linux-toradex.git/arch/powerpc/include/asm/mmu.h, branch v5.4

powerpc/64s: make mmu_partition_table_set_entry TLB flush optional

2019-09-05T04:22:40+00:00

No functional change.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20190902152931.17840-4-npiggin@gmail.com

powerpc/mm: move pgtable_t in asm/mmu.h

2019-05-02T15:20:24+00:00

pgtable_t is now identical for all subarches, move it to the
top level asm/mmu.h

Reviewed-by: Aneesh Kumar K.V 
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman

powerpc/mm: Fix build error with FLATMEM book3s64 config

2019-04-21T13:12:38+00:00

The current value of MAX_PHYSMEM_BITS cannot work with 32 bit configs.
We used to have MAX_PHYSMEM_BITS not defined without SPARSEMEM and 32
bit configs never expected a value to be set for MAX_PHYSMEM_BITS.

Dependent code such as zsmalloc derived the right values based on other
fields. Instead of finding a value that works with different configs,
use new values only for book3s_64. For 64 bit booke, use the definition
of MAX_PHYSMEM_BITS as per commit a7df61a0e2b6 ("[PATCH] ppc64: Increase sparsemem defaults")
That change was done in 2005 and hopefully will work with book3e 64.

Fixes: 8bc086899816 ("powerpc/mm: Only define MAX_PHYSMEM_BITS in SPARSEMEM configurations")
Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

powerpc/64s: Implement KUAP for Radix MMU

2019-04-21T13:06:02+00:00

Kernel Userspace Access Prevention utilises a feature of the Radix MMU
which disallows read and write access to userspace addresses. By
utilising this, the kernel is prevented from accessing user data from
outside of trusted paths that perform proper safety checks, such as
copy_{to/from}_user() and friends.

Userspace access is disabled from early boot and is only enabled when
performing an operation like copy_{to/from}_user(). The register that
controls this (AMR) does not prevent userspace from accessing itself,
so there is no need to save and restore when entering and exiting
userspace.

When entering the kernel from the kernel we save AMR and if it is not
blocking user access (because eg. we faulted doing a user access) we
reblock user access for the duration of the exception (ie. the page
fault) and then restore the AMR when returning back to the kernel.

This feature can be tested by using the lkdtm driver (CONFIG_LKDTM=y)
and performing the following:

  # (echo ACCESS_USERSPACE) > [debugfs]/provoke-crash/DIRECT

If enabled, this should send SIGSEGV to the thread.

We also add paranoid checking of AMR in switch and syscall return
under CONFIG_PPC_KUAP_DEBUG.

Co-authored-by: Michael Ellerman 
Signed-off-by: Russell Currey 
Signed-off-by: Michael Ellerman

powerpc/mm: Define MAX_PHYSMEM_BITS for all 64-bit configs

2019-04-10T04:45:57+00:00

The recent commit 8bc086899816 ("powerpc/mm: Only define
MAX_PHYSMEM_BITS in SPARSEMEM configurations") removed our definition
of MAX_PHYSMEM_BITS when SPARSEMEM is disabled.

This inadvertently broke some 64-bit FLATMEM using configs with eg:

  arch/powerpc/include/asm/book3s/64/mmu-hash.h:584:6: error: "MAX_PHYSMEM_BITS" is not defined, evaluates to 0
   #if (MAX_PHYSMEM_BITS > MAX_EA_BITS_PER_CONTEXT)
        ^~~~~~~~~~~~~~~~

Fix it by making sure we define MAX_PHYSMEM_BITS for all 64-bit
configs regardless of SPARSEMEM.

Fixes: 8bc086899816 ("powerpc/mm: Only define MAX_PHYSMEM_BITS in SPARSEMEM configurations")
Reported-by: Andreas Schwab 
Reported-by: Hugh Dickins 
Reviewed-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

powerpc/mm: Only define MAX_PHYSMEM_BITS in SPARSEMEM configurations

2019-03-20T13:16:45+00:00

MAX_PHYSMEM_BITS only needs to be defined if CONFIG_SPARSEMEM is
enabled, and that was the case before commit 4ffe713b7587
("powerpc/mm: Increase the max addressable memory to 2PB").

On 32-bit systems, where CONFIG_SPARSEMEM is not enabled, we now
define it as 46.  That is larger than the real number of physical
address bits, and breaks calculations in zsmalloc:

  mm/zsmalloc.c:130:49: warning: right shift count is negative
    MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
                                                   ^~
  ...
  mm/zsmalloc.c:253:21: error: variably modified 'size_class' at file scope
    struct size_class *size_class[ZS_SIZE_CLASSES];
                       ^~~~~~~~~~

Fixes: 4ffe713b7587 ("powerpc/mm: Increase the max addressable memory to 2PB")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Ben Hutchings 
Signed-off-by: Michael Ellerman

powerpc/mmu: add is_strict_kernel_rwx() helper

2019-02-23T10:04:32+00:00

Add a helper to know whether STRICT_KERNEL_RWX is enabled.

This is based on rodata_enabled flag which is defined only
when CONFIG_STRICT_KERNEL_RWX is selected.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman

powerpc: simplify BDI switch

2019-02-21T13:10:16+00:00

There is no reason to re-read each time the pointer at
location 0xf0 as it is fixed and known.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman

powerpc/mm: Eliminate not possible mmu features at compile time

2018-12-19T07:56:32+00:00

Depending on the CONFIG selected, many of the MMU features are
not possible. Lets only get the possible ones in MMU_FTRS_POSSIBLE.

This allows gcc to get rid at compile time of code related to
not possible features.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman

powerpc/mm: move platform specific mmu-xxx.h in platform directories

2018-12-04T08:45:01+00:00

The purpose of this patch is to move platform specific
mmu-xxx.h files in platform directories like pte-xxx.h files.

In the meantime this patch creates common nohash and
nohash/32 + nohash/64 mmu.h files for future common parts.

Reviewed-by: Aneesh Kumar K.V 
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman