commit f0a6c68f69 upstream.
Fix the discrepancy between the two places we check for the CP0 counter
erratum in along with the incorrect comparison of the R4400 revision
number against 0x30 which matches none and consistently consider all
R4000 and R4400 processors affected, as documented in processor errata
publications[1][2][3], following the mapping between CP0 PRId register
values and processor models:
PRId | Processor Model
---------+--------------------
00000422 | R4000 Revision 2.2
00000430 | R4000 Revision 3.0
00000440 | R4400 Revision 1.0
00000450 | R4400 Revision 2.0
00000460 | R4400 Revision 3.0
No other revision of either processor has ever been spotted.
Contrary to what has been stated in commit ce202cbb9e ("[MIPS] Assume
R4000/R4400 newer than 3.0 don't have the mfc0 count bug") marking the
CP0 counter as buggy does not preclude it from being used as either a
clock event or a clock source device. It just cannot be used as both at
a time, because in that case clock event interrupts will be occasionally
lost, and the use as a clock event device takes precedence.
Compare against 0x4ff in `can_use_mips_counter' so that a single machine
instruction is produced.
References:
[1] "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0", MIPS
Technologies Inc., May 10, 1994, Erratum 53, p.13
[2] "MIPS R4400PC/SC Errata, Processor Revision 1.0", MIPS Technologies
Inc., February 9, 1994, Erratum 21, p.4
[3] "MIPS R4400PC/SC Errata, Processor Revision 2.0 & 3.0", MIPS
Technologies Inc., January 24, 1995, Erratum 14, p.3
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: ce202cbb9e ("[MIPS] Assume R4000/R4400 newer than 3.0 don't have the mfc0 count bug")
Cc: stable@vger.kernel.org # v2.6.24+
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d17b664173 ]
With KCFLAGS="-O3", I was able to trigger a fortify-source
memcpy() overflow panic on set_vi_srs_handler().
Although O3 level is not supported in the mainline, under some
conditions that may've happened with any optimization settings,
it's just a matter of inlining luck. The panic itself is correct,
more precisely, 50/50 false-positive and not at the same time.
From the one side, no real overflow happens. Exception handler
defined in asm just gets copied to some reserved places in the
memory.
But the reason behind is that C code refers to that exception
handler declares it as `char`, i.e. something of 1 byte length.
It's obvious that the asm function itself is way more than 1 byte,
so fortify logics thought we are going to past the symbol declared.
The standard way to refer to asm symbols from C code which is not
supposed to be called from C is to declare them as
`extern const u8[]`. This is fully correct from any point of view,
as any code itself is just a bunch of bytes (including 0 as it is
for syms like _stext/_etext/etc.), and the exact size is not known
at the moment of compilation.
Adjust the type of the except_vec_vi_*() and related variables.
Make set_handler() take `const` as a second argument to avoid
cast-away warnings and give a little more room for optimization.
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2bc5bab9a7 ]
pgd page is freed by generic implementation pgd_free() since commit
f9cb654cb5 ("asm-generic: pgalloc: provide generic pgd_free()"),
however, there are scenarios that the system uses more than one page as
the pgd table, in such cases the generic implementation pgd_free() won't
be applicable anymore. For example, when PAGE_SIZE_4KB is enabled and
MIPS_VA_BITS_48 is not enabled in a 64bit system, the macro "PGD_ORDER"
will be set as "1", which will cause allocating two pages as the pgd
table. Well, at the same time, the generic implementation pgd_free()
just free one pgd page, which will result in the memory leak.
The memory leak can be easily detected by executing shell command:
"while true; do ls > /dev/null; grep MemFree /proc/meminfo; done"
Fixes: f9cb654cb5 ("asm-generic: pgalloc: provide generic pgd_free()")
Signed-off-by: Yaliang Wang <Yaliang.Wang@windriver.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 244eae91a9 upstream.
Recent tightening of the opcode table in binutils so as to consistently
disallow the assembly or disassembly of CP0 instructions not supported
by the processor architecture chosen has caused a regression like below:
arch/mips/dec/prom/locore.S: Assembler messages:
arch/mips/dec/prom/locore.S:29: Error: opcode not supported on this processor: r4600 (mips3) `rfe'
in a piece of code used to probe for memory with PMAX DECstation models,
which have non-REX firmware. Those computers always have an R2000 CPU
and consequently the exception handler used in memory probing uses the
RFE instruction, which those processors use.
