sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remov

sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

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sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

i386: ansify

Reported by: clang 15

ddb: print the actual syscall name

Some architectures will pretty-print a system call trap in the
backtrace. Rather than printing the symbol, use the syscallname()
function to pull the string from t

ddb: print the actual syscall name

Some architectures will pretty-print a system call trap in the
backtrace. Rather than printing the symbol, use the syscallname()
function to pull the string from the sv_syscallnames array corresponding
to the process. This simplifies the function somewhat.

Mostly, this will result in dropping the "sys" prefix, e.g. "sys_exit"
will now be printed simply as "exit".

Make two minor tweaks to the function signature: use a u_int for the
syscall number since this is a more correct type (see the 'code' member
of struct syscall_args), and make the thread pointer the first argument.
The latter is more natural and conventional.

Suggested by: jrtc27
Reviewed by: jrtc27, markj, jhb
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D37200

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ddb: de-duplicate decode_syscall()

Only i386 and amd64 print the decoded syscall name in the backtrace.
This de-duplication facilitates further changes and adoption by other
platforms.

Reviewed by:

ddb: de-duplicate decode_syscall()

Only i386 and amd64 print the decoded syscall name in the backtrace.
This de-duplication facilitates further changes and adoption by other
platforms.

Reviewed by: jrtc27, markj, jhb
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D36565

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Create sys/reg.h for the common code previously in machine/reg.h

Move the common kernel function signatures from machine/reg.h to a new
sys/reg.h. This is in preperation for adding PT_GETREGSET to p

Create sys/reg.h for the common code previously in machine/reg.h

Move the common kernel function signatures from machine/reg.h to a new
sys/reg.h. This is in preperation for adding PT_GETREGSET to ptrace(2).

Reviewed by: imp, markj
Sponsored by: DARPA, AFRL (original work)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19830

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ddb: replace watchpoint set/clear functions

Use the new kdb variants. Print more specific error messages.

Reviewed by: jhb, markj
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Sponsored by: Klara,

ddb: replace watchpoint set/clear functions

Use the new kdb variants. Print more specific error messages.

Reviewed by: jhb, markj
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D29156

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x86: consolidate hw watchpoint logic into new file

This is a prerequisite to using these functions outside of ddb, but also
provides some cleanup and minor refactoring. This code is almost
entirely

x86: consolidate hw watchpoint logic into new file

This is a prerequisite to using these functions outside of ddb, but also
provides some cleanup and minor refactoring. This code is almost
entirely duplicated between the two implementations, the only
significant difference being the lack of dbreg synchronization on i386.

Cleanups are:
- demote some internal functions to static
- use the constant NDBREGS instead of a '4' literal
- remove K&R definitions
- some added comments

Reviewed by: kib, jhb
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29153

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i386: clean up empty lines in .c and .h files

i386: stop guessing the address of the trap frame in ddb backtrace.

Save the address of the trap frame in %ebp on kernel entry. This
automatically provides it in struct i386_frame.f_frame to unwind

i386: stop guessing the address of the trap frame in ddb backtrace.

Save the address of the trap frame in %ebp on kernel entry. This
automatically provides it in struct i386_frame.f_frame to unwinder.

While there, more accurately handle the terminating frames,

Reviewed by: avg, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D22321

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teach db_nextframe/x86 about [X]xen_intr_upcall interrupt handler

Discussed with: kib, royger
MFC after: 3 weeks
Sponsored by: Panzura

db_nextframe/i386: reduce the number of special frame types

This change removes TRAP_INTERRUPT and TRAP_TIMERINT frame types.

Their names are a bit confusing: trap + interrupt, what is that?
The TR

db_nextframe/i386: reduce the number of special frame types

This change removes TRAP_INTERRUPT and TRAP_TIMERINT frame types.

Their names are a bit confusing: trap + interrupt, what is that?
The TRAP_TIMERINT name is too specific -- can it only be used for timer
"trap-interrupts"? What is so special about them?

My understanding of the code is that INTERRUPT, TRAP_INTERRUPT and
TRAP_TIMERINT differ only in how an offset from callee's frame pointer to a
trap frame on the stack is calculated. And that depends on a number of
arguments that a special handler passes to a callee (a function with a
normal C calling convention).

