linux-stable.git/arch/mips/include, branch v5.4.129 Linux kernel stable tree MIPS: Avoid handcoded DIVU in `__div64_32' altogether 2021-05-19T08:08:32+00:00 Maciej W. Rozycki macro@orcam.me.uk 2021-04-22T20:36:12+00:00 2c44110300b8cee4170391ae689e0126176ecefa commit 25ab14cbe9d1b66fda44c71a2db7582a31b6f5cd upstream. Remove the inline asm with a DIVU instruction from `__div64_32' and use plain C code for the intended DIVMOD calculation instead. GCC is smart enough to know that both the quotient and the remainder are calculated with single DIVU, so with ISAs up to R5 the same instruction is actually produced with overall similar code. For R6 compiled code will work, but separate DIVU and MODU instructions will be produced, which are also interlocked, so scalar implementations will likely not perform as well as older ISAs with their asynchronous MD unit. Likely still faster then the generic algorithm though. This removes a compilation error for R6 however where the original DIVU instruction is not supported anymore and the MDU accumulator registers have been removed and consequently GCC complains as to a constraint it cannot find a register for: In file included from ./include/linux/math.h:5, from ./include/linux/kernel.h:13, from mm/page-writeback.c:15: ./include/linux/math64.h: In function 'div_u64_rem': ./arch/mips/include/asm/div64.h:76:17: error: inconsistent operand constraints in an 'asm' 76 | __asm__("divu $0, %z1, %z2" \ | ^~~~~~~ ./include/asm-generic/div64.h:245:25: note: in expansion of macro '__div64_32' 245 | __rem = __div64_32(&(n), __base); \ | ^~~~~~~~~~ ./include/linux/math64.h:91:22: note: in expansion of macro 'do_div' 91 | *remainder = do_div(dividend, divisor); | ^~~~~~ This has passed correctness verification with test_div64 and reduced the module's average execution time down to 1.0404s from 1.0445s with R3400 @40MHz. The module's MIPS I machine code has also shrunk by 12 bytes or 3 instructions. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 25ab14cbe9d1b66fda44c71a2db7582a31b6f5cd upstream.

Remove the inline asm with a DIVU instruction from `__div64_32' and use
plain C code for the intended DIVMOD calculation instead.  GCC is smart
enough to know that both the quotient and the remainder are calculated
with single DIVU, so with ISAs up to R5 the same instruction is actually
produced with overall similar code.

For R6 compiled code will work, but separate DIVU and MODU instructions
will be produced, which are also interlocked, so scalar implementations
will likely not perform as well as older ISAs with their asynchronous MD
unit.  Likely still faster then the generic algorithm though.

This removes a compilation error for R6 however where the original DIVU
instruction is not supported anymore and the MDU accumulator registers
have been removed and consequently GCC complains as to a constraint it
cannot find a register for:

In file included from ./include/linux/math.h:5,
                 from ./include/linux/kernel.h:13,
                 from mm/page-writeback.c:15:
./include/linux/math64.h: In function 'div_u64_rem':
./arch/mips/include/asm/div64.h:76:17: error: inconsistent operand constraints in an 'asm'
   76 |                 __asm__("divu   $0, %z1, %z2"                           \
      |                 ^~~~~~~
./include/asm-generic/div64.h:245:25: note: in expansion of macro '__div64_32'
  245 |                 __rem = __div64_32(&(n), __base);       \
      |                         ^~~~~~~~~~
./include/linux/math64.h:91:22: note: in expansion of macro 'do_div'
   91 |         *remainder = do_div(dividend, divisor);
      |                      ^~~~~~

This has passed correctness verification with test_div64 and reduced the
module's average execution time down to 1.0404s from 1.0445s with R3400
@40MHz.  The module's MIPS I machine code has also shrunk by 12 bytes or
3 instructions.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MIPS: Avoid DIVU in `__div64_32' is result would be zero 2021-05-19T08:08:32+00:00 Maciej W. Rozycki macro@orcam.me.uk 2021-04-20T02:50:48+00:00 2759b770b53ee98243e4486739103cf9c40672d0 commit c1d337d45ec0a802299688e17d568c4e3a585895 upstream. We already check the high part of the divident against zero to avoid the costly DIVU instruction in that case, needed to reduce the high part of the divident, so we may well check against the divisor instead and set the high part of the quotient to zero right away. We need to treat the high part the divident in that case though as the remainder that would be calculated by the DIVU instruction we avoided. This has passed correctness verification with test_div64 and reduced the module's average execution time down to 1.0445s and 0.2619s from 1.0668s and 0.2629s respectively for an R3400 CPU @40MHz and a 5Kc CPU @160MHz. Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c1d337d45ec0a802299688e17d568c4e3a585895 upstream.

