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  1. Aug 13, 2015
  3. Aug 05, 2015
  5. Jul 31, 2015
    • Andy Lutomirski's avatar
      x86/ldt: Make modify_ldt synchronous · 37868fe1
      Andy Lutomirski authored 
      

modify_ldt() has questionable locking and does not synchronize
threads.  Improve it: redesign the locking and synchronize all
threads' LDTs using an IPI on all modifications.

This will dramatically slow down modify_ldt in multithreaded
programs, but there shouldn't be any multithreaded programs that
care about modify_ldt's performance in the first place.

This fixes some fallout from the CVE-2015-5157 fixes.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: security@kernel.org <security@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: xen-devel <xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/4c6978476782160600471bd865b318db34c7b628.1438291540.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      37868fe1
    • Andy Lutomirski's avatar
      x86/xen: Probe target addresses in set_aliased_prot() before the hypercall · aa1acff3
      Andy Lutomirski authored 
      

The update_va_mapping hypercall can fail if the VA isn't present
in the guest's page tables.  Under certain loads, this can
result in an OOPS when the target address is in unpopulated vmap
space.

While we're at it, add comments to help explain what's going on.

This isn't a great long-term fix.  This code should probably be
changed to use something like set_memory_ro.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Vrabel <dvrabel@cantab.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: security@kernel.org <security@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: xen-devel <xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/0b0e55b995cda11e7829f140b833ef932fcabe3a.1438291540.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      aa1acff3
    • Jiang Liu's avatar
      x86/irq: Use the caller provided polarity setting in mp_check_pin_attr() · 646c4b75
      Jiang Liu authored 
      

Commit d32932d0 ("x86/irq: Convert IOAPIC to use hierarchical
irqdomain interfaces") introduced a regression which causes
malfunction of interrupt lines.

The reason is that the conversion of mp_check_pin_attr() missed to
update the polarity selection of the interrupt pin with the caller
provided setting and instead uses a stale attribute value. That in
turn results in chosing the wrong interrupt flow handler.

Use the caller supplied setting to configure the pin correctly which
also choses the correct interrupt flow handler.

This restores the original behaviour and on the affected
machine/driver (Surface Pro 3, i2c controller) all IOAPIC IRQ
configuration are identical to v4.1.

Fixes: d32932d0 ("x86/irq: Convert IOAPIC to use hierarchical irqdomain interfaces")
Reported-and-tested-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
Reported-and-tested-by: default avatarChen Yu <yu.c.chen@intel.com>
Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Chen Yu <yu.c.chen@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1438242695-23531-1-git-send-email-jiang.liu@linux.intel.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      646c4b75
    • Ricardo Neri's avatar
      efi: Check for NULL efi kernel parameters · 9115c758
      Ricardo Neri authored 
      

Even though it is documented how to specifiy efi parameters, it is
possible to cause a kernel panic due to a dereference of a NULL pointer when
parsing such parameters if "efi" alone is given:

PANIC: early exception 0e rip 10:ffffffff812fb361 error 0 cr2 0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.2.0-rc1+ #450
[ 0.000000]  ffffffff81fe20a9 ffffffff81e03d50 ffffffff8184bb0f 00000000000003f8
[ 0.000000]  0000000000000000 ffffffff81e03e08 ffffffff81f371a1 64656c62616e6520
[ 0.000000]  0000000000000069 000000000000005f 0000000000000000 0000000000000000
[ 0.000000] Call Trace:
[ 0.000000]  [<ffffffff8184bb0f>] dump_stack+0x45/0x57
[ 0.000000]  [<ffffffff81f371a1>] early_idt_handler_common+0x81/0xae
[ 0.000000]  [<ffffffff812fb361>] ? parse_option_str+0x11/0x90
[ 0.000000]  [<ffffffff81f4dd69>] arch_parse_efi_cmdline+0x15/0x42
[ 0.000000]  [<ffffffff81f376e1>] do_early_param+0x50/0x8a
[ 0.000000]  [<ffffffff8106b1b3>] parse_args+0x1e3/0x400
[ 0.000000]  [<ffffffff81f37a43>] parse_early_options+0x24/0x28
[ 0.000000]  [<ffffffff81f37691>] ? loglevel+0x31/0x31
[ 0.000000]  [<ffffffff81f37a78>] parse_early_param+0x31/0x3d
[ 0.000000]  [<ffffffff81f3ae98>] setup_arch+0x2de/0xc08
[ 0.000000]  [<ffffffff8109629a>] ? vprintk_default+0x1a/0x20
[ 0.000000]  [<ffffffff81f37b20>] start_kernel+0x90/0x423
[ 0.000000]  [<ffffffff81f37495>] x86_64_start_reservations+0x2a/0x2c
[ 0.000000]  [<ffffffff81f37582>] x86_64_start_kernel+0xeb/0xef
[ 0.000000] RIP 0xffffffff81ba2efc

This panic is not reproducible with "efi=" as this will result in a non-NULL
zero-length string.

