Allow vectors to be either merged into the kernel .text or put at a
fixed virtual address independently of XIP option. Drop option that
puts vectors at a fixed offset from the kernel text. Add choice to
Kconfig.
Vectors at fixed virtual address may be useful for XIP-aware MTD support
and for noMMU configurations with available IRAM. Configurations without
VECBASE register must put their vectors at specific locations regardless
of the selected option. All other configurations should happily use
merged vectors.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
There's no real dependency between SMP and XIP, allow them to be
selected together. Always define 2- and 4-argument SECTION_VECTOR
macros, always use 4-argument macro for the secondary reset vector and
always define relocation entry for it.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
On XIP kernels it makes sense to have exception vectors and fast
exception handlers together (in a fast memory). In addition, with MTD
XIP support both vectors and fast exception handlers must be outside of
the FLASH.
Add section .exception.text and move fast exception handlers to it.
Put it together with vectors when vectors are outside of the .text.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Pull Xtensa updates from Max Filippov:
- add support for execute in place (XIP) kernels
- improvements in inline assembly: use named arguments and "m"
constraints where possible
- improve stack dumping
- clean up system_call code and syscall tracing
- various small fixes and cleanups
* tag 'xtensa-20191201' of git://github.com/jcmvbkbc/linux-xtensa: (30 commits)
xtensa: clean up system_call/xtensa_rt_sigreturn interaction
xtensa: fix system_call interaction with ptrace
xtensa: rearrange syscall tracing
xtensa: fix syscall_set_return_value
xtensa: drop unneeded headers from coprocessor.S
xtensa: entry: Remove unneeded need_resched() loop
xtensa: use MEMBLOCK_ALLOC_ANYWHERE for KASAN shadow map
xtensa: fix TLB sanity checker
xtensa: get rid of __ARCH_USE_5LEVEL_HACK
xtensa: mm: fix PMD folding implementation
xtensa: make stack dump size configurable
xtensa: improve stack dumping
xtensa: use "m" constraint instead of "r" in futex.h assembly
xtensa: use "m" constraint instead of "a" in cmpxchg.h assembly
xtensa: use named assembly arguments in cmpxchg.h
xtensa: use "m" constraint instead of "a" in atomic.h assembly
xtensa: use named assembly arguments in atomic.h
xtensa: use "m" constraint instead of "a" in bitops.h assembly
xtensa: use named assembly arguments in bitops.h
xtensa: use macros to generate *_bit and test_and_*_bit functions
...
XIP (eXecute In Place) kernel image is the image that can be run
directly from ROM, using RAM only for writable data.
XIP xtensa kernel differs from regular xtensa kernel in the following
ways:
- it has exception/IRQ vectors merged into text section. No vectors
relocation takes place at kernel startup.
- .data/.bss location must be specified in the kernel configuration,
its content is copied there in the _startup function.
- .init.text is merged with the rest of text and is executed from ROM.
- when MMU is used the virtual address where the kernel will be mapped
must be specified in the kernel configuration. It may be in the KSEG
or in the KIO, __pa macro is adjusted to be able to handle both.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Introduce the header arch/xtensa/include/asm/core.h that provides
definitions for XCHAL macros missing in older xtensa releases. Use this
header instead of variant/core.h
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Pull Xtensa fixes and cleanups from Max Filippov:
- use ZONE_NORMAL instead of ZONE_DMA
- fix Image.elf build error caused by assignment of incorrect address
to the .note.Linux section
- clean up debug and property sections in the vmlinux.lds.S
* tag 'xtensa-20181101' of git://github.com/jcmvbkbc/linux-xtensa:
xtensa: clean up xtensa-specific property sections
xtensa: use DWARF_DEBUG in the vmlinux.lds.S
xtensa: add NOTES section to the linker script
xtensa: remove ZONE_DMA
xtensa-specific property sections may be section-specific. They should
be collected in the order of appearance. .gnu.linkonce.prop.* input
sections should be collected into the .xt.prop output section.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Xtensa doesn't have anything custom in its debug sections list. Use
macro DWARF_DEBUG instead of opencoding it.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This section collects all source .note.* sections together in the
vmlinux image. Without it .note.Linux section may be placed at address
0, while the rest of the kernel is at its normal address, resulting in a
huge vmlinux.bin image that may not be linked into the xtensa Image.elf.
Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
platform/hardware.h no longer supply any information for processor.h,
vectors.h, setup.c or vmlinux.lds.S, don't include it.
This header is now empty in the platforms/iss, so remove it altogether.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
vmlinux.lds.S doesn't do anything special with literals, so instead of
keeping them separate put them into the corresponding text sections.
Drop explicit .literal sections from the vmlinux.lds.S, use standard
section macros. Mark literal pool locations in the assembly sources.
Unfortunately assembler doesn't put literals into .init sections and
external libgcc may still have .literal sections, so sed transformation
to the linker script is still needed.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Double exception vector only needs 20 bytes of space for 5 literals, not
48. Reduce the reservation for double exception vector literals
accordingly. This fixes build for configurations with small user
exception vector size.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Currently code for exception/IRQ vectors is stored in kernel image as
initialization data and is copied to its working addresses during
startup. It doesn't always make sense. In many cases vectors location
can be automatically decided at kernel link time and code can be placed
right there. This is especially useful for XIP kernel.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Make kernel load address explicit, independent of the selected MMU
configuration and configurable from Kconfig. Do not restrict it to the
first 512MB of the physical address space.
Cleanup kernel memory layout macros:
- rename VECBASE_RESET_VADDR to VECBASE_VADDR, XC_VADDR to VECTOR_VADDR;
- drop VIRTUAL_MEMORY_ADDRESS and LOAD_MEMORY_ADDRESS;
- introduce PHYS_OFFSET and use it in __va and __pa definitions;
- synchronize MMU/noMMU vectors, drop unused NMI vector;
- replace hardcoded vectors offset of 0x3000 with Kconfig symbol.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
There are no .bootstrap or .ResetVector.text sections linked to the
vmlinux image, drop these sections from vmlinux.ld.S. Drop
RESET_VECTOR_VADDR definition only used for .ResetVector.text.
Drop remapped copies of primary and secondary reset vectors, as modern
gdb don't have problems stepping through instructions at arbitrary
locations. Drop corresponding sections from the corresponding linker
scripts.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
There are multiple factors adding to the issue in different
configurations:
- commit 17290231df ("xtensa: add fixup for double exception raised
in window overflow") added function window_overflow_restore_a0_fixup to
double exception vector overlapping reset vector location of secondary
processor cores.
- on MMUv2 cores RESET_VECTOR1_VADDR may point to uncached kernel memory
making code overlapping depend on cache type and size, so that without
cache or with WT cache reset vector code overwrites double exception
code, making issue even harder to detect.
- on MMUv3 cores RESET_VECTOR1_VADDR may point to unmapped area, as
MMUv3 cores change virtual address map to match MMUv2 layout, but
reset vector virtual address is given for the original MMUv3 mapping.
- physical memory region of the secondary reset vector is not reserved
in the physical memory map, and thus may be allocated and overwritten
at arbitrary moment.
Fix it as follows:
- move window_overflow_restore_a0_fixup code to .text section.
- define RESET_VECTOR1_VADDR so that it points to reset vector in the
cacheable MMUv2 map for cores with MMU.
- reserve reset vector region in the physical memory map. Drop separate
literal section and build mxhead.S with text section literals.
Cc: <stable@vger.kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Double exceptions that happen during register window overflow/underflow
are handled in the topmost stack frame, as if it was the only exception
that occured. However unaligned access exception handler is special
because it needs to analyze instruction that caused the exception, but
the userspace instruction that triggered window exception is completely
irrelevant. Unaligned data access is rather normal in the generic
userspace code, but stack pointer manipulation must always be done by
architecture-aware code and thus unaligned stack means a serious problem
anyway.
Use the default unaligned access handler that raises SIGBUS in case
of unaligned access in window overflow/underflow handler.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