We already check the high part of the divident against zero to avoid the
costly DIVU instruction in that case, needed to reduce the high part of
the divident, so we may well check against the divisor instead and set
the high part of the quotient to zero right away.  We need to treat the
high part the divident in that case though as the remainder that would
be calculated by the DIVU instruction we avoided.

This has passed correctness verification with test_div64 and reduced the
module's average execution time down to 1.0445s and 0.2619s from 1.0668s
and 0.2629s respectively for an R3400 CPU @40MHz and a 5Kc CPU @160MHz.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MIPS: Reinstate platform `__div64_32' handler 2021-05-19T08:08:32+00:00 Maciej W. Rozycki macro@orcam.me.uk 2021-04-20T02:50:40+00:00 02b120493a9c774a792ab587177321ade329bca4 commit c49f71f60754acbff37505e1d16ca796bf8a8140 upstream. Our current MIPS platform `__div64_32' handler is inactive, because it is incorrectly only enabled for 64-bit configurations, for which generic `do_div' code does not call it anyway. The handler is not suitable for being called from there though as it only calculates 32 bits of the quotient under the assumption the 64-bit divident has been suitably reduced. Code for such reduction used to be there, however it has been incorrectly removed with commit c21004cd5b4c ("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0."), which should have only updated an obsoleted constraint for an inline asm involving $hi and $lo register outputs, while possibly wiring the original MIPS variant of the `do_div' macro as `__div64_32' handler for the generic `do_div' implementation Correct the handler as follows then: - Revert most of the commit referred, however retaining the current formatting, except for the final two instructions of the inline asm sequence, which the original commit missed. Omit the original 64-bit parts though. - Rename the original `do_div' macro to `__div64_32'. Use the combined `x' constraint referring to the MD accumulator as a whole, replacing the original individual `h' and `l' constraints used for $hi and $lo registers respectively, of which `h' has been obsoleted with GCC 4.4. Update surrounding code accordingly. We have since removed support for GCC versions before 4.9, so no need for a special arrangement here; GCC has supported the `x' constraint since forever anyway, or at least going back to 1991. - Rename the `__base' local variable in `__div64_32' to `__radix' to avoid a conflict with a local variable in `do_div'. - Actually enable this code for 32-bit rather than 64-bit configurations by qualifying it with BITS_PER_LONG being 32 instead of 64. Include <asm/bitsperlong.h> for this macro rather than <linux/types.h> as we don't need anything else. - Finally include <asm-generic/div64.h> last rather than first. This has passed correctness verification with test_div64 and reduced the module's average execution time down to 1.0668s and 0.2629s from 2.1529s and 0.5647s respectively for an R3400 CPU @40MHz and a 5Kc CPU @160MHz. For a reference 64-bit `do_div' code where we have the DDIVU instruction available to do the whole calculation right away averages at 0.0660s for the latter CPU. Fixes: c21004cd5b4c ("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0.") Reported-by: Huacai Chen <chenhuacai@kernel.org> Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Cc: stable@vger.kernel.org # v2.6.30+ Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c49f71f60754acbff37505e1d16ca796bf8a8140 upstream.

Our current MIPS platform `__div64_32' handler is inactive, because it
is incorrectly only enabled for 64-bit configurations, for which generic
`do_div' code does not call it anyway.

The handler is not suitable for being called from there though as it
only calculates 32 bits of the quotient under the assumption the 64-bit
divident has been suitably reduced.  Code for such reduction used to be
there, however it has been incorrectly removed with commit c21004cd5b4c
("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0."), which should
have only updated an obsoleted constraint for an inline asm involving
$hi and $lo register outputs, while possibly wiring the original MIPS
variant of the `do_div' macro as `__div64_32' handler for the generic
`do_div' implementation

Correct the handler as follows then:

- Revert most of the commit referred, however retaining the current
  formatting, except for the final two instructions of the inline asm
  sequence, which the original commit missed.  Omit the original 64-bit
  parts though.

