Michael Ellerman [Tue, 26 May 2020 12:54:27 +0000 (22:54 +1000)]
Merge "Use hugepages to map kernel mem on 8xx" into next
Merge Christophe's large series to use huge pages for the linear
mapping on 8xx.
From his cover letter:
The main purpose of this big series is to:
- reorganise huge page handling to avoid using mm_slices.
- use huge pages to map kernel memory on the 8xx.
The 8xx supports 4 page sizes: 4k, 16k, 512k and 8M.
It uses 2 Level page tables, PGD having 1024 entries, each entry
covering 4M address space. Then each page table has 1024 entries.
At the time being, page sizes are managed in PGD entries, implying
the use of mm_slices as it can't mix several pages of the same size
in one page table.
The first purpose of this series is to reorganise things so that
standard page tables can also handle 512k pages. This is done by
adding a new _PAGE_HUGE flag which will be copied into the Level 1
entry in the TLB miss handler. That done, we have 2 types of pages:
- PGD entries to regular page tables handling 4k/16k and 512k pages
- PGD entries to hugepd tables handling 8M pages.
There is no need to mix 8M pages with other sizes, because a 8M page
will use more than what a single PGD covers.
Then comes the second purpose of this series. At the time being, the
8xx has implemented special handling in the TLB miss handlers in order
to transparently map kernel linear address space and the IMMR using
huge pages by building the TLB entries in assembly at the time of the
exception.
As mm_slices is only for user space pages, and also because it would
anyway not be convenient to slice kernel address space, it was not
possible to use huge pages for kernel address space. But after step
one of the series, it is now more flexible to use huge pages.
This series drop all assembly 'just in time' handling of huge pages
and use huge pages in page tables instead.
Once the above is done, then comes icing on the cake:
- Use huge pages for KASAN shadow mapping
- Allow pinned TLBs with strict kernel rwx
- Allow pinned TLBs with debug pagealloc
Then, last but not least, those modifications for the 8xx allows the
following improvement on book3s/32:
- Mapping KASAN shadow with BATs
- Allowing BATs with debug pagealloc
All this allows to considerably simplify TLB miss handlers and associated
initialisation. The overhead of reading page tables is negligible
compared to the reduction of the miss handlers.
While we were at touching pte_update(), some cleanup was done
there too.
Tested widely on 8xx and 832x. Boot tested on QEMU MAC99.
Christophe Leroy [Tue, 19 May 2020 05:49:28 +0000 (05:49 +0000)]
powerpc/32s: Allow mapping with BATs with DEBUG_PAGEALLOC
DEBUG_PAGEALLOC only manages RW data.
Text and RO data can still be mapped with BATs.
In order to map with BATs, also enforce data alignment. Set
by default to 256M which is a good compromise for keeping
enough BATs for also KASAN and IMMR.
Christophe Leroy [Tue, 19 May 2020 05:49:26 +0000 (05:49 +0000)]
powerpc/8xx: Allow large TLBs with DEBUG_PAGEALLOC
DEBUG_PAGEALLOC only manages RW data.
Text and RO data can still be mapped with hugepages and pinned TLB.
In order to map with hugepages, also enforce a 512kB data alignment
minimum. That's a trade-off between size of speed, taking into
account that DEBUG_PAGEALLOC is a debug option. Anyway the alignment
is still tunable.
We also allow tuning of alignment for book3s to limit the complexity
of the test in Kconfig that will anyway disappear in the following
patches once DEBUG_PAGEALLOC is handled together with BATs.
Christophe Leroy [Tue, 19 May 2020 05:49:25 +0000 (05:49 +0000)]
powerpc/8xx: Allow STRICT_KERNEL_RwX with pinned TLB
Pinned TLB are 8M. Now that there is no strict boundary anymore
between text and RO data, it is possible to use 8M pinned executable
TLB that covers both text and RO data.
When PIN_TLB_DATA or PIN_TLB_TEXT is selected, enforce 8M RW data
alignment and allow STRICT_KERNEL_RWX.
Christophe Leroy [Tue, 19 May 2020 05:49:22 +0000 (05:49 +0000)]
powerpc/8xx: Add a function to early map kernel via huge pages
Add a function to early map kernel memory using huge pages.
For 512k pages, just use standard page table and map in using 512k
pages.
For 8M pages, create a hugepd table and populate the two PGD
entries with it.
This function can only be used to create page tables at startup. Once
the regular SLAB allocation functions replace memblock functions,
this function cannot allocate new pages anymore. However it can still
update existing mappings with new protections.
hugepd_none() macro is moved into asm/hugetlb.h to be usable outside
of mm/hugetlbpage.c
Now that linear and IMMR dedicated TLB handling is gone, kernel
boundary address comparison is similar in ITLB miss handler and
in DTLB miss handler.
Create a macro named compare_to_kernel_boundary.
When TASK_SIZE is strictly below 0x80000000 and PAGE_OFFSET is
above 0x80000000, it is enough to compare to 0x8000000, and this
can be done with a single instruction.
Using not. instruction, we get to use 'blt' conditional branch as
when doing a regular comparison:
0x00000000 <= addr <= 0x7fffffff ==>
0xffffffff >= NOT(addr) >= 0x80000000
The above test corresponds to a 'blt'
Otherwise, do a regular comparison using two instructions.
Christophe Leroy [Tue, 19 May 2020 05:49:16 +0000 (05:49 +0000)]
powerpc/8xx: Drop special handling of Linear and IMMR mappings in I/D TLB handlers
Up to now, linear and IMMR mappings are managed via huge TLB entries
through specific code directly in TLB miss handlers. This implies
some patching of the TLB miss handlers at startup, and a lot of
dedicated code.
Remove all this specific dedicated code.
For now we are back to normal handling via standard 4k pages. In the
next patches, linear memory mapping and IMMR mapping will be managed
through huge pages.
Christophe Leroy [Tue, 19 May 2020 05:49:15 +0000 (05:49 +0000)]
powerpc/8xx: Always pin TLBs at startup.
At startup, map 32 Mbytes of memory through 4 pages of 8M,
and PIN them inconditionnaly. They need to be pinned because
KASAN is using page tables early and the TLBs might be
dynamically replaced otherwise.
Remove RSV4I flag after installing mappings unless
CONFIG_PIN_TLB_XXXX is selected.
Christophe Leroy [Tue, 19 May 2020 05:49:13 +0000 (05:49 +0000)]
powerpc/8xx: Add function to set pinned TLBs
Pinned TLBs cannot be modified when the MMU is enabled.
Create a function to rewrite the pinned TLB entries with MMU off.
To set pinned TLB, we have to turn off MMU, disable pinning,
do a TLB flush (Either with tlbie and tlbia) then reprogam
the TLB entries, enable pinning and turn on MMU.
If using tlbie, it cleared entries in both instruction and data
TLB regardless whether pinning is disabled or not.
If using tlbia, it clears all entries of the TLB which has
disabled pinning.
To make it easy, just clear all entries in both TLBs, and
reprogram them.
The function takes two arguments, the top of the memory to
consider and whether data is RO under _sinittext.
When DEBUG_PAGEALLOC is set, the top is the end of kernel rodata.
Otherwise, that's the top of physical RAM.
Everything below _sinittext is set RX, over _sinittext that's RW.
Christophe Leroy [Tue, 19 May 2020 05:49:09 +0000 (05:49 +0000)]
powerpc/8xx: Manage 512k huge pages as standard pages.
At the time being, 512k huge pages are handled through hugepd page
tables. The PMD entry is flagged as a hugepd pointer and it
means that only 512k hugepages can be managed in that 4M block.
However, the hugepd table has the same size as a normal page
table, and 512k entries can therefore be nested with normal pages.
On the 8xx, TLB loading is performed by software and allthough the
page tables are organised to match the L1 and L2 level defined by
the HW, all TLB entries have both L1 and L2 independent entries.
