Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility. Thanks to Peter Zijlstra for fixing the lockdep
warning. Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
For the 'return' command, GDB needs to adjust WINDOWBASE.
In case WB is different from 0, we need to rotate the
window register file and update WINDOWSTART and WMASK.
This patch also removes some ret|= statements for
__get_user/__put_user as the address range was alrady
checked a couple of lines earlier.
Signed-off-by: Chris Zankel <chris@zankel.net>
When building with binutils-2.18, vmlinux includes .note.gnu.build-id
sections that need to be stripped out when building the binary image.
The old .xt.insn sections haven't been used for a long time, so don't
bother stripping them.
Signed-off-by: Bob Wilson <bob.wilson@acm.org>
Signed-off-by: Chris Zankel <chris@zankel.net>
For processor configurations that have optional registers
(compiler-used but non-coprocessor), user space registers
might get corrupted when there are only 4 registers in
the current window-frame, ie. register a4 belongs to the
oldest frame in the register file.
Signed-off-by: Chris Zankel <chris@zankel.net>
Supporting the sa_restorer function allows for better security
since the sigreturn system call doesn't need to be placed on
the stack, so the stack doesn't need to be executable. This
requires support from the c-library as it has to provide the
restorer function.
Signed-off-by: Chris Zankel <chris@zankel.net>
The Xtensa architecture allows to define custom instructions and
registers. Registers that are bound to a coprocessor are only
accessible if the corresponding enable bit is set, which allows
to implement a 'lazy' context switch mechanism. Other registers
needs to be saved and restore at the time of the context switch
or during interrupt handling.
This patch adds support for these additional states:
- save and restore registers that are used by the compiler upon
interrupt entry and exit.
- context switch additional registers unbound to any coprocessor
- 'lazy' context switch of registers bound to a coprocessor
- ptrace interface to provide access to additional registers
- update configuration files in include/asm-xtensa/variant-fsf
Signed-off-by: Chris Zankel <chris@zankel.net>
We will never (need to) support signal handling coming from a
double exception. There are too many things that could go wrong
and delivering signals is not the fastest method for IPC, anyway.
Signed-off-by: Chris Zankel <chris@zankel.net>
We need to use vmalloc_exec for module loading. Also remove
the definitions MODULE_START and MODULE_END, which wasn't
used, and increase the VMALLOC memory range accordingly.
Signed-off-by: Chris Zankel <chris@zankel.net>
Register a2 is saved in depc but wasn't getting restored before
returning from _spill_registers when there weren't any registers
to spill. The mask to cut the top bit from the rotated WINDOWMASK
register was also one bit short.
Signed-off-by: CHris Zankel <chris@zankel.net>
Move boot-redboot load address from 0xD0200000 to 0xD1000000
to make space for larger kernel images, in particular those with
an embedded initramfs filesystem.
Also properly set the ELF start address in boot-elf images so
that PC need not be set manually when loading them using GDB.
Signed-off-by: Marc Gauthier <marc@tensilica.com>
Remove oldmask from the sigcontext structure. Also update wmask
and windowstart when we flush the AR registers to stack.
Signed-off-by: Chris Zankel <chris@zankel.net>
Remove additional registers from the ELF gregset structure that
are only used by the kernel or are not required or invalid in
user-space. The ar registers are always aligned to a windowbase
value of 0, and the WB register is always assumed to be 0.
Increase the size of the structure to 128 entries. This will
provide enough space in future.
Signed-off-by: Chris Zankel <chris@zankel.net>
The simcall asm macro assumes Windowed ABI parameter passing
in registers, and doesn't work if its containing function gets
inlined. This fix prevents that from happening.
Signed-off-by: Marc Gauthier <marc@tensilica.com>
The TLB entry for the user address doesn't exist at the time we
want to flush the caches, so use the page address. Note that processor
configurations with cache-aliasing issues are treated separately.
Signed-off-by: Chris Zankel <chris@zankel.net>
Create arch/xtensa/platforms/ directory to concentrate
all platforms under that subdirectory and moves the ISS platform
to that directory.
Signed-off-by: Chris Zankel <chris@zankel.net>
Xtensa requires separate .literal section for each .text section.
Adding addition init sections for cpuinit, meminit, and devinit,
broke the Xtensa linker script, so, add these literal sections
manually for now.
Signed-off-by: Chris Zankel <chris@zankel.net>