While adding 64-bit support this code was correctly excluded for 64-bit
configurations, however it should have also been excluded for irrelevant
32-bit configurations. Do this now then, and only enable PMAX memory
probing for R3k systems.
Reported-by: Jan-Benedict Glaw <jbglaw@lug-owl.de>
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org # v2.6.12+
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 95339b7067 ]
A large number of the following errors is reported when compiling
with clang:
cvmx-bootinfo.h:326:3: error: adding 'int' to a string does not append to the string [-Werror,-Wstring-plus-int]
ENUM_BRD_TYPE_CASE(CVMX_BOARD_TYPE_NULL)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cvmx-bootinfo.h:321:20: note: expanded from macro 'ENUM_BRD_TYPE_CASE'
case x: return(#x + 16); /* Skip CVMX_BOARD_TYPE_ */
~~~^~~~
cvmx-bootinfo.h:326:3: note: use array indexing to silence this warning
cvmx-bootinfo.h:321:20: note: expanded from macro 'ENUM_BRD_TYPE_CASE'
case x: return(#x + 16); /* Skip CVMX_BOARD_TYPE_ */
^
Follow the prompts to use the address operator '&' to fix this error.
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f2c6c22fa8 ]
LLVM's integrated assembler does not support 'slti <reg>, <imm>':
<instantiation>:16:12: error: invalid operand for instruction
slti $12, (0x6300 | 0x0008)
^
arch/mips/kernel/head.S:86:2: note: while in macro instantiation
kernel_entry_setup # cpu specific setup
^
<instantiation>:16:12: error: invalid operand for instruction
slti $12, (0x6300 | 0x0008)
^
arch/mips/kernel/head.S:150:2: note: while in macro instantiation
smp_slave_setup
^
To increase compatibility with LLVM's integrated assembler, use the full
form of 'slti <reg>, <reg>, <imm>', which matches the rest of
arch/mips/. This does not result in any change for GNU as.
Link: https://github.com/ClangBuiltLinux/linux/issues/1526
Reported-by: Ryutaroh Matsumoto <ryutaroh@ict.e.titech.ac.jp>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit a923a2676e upstream.
Fix assembly errors like:
{standard input}: Assembler messages:
{standard input}:287: Error: opcode not supported on this processor: mips3 (mips3) `dins $10,$7,32,32'
{standard input}:680: Error: opcode not supported on this processor: mips3 (mips3) `dins $10,$7,32,32'
{standard input}:1274: Error: opcode not supported on this processor: mips3 (mips3) `dins $12,$9,32,32'
{standard input}:2175: Error: opcode not supported on this processor: mips3 (mips3) `dins $10,$7,32,32'
make[1]: *** [scripts/Makefile.build:277: mm/highmem.o] Error 1
with code produced from `__cmpxchg64' for MIPS64r2 CPU configurations
using CONFIG_32BIT and CONFIG_PHYS_ADDR_T_64BIT.
This is due to MIPS_ISA_ARCH_LEVEL downgrading the assembly architecture
to `r4000' i.e. MIPS III for MIPS64r2 configurations, while there is a
block of code containing a DINS MIPS64r2 instruction conditionalized on
MIPS_ISA_REV >= 2 within the scope of the downgrade.
The assembly architecture override code pattern has been put there for
LL/SC instructions, so that code compiles for configurations that select
a processor to build for that does not support these instructions while
still providing run-time support for processors that do, dynamically
switched by non-constant `cpu_has_llsc'. It went in with linux-mips.org
commit aac8aa7717 ("Enable a suitable ISA for the assembler around
ll/sc so that code builds even for processors that don't support the
instructions. Plus minor formatting fixes.") back in 2005.
Fix the problem by wrapping these instructions along with the adjacent
SYNC instructions only, following the practice established with commit
cfd54de3b0 ("MIPS: Avoid move psuedo-instruction whilst using
MIPS_ISA_LEVEL") and commit 378ed6f0e3 ("MIPS: Avoid using .set mips0
to restore ISA"). Strictly speaking the SYNC instructions do not have
to be wrapped as they are only used as a Loongson3 erratum workaround,
so they will be enabled in the assembler by default, but do this so as
to keep code consistent with other places.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: c7e2d71dda ("MIPS: Fix set_pte() for Netlogic XLR using cmpxchg64()")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 18b8f5b6fc ]
mips_cm_error_report() extracts the cause and other cause from the error
register using shifts. This works fine for the former, as it is stored
in the top bits, and the shift will thus remove all non-related bits.