It means that even if two TLB entries are associated with the same
PMD entry, they can be loaded with different values in L1 part.
The L1 entry contains the page size (PS field):
- 00 for 4k and 16 pages
- 01 for 512k pages
- 11 for 8M pages
By adding a flag for hugepages in the PTE (_PAGE_HUGE) and copying it
into the lower bit of PS, we can then manage 512k pages with normal
page tables:
- PMD entry has PS=11 for 8M pages
- PMD entry has PS=00 for other pages.
As a PMD entry covers 4M areas, a PMD will either point to a hugepd
table having a single entry to an 8M page, or the PMD will point to
a standard page table which will have either entries to 4k or 16k or
512k pages. For 512k pages, as the L1 entry will not know it is a
512k page before the PTE is read, there will be 128 entries in the
PTE as if it was 4k pages. But when loading the TLB, it will be
flagged as a 512k page.
Note that we can't use pmd_ptr() in asm/nohash/32/pgtable.h because
it is not defined yet.
In ITLB miss, we keep the possibility to opt it out as when kernel
text is pinned and no user hugepages are used, we can save several
instruction by not using r11.
In DTLB miss, that's just one instruction so it's not worth bothering
with it.
Christophe Leroy [Tue, 19 May 2020 05:49:08 +0000 (05:49 +0000)]
powerpc/8xx: Prepare handlers for _PAGE_HUGE for 512k pages.
Prepare ITLB handler to handle _PAGE_HUGE when CONFIG_HUGETLBFS
is enabled. This means that the L1 entry has to be kept in r11
until L2 entry is read, in order to insert _PAGE_HUGE into it.
Also move pgd_offset helpers before pte_update() as they
will be needed there in next patch.
Christophe Leroy [Tue, 19 May 2020 05:49:06 +0000 (05:49 +0000)]
powerpc/mm: Reduce hugepd size for 8M hugepages on 8xx
Commit 55c8fc3f4930 ("powerpc/8xx: reintroduce 16K pages with HW
assistance") redefined pte_t as a struct of 4 pte_basic_t, because
in 16K pages mode there are four identical entries in the page table.
But hugepd entries for 8M pages require only one entry of size
pte_basic_t. So there is no point in creating a cache for 4 entries
page tables.
Calculate PTE_T_ORDER using the size of pte_basic_t instead of pte_t.
Define specific huge_pte helpers (set_huge_pte_at(), huge_pte_clear(),
huge_ptep_set_wrprotect()) to write the pte in a single entry instead
of using set_pte_at() which writes 4 identical entries in 16k pages
mode. Also make sure that __ptep_set_access_flags() properly handle
the huge_pte case.
Define set_pte_filter() inline otherwise GCC doesn't inline it anymore
because it is now used twice, and that gives a pretty suboptimal code
because of pte_t being a struct of 4 entries.
Those functions are also used for 512k pages which only require one
entry as well allthough replicating it four times was harmless as 512k
pages entries are spread every 128 bytes in the table.
Christophe Leroy [Tue, 19 May 2020 05:48:58 +0000 (05:48 +0000)]
powerpc/mm: Allocate static page tables for fixmap
Allocate static page tables for the fixmap area. This allows
setting mappings through page tables before memblock is ready.
That's needed to use early_ioremap() early and to use standard
page mappings with fixmap.
Christophe Leroy [Tue, 19 May 2020 05:48:55 +0000 (05:48 +0000)]
powerpc/ptdump: Handle hugepd at PGD level
The 8xx is about to map kernel linear space and IMMR using huge
pages.
In order to display those pages properly, ptdump needs to handle
hugepd tables at PGD level.
For the time being do it only at PGD level. Further patches may
add handling of hugepd tables at lower level for other platforms
when needed in the future.
Christophe Leroy [Tue, 19 May 2020 05:48:48 +0000 (05:48 +0000)]
powerpc/kasan: Declare kasan_init_region() weak
In order to alloc sub-arches to alloc KASAN regions using optimised
methods (Huge pages on 8xx, BATs on BOOK3S, ...), declare
kasan_init_region() weak.
