The XSAVE feature set is the future proof way for x86 CPUs to
manage extended CPU state. Extended state is MMX, FPU, SSE, AVX etc
registers. This is a replacement for the current FXSAVE and the
512 byte FPU region.
XSAVE introduces a few problems that this commit has to address
* The alignment of the XSAVE region is 64bytes, instead of the 16
bytes of the FXSAVE region
* XSAVE region size is dependent on the desired features, which
are detected at run time
* There are multiple variants of the XSAVE instruction that have
different potential optimizations, but are not always supported
The solutions to these are
* Re-order the FPU state and user registers in the user context
struct so that the new XSAVE region is first, and is thus
aligned to 64bytes without needing lots of padding
* Provide config options for desired features (including XSAVE
instruction variant) and required XSAVE region size. These
are checked at boot time to ensure the CPU meets these
requirements
This macro allows for using the value of a CONFIG_ variable in situations
where it may not be defined. This could be due to it being a dependency
on another CONFIG_ variable that is not currently defined. This arrises
from code blocks like
if (config_set(CONFIG_FOO)) {
return CONFIG_VAR_DEPENDS_ON_FOO;
}
This will not compile when CONFIG_FOO is not set. Using
return config_default(CONFIG_VAR_DEPENDS_ON_FOO, 42);
Provides a way for this to be built
The address being calculated is the end of the user context array.
There is no need for this to be done as a magic number offset
from the tcb_t, this commit takes an index into the actual array,
using the constant that is defined as the length of that array.
Its probable this was meant to be a boolean flag to represent
whether or not the TCB had a bound notification object. However,
this field is unused and its presence is confusing.
Benchmark feature that currently:
- Keeps track of system calls info
- Start time
- Duration
- Capability type
- Invocation tag
- Log the number of invocations of each system call*
- Log the number of invocations for each capability type per syscall.
- Has 3 new syscalls (dump, reset, get size).
- This new feature uses the existing log buffer (which is 1MiB for x86
and ARM). Since the number of syscall invocations is not
deterministic, the logged number of invocations is limited by the size
of the buffer. I suggested to enable the users to pass their own
user-level buffer, to enable more flexibility, later.
- ENABLE_BENCHMARKS is now a parent config option of trace points and
system call track features, they can't be used at the same time.
lockTLBEntry, an assembly function, had tlb_lock_count as a symbol that
needed to be placed sufficiently close to be loaded and stored with
offset-from-pc addressing. When assembled, the symbol would turn up
between functions, as opposed to within a literal pool (it's a variable,
not a constant) or the .bss / data sections. The decompiler doesn't
handle that use case, and likely won't. This change turns
tlb_lock_count into a C global variable (so that it will be placed in
the .bss / data sections), and splits lockTLBEntry into two parts so the
critical section will still fit in a 64-byte aligned region, and
therefore be guaranteed to live within a single page.
x86_64 (with PCIDs enabled) supports a more fine grained invalidation
approach for the TLB and Page Structure Cache. This change expands
the number and kinds of information passed for certain invalidations,
and provides an implementation of this for ia32.
Originally building the kernel was largely considered to be done in
one of two ways
1. Release build with no assertions, no debug symbols and no printing.
This was generally considered to be a 'verified' build
2. Debug build with assertions, debug symbols and printing
Since then various options were added, such as the 'code injection'
option, which we wanted on builds that did not have assertions or
other options that affected performance. As such it did not depend
upon a debug build and had large warning signs saying that enabling
this in a release build would not give you a verified or trusted
kernel.
Most recently the ability to print from the kernel in release mode
was added. For the same reason that tying the ability to print with
the performance reduction of various debugging was not always desireable.
This change attempts to unify the current state and have a single top
level option to enable a 'verification friendly' build. All other
options (assertions, printing, code injection) then depend upon
this configuration not being set.
vcpu.c:
encapsulate inline assembly into inline functions that added to
device_pl2.h file.
other files:
replace #ifdef ARM_HYP with config_set(ARM_HYP)
machine_pl2.h:
new place for hyp mode inline functions.
boot.c:
replace #ifdef ARM_HYP with config_set(ARM_HYP).
vcpu.h, machine_pl2.h:
add empty functions when ARM_HYP is not defined to
pass compilation.
