Skip to content

L
linux
Switch branch/tag
  1. 28 May, 2020 36 commits
  3. 26 May, 2020 4 commits
    • Cédric Le Goater's avatar
      powerpc/xive: Clear the page tables for the ESB IO mapping · a101950f
      Cédric Le Goater authored 
      Commit 1ca3dec2 ("powerpc/xive: Prevent page fault issues in the
machine crash handler") fixed an issue in the FW assisted dump of
machines using hash MMU and the XIVE interrupt mode under the POWER
hypervisor. It forced the mapping of the ESB page of interrupts being
mapped in the Linux IRQ number space to make sure the 'crash kexec'
sequence worked during such an event. But it didn't handle the
un-mapping.

This mapping is now blocking the removal of a passthrough IO adapter
under the POWER hypervisor because it expects the guest OS to have
cleared all page table entries related to the adapter. If some are
still present, the RTAS call which isolates the PCI slot returns error
9001 "valid outstanding translations".

Remove these mapping in the IRQ data cleanup routine.

Under KVM, this cleanup is not required because the ESB pages for the
adapter interrupts are un-mapped from the guest by the hypervisor in
the KVM XIVE native device. This is now redundant but it's harmless.

Fixes: 1ca3dec2 ("powerpc/xive: Prevent page fault issues in the machine crash handler")
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200429075122.1216388-2-clg@kaod.org
      a101950f
    • Michael Ellerman's avatar
      powerpc: Add ppc_inst_as_u64() · 16ef9767
      Michael Ellerman authored 
      The code patching code wants to get the value of a struct ppc_inst as
a u64 when the instruction is prefixed, so we can pass the u64 down to
__put_user_asm() and write it with a single store.

The optprobes code wants to load a struct ppc_inst as an immediate
into a register so it is useful to have it as a u64 to use the
existing helper function.

Currently this is a bit awkward because the value differs based on the
CPU endianness, so add a helper to do the conversion.

This fixes the usage in arch_prepare_optimized_kprobe() which was
previously incorrect on big endian.

Fixes: 650b55b7 ("powerpc: Add prefixed instructions to instruction data type")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Tested-by: default avatarJordan Niethe <jniethe5@gmail.com>
Link: https://lore.kernel.org/r/20200526072630.2487363-1-mpe@ellerman.id.au
      16ef9767
    • Michael Ellerman's avatar
      powerpc: Add ppc_inst_next() · c5ff46d6
      Michael Ellerman authored 
      In a few places we want to calculate the address of the next
instruction. Previously that was simple, we just added 4 bytes, or if
using a u32 * we incremented that pointer by 1.

But prefixed instructions make it more complicated, we need to advance
by either 4 or 8 bytes depending on the actual instruction. We also
can't do pointer arithmetic using struct ppc_inst, because it is
always 8 bytes in size on 64-bit, even though we might only need to
advance by 4 bytes.

So add a ppc_inst_next() helper which calculates the location of the
next instruction, if the given instruction was located at the given
address. Note the instruction doesn't need to actually be at the
address in memory.

Although it would seem natural for the value to be passed by value,
that makes it too easy to write a loop that will read off the end of a
page, eg:

	for (; src < end; src = ppc_inst_next(src, *src),
			  dest = ppc_inst_next(dest, *dest))

As noticed by Christophe and Jordan, if end is the exact end of a
page, and the next page is not mapped, this will fault, because *dest
will read 8 bytes, 4 bytes into the next page.

So value is passed by reference, so the helper can be careful to use
ppc_inst_read() on it.
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarJordan Niethe <jniethe5@gmail.com>
Link: https://lore.kernel.org/r/20200522133318.1681406-1-mpe@ellerman.id.au
      c5ff46d6
    • Michael Ellerman's avatar
      Merge branch 'fixes' into next · baddc87d
      Michael Ellerman authored 
      Merge our fixes branch from this cycle. It contains several important
fixes we need in next for testing purposes, and also some that will
conflict with upcoming changes.
      baddc87d
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7