Also make kasan_init_shadow_page_tables() accessible from outside,
so that it can be called from the specific kasan_init_region()
functions if needed.
And populate remaining KASAN address space only once performed
the region mapping, to allow 8xx to allocate hugepd instead of
standard page tables for mapping via 8M hugepages.
Christophe Leroy [Tue, 19 May 2020 05:48:47 +0000 (05:48 +0000)]
powerpc/kasan: Refactor update of early shadow mappings
kasan_remap_early_shadow_ro() and kasan_unmap_early_shadow_vmalloc()
are both updating the early shadow mapping: the first one sets
the mapping read-only while the other clears the mapping.
Doing kasan pages allocation in MMU_init is too early, kernel doesn't
have access yet to the entire memory space and memblock_alloc() fails
when the kernel is a bit big.
Christophe Leroy [Tue, 19 May 2020 05:48:44 +0000 (05:48 +0000)]
powerpc/kasan: Fix issues by lowering KASAN_SHADOW_END
At the time being, KASAN_SHADOW_END is 0x100000000, which
is 0 in 32 bits representation.
This leads to a couple of issues:
- kasan_remap_early_shadow_ro() does nothing because the comparison
k_cur < k_end is always false.
- In ptdump, address comparison for markers display fails and the
marker's name is printed at the start of the KASAN area instead of
being printed at the end.
However, there is no need to shadow the KASAN shadow area itself,
so the KASAN shadow area can stop shadowing memory at the start
of itself.
With a PAGE_OFFSET set to 0xc0000000, KASAN shadow area is then going
from 0xf8000000 to 0xff000000.
Nicholas Piggin [Mon, 11 May 2020 12:58:24 +0000 (22:58 +1000)]
powerpc/64s/hash: Add stress_slb kernel boot option to increase SLB faults
This option increases the number of SLB misses by limiting the number
of kernel SLB entries, and increased flushing of cached lookaside
information. This helps stress test difficult to hit paths in the
kernel.
Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Relocate the code into arch/powerpc/mm, s/torture/stress/] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200511125825.3081305-1-mpe@ellerman.id.au
Fix it by converting pud_index() and friends to static inline
functions.
UBSAN: shift-out-of-bounds in arch/powerpc/mm/ptdump/ptdump.c:282:15
shift exponent 34 is too large for 32-bit type 'int'
CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4-next-20200303+ #13
Call Trace:
dump_stack+0xf4/0x164 (unreliable)
ubsan_epilogue+0x18/0x78
__ubsan_handle_shift_out_of_bounds+0x160/0x21c
walk_pagetables+0x2cc/0x700
walk_pud at arch/powerpc/mm/ptdump/ptdump.c:282
(inlined by) walk_pagetables at arch/powerpc/mm/ptdump/ptdump.c:311
ptdump_check_wx+0x8c/0xf0
mark_rodata_ro+0x48/0x80
kernel_init+0x74/0x194
ret_from_kernel_thread+0x5c/0x74
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Link: https://lore.kernel.org/r/20200306044852.3236-1-cai@lca.pw
Nicholas Piggin [Wed, 29 Apr 2020 07:02:47 +0000 (17:02 +1000)]
powerpc/64s: Fix early_init_mmu section mismatch
Christian reports:
MODPOST vmlinux.o
WARNING: modpost: vmlinux.o(.text.unlikely+0x1a0): Section mismatch in
reference from the function .early_init_mmu() to the function
.init.text:.radix__early_init_mmu()
The function .early_init_mmu() references
the function __init .radix__early_init_mmu().
This is often because .early_init_mmu lacks a __init
annotation or the annotation of .radix__early_init_mmu is wrong.
WARNING: modpost: vmlinux.o(.text.unlikely+0x1ac): Section mismatch in
reference from the function .early_init_mmu() to the function
.init.text:.hash__early_init_mmu()
The function .early_init_mmu() references
the function __init .hash__early_init_mmu().