Thus, verify that the pointer to the parameter string is not NULL. This is
consistent with other parameter-parsing functions which check for NULL pointers.

Signed-off-by: default avatarRicardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
      9115c758
    • Dmitry Skorodumov's avatar
      x86/efi: Use all 64 bit of efi_memmap in setup_e820() · 7cc03e48
      Dmitry Skorodumov authored 
      

The efi_info structure stores low 32 bits of memory map
in efi_memmap and high 32 bits in efi_memmap_hi.

While constructing pointer in the setup_e820(), need
to take into account all 64 bit of the pointer.

It is because on 64bit machine the function
efi_get_memory_map() may return full 64bit pointer and before
the patch that pointer was truncated.

The issue is triggered on Parallles virtual machine and
fixed with this patch.

Signed-off-by: default avatarDmitry Skorodumov <sdmitry@parallels.com>
Cc: Denis V. Lunev <den@openvz.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
      7cc03e48
  7. Jul 30, 2015
    • Daniel Borkmann's avatar
      ebpf, x86: fix general protection fault when tail call is invoked · 2482abb9
      Daniel Borkmann authored 
      

With eBPF JIT compiler enabled on x86_64, I was able to reliably trigger
the following general protection fault out of an eBPF program with a simple
tail call, f.e. tracex5 (or a stripped down version of it):

  [  927.097918] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
  [...]
  [  927.100870] task: ffff8801f228b780 ti: ffff880016a64000 task.ti: ffff880016a64000
  [  927.102096] RIP: 0010:[<ffffffffa002440d>]  [<ffffffffa002440d>] 0xffffffffa002440d
  [  927.103390] RSP: 0018:ffff880016a67a68  EFLAGS: 00010006
  [  927.104683] RAX: 5a5a5a5a5a5a5a5a RBX: 0000000000000000 RCX: 0000000000000001
  [  927.105921] RDX: 0000000000000000 RSI: ffff88014e438000 RDI: ffff880016a67e00
  [  927.107137] RBP: ffff880016a67c90 R08: 0000000000000000 R09: 0000000000000001
  [  927.108351] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880016a67e00
  [  927.109567] R13: 0000000000000000 R14: ffff88026500e460 R15: ffff880220a81520
  [  927.110787] FS:  00007fe7d5c1f740(0000) GS:ffff880265000000(0000) knlGS:0000000000000000
  [  927.112021] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [  927.113255] CR2: 0000003e7bbb91a0 CR3: 000000006e04b000 CR4: 00000000001407e0
  [  927.114500] Stack:
  [  927.115737]  ffffc90008cdb000 ffff880016a67e00 ffff88026500e460 ffff880220a81520
  [  927.117005]  0000000100000000 000000000000001b ffff880016a67aa8 ffffffff8106c548
  [  927.118276]  00007ffcdaf22e58 0000000000000000 0000000000000000 ffff880016a67ff0
  [  927.119543] Call Trace:
  [  927.120797]  [<ffffffff8106c548>] ? lookup_address+0x28/0x30
  [  927.122058]  [<ffffffff8113d176>] ? __module_text_address+0x16/0x70
  [  927.123314]  [<ffffffff8117bf0e>] ? is_ftrace_trampoline+0x3e/0x70
  [  927.124562]  [<ffffffff810c1a0f>] ? __kernel_text_address+0x5f/0x80
  [  927.125806]  [<ffffffff8102086f>] ? print_context_stack+0x7f/0xf0
  [  927.127033]  [<ffffffff810f7852>] ? __lock_acquire+0x572/0x2050
  [  927.128254]  [<ffffffff810f7852>] ? __lock_acquire+0x572/0x2050
  [  927.129461]  [<ffffffff8119edfa>] ? trace_call_bpf+0x3a/0x140
  [  927.130654]  [<ffffffff8119ee4a>] trace_call_bpf+0x8a/0x140
  [  927.131837]  [<ffffffff8119edfa>] ? trace_call_bpf+0x3a/0x140
  [  927.133015]  [<ffffffff8119f008>] kprobe_perf_func+0x28/0x220
  [  927.134195]  [<ffffffff811a1668>] kprobe_dispatcher+0x38/0x60
  [  927.135367]  [<ffffffff81174b91>] ? seccomp_phase1+0x1/0x230
  [  927.136523]  [<ffffffff81061400>] kprobe_ftrace_handler+0xf0/0x150
  [  927.137666]  [<ffffffff81174b95>] ? seccomp_phase1+0x5/0x230
  [  927.138802]  [<ffffffff8117950c>] ftrace_ops_recurs_func+0x5c/0xb0
  [  927.139934]  [<ffffffffa022b0d5>] 0xffffffffa022b0d5
  [  927.141066]  [<ffffffff81174b91>] ? seccomp_phase1+0x1/0x230
  [  927.142199]  [<ffffffff81174b95>] seccomp_phase1+0x5/0x230
  [  927.143323]  [<ffffffff8102c0a4>] syscall_trace_enter_phase1+0xc4/0x150
  [  927.144450]  [<ffffffff81174b95>] ? seccomp_phase1+0x5/0x230
  [  927.145572]  [<ffffffff8102c0a4>] ? syscall_trace_enter_phase1+0xc4/0x150
  [  927.146666]  [<ffffffff817f9a9f>] tracesys+0xd/0x44
  [  927.147723] Code: 48 8b 46 10 48 39 d0 76 2c 8b 85 fc fd ff ff 83 f8 20 77 21 83
                       c0 01 89 85 fc fd ff ff 48 8d 44 d6 80 48 8b 00 48 83 f8 00 74
                       0a <48> 8b 40 20 48 83 c0 33 ff e0 48 89 d8 48 8b 9d d8 fd ff
                       ff 4c
  [  927.150046] RIP  [<ffffffffa002440d>] 0xffffffffa002440d