- Rename the original `do_div' macro to `__div64_32'.  Use the combined
  `x' constraint referring to the MD accumulator as a whole, replacing
  the original individual `h' and `l' constraints used for $hi and $lo
  registers respectively, of which `h' has been obsoleted with GCC 4.4.
  Update surrounding code accordingly.

  We have since removed support for GCC versions before 4.9, so no need
  for a special arrangement here; GCC has supported the `x' constraint
  since forever anyway, or at least going back to 1991.

- Rename the `__base' local variable in `__div64_32' to `__radix' to
  avoid a conflict with a local variable in `do_div'.

- Actually enable this code for 32-bit rather than 64-bit configurations
  by qualifying it with BITS_PER_LONG being 32 instead of 64.  Include
  <asm/bitsperlong.h> for this macro rather than <linux/types.h> as we
  don't need anything else.

- Finally include <asm-generic/div64.h> last rather than first.

This has passed correctness verification with test_div64 and reduced the
module's average execution time down to 1.0668s and 0.2629s from 2.1529s
and 0.5647s respectively for an R3400 CPU @40MHz and a 5Kc CPU @160MHz.
For a reference 64-bit `do_div' code where we have the DDIVU instruction
available to do the whole calculation right away averages at 0.0660s for
the latter CPU.

Fixes: c21004cd5b4c ("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0.")
Reported-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v2.6.30+
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mips: Do not include hi and lo in clobber list for R6 2021-05-07T08:51:36+00:00 Romain Naour romain.naour@gmail.com 2021-04-20T21:12:10+00:00 91b08c5319a5fa7c933a9f4606d9ffb90b14470c commit 1d7ba0165d8206ac073f7ac3b14fc0836b66eae7 upstream. From [1] "GCC 10 (PR 91233) won't silently allow registers that are not architecturally available to be present in the clobber list anymore, resulting in build failure for mips*r6 targets in form of: ... .../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target 146 | __asm__ volatile ( \ | ^~~~~~~ This is because base R6 ISA doesn't define hi and lo registers w/o DSP extension. This patch provides the alternative clobber list for r6 targets that won't include those registers." Since kernel 5.4 and mips support for generic vDSO [2], the kernel fail to build for mips r6 cpus with gcc 10 for the same reason as glibc. [1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8 [2] '24640f233b46 ("mips: Add support for generic vDSO")' Signed-off-by: Romain Naour <romain.naour@gmail.com> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1d7ba0165d8206ac073f7ac3b14fc0836b66eae7 upstream.

From [1]
"GCC 10 (PR 91233) won't silently allow registers that are not
architecturally available to be present in the clobber list anymore,
resulting in build failure for mips*r6 targets in form of:
...
.../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target
  146 |  __asm__ volatile (      \
      |  ^~~~~~~

This is because base R6 ISA doesn't define hi and lo registers w/o DSP
extension. This patch provides the alternative clobber list for r6 targets
that won't include those registers."

Since kernel 5.4 and mips support for generic vDSO [2], the kernel fail to
build for mips r6 cpus with gcc 10 for the same reason as glibc.

[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8
[2] '24640f233b46 ("mips: Add support for generic vDSO")'

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MIPS: Drop 32-bit asm string functions 2021-03-07T11:20:43+00:00 Paul Burton paul.burton@mips.com 2019-10-08T19:46:01+00:00 584149c771ec0110da184445bfdfb42beeb39bd9 commit 3c0be5849259b729580c23549330973a2dd513a2 upstream. We have assembly implementations of strcpy(), strncpy(), strcmp() & strncmp() which: - Are simple byte-at-a-time loops with no particular optimizations. As a comment in the code describes, they're "rather naive". - Offer no clear performance advantage over the generic C implementations - in microbenchmarks performed by Alexander Lobakin the asm functions sometimes win & sometimes lose, but generally not by large margins in either direction. - Don't support 64-bit kernels, where we already make use of the generic C implementations. - Tend to bloat kernel code size due to inlining. - Don't support CONFIG_FORTIFY_SOURCE. - Won't support nanoMIPS without rework. For all of these reasons, delete the asm implementations & make use of the generic C implementations for 32-bit kernels just like we already do for 64-bit kernels. Signed-off-by: Paul Burton <paul.burton@mips.com> URL: https://lore.kernel.org/linux-mips/a2a35f1cf58d6db19eb4af9b4ae21e35@dlink.ru/ Cc: Alexander Lobakin <alobakin@dlink.ru> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Cc: linux-mips@vger.kernel.org Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3c0be5849259b729580c23549330973a2dd513a2 upstream.