This is often because .early_init_mmu lacks a __init
annotation or the annotation of .hash__early_init_mmu is wrong.
The compiler is uninlining early_init_mmu and not putting it in an init
section because there is no annotation. Add it.
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de> Link: https://lore.kernel.org/r/20200429070247.1678172-1-npiggin@gmail.com
Geoff Levand [Sat, 16 May 2020 16:20:46 +0000 (09:20 -0700)]
powerpc/ps3: Add check for otheros image size
The ps3's otheros flash loader has a size limit of 16 MiB for the
uncompressed image. If that limit will be reached output the
flash image file as 'otheros-too-big.bld'.
ie. hstart is above hend, which indicates no huge page flush is
needed.
However the current logic incorrectly sets hflush = true in this case,
because hstart != hend.
That causes us to call __tlbie_va_range() passing hstart/hend, to do a
huge page flush even though we don't need to. __tlbie_va_range() will
skip the actual tlbie operation for start > end. But it will still end
up calling fixup_tlbie_va_range() and doing the TLB fixups in there,
which is harmless but unnecessary work.
Reported-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Drop else case, hflush is already false, flesh out change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200513030616.152288-1-aneesh.kumar@linux.ibm.com
Michael Ellerman [Wed, 20 May 2020 13:37:33 +0000 (23:37 +1000)]
Merge branch 'topic/uaccess-ppc' into next
Merge our uaccess-ppc topic branch. It is based on the uaccess topic
branch that we're sharing with Viro.
This includes the addition of user_[read|write]_access_begin(), as
well as some powerpc specific changes to our uaccess routines that
would conflict badly if merged separately.
Xmon allows overwriting breakpoints because it's supported by only
one DAWR. But with multiple DAWRs, overwriting becomes ambiguous
or unnecessary complicated. So let's not allow it.
Ravi Bangoria [Thu, 14 May 2020 11:17:39 +0000 (16:47 +0530)]
powerpc/watchpoint: Don't allow concurrent perf and ptrace events
With Book3s DAWR, ptrace and perf watchpoints on powerpc behaves
differently. Ptrace watchpoint works in one-shot mode and generates
signal before executing instruction. It's ptrace user's job to
single-step the instruction and re-enable the watchpoint. OTOH, in
case of perf watchpoint, kernel emulates/single-steps the instruction
and then generates event. If perf and ptrace creates two events with
same or overlapping address ranges, it's ambiguous to decide who
should single-step the instruction. Because of this issue, don't
allow perf and ptrace watchpoint at the same time if their address
range overlaps.
Ravi Bangoria [Thu, 14 May 2020 11:17:38 +0000 (16:47 +0530)]
powerpc/watchpoint: Prepare handler to handle more than one watchpoint
Currently we assume that we have only one watchpoint supported by hw.
Get rid of that assumption and use dynamic loop instead. This should
make supporting more watchpoints very easy.
With more than one watchpoint, exception handler needs to know which
DAWR caused the exception, and hw currently does not provide it. So
we need sw logic for the same. To figure out which DAWR caused the
exception, check all different combinations of user specified range,
DAWR address range, actual access range and DAWRX constrains. For ex,
if user specified range and actual access range overlaps but DAWRX is
configured for readonly watchpoint and the instruction is store, this
DAWR must not have caused exception.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Reviewed-by: Michael Neuling <mikey@neuling.org>
[mpe: Unsplit multi-line printk() strings, fix some sparse warnings] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200514111741.97993-14-ravi.bangoria@linux.ibm.com
Ravi Bangoria [Thu, 14 May 2020 11:17:33 +0000 (16:47 +0530)]
powerpc/watchpoint: Disable all available watchpoints when !dawr_force_enable
Instead of disabling only first watchpoint, disable all available
watchpoints while clearing dawr_force_enable.
Callback function is used only for disabling watchpoint, rename it
to disable_dawrs_cb(). And null_brk parameter is not really required
while disabling watchpoint, remove it.