The code section with the instructions that traps points into the eBPF JIT
image of the root program (the one invoking the tail call instruction).

Using bpf_jit_disasm -o on the eBPF root program image:

  [...]
  4e:   mov    -0x204(%rbp),%eax
        8b 85 fc fd ff ff
  54:   cmp    $0x20,%eax               <--- if (tail_call_cnt > MAX_TAIL_CALL_CNT)
        83 f8 20
  57:   ja     0x000000000000007a
        77 21
  59:   add    $0x1,%eax                <--- tail_call_cnt++
        83 c0 01
  5c:   mov    %eax,-0x204(%rbp)
        89 85 fc fd ff ff
  62:   lea    -0x80(%rsi,%rdx,8),%rax  <--- prog = array->prog[index]
        48 8d 44 d6 80
  67:   mov    (%rax),%rax
        48 8b 00
  6a:   cmp    $0x0,%rax                <--- check for NULL
        48 83 f8 00
  6e:   je     0x000000000000007a
        74 0a
  70:   mov    0x20(%rax),%rax          <--- GPF triggered here! fetch of bpf_func
        48 8b 40 20                              [ matches <48> 8b 40 20 ... from above ]
  74:   add    $0x33,%rax               <--- prologue skip of new prog
        48 83 c0 33
  78:   jmpq   *%rax                    <--- jump to new prog insns
        ff e0
  [...]

The problem is that rax has 5a5a5a5a5a5a5a5a, which suggests a tail call
jump to map slot 0 is pointing to a poisoned page. The issue is the following:

lea instruction has a wrong offset, i.e. it should be ...

  lea    0x80(%rsi,%rdx,8),%rax

... but it actually seems to be ...

  lea   -0x80(%rsi,%rdx,8),%rax

... where 0x80 is offsetof(struct bpf_array, prog), thus the offset needs
to be positive instead of negative. Disassembling the interpreter, we btw
similarly do:

  [...]
  c88:  lea     0x80(%rax,%rdx,8),%rax  <--- prog = array->prog[index]
        48 8d 84 d0 80 00 00 00
  c90:  add     $0x1,%r13d
        41 83 c5 01
  c94:  mov     (%rax),%rax
        48 8b 00
  [...]

Now the other interesting fact is that this panic triggers only when things
like CONFIG_LOCKDEP are being used. In that case offsetof(struct bpf_array,
prog) starts at offset 0x80 and in non-CONFIG_LOCKDEP case at offset 0x50.
Reason is that the work_struct inside struct bpf_map grows by 48 bytes in my
case due to the lockdep_map member (which also has CONFIG_LOCK_STAT enabled
members).

