This patch reworks the feature fixup mecanism so vdso's can be fixed up.
The main issue was that the construct:
.long label (or .llong on 64 bits)
will not work in the case of a shared library like the vdso. It will
generate an empty placeholder in the fixup table along with a reloc,
which is not something we can deal with in the vdso.
The idea here (thanks Alan Modra !) is to instead use something like:
1:
.long label - 1b
That is, the feature fixup tables no longer contain addresses of bits of
code to patch, but offsets of such code from the fixup table entry
itself. That is properly resolved by ld when building the .so's. I've
modified the fixup mecanism generically to use that method for the rest
of the kernel as well.
Another trick is that the 32 bits vDSO included in the 64 bits kernel
need to have a table in the 64 bits format. However, gas does not
support 32 bits code with a statement of the form:
.llong label - 1b (Or even just .llong label)
That is, it cannot emit the right fixup/relocation for the linker to use
to assign a 32 bits address to an .llong field. Thus, in the specific
case of the 32 bits vdso built as part of the 64 bits kernel, we are
using a modified macro that generates:
.long 0xffffffff
.llong label - 1b
Note that is assumes that the value is negative which is enforced by
the .lds (those offsets are always negative as the .text is always
before the fixup table and gas doesn't support emiting the reloc the
other way around).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
There are currently two versions of the functions for applying the
feature fixups, one for CPU features and one for firmware features. In
addition, they are both in assembly and with separate implementations
for 32 and 64 bits. identify_cpu() is also implemented in assembly and
separately for 32 and 64 bits.
This patch replaces them with a pair of C functions. The call sites are
slightly moved on ppc64 as well to be called from C instead of from
assembly, though it's a very small change, and thus shouldn't cause any
problem.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We need to export ppc64_firmware_features for modules. Before we do that
I think we should probably rename it to powerpc_firmware_features.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
So that we can use firmware_has_feature() in a BUG_ON() and have the compiler
elide the code entirely if the feature can never be set, change
firmware_has_feature to a macro. Unfortunate, but necessary at least until
GCC bug #26724 is fixed.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
It has been decreed that platform numbers are evil, so as a step in that
direction, replace platform_is_lpar() with a FW_FEATURE_LPAR bit.
Currently FW_FEATURE_LPAR really means i/pSeries LPAR, in the future we might
have to clean that up if we need to be more specific about what LPAR actually
means. But that's another patch ...
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Currently we have some stuff in firmware.h and kernel/firmware.c that is
#ifdef CONFIG_PPC_PSERIES. Move it all into platforms/pseries.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The fwnmi vectors can be anywhere < 32 MB, so we need to use a trampoline
for them. The kdump kernel will register the trampoline addresses, which will
then jump up to the real code above 32 MB.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch merges platform codes. systemcfg->platform is no longer used,
systemcfg use in general is deprecated as much as possible (and renamed
_systemcfg before it gets completely moved elsewhere in a future patch),
_machine is now used on ppc64 along as ppc32. Platform codes aren't gone
yet but we are getting a step closer. A bunch of asm code in head[_64].S
is also turned into C code.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