So, this change makes that logic explicit and collapses all interrupt frame
types into the INTERRUPT type.

Reviewed by: markj
Discussed with: kib, jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22303

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Use bool instead of boolean_t here. No reason to use boolean_t.

Also, stop passing FALSE to a bool parameter.

i386 4/4G split.

The change makes the user and kernel address spaces on i386
independent, giving each almost the full 4G of usable virtual addresses
except for one PDE at top used for trampoline and

i386 4/4G split.

The change makes the user and kernel address spaces on i386
independent, giving each almost the full 4G of usable virtual addresses
except for one PDE at top used for trampoline and per-CPU trampoline
stacks, and system structures that must be always mapped, namely IDT,
GDT, common TSS and LDT, and process-private TSS and LDT if allocated.

By using 1:1 mapping for the kernel text and data, it appeared
possible to eliminate assembler part of the locore.S which bootstraps
initial page table and KPTmap. The code is rewritten in C and moved
into the pmap_cold(). The comment in vmparam.h explains the KVA
layout.

There is no PCID mechanism available in protected mode, so each
kernel/user switch forth and back completely flushes the TLB, except
for the trampoline PTD region. The TLB invalidations for userspace
becomes trivial, because IPI handlers switch page tables. On the other
hand, context switches no longer need to reload %cr3.

copyout(9) was rewritten to use vm_fault_quick_hold(). An issue for
new copyout(9) is compatibility with wiring user buffers around sysctl
handlers. This explains two kind of locks for copyout ptes and
accounting of the vslock() calls. The vm_fault_quick_hold() AKA slow
path, is only tried after the 'fast path' failed, which temporary
changes mapping to the userspace and copies the data to/from small
per-cpu buffer in the trampoline. If a page fault occurs during the
copy, it is short-circuit by exception.s to not even reach C code.

The change was motivated by the need to implement the Meltdown
mitigation, but instead of KPTI the full split is done. The i386
architecture already shows the sizing problems, in particular, it is
impossible to link clang and lld with debugging. I expect that the
issues due to the virtual address space limits would only exaggerate
and the split gives more liveness to the platform.

Tested by: pho
Discussed with: bde
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D14633

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Revert r323722. A better fix will be committed shortly, as well as
some still useful bits of the reverted revision.

The problem with the committed fix is that there are still issues with
returning

Revert r323722. A better fix will be committed shortly, as well as
some still useful bits of the reverted revision.

The problem with the committed fix is that there are still issues with
returning from NMI, when NMI interrupted kernel in a moment where the
kernel segments selectors were still not loaded into registers. If
this happens, the NMI return would loose the userspace selectors
because r323722 does not reload segment registers on return to kernel
mode.

Fixing the problem is complicated. Since an alternative approach to
handle the original bug exists, it makes sence to stop adding more
complexity.

Discussed with: bde
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Fix handling of the segment registers on i386.

Suppose that userspace is executing with the non-standard segment
descriptors. Then, until exception or interrupt handler executed
SET_KERNEL_SEGS, ke

Fix handling of the segment registers on i386.

Suppose that userspace is executing with the non-standard segment
descriptors. Then, until exception or interrupt handler executed
SET_KERNEL_SEGS, kernel is still executing with user %ds, %es and %fs.
If an interrupt occurs in this window, the interrupt handler is
executed unsafely, relying on usability of the usermode registers. If
the interrupt results in the context switch on return, the
contamination of the kernel state spreads to the thread we switched
to. As result, kernel data accesses might fault or, if only the base
is changed, completely messed up.

More, if the user segment was allocated in LDT, another thread might
mark the descriptor as invalid before doreti code tried to reload
them. In this case kernel panics.

The issue exists for all exception entry points which use trap gate,
and thus do not automatically disable interrupts on entry, and for
lcall_handler.

Fix is two-fold: first, we need to disable interrupts for all kernel
entries, changing the IDT descriptor types from trap gate to interrupt
gate. Interrupts are re-enabled not earlier than the kernel segments
are loaded into the segment registers. Second, we only load the
segment registers from the trap frame when returning to usermode. For
the later, all interrupt return paths must happen through the doreti
common code.