Changing the emitter to always use the 4 byte displacement in the lea
instruction fixes the panic on my side. It increases the tail call instruction
emission by 3 more byte, but it should cover us from various combinations
(and perhaps other future increases on related structures).

After patch, disassembly:

  [...]
  9e:   lea    0x80(%rsi,%rdx,8),%rax   <--- CONFIG_LOCKDEP/CONFIG_LOCK_STAT
        48 8d 84 d6 80 00 00 00
  a6:   mov    (%rax),%rax
        48 8b 00
  [...]

  [...]
  9e:   lea    0x50(%rsi,%rdx,8),%rax   <--- No CONFIG_LOCKDEP
        48 8d 84 d6 50 00 00 00
  a6:   mov    (%rax),%rax
        48 8b 00
  [...]

Fixes: b52f00e6 ("x86: bpf_jit: implement bpf_tail_call() helper")
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2482abb9
  9. Jul 26, 2015
    • Thomas Gleixner's avatar
      x86/mm/pat: Revert 'Adjust default caching mode translation tables' · 1a4e8795
      Thomas Gleixner authored 
      

Toshi explains:

"No, the default values need to be set to the fallback types,
 i.e. minimal supported mode.  For WC and WT, UC is the fallback type.

 When PAT is disabled, pat_init() does update the tables below to
 enable WT per the default BIOS setup.  However, when PAT is enabled,
 but CPU has PAT -errata, WT falls back to UC per the default values."

Revert: ca1fec58 'x86/mm/pat: Adjust default caching mode translation tables'
Requested-by: default avatarToshi Kani <toshi.kani@hp.com>
Cc: Jan Beulich <jbeulich@suse.de>
Link: http://lkml.kernel.org/r/1437577776.3214.252.camel@hp.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      1a4e8795
    • Matt Fleming's avatar
      perf/x86/intel/cqm: Return cached counter value from IRQ context · 2c534c0d
      Matt Fleming authored 
      

Peter reported the following potential crash which I was able to
reproduce with his test program,

[  148.765788] ------------[ cut here ]------------
[  148.765796] WARNING: CPU: 34 PID: 2840 at kernel/smp.c:417 smp_call_function_many+0xb6/0x260()
[  148.765797] Modules linked in:
[  148.765800] CPU: 34 PID: 2840 Comm: perf Not tainted 4.2.0-rc1+ #4
[  148.765803]  ffffffff81cdc398 ffff88085f105950 ffffffff818bdfd5 0000000000000007
[  148.765805]  0000000000000000 ffff88085f105990 ffffffff810e413a 0000000000000000
[  148.765807]  ffffffff82301080 0000000000000022 ffffffff8107f640 ffffffff8107f640
[  148.765809] Call Trace:
[  148.765810]  <NMI>  [<ffffffff818bdfd5>] dump_stack+0x45/0x57
[  148.765818]  [<ffffffff810e413a>] warn_slowpath_common+0x8a/0xc0
[  148.765822]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
[  148.765824]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
[  148.765825]  [<ffffffff810e422a>] warn_slowpath_null+0x1a/0x20
[  148.765827]  [<ffffffff811613f6>] smp_call_function_many+0xb6/0x260
[  148.765829]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
[  148.765831]  [<ffffffff81161748>] on_each_cpu_mask+0x28/0x60
[  148.765832]  [<ffffffff8107f6ef>] intel_cqm_event_count+0x7f/0xe0
[  148.765836]  [<ffffffff811cdd35>] perf_output_read+0x2a5/0x400
[  148.765839]  [<ffffffff811d2e5a>] perf_output_sample+0x31a/0x590
[  148.765840]  [<ffffffff811d333d>] ? perf_prepare_sample+0x26d/0x380
[  148.765841]  [<ffffffff811d3497>] perf_event_output+0x47/0x60
[  148.765843]  [<ffffffff811d36c5>] __perf_event_overflow+0x215/0x240
[  148.765844]  [<ffffffff811d4124>] perf_event_overflow+0x14/0x20
[  148.765847]  [<ffffffff8107e7f4>] intel_pmu_handle_irq+0x1d4/0x440
[  148.765849]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765853]  [<ffffffff81219bad>] ? vunmap_page_range+0x19d/0x2f0
[  148.765854]  [<ffffffff81219d11>] ? unmap_kernel_range_noflush+0x11/0x20
[  148.765859]  [<ffffffff814ce6fe>] ? ghes_copy_tofrom_phys+0x11e/0x2a0
[  148.765863]  [<ffffffff8109e5db>] ? native_apic_msr_write+0x2b/0x30
[  148.765865]  [<ffffffff8109e44d>] ? x2apic_send_IPI_self+0x1d/0x20
[  148.765869]  [<ffffffff81065135>] ? arch_irq_work_raise+0x35/0x40
[  148.765872]  [<ffffffff811c8d86>] ? irq_work_queue+0x66/0x80
[  148.765875]  [<ffffffff81075306>] perf_event_nmi_handler+0x26/0x40
[  148.765877]  [<ffffffff81063ed9>] nmi_handle+0x79/0x100
[  148.765879]  [<ffffffff81064422>] default_do_nmi+0x42/0x100
[  148.765880]  [<ffffffff81064563>] do_nmi+0x83/0xb0
[  148.765884]  [<ffffffff818c7c0f>] end_repeat_nmi+0x1e/0x2e
[  148.765886]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765888]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765890]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765891]  <<EOE>>  [<ffffffff8110ab66>] finish_task_switch+0x156/0x210
[  148.765898]  [<ffffffff818c1671>] __schedule+0x341/0x920
[  148.765899]  [<ffffffff818c1c87>] schedule+0x37/0x80
[  148.765903]  [<ffffffff810ae1af>] ? do_page_fault+0x2f/0x80
[  148.765905]  [<ffffffff818c1f4a>] schedule_user+0x1a/0x50
[  148.765907]  [<ffffffff818c666c>] retint_careful+0x14/0x32
[  148.765908] ---[ end trace e33ff2be78e14901 ]---

