Note that setting the PTE_MODIFIED bit based on whether write is possible
is incorrect. We should set PTE_MODIFIED based on whether the access
is a write operation.
relative to the start address (unless the start address is 0, which is
not the case).
This is currently not a problem because all powerpc architectures are
using loader(8) which passes metadata to the kernel including the
correct `endkernel' address. If we don't use loader(8), register 4
and 5 will have the size of the kernel ELF file, not its end address.
We fix that simply by adding `kernel_text' to `end' to compute
`endkernel'.
Discussed with: nathanw
This is required for ARM EABI. Section 7.1.1 of the Procedure Call for the
ARM Architecture (AAPCS) defines wchar_t as either an unsigned int or an
unsigned short with the former preferred.
Because of this requirement we need to move the definition of __wchar_t to
a machine dependent header. It also cleans up the macros defining the limits
of wchar_t by defining __WCHAR_MIN and __WCHAR_MAX in the same machine
dependent header then using them to define WCHAR_MIN and WCHAR_MAX
respectively.
Discussed with: bde
usermode, using shared page. The structures and functions have vdso
prefix, to indicate the intended location of the code in some future.
The versioned per-algorithm data is exported in the format of struct
vdso_timehands, which mostly repeats the content of in-kernel struct
timehands. Usermode reading of the structure can be lockless.
Compatibility export for 32bit processes on 64bit host is also
provided. Kernel also provides usermode with indication about
currently used timecounter, so that libc can fall back to syscall if
configured timecounter is unknown to usermode code.
The shared data updates are initiated both from the tc_windup(), where
a fast task is queued to do the update, and from sysctl handlers which
change timecounter. A manual override switch
kern.timecounter.fast_gettime allows to turn off the mechanism.
Only x86 architectures export the real algorithm data, and there, only
for tsc timecounter. HPET counters page could be exported as well, but
I prefer to not further glue the kernel and libc ABI there until
proper vdso-based solution is developed.
Minimal stubs neccessary for non-x86 architectures to still compile
are provided.
Discussed with: bde
Reviewed by: jhb
Tested by: flo
MFC after: 1 month
layer, but it is read directly by the MI VM layer. This change introduces
pmap_page_is_write_mapped() in order to completely encapsulate all direct
access to PGA_WRITEABLE in the pmap layer.
Aesthetics aside, I am making this change because amd64 will likely begin
using an alternative method to track write mappings, and having
pmap_page_is_write_mapped() in place allows me to make such a change
without further modification to the MI VM layer.
As an added bonus, tidy up some nearby comments concerning page flags.
Reviewed by: kib
MFC after: 6 weeks
implementation specific vs. the common architecture definition.
Bring PPC4XX defines (PSL, SPR, TLB). Note the new definitions under
BOOKE_PPC4XX are not used in the code yet.
This change set is not supposed to affect existing E500 support, it's just
another reorg step before bringing support for E500mc, E5500 and PPC465.
Obtained from: AppliedMicro, Freescale, Semihalf
in_cksum.h required ip.h to be included for struct ip. To be
able to use some general checksum functions like in_addword()
in a non-IPv4 context, limit the (also exported to user space)
IPv4 specific functions to the times, when the ip.h header is
present and IPVERSION is defined (to 4).
We should consider more general checksum (updating) functions
to also allow easier incremental checksum updates in the L3/4
stack and firewalls, as well as ponder further requirements by
certain NIC drivers needing slightly different pseudo values
in offloading cases. Thinking in terms of a better "library".
Sponsored by: The FreeBSD Foundation
Sponsored by: iXsystems
Reviewed by: gnn (as part of the whole)
MFC After: 3 days
1. Define all registers. These definitions are needed to support
the FCM driver for direct-connect NAND.
2. Repurpose lbc_read_reg() and lbc_write_reg() for use by localbus
attached device drivers. Use bus_space functions directly in the
lbc driver itself.
3. Be smarter about programming LAWs and mapping memory. The ranges
defined in the FDT are per bank (= chip select) and since we can
have up to 8 banks, we could easily use more than 8 LAWs or TLB
enrties when per-bank memory ranges need multiple LAWs or TLBs
due to alignment or size constraints.
We now combine all memory ranges into the fewest possible set of
contiguous regions and program the hardware for that. Thus, a
cleverly written FDT with 8 devices may still only need 1 LAW or
1 TLB entry. Note that the memory ranges can be assigned randomly
to the banks. We sort as we build to handle that.
4. Support the FCM when programming the OR register. This is mostly
for documention purposes as we do not have a way to define the
mode for a bank.
5. Remove Semihalf-ism: do not define DEBUG (only to undefine it
again).
FDT does not define all ranges possible for a particular node (e.g.
PCI).
While here, only update the trgt_mem and trgt_io pointers if there's
no error. This avoids that we knowingly write an invalid target (= -1).
for variables that live in the boot page.
o Add bp_trace (yes, it's in the boot page) that gets zeroed before we
try to wake a core and to which the core being woken can write markers
so that we know where the core was in case it doesn't wake up. The
boot code does not yet write markers (too follow).
o Disable the boot page translation to allow the last 4K page to be used
for whatever we please. It would get mapped otherwise.
o Fix kernstart in the case of SMP. The start argument is typically page
aligned due to the alignment requirements that come with having a boot
page. The point of using trunc_page is that we get the actual load
address given that the entry point is immediately following the ELF
headers. In the SMP case this ended up exactly 4K after the load
address. Hence subtracting 1 from start.
exceptions early enough during boot that the kernel will do ithe same.
Use lwsync only when compiling for LP64 and revert to the more proven isync
when compiling for ILP32. Note that in the end (i.e. between revision 222198
and this change) ILP32 changed from using sync to using isync. As per Nathan
the isync is needed to make sure I/O accesses are properly serialized with
locks and isync tends to be more effecient than sync.
While here, undefine __ATOMIC_ACQ and __ATOMIC_REL at the end of the file
so as not to leak their definitions.
Discussed with: nwhitehorn
range operations like pmap_remove() and pmap_protect() as well as allowing
simple operations like pmap_extract() not to involve any global state.
This substantially reduces lock coverages for the global table lock and
improves concurrency.
- Use isync/lwsync unconditionally for acquire/release. Use of isync
guarantees a complete memory barrier, which is important for serialization
of bus space accesses with mutexes on multi-processor systems.
- Go back to using sync as the I/O memory barrier, which solves the same
problem as above with respect to mutex release using lwsync, while not
penalizing non-I/O operations like a return to sync on the atomic release
operations would.
- Place an acquisition barrier around thread lock acquisition in
cpu_switchin().
guarantees on acquire for the tlbie mutex. Conversely, the TLB invalidation
sequence provides guarantees that do not need to be redundantly applied on
release. Roll a small custom lock that is just right. Simultaneously,
convert the SLB tree changes back to lwsync, as changing them to sync
was a misdiagnosis of the tlbie barrier problem this commit actually fixes.
not provide general barriers, but only barriers in the context of the
atomic sequences here. As such, make them private and keep the global
*mb() routines using a variant of sync.
isync to implement read and write barriers, following Appendix B.2 of
Book II of the architecture manual. This provides a 25% speed increase
to fork() on the PowerPC G4.