Ravi Bangoria [Thu, 14 May 2020 11:17:29 +0000 (16:47 +0530)]
powerpc/watchpoint/ptrace: Return actual num of available watchpoints
User can ask for num of available watchpoints(dbginfo.num_data_bps)
using ptrace(PPC_PTRACE_GETHWDBGINFO). Return actual number of
available watchpoints on the machine rather than hardcoded 1.
Ravi Bangoria [Thu, 14 May 2020 11:17:28 +0000 (16:47 +0530)]
powerpc/watchpoint: Introduce function to get nr watchpoints dynamically
So far we had only one watchpoint, so we have hardcoded HBP_NUM to 1.
But Power10 is introducing 2nd DAWR and thus kernel should be able to
dynamically find actual number of watchpoints supported by hw it's
running on. Introduce function for the same. Also convert HBP_NUM macro
to HBP_NUM_MAX, which will now represent maximum number of watchpoints
supported by Powerpc.
Jordan Niethe [Wed, 6 May 2020 03:40:49 +0000 (13:40 +1000)]
powerpc sstep: Add support for prefixed load/stores
This adds emulation support for the following prefixed integer
load/stores:
* Prefixed Load Byte and Zero (plbz)
* Prefixed Load Halfword and Zero (plhz)
* Prefixed Load Halfword Algebraic (plha)
* Prefixed Load Word and Zero (plwz)
* Prefixed Load Word Algebraic (plwa)
* Prefixed Load Doubleword (pld)
* Prefixed Store Byte (pstb)
* Prefixed Store Halfword (psth)
* Prefixed Store Word (pstw)
* Prefixed Store Doubleword (pstd)
* Prefixed Load Quadword (plq)
* Prefixed Store Quadword (pstq)
the follow prefixed floating-point load/stores:
* Prefixed Load Floating-Point Single (plfs)
* Prefixed Load Floating-Point Double (plfd)
* Prefixed Store Floating-Point Single (pstfs)
* Prefixed Store Floating-Point Double (pstfd)
and for the following prefixed VSX load/stores:
* Prefixed Load VSX Scalar Doubleword (plxsd)
* Prefixed Load VSX Scalar Single-Precision (plxssp)
* Prefixed Load VSX Vector [0|1] (plxv, plxv0, plxv1)
* Prefixed Store VSX Scalar Doubleword (pstxsd)
* Prefixed Store VSX Scalar Single-Precision (pstxssp)
* Prefixed Store VSX Vector [0|1] (pstxv, pstxv0, pstxv1)
Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Reviewed-by: Balamuruhan S <bala24@linux.ibm.com>
[mpe: Use CONFIG_PPC64 not __powerpc64__, use get_op()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-30-jniethe5@gmail.com
Jordan Niethe [Wed, 6 May 2020 03:40:48 +0000 (13:40 +1000)]
powerpc: Support prefixed instructions in alignment handler
If a prefixed instruction results in an alignment exception, the
SRR1_PREFIXED bit is set. The handler attempts to emulate the
responsible instruction and then increment the NIP past it. Use
SRR1_PREFIXED to determine by how much the NIP should be incremented.
Prefixed instructions are not permitted to cross 64-byte boundaries. If
they do the alignment interrupt is invoked with SRR1 BOUNDARY bit set.
If this occurs send a SIGBUS to the offending process if in user mode.
If in kernel mode call bad_page_fault().