We have assembly implementations of strcpy(), strncpy(), strcmp() &
strncmp() which:

 - Are simple byte-at-a-time loops with no particular optimizations. As
   a comment in the code describes, they're "rather naive".

 - Offer no clear performance advantage over the generic C
   implementations - in microbenchmarks performed by Alexander Lobakin
   the asm functions sometimes win & sometimes lose, but generally not
   by large margins in either direction.

 - Don't support 64-bit kernels, where we already make use of the
   generic C implementations.

 - Tend to bloat kernel code size due to inlining.

 - Don't support CONFIG_FORTIFY_SOURCE.

 - Won't support nanoMIPS without rework.

For all of these reasons, delete the asm implementations & make use of
the generic C implementations for 32-bit kernels just like we already do
for 64-bit kernels.

Signed-off-by: Paul Burton <paul.burton@mips.com>
URL: https://lore.kernel.org/linux-mips/a2a35f1cf58d6db19eb4af9b4ae21e35@dlink.ru/
Cc: Alexander Lobakin <alobakin@dlink.ru>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MIPS: properly stop .eh_frame generation 2021-03-04T09:26:21+00:00 Alexander Lobakin alobakin@pm.me 2021-01-10T11:56:28+00:00 de9b26b5133fdfd34b15296a0b75516cbb2314bf [ Upstream commit 894ef530012fb5078466efdfb2c15d8b2f1565cd ] Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler from emitting .eh_frame symbols. However, as MIPS heavily uses CFI, that's not enough. Use the approach taken for x86 (as it also uses CFI) and explicitly put CFI symbols into the .debug_frame section (except for VDSO). This allows us to drop .eh_frame from DISCARDS as it's no longer being generated. Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 894ef530012fb5078466efdfb2c15d8b2f1565cd ]

Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added
-fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler
from emitting .eh_frame symbols.
However, as MIPS heavily uses CFI, that's not enough. Use the
approach taken for x86 (as it also uses CFI) and explicitly put CFI
symbols into the .debug_frame section (except for VDSO).
This allows us to drop .eh_frame from DISCARDS as it's no longer
being generated.

Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly")
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed 2020-12-02T07:49:50+00:00 Arnd Bergmann arnd@arndb.de 2020-11-11T16:52:58+00:00 1bef5f25a69234613b92a0e2456870fee4a57efc [ Upstream commit cef397038167ac15d085914493d6c86385773709 ] Stefan Agner reported a bug when using zsram on 32-bit Arm machines with RAM above the 4GB address boundary: Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = a27bd01c [00000000] *pgd=236a0003, *pmd=1ffa64003 Internal error: Oops: 207 [#1] SMP ARM Modules linked in: mdio_bcm_unimac(+) brcmfmac cfg80211 brcmutil raspberrypi_hwmon hci_uart crc32_arm_ce bcm2711_thermal phy_generic genet CPU: 0 PID: 123 Comm: mkfs.ext4 Not tainted 5.9.6 #1 Hardware name: BCM2711 PC is at zs_map_object+0x94/0x338 LR is at zram_bvec_rw.constprop.0+0x330/0xa64 pc : [<c0602b38>] lr : [<c0bda6a0>] psr: 60000013 sp : e376bbe0 ip : 00000000 fp : c1e2921c r10: 00000002 r9 : c1dda730 r8 : 00000000 r7 : e8ff7a00 r6 : 00000000 r5 : 02f9ffa0 r4 : e3710000 r3 : 000fdffe r2 : c1e0ce80 r1 : ebf979a0 r0 : 00000000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 30c5383d Table: 235c2a80 DAC: fffffffd Process mkfs.ext4 (pid: 123, stack limit = 0x495a22e6) Stack: (0xe376bbe0 to 0xe376c000) As it turns out, zsram needs to know the maximum memory size, which is defined in MAX_PHYSMEM_BITS when CONFIG_SPARSEMEM is set, or in MAX_POSSIBLE_PHYSMEM_BITS on the x86 architecture. The same problem will be hit on all 32-bit architectures that have a physical address space larger than 4GB and happen to not enable sparsemem and include asm/sparsemem.h from asm/pgtable.h. After the initial discussion, I suggested just always defining MAX_POSSIBLE_PHYSMEM_BITS whenever CONFIG_PHYS_ADDR_T_64BIT is set, or provoking a build error otherwise. This addresses all configurations that can currently have this runtime bug, but leaves all other configurations unchanged. I looked up the possible number of bits in source code and datasheets, here is what I found: - on ARC, CONFIG_ARC_HAS_PAE40 controls whether 32 or 40 bits are used - on ARM, CONFIG_LPAE enables 40 bit addressing, without it we never support more than 32 bits, even though supersections in theory allow up to 40 bits as well. - on MIPS, some MIPS32r1 or later chips support 36 bits, and MIPS32r5 XPA supports up to 60 bits in theory, but 40 bits are more than anyone will ever ship - On PowerPC, there are three different implementations of 36 bit addressing, but 32-bit is used without CONFIG_PTE_64BIT - On RISC-V, the normal page table format can support 34 bit addressing. There is no highmem support on RISC-V, so anything above 2GB is unused, but it might be useful to eventually support CONFIG_ZRAM for high pages. Fixes: 61989a80fb3a ("staging: zsmalloc: zsmalloc memory allocation library") Fixes: 02390b87a945 ("mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS") Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Reviewed-by: Stefan Agner <stefan@agner.ch> Tested-by: Stefan Agner <stefan@agner.ch> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Link: https://lore.kernel.org/linux-mm/bdfa44bf1c570b05d6c70898e2bbb0acf234ecdf.1604762181.git.stefan@agner.ch/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit cef397038167ac15d085914493d6c86385773709 ]

