 38 fixes and cleanups for the FPU emulator /
     kernel
   - Further FPU remulator work to support new features.  This sits on a
     separate branch which also has been pulled into the 4.1 KVM branch
   - Clean up and fixes for the SEAD3 eval board; remove unused file
   - Various updates for Netlogic platforms
   - A number of small updates for Loongson 3 platforms
   - Increase the memory limit for ATH79 platforms to 256MB
   - A fair number of fixes and updates for BCM47xx platforms
   - Finish the implementation of XPA support
   - MIPS FDC support.  No, not floppy controller but Fast Debug Channel :)
   - Detect the R16000 used in SGI legacy platforms
   - Fix Kconfig dependencies for the SSB bus support"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (265 commits)
  MIPS: Makefile: Fix MIPS ASE detection code
  MIPS: asm: elf: Set O32 default FPU flags
  MIPS: BCM47XX: Fix detecting Microsoft MN-700 & Asus WL500G
  MIPS: Kconfig: Disable SMP/CPS for 64-bit
  MIPS: Hibernate: flush TLB entries earlier
  MIPS: smp-cps: cpu_set FPU mask if FPU present
  MIPS: lose_fpu(): Disable FPU when MSA enabled
  MIPS: ralink: add missing symbol for RALINK_ILL_ACC
  MIPS: ralink: Fix bad config symbol in PCI makefile.
  SSB: fix Kconfig dependencies
  MIPS: Malta: Detect and fix bad memsize values
  Revert "MIPS: Avoid pipeline stalls on some MIPS32R2 cores."
  MIPS: Octeon: Delete override of cpu_has_mips_r2_exec_hazard.
  MIPS: Fix cpu_has_mips_r2_exec_hazard.
  MIPS: kernel: entry.S: Set correct ISA level for mips_ihb
  MIPS: asm: spinlock: Fix addiu instruction for R10000_LLSC_WAR case
  MIPS: r4kcache: Use correct base register for MIPS R6 cache flushes
  MIPS: Kconfig: Fix typo for the r2-to-r6 emulator kernel parameter
  MIPS: unaligned: Fix regular load/store instruction emulation for EVA
  MIPS: unaligned: Surround load/store macros in do {} while statements
  ...

mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE

2015-04-14T23:49:05+00:00

The arch_randomize_brk() function is used on several architectures,
even those that don't support ET_DYN ASLR. To avoid bulky extern/#define
tricks, consolidate the support under CONFIG_ARCH_HAS_ELF_RANDOMIZE for
the architectures that support it, while still handling CONFIG_COMPAT_BRK.

Signed-off-by: Kees Cook 
Cc: Hector Marco-Gisbert 
Cc: Russell King 
Reviewed-by: Ingo Molnar 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Alexander Viro 
Cc: Oleg Nesterov 
Cc: Andy Lutomirski 
Cc: "David A. Long" 
Cc: Andrey Ryabinin 
Cc: Arun Chandran 
Cc: Yann Droneaud 
Cc: Min-Hua Chen 
Cc: Paul Burton 
Cc: Alex Smith 
Cc: Markos Chandras 
Cc: Vineeth Vijayan 
Cc: Jeff Bailey 
Cc: Michael Holzheu 
Cc: Ben Hutchings 
Cc: Behan Webster 
Cc: Ismael Ripoll 
Cc: Jan-Simon Mller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch '4.0-fixes' into mips-for-linux-next

2015-04-13T14:03:32+00:00

MIPS: asm: elf: Set O32 default FPU flags

2015-04-10T13:41:54+00:00

Set good default FPU flags (FR0) for O32 binaries similar to what the
kernel does for the N64/N32 ones. This also fixes a regression
introduced in commit 46490b572544 ("MIPS: kernel: elf: Improve the
overall ABI and FPU mode checks") when MIPS_O32_FP64_SUPPORT is
disabled. In that case, the mips_set_personality_fp() did not set the
FPU mode at all because it assumed that the FPU mode was already set
properly. That led to O32 userland problems.

