linux-stable.git/include/asm-generic, branch v5.4.78

mm: always have io_remap_pfn_range() set pgprot_decrypted()

2020-11-10T11:37:27+00:00

commit f8f6ae5d077a9bdaf5cbf2ac960a5d1a04b47482 upstream.

The purpose of io_remap_pfn_range() is to map IO memory, such as a
memory mapped IO exposed through a PCI BAR.  IO devices do not
understand encryption, so this memory must always be decrypted.
Automatically call pgprot_decrypted() as part of the generic
implementation.

This fixes a bug where enabling AMD SME causes subsystems, such as RDMA,
using io_remap_pfn_range() to expose BAR pages to user space to fail.
The CPU will encrypt access to those BAR pages instead of passing
unencrypted IO directly to the device.

Places not mapping IO should use remap_pfn_range().

Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption")
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Andrew Morton 
Cc: Arnd Bergmann 
Cc: Tom Lendacky 
Cc: Thomas Gleixner 
Cc: Andrey Ryabinin 
Cc: Borislav Petkov 
Cc: Brijesh Singh 
Cc: Jonathan Corbet 
Cc: Dmitry Vyukov 
Cc: "Dave Young" 
Cc: Alexander Potapenko 
Cc: Konrad Rzeszutek Wilk 
Cc: Andy Lutomirski 
Cc: Larry Woodman 
Cc: Matt Fleming 
Cc: Ingo Molnar 
Cc: "Michael S. Tsirkin" 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Toshimitsu Kani 
Cc: 
Link: https://lkml.kernel.org/r/0-v1-025d64bdf6c4+e-amd_sme_fix_jgg@nvidia.com
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

bpf: Prevent .BTF section elimination

2020-10-14T08:32:58+00:00

commit 65c204398928f9c79f1a29912b410439f7052635 upstream.

Systems with memory or disk constraints often reduce the kernel footprint
by configuring LD_DEAD_CODE_DATA_ELIMINATION. However, this can result in
removal of any BTF information.

Use the KEEP() macro to preserve the BTF data as done with other important
sections, while still allowing for smaller kernels.

Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF")
Signed-off-by: Tony Ambardar 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/a635b5d3e2da044e7b51ec1315e8910fbce0083f.1600417359.git.Tony.Ambardar@gmail.com
Signed-off-by: Greg Kroah-Hartman

mm/gup: fix gup_fast with dynamic page table folding

2020-10-01T11:18:24+00:00

commit d3f7b1bb204099f2f7306318896223e8599bb6a2 upstream.

Currently to make sure that every page table entry is read just once
gup_fast walks perform READ_ONCE and pass pXd value down to the next
gup_pXd_range function by value e.g.:

  static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
                           unsigned int flags, struct page **pages, int *nr)
  ...
          pudp = pud_offset(&p4d, addr);

This function passes a reference on that local value copy to pXd_offset,
and might get the very same pointer in return.  This happens when the
level is folded (on most arches), and that pointer should not be
iterated.

On s390 due to the fact that each task might have different 5,4 or
3-level address translation and hence different levels folded the logic
is more complex and non-iteratable pointer to a local copy leads to
severe problems.

Here is an example of what happens with gup_fast on s390, for a task
with 3-level paging, crossing a 2 GB pud boundary:

  // addr = 0x1007ffff000, end = 0x10080001000
  static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
                           unsigned int flags, struct page **pages, int *nr)
  {
        unsigned long next;
        pud_t *pudp;

        // pud_offset returns &p4d itself (a pointer to a value on stack)
        pudp = pud_offset(&p4d, addr);
        do {
                // on second iteratation reading "random" stack value
                pud_t pud = READ_ONCE(*pudp);

                // next = 0x10080000000, due to PUD_SIZE/MASK != PGDIR_SIZE/MASK on s390
                next = pud_addr_end(addr, end);
                ...
        } while (pudp++, addr = next, addr != end); // pudp++ iterating over stack

        return 1;
  }

This happens since s390 moved to common gup code with commit
d1874a0c2805 ("s390/mm: make the pxd_offset functions more robust") and
commit 1a42010cdc26 ("s390/mm: convert to the generic
get_user_pages_fast code").

s390 tried to mimic static level folding by changing pXd_offset
primitives to always calculate top level page table offset in pgd_offset
and just return the value passed when pXd_offset has to act as folded.

What is crucial for gup_fast and what has been overlooked is that
PxD_SIZE/MASK and thus pXd_addr_end should also change correspondingly.
And the latter is not possible with dynamic folding.