The CQM task events are not safe to be called from within interrupt
context because they require performing an IPI to read the counter value
on all sockets. And performing IPIs from within IRQ context is a
"no-no".

Make do with the last read counter value currently event in
event->count when we're invoked in this context.

Reported-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Will Auld <will.auld@intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1437490509-15373-1-git-send-email-matt@codeblueprint.co.uk


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      2c534c0d
  11. Jul 24, 2015
  13. Jul 23, 2015
  15. Jul 22, 2015
    • Toshi Kani's avatar
      x86/mm: Remove region_is_ram() call from ioremap · 9a58eebe
      Toshi Kani authored 
      

__ioremap_caller() calls region_is_ram() to walk through the
iomem_resource table to check if a target range is in RAM, which was
added to improve the lookup performance over page_is_ram() (commit
906e36c5 "x86: use optimized ioresource lookup in ioremap
function"). page_is_ram() was no longer used when this change was
added, though.

__ioremap_caller() then calls walk_system_ram_range(), which had
replaced page_is_ram() to improve the lookup performance (commit
c81c8a1e "x86, ioremap: Speed up check for RAM pages").

Since both checks walk through the same iomem_resource table for
the same purpose, there is no need to call both functions.

Aside of that walk_system_ram_range() is the only useful check at the
moment because region_is_ram() always returns -1 due to an
implementation bug. That bug in region_is_ram() cannot be fixed
without breaking existing ioremap callers, which rely on the subtle
difference of walk_system_ram_range() versus non page aligned ranges.

Once these offending callers are fixed we can use region_is_ram() and
remove walk_system_ram_range().

[ tglx: Massaged changelog ]

Signed-off-by: default avatarToshi Kani <toshi.kani@hp.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1437088996-28511-3-git-send-email-toshi.kani@hp.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      9a58eebe
    • Toshi Kani's avatar
      x86/mm: Move warning from __ioremap_check_ram() to the call site · 1c9cf9b2
      Toshi Kani authored 
      

__ioremap_check_ram() has a WARN_ONCE() which is emitted when the
given pfn range is not RAM. The warning is bogus in two aspects:

- it never triggers since walk_system_ram_range() only calls
  __ioremap_check_ram() for RAM ranges.

- the warning message is wrong as it says: "ioremap on RAM' after it
  established that the pfn range is not RAM.

Move the WARN_ONCE() to __ioremap_caller(), and update the message to
include the address range so we get an actual warning when something
tries to ioremap system RAM.

[ tglx: Massaged changelog ]

Signed-off-by: default avatarToshi Kani <toshi.kani@hp.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1437088996-28511-2-git-send-email-toshi.kani@hp.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      1c9cf9b2
  17. Jul 21, 2015
  19. Jul 18, 2015
  21. Jul 17, 2015