Jordan Niethe [Fri, 15 May 2020 02:12:55 +0000 (12:12 +1000)]
powerpc: Add prefixed instructions to instruction data type
For powerpc64, redefine the ppc_inst type so both word and prefixed
instructions can be represented. On powerpc32 the type will remain the
same. Update places which had assumed instructions to be 4 bytes long.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Reviewed-by: Alistair Popple <alistair@popple.id.au>
[mpe: Rework the get_user_inst() macros to be parameterised, and don't
assign to the dest if an error occurred. Use CONFIG_PPC64 not
__powerpc64__ in a few places. Address other comments from
Christophe. Fix some sparse complaints.] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-24-jniethe5@gmail.com
Jordan Niethe [Fri, 15 May 2020 01:15:28 +0000 (11:15 +1000)]
powerpc/optprobes: Add register argument to patch_imm64_load_insns()
Currently patch_imm32_load_insns() is used to load an instruction to
r4 to be emulated by emulate_step(). For prefixed instructions we
would like to be able to load a 64bit immediate to r4. To prepare for
this make patch_imm64_load_insns() take an argument that decides which
register to load an immediate to - rather than hardcoding r3.
Jordan Niethe [Wed, 6 May 2020 03:40:42 +0000 (13:40 +1000)]
powerpc: Define new SRR1 bits for a ISA v3.1
Add the BOUNDARY SRR1 bit definition for when the cause of an
alignment exception is a prefixed instruction that crosses a 64-byte
boundary. Add the PREFIXED SRR1 bit definition for exceptions caused
by prefixed instructions.
Bit 35 of SRR1 is called SRR1_ISI_N_OR_G. This name comes from it
being used to indicate that an ISI was due to the access being no-exec
or guarded. ISA v3.1 adds another purpose. It is also set if there is
an access in a cache-inhibited location for prefixed instruction.
Rename from SRR1_ISI_N_OR_G to SRR1_ISI_N_G_OR_CIP.
Alistair Popple [Wed, 6 May 2020 03:40:41 +0000 (13:40 +1000)]
powerpc: Enable Prefixed Instructions
Prefix instructions have their own FSCR bit which needs to enabled via
a CPU feature. The kernel will save the FSCR for problem state but it
needs to be enabled initially.
If prefixed instructions are made unavailable by the [H]FSCR, attempting
to use them will cause a facility unavailable exception. Add "PREFIX" to
the facility_strings[].
Currently there are no prefixed instructions that are actually emulated
by emulate_instruction() within facility_unavailable_exception().
However, when caused by a prefixed instructions the SRR1 PREFIXED bit is
set. Prepare for dealing with emulated prefixed instructions by checking
for this bit.
Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Link: https://lore.kernel.org/r/20200506034050.24806-22-jniethe5@gmail.com
Jordan Niethe [Wed, 6 May 2020 03:40:40 +0000 (13:40 +1000)]
powerpc: Make test_translate_branch() independent of instruction length
test_translate_branch() uses two pointers to instructions within a
buffer, p and q, to test patch_branch(). The pointer arithmetic done on
them assumes a size of 4. This will not work if the instruction length
changes. Instead do the arithmetic relative to the void * to the buffer.
Jordan Niethe [Wed, 6 May 2020 03:40:39 +0000 (13:40 +1000)]
powerpc/xmon: Move insertion of breakpoint for xol'ing
When a new breakpoint is created, the second instruction of that
breakpoint is patched with a trap instruction. This assumes the length
of the instruction is always the same. In preparation for prefixed
instructions, remove this assumption. Insert the trap instruction at the
same time the first instruction is inserted.
Jordan Niethe [Wed, 6 May 2020 03:40:38 +0000 (13:40 +1000)]
powerpc/xmon: Use a function for reading instructions
Currently in xmon, mread() is used for reading instructions. In
preparation for prefixed instructions, create and use a new function,
mread_instr(), especially for reading instructions.
Jordan Niethe [Wed, 6 May 2020 03:40:35 +0000 (13:40 +1000)]
powerpc/kprobes: Use patch_instruction()
Instead of using memcpy() and flush_icache_range() use
patch_instruction() which not only accomplishes both of these steps but
will also make it easier to add support for prefixed instructions.
Jordan Niethe [Wed, 6 May 2020 03:40:34 +0000 (13:40 +1000)]
powerpc: Add a probe_kernel_read_inst() function
Introduce a probe_kernel_read_inst() function to use in cases where
probe_kernel_read() is used for getting an instruction. This will be
more useful for prefixed instructions.
