linux-stable.git/arch/mips/include, branch linux-5.11.y Linux kernel stable tree MIPS: Avoid handcoded DIVU in `__div64_32' altogether 2021-05-19T08:29:56+00:00 Maciej W. Rozycki macro@orcam.me.uk 2021-04-22T20:36:12+00:00 6470518351f49f55a7c5919934c7163b6ab47b83 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 2021-05-19T08:29:56+00:00 Maciej W. Rozycki macro@orcam.me.uk 2021-04-20T02:50:48+00:00 cd45216aa90b823a7bb98732a622c344c282aadc 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 2021-05-19T08:29:56+00:00 Maciej W. Rozycki macro@orcam.me.uk 2021-04-20T02:50:40+00:00 93d5be9a64b9d9bac3d92986b62db8c14479feac 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: fix local_irq_{disable,enable} in asmmacro.h 2021-05-14T08:50:01+00:00 Huang Pei huangpei@loongson.cn 2021-03-23T02:34:02+00:00 cf093c0b8af2b0a399249842a69f8cb38200a2e0 [ Upstream commit 05c4e2721d7af0df7bc1378a23712a0fd16947b5 ] commit ba9196d2e005 ("MIPS: Make DIEI support as a config option") use CPU_HAS_DIEI to indicate whether di/ei is implemented correctly, without this patch, "local_irq_disable" from entry.S in 3A1000 (with buggy di/ei) lose protection of commit e97c5b609880 ("MIPS: Make irqflags.h functions preempt-safe for non-mipsr2 cpus") Fixes: ba9196d2e005 ("MIPS: Make DIEI support as a config option") Signed-off-by: Huang Pei <huangpei@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 05c4e2721d7af0df7bc1378a23712a0fd16947b5 ]

commit ba9196d2e005 ("MIPS: Make DIEI support as a config option")
use CPU_HAS_DIEI to indicate whether di/ei is implemented correctly,
without this patch, "local_irq_disable" from entry.S in 3A1000
(with buggy di/ei) lose protection of commit e97c5b609880 ("MIPS:
Make irqflags.h functions preempt-safe for non-mipsr2 cpus")

Fixes: ba9196d2e005 ("MIPS: Make DIEI support as a config option")
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
mips: Do not include hi and lo in clobber list for R6 2021-05-07T09:11:22+00:00 Romain Naour romain.naour@gmail.com 2021-04-20T21:12:10+00:00 e370213feea79476f36cf9a1a17ca711cc773aac 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: kernel: Reserve exception base early to prevent corruption 2021-03-17T16:11:29+00:00 Thomas Bogendoerfer tsbogend@alpha.franken.de 2021-03-08T09:24:47+00:00 f4d509c9978c586161e262481bc9ae59906bd706 [ Upstream commit bd67b711bfaa02cf19e88aa2d9edae5c1c1d2739 ] BMIPS is one of the few platforms that do change the exception base. After commit 2dcb39645441 ("memblock: do not start bottom-up allocations with kernel_end") we started seeing BMIPS boards fail to boot with the built-in FDT being corrupted. Before the cited commit, early allocations would be in the [kernel_end, RAM_END] range, but after commit they would be within [RAM_START + PAGE_SIZE, RAM_END]. The custom exception base handler that is installed by bmips_ebase_setup() done for BMIPS5000 CPUs ends-up trampling on the memory region allocated by unflatten_and_copy_device_tree() thus corrupting the FDT used by the kernel. To fix this, we need to perform an early reservation of the custom exception space. Additional we reserve the first 4k (1k for R3k) for either normal exception vector space (legacy CPUs) or special vectors like cache exceptions. Huge thanks to Serge for analysing and proposing a solution to this issue. Fixes: 2dcb39645441 ("memblock: do not start bottom-up allocations with kernel_end") Reported-by: Kamal Dasu <kdasu.kdev@gmail.com> Debugged-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Tested-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit bd67b711bfaa02cf19e88aa2d9edae5c1c1d2739 ]

BMIPS is one of the few platforms that do change the exception base.
After commit 2dcb39645441 ("memblock: do not start bottom-up allocations
with kernel_end") we started seeing BMIPS boards fail to boot with the
built-in FDT being corrupted.

Before the cited commit, early allocations would be in the [kernel_end,
RAM_END] range, but after commit they would be within [RAM_START +
PAGE_SIZE, RAM_END].

The custom exception base handler that is installed by
bmips_ebase_setup() done for BMIPS5000 CPUs ends-up trampling on the
memory region allocated by unflatten_and_copy_device_tree() thus
corrupting the FDT used by the kernel.

To fix this, we need to perform an early reservation of the custom
exception space. Additional we reserve the first 4k (1k for R3k) for
either normal exception vector space (legacy CPUs) or special vectors
like cache exceptions.

Huge thanks to Serge for analysing and proposing a solution to this
issue.

