We only support breakpoint/watchpoint of length 1, 2, 4 and 8. If we can
support other length as well, then user may watch more data with less
number of watchpoints (provided hardware supports it). For example: if we
have to watch only 4th, 5th and 6th byte from a 64 bit aligned address, we
will have to use two slots to implement it currently. One slot will watch a
half word at offset 4 and other a byte at offset 6. If we can have a
watchpoint of length 3 then we can watch it with single slot as well.
ARM64 hardware does support such functionality, therefore adding these new
definitions in generic layer.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Make perf build for x86 once the UAPI disintegration patches for that arch
have been applied by adding the appropriate -I flags - in the right order -
and then converting some #includes that use ../.. notation to find main kernel
headerfiles to use <asm/foo.h> and <linux/foo.h> instead.
Note that -Iarch/foo/include/uapi is present _before_ -Iarch/foo/include.
This makes sure we get the userspace version of the pt_regs struct. Ideally,
we wouldn't have the latter -I flag at all, but unfortunately we want
asm/svm.h and asm/vmx.h in builtin-kvm.c and these aren't part of the UAPI -
at least not for x86. I wonder if the bits outside of the __KERNEL__ guards
*should* be transferred there.
I note also that perf seems to do its dependency handling manually by listing
all the header files it might want to use in LIB_H in the Makefile. Can this
be changed to use -MD?
Note that to do make this work, we need to export and UAPI disintegrate
linux/hw_breakpoint.h, which I think should've been exported previously so that
perf can access the bits. We have to do this in the same patch to maintain
bisectability.
Signed-off-by: David Howells <dhowells@redhat.com>