To fix the issue in addition to pXd values pass original pXdp pointers
down to gup_pXd_range functions.  And introduce pXd_offset_lockless
helpers, which take an additional pXd entry value parameter.  This has
already been discussed in

  https://lkml.kernel.org/r/20190418100218.0a4afd51@mschwideX1

Fixes: 1a42010cdc26 ("s390/mm: convert to the generic get_user_pages_fast code")
Signed-off-by: Vasily Gorbik 
Signed-off-by: Andrew Morton 
Reviewed-by: Gerald Schaefer 
Reviewed-by: Alexander Gordeev 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Mike Rapoport 
Reviewed-by: John Hubbard 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Dave Hansen 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Jeff Dike 
Cc: Richard Weinberger 
Cc: Dave Hansen 
Cc: Andy Lutomirski 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Arnd Bergmann 
Cc: Andrey Ryabinin 
Cc: Heiko Carstens 
Cc: Christian Borntraeger 
Cc: Claudio Imbrenda 
Cc: 	[5.2+]
Link: https://lkml.kernel.org/r/patch.git-943f1e5dcff2.your-ad-here.call-01599856292-ext-8676@work.hours
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

include/asm-generic/vmlinux.lds.h: align ro_after_init

2020-08-19T06:16:25+00:00

commit 7f897acbe5d57995438c831670b7c400e9c0dc00 upstream.

Since the patch [1], building the kernel using a toolchain built with
binutils 2.33.1 prevents booting a sh4 system under Qemu.  Apply the patch
provided by Alan Modra [2] that fix alignment of rodata.

[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ebd2263ba9a9124d93bbc0ece63d7e0fae89b40e
[2] https://www.sourceware.org/ml/binutils/2019-12/msg00112.html

Signed-off-by: Romain Naour 
Signed-off-by: Andrew Morton 
Cc: Alan Modra 
Cc: Bin Meng 
Cc: Chen Zhou 
Cc: Geert Uytterhoeven 
Cc: John Paul Adrian Glaubitz 
Cc: Krzysztof Kozlowski 
Cc: Kuninori Morimoto 
Cc: Rich Felker 
Cc: Sam Ravnborg 
Cc: Yoshinori Sato 
Cc: Arnd Bergmann 
Cc: 
Link: https://marc.info/?l=linux-sh&m=158429470221261
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86, vmlinux.lds: Page-align end of ..page_aligned sections

2020-07-29T08:18:45+00:00

commit de2b41be8fcccb2f5b6c480d35df590476344201 upstream.

On x86-32 the idt_table with 256 entries needs only 2048 bytes. It is
page-aligned, but the end of the .bss..page_aligned section is not
guaranteed to be page-aligned.

As a result, objects from other .bss sections may end up on the same 4k
page as the idt_table, and will accidentially get mapped read-only during
boot, causing unexpected page-faults when the kernel writes to them.

This could be worked around by making the objects in the page aligned
sections page sized, but that's wrong.

Explicit sections which store only page aligned objects have an implicit
guarantee that the object is alone in the page in which it is placed. That
works for all objects except the last one. That's inconsistent.

Enforcing page sized objects for these sections would wreckage memory
sanitizers, because the object becomes artificially larger than it should
be and out of bound access becomes legit.

Align the end of the .bss..page_aligned and .data..page_aligned section on
page-size so all objects places in these sections are guaranteed to have
their own page.

[ tglx: Amended changelog ]

Signed-off-by: Joerg Roedel 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200721093448.10417-1-joro@8bytes.org
Signed-off-by: Greg Kroah-Hartman

asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible()

2020-07-29T08:18:40+00:00

[ Upstream commit bd024e82e4cd95c7f1a475a55f99871936c2b2db ]

Although mmiowb() is concerned only with serialising MMIO writes occuring
in contexts where a spinlock is held, the call to mmiowb_set_pending()
from the MMIO write accessors can occur in preemptible contexts, such
as during driver probe() functions where ordering between CPUs is not
usually a concern, assuming that the task migration path provides the
necessary ordering guarantees.

Unfortunately, the default implementation of mmiowb_set_pending() is not
preempt-safe, as it makes use of a a per-cpu variable to track its
internal state. This has been reported to generate the following splat
on riscv:

 | BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
 | caller is regmap_mmio_write32le+0x1c/0x46
 | CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc3-hfu+ #1
 | Call Trace:
 |  walk_stackframe+0x0/0x7a
 |  dump_stack+0x6e/0x88
 |  regmap_mmio_write32le+0x18/0x46
 |  check_preemption_disabled+0xa4/0xaa
 |  regmap_mmio_write32le+0x18/0x46
 |  regmap_mmio_write+0x26/0x44
 |  regmap_write+0x28/0x48
 |  sifive_gpio_probe+0xc0/0x1da

Although it's possible to fix the driver in this case, other splats have
been seen from other drivers, including the infamous 8250 UART, and so
it's better to address this problem in the mmiowb core itself.

Fix mmiowb_set_pending() by using the raw_cpu_ptr() to get at the mmiowb
state and then only updating the 'mmiowb_pending' field if we are not
preemptible (i.e. we have a non-zero nesting count).

Cc: Arnd Bergmann 
Cc: Paul Walmsley 
Cc: Guo Ren 
Cc: Michael Ellerman 
Reported-by: Palmer Dabbelt 
Reported-by: Emil Renner Berthing 
Tested-by: Emil Renner Berthing 
Reviewed-by: Palmer Dabbelt 
Acked-by: Palmer Dabbelt 
Link: https://lore.kernel.org/r/20200716112816.7356-1-will@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Sasha Levin

bpf: Support llvm-objcopy for vmlinux BTF

2020-06-17T14:40:20+00:00

commit 90ceddcb495008ac8ba7a3dce297841efcd7d584 upstream.