Jordan Niethe [Wed, 6 May 2020 03:40:33 +0000 (13:40 +1000)]
powerpc: Add a probe_user_read_inst() function
Introduce a probe_user_read_inst() function to use in cases where
probe_user_read() is used for getting an instruction. This will be
more useful for prefixed instructions.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Reviewed-by: Alistair Popple <alistair@popple.id.au>
[mpe: Don't write to *inst on error, fold in __user annotations] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-14-jniethe5@gmail.com
Jordan Niethe [Wed, 6 May 2020 03:40:32 +0000 (13:40 +1000)]
powerpc: Use a function for reading instructions
Prefixed instructions will mean there are instructions of different
length. As a result dereferencing a pointer to an instruction will not
necessarily give the desired result. Introduce a function for reading
instructions from memory into the instruction data type.
Jordan Niethe [Wed, 6 May 2020 03:40:31 +0000 (13:40 +1000)]
powerpc: Use a datatype for instructions
Currently unsigned ints are used to represent instructions on powerpc.
This has worked well as instructions have always been 4 byte words.
However, ISA v3.1 introduces some changes to instructions that mean
this scheme will no longer work as well. This change is Prefixed
Instructions. A prefixed instruction is made up of a word prefix
followed by a word suffix to make an 8 byte double word instruction.
No matter the endianness of the system the prefix always comes first.
Prefixed instructions are only planned for powerpc64.
Introduce a ppc_inst type to represent both prefixed and word
instructions on powerpc64 while keeping it possible to exclusively
have word instructions on powerpc32.
Jordan Niethe [Wed, 6 May 2020 03:40:28 +0000 (13:40 +1000)]
powerpc: Use a function for getting the instruction op code
In preparation for using a data type for instructions that can not be
directly used with the '>>' operator use a function for getting the op
code of an instruction.
Jordan Niethe [Wed, 6 May 2020 03:40:27 +0000 (13:40 +1000)]
powerpc: Use an accessor for instructions
In preparation for introducing a more complicated instruction type to
accommodate prefixed instructions use an accessor for getting an
instruction as a u32.
Jordan Niethe [Wed, 6 May 2020 03:40:26 +0000 (13:40 +1000)]
powerpc: Use a macro for creating instructions from u32s
In preparation for instructions having a more complex data type start
using a macro, ppc_inst(), for making an instruction out of a u32. A
macro is used so that instructions can be used as initializer elements.
Currently this does nothing, but it will allow for creating a data type
that can represent prefixed instructions.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Change include guard to _ASM_POWERPC_INST_H] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Alistair Popple <alistair@popple.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-7-jniethe5@gmail.com
Jordan Niethe [Wed, 6 May 2020 03:40:25 +0000 (13:40 +1000)]
powerpc: Change calling convention for create_branch() et. al.
create_branch(), create_cond_branch() and translate_branch() return the
instruction that they create, or return 0 to signal an error. Separate
these concerns in preparation for an instruction type that is not just
an unsigned int. Fill the created instruction to a pointer passed as
the first parameter to the function and use a non-zero return value to
signify an error.
Jordan Niethe [Wed, 6 May 2020 03:40:24 +0000 (13:40 +1000)]
powerpc/xmon: Use bitwise calculations in_breakpoint_table()
A modulo operation is used for calculating the current offset from a
breakpoint within the breakpoint table. As instruction lengths are
always a power of 2, this can be replaced with a bitwise 'and'. The
current check for word alignment can be replaced with checking that the
lower 2 bits are not set.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Alistair Popple <alistair@popple.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-5-jniethe5@gmail.com
Jordan Niethe [Wed, 6 May 2020 03:40:23 +0000 (13:40 +1000)]
powerpc/xmon: Move breakpoints to text section
The instructions for xmon's breakpoint are stored bpt_table[] which is in
the data section. This is problematic as the data section may be marked
as no execute. Move bpt_table[] to the text section.
projects / users / willy / linux.git / log