There is no way to disable interrupts on call gate, which is the
supposed mode of servicing for lcall $7,$0 syscalls. Change the LDT
descriptor 0 into a code segment type and point it to the userspace
trampoline which redirects the syscall to int $0x80.

All the measures make the segment register handling similar to that of
amd64. We do not apply amd64 optimizations of not reloading segment
registers on return from the syscall.

Reported by: Maxime Villard <max@m00nbsd.net>
Tested by: pho (the non-lcall part)
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D12402

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Don't access the reserved registers %dr4 and %dr5 on i386.

On the original i386, %dr[4-5] were unimplemented but not very clearly
reserved, so debuggers read them to print them. i386 was still doin

Don't access the reserved registers %dr4 and %dr5 on i386.

On the original i386, %dr[4-5] were unimplemented but not very clearly
reserved, so debuggers read them to print them. i386 was still doing
this.

On the original athlon64, %dr[4-5] are documented as reserved but are
aliased to %dr[6-7] unless CR4_DE is set, when accessing them traps.

On 2 of my systems, accessing %dr[4-5] trapped sometimes. On my Haswell
system, the apparent randomness was because the boot CPU starts with
CR4_DE set while all other CPUs start with CR4_DE clear. FreeBSD
doesn't support the data breakpoints enabled by CR4_DE and it never
changes this flag, so the flag remains different across CPUs and
the behaviour seemed inconsistent except while booting when the CPU
doesn't change.

The invalid accesses broke:
- read access for printing the registers in ddb "show watches" on CPUs
with CR4_DE set
- read accesses in fill_dbregs() on CPUs with CR4_DE set. This didn't
implement panic(3) since the user case always skipped %dr[4-5].
- write accesses in set_dbregs(). This also didn't affect userland.
When it didn't trap, the aliasing made it fragile.

Don't print the dummy (zero) values of %dr[4-5] in "show watches" for
i386 or amd64. Fix style bugs near this printing.

amd64 also has space in the dbregs struct for the reserved %dr[8-15]
and already didn't print the dummy values for these, and never accessed
any of the 10 reserved debug registers.

Remove cpufuncs for making the invalid accesses. Even amd64 had these.

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Determine the operand/address size of %cs in a new function
db_segsize().

Use db_segsize() to set the default operand/address size for
disassembling. Allow overriding this with the "alternate" disp

Determine the operand/address size of %cs in a new function
db_segsize().

Use db_segsize() to set the default operand/address size for
disassembling. Allow overriding this with the "alternate" display
format /I. The API of db_disasm() should be debooleanized to pass a
more general request (amd64 needs overrides to sizes of 16, 32, and
64, but this commit doesn't implement anything for amd64 since much
larger changes are needed to restore the amd64 disassmbler's support
for non-default sizes).

Fix db_print_loc_and_inst() to ask for the normal format and not the
alternate in normal operation.

This is most useful for vm86 mode, but also works for 16-bit protected
mode.

Use db_segsize() to avoid trying to print a garbage stack trace if %cs
is 16 bits. Print something like the stack trace termination message
for a trap boundary instead.

Document that the alternate format is now useful on i386.

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Use the MI macro TRAPF_USERMODE() instead of open-coded checks for
SEL_UPL and sometimes PSL_VM. This is just a style change on amd64,
but on i386 it fixes 1 unimportant place where the PSL_VM check

Use the MI macro TRAPF_USERMODE() instead of open-coded checks for
SEL_UPL and sometimes PSL_VM. This is just a style change on amd64,
but on i386 it fixes 1 unimportant place where the PSL_VM check was
missing and starts fixing 1 important place where the PSL_VM check
had a logic error.

Fix logic errors in treating vm86 bioscall mode as kernel mode. The
main place checked all the necessary flags, but put the necessary
parentheses for the PSL_VM and PCB_VM86CALL checks in the wrong
place. The broken case is only reached if a vm86 bioscall uses a
%cs which is nonzero mod 4, but that is unusual -- most bios calls
start with %cs = 0xc000 or 0xf000 and rarely change it. Another
place was missing the check for PCB_VM86CALL, but was only reachable
if there are bugs virtualizing PSL_I.