Stefan Agner reported a bug when using zsram on 32-bit Arm machines
with RAM above the 4GB address boundary:

  Unable to handle kernel NULL pointer dereference at virtual address 00000000
  pgd = a27bd01c
  [00000000] *pgd=236a0003, *pmd=1ffa64003
  Internal error: Oops: 207 [#1] SMP ARM
  Modules linked in: mdio_bcm_unimac(+) brcmfmac cfg80211 brcmutil raspberrypi_hwmon hci_uart crc32_arm_ce bcm2711_thermal phy_generic genet
  CPU: 0 PID: 123 Comm: mkfs.ext4 Not tainted 5.9.6 #1
  Hardware name: BCM2711
  PC is at zs_map_object+0x94/0x338
  LR is at zram_bvec_rw.constprop.0+0x330/0xa64
  pc : [<c0602b38>]    lr : [<c0bda6a0>]    psr: 60000013
  sp : e376bbe0  ip : 00000000  fp : c1e2921c
  r10: 00000002  r9 : c1dda730  r8 : 00000000
  r7 : e8ff7a00  r6 : 00000000  r5 : 02f9ffa0  r4 : e3710000
  r3 : 000fdffe  r2 : c1e0ce80  r1 : ebf979a0  r0 : 00000000
  Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
  Control: 30c5383d  Table: 235c2a80  DAC: fffffffd
  Process mkfs.ext4 (pid: 123, stack limit = 0x495a22e6)
  Stack: (0xe376bbe0 to 0xe376c000)

As it turns out, zsram needs to know the maximum memory size, which
is defined in MAX_PHYSMEM_BITS when CONFIG_SPARSEMEM is set, or in
MAX_POSSIBLE_PHYSMEM_BITS on the x86 architecture.

The same problem will be hit on all 32-bit architectures that have a
physical address space larger than 4GB and happen to not enable sparsemem
and include asm/sparsemem.h from asm/pgtable.h.

After the initial discussion, I suggested just always defining
MAX_POSSIBLE_PHYSMEM_BITS whenever CONFIG_PHYS_ADDR_T_64BIT is
set, or provoking a build error otherwise. This addresses all
configurations that can currently have this runtime bug, but
leaves all other configurations unchanged.

I looked up the possible number of bits in source code and
datasheets, here is what I found:

 - on ARC, CONFIG_ARC_HAS_PAE40 controls whether 32 or 40 bits are used
 - on ARM, CONFIG_LPAE enables 40 bit addressing, without it we never
   support more than 32 bits, even though supersections in theory allow
   up to 40 bits as well.
 - on MIPS, some MIPS32r1 or later chips support 36 bits, and MIPS32r5
   XPA supports up to 60 bits in theory, but 40 bits are more than
   anyone will ever ship
 - On PowerPC, there are three different implementations of 36 bit
   addressing, but 32-bit is used without CONFIG_PTE_64BIT
 - On RISC-V, the normal page table format can support 34 bit
   addressing. There is no highmem support on RISC-V, so anything
   above 2GB is unused, but it might be useful to eventually support
   CONFIG_ZRAM for high pages.