Fixes: 2dcb39645441 ("memblock: do not start bottom-up allocations with kernel_end")
Reported-by: Kamal Dasu <kdasu.kdev@gmail.com>
Debugged-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
MIPS: relocatable: Provide kaslr_offset() to get the kernel offset 2021-03-04T11:14:23+00:00 Jinyang He hejinyang@loongson.cn 2021-02-05T10:11:21+00:00 cd123dfb900c814522a1dc89bd0bd699c9dc821f [ Upstream commit d4d3ef8b347b73aa60f60f4be06acf1643e79f34 ] Provide kaslr_offset() to get the kernel offset when KASLR is enabled. Error may occur before update_kaslr_offset(), so put it at the end of the offset branch. Fixes: a307a4ce9ecd ("MIPS: Loongson64: Add KASLR support") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d4d3ef8b347b73aa60f60f4be06acf1643e79f34 ]

Provide kaslr_offset() to get the kernel offset when KASLR is enabled.
Error may occur before update_kaslr_offset(), so put it at the end of
the offset branch.

Fixes: a307a4ce9ecd ("MIPS: Loongson64: Add KASLR support")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
MIPS: Compare __SYNC_loongson3_war against 0 2021-03-04T11:14:13+00:00 Nathan Chancellor natechancellor@gmail.com 2021-01-14T17:34:16+00:00 5069373cae8a8fa010b5284ab8b7c650f933b1ac [ Upstream commit 8790ccf8daf1a8c53b6cb8ce0c9a109274bd3fa8 ] When building with clang when CONFIG_CPU_LOONGSON3_WORKAROUNDS is enabled: In file included from lib/errseq.c:4: In file included from ./include/linux/atomic.h:7: ./arch/mips/include/asm/atomic.h:52:1: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare] ATOMIC_OPS(atomic64, s64) ^ ./arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS' return cmpxchg(&v->counter, o, n); ^ ./arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg' if (!__SYNC_loongson3_war) ^ ./arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war' # define __SYNC_loongson3_war (1 << 31) ^ While it is not wrong that the result of this shift is always true in a boolean context, it is not a problem here. Regardless, the warning is really noisy so rather than making the shift a boolean implicitly, use it in an equality comparison so the shift is used as an integer value. Fixes: 4d1dbfe6cbec ("MIPS: atomic: Emit Loongson3 sync workarounds within asm") Fixes: a91f2a1dba44 ("MIPS: cmpxchg: Omit redundant barriers for Loongson3") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8790ccf8daf1a8c53b6cb8ce0c9a109274bd3fa8 ]

When building with clang when CONFIG_CPU_LOONGSON3_WORKAROUNDS is
enabled:

 In file included from lib/errseq.c:4:
 In file included from ./include/linux/atomic.h:7:
 ./arch/mips/include/asm/atomic.h:52:1: warning: converting the result of
 '<<' to a boolean always evaluates to true
 [-Wtautological-constant-compare]
 ATOMIC_OPS(atomic64, s64)
 ^
 ./arch/mips/include/asm/atomic.h:40:9: note: expanded from macro
 'ATOMIC_OPS'
         return cmpxchg(&v->counter, o, n);
                ^
 ./arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro
 'cmpxchg'
         if (!__SYNC_loongson3_war)
              ^
 ./arch/mips/include/asm/sync.h:147:34: note: expanded from macro
 '__SYNC_loongson3_war'
 # define __SYNC_loongson3_war   (1 << 31)
                                    ^

While it is not wrong that the result of this shift is always true in a
boolean context, it is not a problem here. Regardless, the warning is
really noisy so rather than making the shift a boolean implicitly, use
it in an equality comparison so the shift is used as an integer value.

Fixes: 4d1dbfe6cbec ("MIPS: atomic: Emit Loongson3 sync workarounds within asm")
Fixes: a91f2a1dba44 ("MIPS: cmpxchg: Omit redundant barriers for Loongson3")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
MIPS: properly stop .eh_frame generation 2021-03-04T11:14:13+00:00 Alexander Lobakin alobakin@pm.me 2021-01-10T11:56:28+00:00 ebd7426b1267433d052fcf54b46d00f0e9338da5 [ 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>
mips/mm/highmem: use set_pte() for kmap_local() 2021-01-24T18:34:52+00:00 Thomas Gleixner tglx@linutronix.de 2021-01-24T05:02:07+00:00 8c0d5d78f3596e203e9cd27563a8380649c03ad0 set_pte_at() on MIPS invokes update_cache() which might recurse into kmap_local(). Use set_pte() like the original MIPS highmem implementation did. Link: https://lkml.kernel.org/r/20210112170411.187513575@linutronix.de Fixes: a4c33e83bca1 ("mips/mm/highmem: Switch to generic kmap atomic") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Paul Cercueil <paul@crapouillou.net> Reported-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
set_pte_at() on MIPS invokes update_cache() which might recurse into
kmap_local().

Use set_pte() like the original MIPS highmem implementation did.

Link: https://lkml.kernel.org/r/20210112170411.187513575@linutronix.de
Fixes: a4c33e83bca1 ("mips/mm/highmem: Switch to generic kmap atomic")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Paul Cercueil <paul@crapouillou.net>
Reported-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>