Add a macro TF_HAS_STACKREGS() and use this instead of converting
open-coded checks of SEL_UPL, etc. to TRAPF_USERMODE() when we only
care about whether the frame has stack registers. This fixes 3
places in my recent fix for register variables in vm86 mode where I
messed up the PSL_VM check and cleans up other places.

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Fix the variables $esp, $ds, $es, $fs, $gs and $ss in vm86 mode.

Fix PC_REGS() so that printing of instructions works in some useful
cases. ddb only understands a single flat address space, but thi

Fix the variables $esp, $ds, $es, $fs, $gs and $ss in vm86 mode.

Fix PC_REGS() so that printing of instructions works in some useful
cases. ddb only understands a single flat address space, but this
macro allows mapping $cs:$eip into vm86's flat address space well
enough for the MI parts of ddb. This doesn't work for the MD parts
that do stack traces, and there are no similar macros for data addresses.

PC_REGS() has to use the trapframe pointer instead of the pcb for this.
For other CPUs, the trapframe pointer is not available except by tracing
back to it. But tracing back through vm86 trapframes is broken even
starting with one.

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Various changes to the registers displayed in DDB for x86.
- Fix segment registers to only display the low 16 bits.
- Remove unused handlers and entries for the debug registers.
- Display xcr0 (if va

Various changes to the registers displayed in DDB for x86.
- Fix segment registers to only display the low 16 bits.
- Remove unused handlers and entries for the debug registers.
- Display xcr0 (if valid) in 'show sysregs'.
- Add '0x' prefix to MSR values to match other values in 'show sysregs'.
- MFamd64: Display various MSRs in 'show sysregs'.
- Add a 'show dbregs' to display the value of debug registers.
- Dynamically size the column width for register values to properly
align columns on 64-bit platforms.
- Display %gs for i386 in 'show registers'.

Differential Revision: https://reviews.freebsd.org/D2784
Reviewed by: kib, markj
MFC after: 2 weeks

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Let the unwinder handle faults during function prologues or epilogues.

The i386 and amd64 DDB stack unwinders contain code to detect and handle
the case where the first frame is not completely set u

Let the unwinder handle faults during function prologues or epilogues.

The i386 and amd64 DDB stack unwinders contain code to detect and handle
the case where the first frame is not completely set up or torn down. This
code was accidentally unused however, since db_backtrace() was never called
with a non-NULL trap frame. This change fixes that.

Also remove get_rsp() from the amd64 code. It appears to have come from
i386, which needs to take into account whether the exception triggered a
CPL switch, since SS:ESP is only pushed onto the stack if so. On amd64,
SS:RSP is pushed regardless, so get_rsp() was doing the wrong thing for
kernel-mode exceptions. As a result, we can also remove custom print
functions for these registers.

Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D2881

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Improve stack unwinding on i386 and amd64 after an IP fault.

If we can't find a symbol corresponding to the faulting instruction, assume
that the previously-executed function is a call and attempt t

Improve stack unwinding on i386 and amd64 after an IP fault.

If we can't find a symbol corresponding to the faulting instruction, assume
that the previously-executed function is a call and attempt to find the
calling function using the return address on the stack. Otherwise we end
up associating the last stack frame with the current call, which is
incorrect and causes the unwinder to skip printing of the calling function,
resulting in a confusing backtrace.

Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D2859

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Remove lazy pmap switch code from i386. Naive benchmark with md(4)
shows no difference with the code removed.

On both amd64 and i386, assert that a released pmap is not active.

Proposed and review

Remove lazy pmap switch code from i386. Naive benchmark with md(4)
shows no difference with the code removed.

On both amd64 and i386, assert that a released pmap is not active.

Proposed and reviewed by: alc
Discussed with: Svatopluk Kraus <onwahe@gmail.com>, peter
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

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Print the frame addresses for the backtraces on i386 and amd64. It
allows both to inspect the frame sizes and to manually peek into the
frames from ddb, if needed.

Reviewed by: dim
MFC after: 2 weeks