Signed-off-by: Markos Chandras 
Reported-by: Mans Rullgard 
Fixes: 46490b572544 ("MIPS: kernel: elf: Improve the overall ABI and FPU mode checks")
Tested-by: Mans Rullgard 
Tested-by: Aaro Koskinen 
Cc: Matthew Fortune 
Cc: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/9344/
Signed-off-by: Ralf Baechle

MIPS: Respect the ISA level in FCSR handling

2015-04-07T23:10:37+00:00

Define the central place the default FCSR value is set from, initialised
in `cpu_probe'.  Determine the FCSR mask applied to values written to
the register with CTC1 in the full emulation mode and via ptrace(2),
according to the ISA level of processor hardware or the writability of
bits 31:18 if actual FPU hardware is used.

Software may rely on FCSR bits whose functions our emulator does not
implement, so it should not allow them to be set or software may get
confused.  For ptrace(2) it's just sanity.

[ralf@linux-mips.org: Fixed double inclusion of .]

Signed-off-by: Maciej W. Rozycki 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9711/
Signed-off-by: Ralf Baechle

MIPS: kernel: elf: Improve the overall ABI and FPU mode checks

2015-02-17T15:37:39+00:00

The previous implementation did not cover all possible FPU combinations
and it silently allowed ABI incompatible objects to be loaded with the
wrong ABI. For example, the previous logic would set the FP_64 ABI as
the matching ABI for an FP_XX object combined with an FP_64A object.
This was wrong, and the matching ABI should have been FP_64A.
The previous logic is now replaced with a new one which determines
the appropriate FPU mode to be used rather than the FP ABI. This has
the advantage that the entire logic is much simpler since it is the FPU
mode we are interested in rather than the FP ABI resulting to code
simplifications. This also removes the now obsolete FP32XX_HYBRID_FPRS
option.

Cc: Matthew Fortune 
Cc: Paul Burton 
Signed-off-by: Markos Chandras

MIPS: ELF: Set FP mode according to .MIPS.abiflags

2014-11-24T06:45:07+00:00

This patch reads the .MIPS.abiflags section when it is present, and sets
the FP mode of the task accordingly. Any loaded ELF files which do not
contain a .MIPS.abiflags section will continue to observe the previous
behaviour, that is FR=1 if EF_MIPS_FP64 is set else FR=0.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro 
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7681/
Signed-off-by: Ralf Baechle

MIPS: ELF: Add definition for the .MIPS.abiflags section

2014-11-24T06:45:07+00:00

New toolchains will generate a .MIPS.abiflags section, referenced by a
new PT_MIPS_ABIFLAGS program header. This section will provide
information about the requirements of the ELF, including the ISA level
the code is built for, the ASEs it requires, the size of various
registers and its expectations of the floating point mode. This patch
introduces a definition of the structure of this section and the program
header, for use in a subsequent patch.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro 
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7682/
Signed-off-by: Ralf Baechle

MIPS: Support for hybrid FPRs

2014-11-24T06:45:07+00:00

Hybrid FPRs is a scheme where scalar FP registers are 64b wide, but
accesses to odd indexed single registers use bits 63:32 of the
preceeding even indexed 64b register. In this mode all FP code
except that built for the plain FP64 ABI can execute correctly. Most
notably a combination of FP64A & FP32 code can execute correctly,
allowing for existing FP32 binaries to be linked with new FP64A binaries
that can make use of 64 bit FP & MSA.

Hybrid FPRs are implemented by setting both the FR & FRE bits, trapping
& emulating single precision FP instructions (via Reserved Instruction
exceptions) whilst allowing others to execute natively. It therefore has
a penalty in terms of execution speed, and should only be used when no
fully native mode can be. As more binaries are recompiled to use either
the FPXX or FP64(A) ABIs, the need for hybrid FPRs should diminish.
However in the short to mid term it allows for a gradual transition
towards that world, rather than a complete ABI break which is not
feasible for some users & not desirable for many.

A task will be executed using the hybrid FPR scheme when its
TIF_HYBRID_FPREGS flag is set & TIF_32BIT_FPREGS is clear. A further
patch will set the flags as necessary, this patch simply adds the
infrastructure necessary for the hybrid FPR mode to work.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro 
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7683/
Signed-off-by: Ralf Baechle