code into it. Before sync with whole of them, just move ixgbe.c and ixv.c's
common code into ix_txrx.c from ixgbe.c. In this commit, only ixgbe.c is split
into the device dependent part and the common part. ixv.c isn't change to make
this commit no functional change. To use ixv.c with ix_txrx.c, it's required
to modify the common part's API and functions themselves.
This commit is done to make the next change easy to understand.
There are 8 Debug Registers on i386 (available at least since 80386) and 16
on AMD64. Currently DR4 and DR5 are reserved on both cpu-families and
DR9-DR15 are still reserved on AMD64. Therefore add accessors for DR0-DR3,
DR6-DR7 for all ports.
Debug Registers x86:
* DR0-DR3 Debug Address Registers
* DR4-DR5 Reserved
* DR6 Debug Status Register
* DR7 Debug Control Register
* DR8-DR15 Reserved
Access the registers is available only from a kernel (ring 0) as there is
needed top protected access. For this reason there is need to use special
XEN functions to get and set the registers in the XEN3 kernels.
XEN specific functions as defined in NetBSD:
- HYPERVISOR_get_debugreg()
- HYPERVISOR_set_debugreg()
This code extends the existing rdr6() and ldr6() accessor for additional:
- rdr0() & ldr0()
- rdr1() & ldr1()
- rdr2() & ldr2()
- rdr3() & ldr3()
- rdr7() & ldr7()
Traditionally accessors for DR6 were passing vaddr_t argument, while it's
appropriate type for DR0-DR3, DR6-DR7 should be using u_long, however it's
not a big deal. The resulting functionality should be equivalent so stick
to this convention and use the vaddr_t type for all DR accessors.
There was already a function defined for rdr6() in XEN, but it had a nit on
AMD64 as it was casting HYPERVISOR_get_debugreg() to u_int (32-bit on
AMD64), truncating result. It still works for DR6, but for the sake of
simplicity always return full 64-bit value.
New accessors duplicate functionality of the dr0() function available on
i386 within the KSTACK_CHECK_DR0 option. dr0() is a specialized layer with
logic to set appropriate types of interrupts, now accessors are designed to
pass verbatim values from user-land (with simple sanity checks in the
kernel). At the moment there are no plans to make possible to coexist
KSTACK_CHECK_DR0 with debug registers for user applications (debuggers).
options KSTACK_CHECK_DR0
Detect kernel stack overflow using DR0 register. This option uses DR0
register exclusively so you can't use DR0 register for other purpose
(e.g., hardware breakpoint) if you turn this on.
The KSTACK_CHECK_DR0 functionality was designed for i386 and never ported
to amd64.
Code tested on i386 and amd64 with kernels: GENERIC, XEN3_DOMU, XEN3_DOM0.
Sponsored by <The NetBSD Foundation>
According to the AMD64 SysV ABI the first returned value is passed in RAX,
not in RDI. Actually RDI is used for the first argument passed to a
function.
So far this function was dead code, it will be used for a ptrace(2)
feature to support CPU watchpoints.
The rdr6() function reads state of the DR6 register and returns its value.
Sponsored by <The NetBSD Foundation>
# if used with o, x or X specifiers the value is preceeded with 0, 0x or 0X
respectively for values different than zero.
Noted by <christos>
Sponsored by <The NetBSD Foundation>
and i386. The old design was error-prone, and it didn't allow us to map the
data segment with large pages.
Now, the VA is allocated dynamically in the pmap bootstrap code, and entered
manually later. We go from using &local_apic to using *local_apic_va, and we
therefore need one more level of indirection in the asm code.
Discussed on tech-kern.