Simplify gen_btf logic to make it work with llvm-objcopy. The existing
'file format' and 'architecture' parsing logic is brittle and does not
work with llvm-objcopy/llvm-objdump.

'file format' output of llvm-objdump>=11 will match GNU objdump, but
'architecture' (bfdarch) may not.

.BTF in .tmp_vmlinux.btf is non-SHF_ALLOC. Add the SHF_ALLOC flag
because it is part of vmlinux image used for introspection. C code
can reference the section via linker script defined __start_BTF and
__stop_BTF. This fixes a small problem that previous .BTF had the
SHF_WRITE flag (objcopy -I binary -O elf* synthesized .data).

Additionally, `objcopy -I binary` synthesized symbols
_binary__btf_vmlinux_bin_start and _binary__btf_vmlinux_bin_stop (not
used elsewhere) are replaced with more commonplace __start_BTF and
__stop_BTF.

Add 2>/dev/null because GNU objcopy (but not llvm-objcopy) warns
"empty loadable segment detected at vaddr=0xffffffff81000000, is this intentional?"

We use a dd command to change the e_type field in the ELF header from
ET_EXEC to ET_REL so that lld will accept .btf.vmlinux.bin.o.  Accepting
ET_EXEC as an input file is an extremely rare GNU ld feature that lld
does not intend to support, because this is error-prone.

The output section description .BTF in include/asm-generic/vmlinux.lds.h
avoids potential subtle orphan section placement issues and suppresses
--orphan-handling=warn warnings.

Fixes: df786c9b9476 ("bpf: Force .BTF section start to zero when dumping from vmlinux")
Fixes: cb0cc635c7a9 ("powerpc: Include .BTF section")
Reported-by: Nathan Chancellor 
Signed-off-by: Fangrui Song 
Signed-off-by: Daniel Borkmann 
Tested-by: Stanislav Fomichev 
Tested-by: Andrii Nakryiko 
Reviewed-by: Stanislav Fomichev 
Reviewed-by: Kees Cook 
Acked-by: Andrii Nakryiko 
Acked-by: Michael Ellerman  (powerpc)
Link: https://github.com/ClangBuiltLinux/linux/issues/871
Link: https://lore.kernel.org/bpf/20200318222746.173648-1-maskray@google.com
Signed-off-by: Maria Teguiani 
Tested-by: Matthias Maennich 
Signed-off-by: Greg Kroah-Hartman

include/asm-generic/topology.h: guard cpumask_of_node() macro argument

2020-06-03T06:21:27+00:00

[ Upstream commit 4377748c7b5187c3342a60fa2ceb60c8a57a8488 ]

drivers/hwmon/amd_energy.c:195:15: error: invalid operands to binary expression ('void' and 'int')
                                        (channel - data->nr_cpus));
                                        ~~~~~~~~~^~~~~~~~~~~~~~~~~
include/asm-generic/topology.h:51:42: note: expanded from macro 'cpumask_of_node'
    #define cpumask_of_node(node)       ((void)node, cpu_online_mask)
                                               ^~~~
include/linux/cpumask.h:618:72: note: expanded from macro 'cpumask_first_and'
 #define cpumask_first_and(src1p, src2p) cpumask_next_and(-1, (src1p), (src2p))
                                                                       ^~~~~

Fixes: f0b848ce6fe9 ("cpumask: Introduce cpumask_of_{node,pcibus} to replace {node,pcibus}_to_cpumask")
Fixes: 8abee9566b7e ("hwmon: Add amd_energy driver to report energy counters")
Signed-off-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Acked-by: Guenter Roeck 
Link: http://lkml.kernel.org/r/20200527134623.930247-1-arnd@arndb.de
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

x86/Hyper-V: Report crash data in die() when panic_on_oops is set

2020-04-23T08:36:24+00:00

commit f3a99e761efa616028b255b4de58e9b5b87c5545 upstream.

When oops happens with panic_on_oops unset, the oops
thread is killed by die() and system continues to run.
In such case, guest should not report crash register
data to host since system still runs. Check panic_on_oops
and return directly in hyperv_report_panic() when the function
is called in the die() and panic_on_oops is unset. Fix it.

Fixes: 7ed4325a44ea ("Drivers: hv: vmbus: Make panic reporting to be more useful")
Signed-off-by: Tianyu Lan 
Reviewed-by: Michael Kelley 
Link: https://lore.kernel.org/r/20200406155331.2105-7-Tianyu.Lan@microsoft.com
Signed-off-by: Wei Liu 
Signed-off-by: Greg Kroah-Hartman

lib/vdso: Make __arch_update_vdso_data() logic understandable

2020-03-05T15:43:49+00:00

commit 9a6b55ac4a44060bcb782baf002859b2a2c63267 upstream.

The function name suggests that this is a boolean checking whether the
architecture asks for an update of the VDSO data, but it works the other
way round. To spare further confusion invert the logic.

Fixes: 44f57d788e7d ("timekeeping: Provide a generic update_vsyscall() implementation")
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20200114185946.656652824@linutronix.de
Signed-off-by: Greg Kroah-Hartman