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  1. 21 2月, 2012 8 次提交
  3. 20 2月, 2012 1 次提交
    • D
      Wrap accesses to the fd_sets in struct fdtable · 1dce27c5
      由 David Howells 提交于 
      Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.

The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.

This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:

	void __set_close_on_exec(int fd, struct fdtable *fdt);
	void __clear_close_on_exec(int fd, struct fdtable *fdt);
	bool close_on_exec(int fd, const struct fdtable *fdt);
	void __set_open_fd(int fd, struct fdtable *fdt);
	void __clear_open_fd(int fd, struct fdtable *fdt);
	bool fd_is_open(int fd, const struct fdtable *fdt);

Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.

Note also that I haven't added wrappers for looking behind the scenes at the
the array.  Possibly that should exist too.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.ukSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
      1dce27c5
  5. 15 2月, 2012 18 次提交
  7. 05 2月, 2012 2 次提交
  9. 04 2月, 2012 2 次提交
  11. 03 2月, 2012 7 次提交
    • W
      ARM: 7314/1: kuser: consistently use usr_ret for returning from helpers · 5a97d0ae
      由 Will Deacon 提交于 
      __kuser_cmpxchg64 has a return path using bx lr to get back to the caller.
This is actually ok since the code in question is predicated on
CONFIG_CPU_32v6K, but for the sake of consistency using the usr_ret
macro is probably better.
Acked-by: NDave Martin <dave.martin@linaro.org>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      5a97d0ae
    • C
      ARM: 7302/1: Add TLB flushing for both entries in a PMD · 6d3ec1ae
      由 Catalin Marinas 提交于 
      Linux uses two PMD entries for a PTE with the classic page table format,
covering 2MB range. However, the __pte_free_tlb() function only adds a
single TLB flush corresponding to 1MB range covering 'addr'. On
Cortex-A15, level 1 entries can be cached by the TLB independently of
the level 2 entries and without additional flushing a PMD entry would be
left pointing at the wrong PTE. The patch limits the TLB flushing range
to two 4KB pages around the 1MB boundary within PMD.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      6d3ec1ae
    • W
      ARM: 7303/1: perf: add empty NODE event definitions for Cortex-A5 and Cortex-A15 · 91756acb
      由 Will Deacon 提交于 
      Commit 89d6c0b5 ("perf, arch: Add generic NODE cache events") added
empty NODE event definitions for the ARM PMU implementations. This was
merged along with Cortex-A5 and Cortex-A15 PMU support, so they missed
out on the original patch.

This patch adds the empty definitions to Cortex-A5 and Cortex-A15.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      91756acb
    • W
      ARM: 7308/1: vfp: flush thread hwstate before copying ptrace registers · 8130b9d7
      由 Will Deacon 提交于 
      If we are context switched whilst copying into a thread's
vfp_hard_struct then the partial copy may be corrupted by the VFP
context switching code (see "ARM: vfp: flush thread hwstate before
restoring context from sigframe").

This patch updates the ptrace VFP set code so that the thread state is
flushed before the copy, therefore disabling VFP and preventing
corruption from occurring.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      8130b9d7
    • D
      ARM: 7307/1: vfp: fix ptrace regset modification race · 247f4993
      由 Dave Martin 提交于 
      In a preemptible kernel, vfp_set() can be preempted, causing the
hardware VFP context to be switched while the thread vfp state is
being read and modified.  This leads to a race condition which can
cause the thread vfp state to become corrupted if lazy VFP context
save occurs due to preemption in between the time thread->vfpstate
is read and the time the modified state is written back.

This may occur if preemption occurs during the execution of a
ptrace() call which modifies the VFP register state of a thread.
Such instances should be very rare in most realistic scenarios --
none has been reported, so far as I am aware.  Only uniprocessor
systems should be affected, since VFP context save is not currently
lazy in SMP kernels.

The problem was introduced by my earlier patch migrating to use
regsets to implement ptrace.

This patch does a vfp_sync_hwstate() before reading
thread->vfpstate, to make sure that the thread's VFP state is not
live in the hardware registers while the registers are modified.

Thanks to Will Deacon for spotting this.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      247f4993
    • W
      ARM: 7306/1: vfp: flush thread hwstate before restoring context from sigframe · 2af276df
      由 Will Deacon 提交于 
      Following execution of a signal handler, we currently restore the VFP
context from the ucontext in the signal frame. This involves copying
from the user stack into the current thread's vfp_hard_struct and then
flushing the new data out to the hardware registers.

This is problematic when using a preemptible kernel because we could be
context switched whilst updating the vfp_hard_struct. If the current
thread has made use of VFP since the last context switch, the VFP
notifier will copy from the hardware registers into the vfp_hard_struct,
overwriting any data that had been partially copied by the signal code.

Disabling preemption across copy_from_user calls is a terrible idea, so
instead we move the VFP thread flush *before* we update the
vfp_hard_struct. Since the flushing is performed lazily, this has the
effect of disabling VFP and clearing the CPU's VFP state pointer,
therefore preventing the thread from being updated with stale data on
the next context switch.

Cc: stable <stable@vger.kernel.org>
Tested-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      2af276df
    • R
      Revert "ARM: 7304/1: ioremap: fix boundary check when reusing static mapping" · 97f10409
      由 Russell King 提交于 
      This reverts commit 3c424f35.

Joachim Eastwood reports:
| "ARM: 7304/1: ioremap: fix boundary check when reusing static mapping"
| Commit: 3c424f35 in Linus master
|
| Breaks booting on my custom AT91RM9200 board.
| There isn't any error messages or anything that indicates what goes
| wrong it just stops after; Uncompressing Linux... done, booting the
| kernel.
|
| Reverting it makes my board boot again.

and further debugging reveals:

ioremap: pfn=fffff phys=fffff000 offset=400 size=1000
ioremap: area c3ffdfc0: phys_addr=200000 pfn=200 size=4000
ioremap: found: addr fef74000 => fed73000 => fed73400

Clearly, an area for pfn 0x200, 16K can't ever satisfy a request for pfn
0xfffff.  This happens because the changed if statement becomes:

                if (0x00200 > 0xfffff ||
                    0xfffff000 + 0x400 + 0x1000-1 > 0x00200000 + 0x4000-1)
and therefore:
                if (0x00200 > 0xfffff ||
                    0x000003ff > 0x00203fff)

The if condition fails, and so we _believe_ that the SRAM mapping fits
our request.  Clearly that's totally bogus.

Moreover, the original premise of the 'fix' patch was wrong:
|    The condition checking boundaries of the requested and existing
|    mappings didn't take in-page offset into consideration though,
|    which lead to obscure and hard to debug problems when requested
|    mapping crossed end of the static one.

as the code immediately above this loop does:

        size = PAGE_ALIGN(offset + size);

so 'size' already contains the requested offset into the page.

So, revert the broken 'fix'.
Acked-by: NNicolas Pitre <nico@linaro.org>
      97f10409
  13. 02 2月, 2012 2 次提交