However, the latter is stored in the bottom bits, hence thus needs masking
to get rid of non-related bits. Without such masking, using it as an
index into the cm2_causes[] array will lead to an out-of-bounds access,
probably causing a crash.
Fix this by using FIELD_GET() instead. Bite the bullet and convert all
MIPS CM handling to the bitfield API, to improve readability and safety.
Fixes: 3885c2b463 ("MIPS: CM: Add support for reporting CM cache errors")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 47ce8527fb ]
Accessing raw timers (currently only CLOCK_MONOTONIC_RAW) through VDSO
doesn't return the correct time when using the GIC as clock source.
The address of the GIC mapped page is in this case not calculated
correctly. The GIC mapped page is calculated from the VDSO data by
subtracting PAGE_SIZE:
void *get_gic(const struct vdso_data *data) {
return (void __iomem *)data - PAGE_SIZE;
}
However, the data pointer is not page aligned for raw clock sources.
This is because the VDSO data for raw clock sources (CS_RAW = 1) is
stored after the VDSO data for coarse clock sources (CS_HRES_COARSE = 0).
Therefore, only the VDSO data for CS_HRES_COARSE is page aligned:
+--------------------+
| |
| vd[CS_RAW] | ---+
| vd[CS_HRES_COARSE] | |
+--------------------+ | -PAGE_SIZE
| | |
| GIC mapped page | <--+
| |
+--------------------+
When __arch_get_hw_counter() is called with &vd[CS_RAW], get_gic returns
the wrong address (somewhere inside the GIC mapped page). The GIC counter
values are not returned which results in an invalid time.
Fixes: a7f4df4e21 ("MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime()")
Signed-off-by: Martin Fäcknitz <faecknitz@hotsplots.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit cad065ed8d upstream.
MIPS MT extensions were added with the MIPS 34K processor, which was
based on the MIPS32r2 ISA.
This fixes a build error when building a generic kernel for a MIPS32r1
CPU.
Fixes: c434b9f80b ("MIPS: Kconfig: add MIPS_GENERIC_KERNEL symbol")
Cc: stable@vger.kernel.org # v5.9
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ed914d48b6 ]
This fixes Page Table accounting bug.
MIPS is the ONLY arch just defining __HAVE_ARCH_PMD_ALLOC_ONE alone.
Since commit b2b29d6d01 (mm: account PMD tables like PTE tables),
"pmd_free" in asm-generic with PMD table accounting and "pmd_alloc_one"
in MIPS without PMD table accounting causes PageTable accounting number
negative, which read by global_zone_page_state(), always returns 0.
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 33ae8f801a ]
If multiple threads are accessing the same huge page at the same
time, hugetlb_cow will be called if one thread write the COW huge
page. And function huge_ptep_clear_flush is called to notify other
threads to clear the huge pte tlb entry. The other threads clear
the huge pte tlb entry and reload it from page table, the reload
huge pte entry may be old.
This patch fixes this issue on mips platform, and it clears huge
pte entry before notifying other threads to flush current huge
page entry, it is similar with other architectures.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit cf02ce742f ]
When 32-bit MIPS huge page support is enabled, we halve the number of
pointers a PTE page holds, making its last half go to waste.
Correspondingly, we should halve the number of kmap entries, as we just
initialized only a single pte table for that in pagetable_init().
Fixes: 35476311e5 ("MIPS: Add partial 32-bit huge page support")
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>
commit 25ab14cbe9 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 c1d337d45e 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 c49f71f607 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 c21004cd5b
("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: c21004cd5b ("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>
[ Upstream commit 05c4e2721d ]
commit ba9196d2e0 ("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 e97c5b6098 ("MIPS:
Make irqflags.h functions preempt-safe for non-mipsr2 cpus")
Fixes: ba9196d2e0 ("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>
commit 1d7ba0165d 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>
[ Upstream commit 8790ccf8da ]
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: 4d1dbfe6cb ("MIPS: atomic: Emit Loongson3 sync workarounds within asm")
Fixes: a91f2a1dba ("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 894ef53001 ]
Commit 866b6a89c6 ("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: 866b6a89c6 ("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>
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: 61989a80fb ("staging: zsmalloc: zsmalloc memory allocation library")
Fixes: 02390b87a9 ("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>