Fixes: 61989a80fb3a ("staging: zsmalloc: zsmalloc memory allocation library")
Fixes: 02390b87a945 ("mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS")
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/linux-mm/bdfa44bf1c570b05d6c70898e2bbb0acf234ecdf.1604762181.git.stefan@agner.ch/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
MIPS: Add the missing 'CPU_1074K' into __get_cpu_type() 2020-10-01T11:18:20+00:00 Wei Li liwei391@huawei.com 2020-09-23T06:53:12+00:00 5c58104841fe073bbf8a80b4079f58e04005f27d [ Upstream commit e393fbe6fa27af23f78df6e16a8fd2963578a8c4 ] Commit 442e14a2c55e ("MIPS: Add 1074K CPU support explicitly.") split 1074K from the 74K as an unique CPU type, while it missed to add the 'CPU_1074K' in __get_cpu_type(). So let's add it back. Fixes: 442e14a2c55e ("MIPS: Add 1074K CPU support explicitly.") Signed-off-by: Wei Li <liwei391@huawei.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e393fbe6fa27af23f78df6e16a8fd2963578a8c4 ]

Commit 442e14a2c55e ("MIPS: Add 1074K CPU support explicitly.") split
1074K from the 74K as an unique CPU type, while it missed to add the
'CPU_1074K' in __get_cpu_type(). So let's add it back.

Fixes: 442e14a2c55e ("MIPS: Add 1074K CPU support explicitly.")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
KVM: Pass MMU notifier range flags to kvm_unmap_hva_range() 2020-08-26T08:41:08+00:00 Will Deacon will@kernel.org 2020-08-11T10:27:24+00:00 e1818ffcca0ea32d541ed554a44bb1de975ab8fa commit fdfe7cbd58806522e799e2a50a15aee7f2cbb7b6 upstream. The 'flags' field of 'struct mmu_notifier_range' is used to indicate whether invalidate_range_{start,end}() are permitted to block. In the case of kvm_mmu_notifier_invalidate_range_start(), this field is not forwarded on to the architecture-specific implementation of kvm_unmap_hva_range() and therefore the backend cannot sensibly decide whether or not to block. Add an extra 'flags' parameter to kvm_unmap_hva_range() so that architectures are aware as to whether or not they are permitted to block. Cc: <stable@vger.kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20200811102725.7121-2-will@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit fdfe7cbd58806522e799e2a50a15aee7f2cbb7b6 upstream.

The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.

Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.

Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-2-will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mips: MAAR: Use more precise address mask 2020-06-22T07:31:07+00:00 Serge Semin Sergey.Semin@baikalelectronics.ru 2020-05-21T00:34:37+00:00 34a45e84edc5c02f2f99d1e9ab8416c4f0fd475a [ Upstream commit bbb5946eb545fab8ad8f46bce8a803e1c0c39d47 ] Indeed according to the MIPS32 Privileged Resource Architecgture the MAAR pair register address field either takes [12:31] bits for non-XPA systems and [12:55] otherwise. In any case the current address mask is just wrong for 64-bit and 32-bits XPA chips. So lets extend it to 59-bits of physical address value. This shall cover the 64-bits architecture and systems with XPA enabled, and won't cause any problem for non-XPA 32-bit systems, since address values exceeding the architecture specific MAAR mask will be just truncated with setting zeros in the unsupported upper bits. Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit bbb5946eb545fab8ad8f46bce8a803e1c0c39d47 ]

Indeed according to the MIPS32 Privileged Resource Architecgture the MAAR
pair register address field either takes [12:31] bits for non-XPA systems
and [12:55] otherwise. In any case the current address mask is just
wrong for 64-bit and 32-bits XPA chips. So lets extend it to 59-bits
of physical address value. This shall cover the 64-bits architecture and
systems with XPA enabled, and won't cause any problem for non-XPA 32-bit
systems, since address values exceeding the architecture specific MAAR
mask will be just truncated with setting zeros in the unsupported upper
bits.

Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>