When we enable THREAD_INFO_IN_TASK we will remove our definition of
current_thread_info(). Instead it will come from linux/thread_info.h

So switch processor.h to include the latter, so that it can continue
to find current_thread_info().

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently INIT_SP_LIMIT uses sizeof(init_thread_info), but that symbol
won't exist when we enable THREAD_INFO_IN_TASK. So just use the sizeof
the type which is the same value but will continue to work.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Rather than using the thread info use task_stack_page() to initialise
paca->kstack, that way it will work with THREAD_INFO_IN_TASK.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Update a few comments that talk about current_thread_info() in
preparation for THREAD_INFO_IN_TASK.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We have a few places that use current_thread_info()->task to access
current. This won't work with THREAD_INFO_IN_TASK so fix them now.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

A few places use CURRENT_THREAD_INFO, or the C version, to find the
stack. This will no longer work with THREAD_INFO_IN_TASK so change
them to find the stack in other ways.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The purpose of the pointer given to call_do_softirq() and
call_do_irq() is to point the new stack. Currently that's the same
thing as the thread_info, but won't be with THREAD_INFO_IN_TASK.

So change the parameter to void* and rename it 'sp'.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch renames THREAD_INFO to TASK_STACK, because it is in fact
the offset of the pointer to the stack in task_struct so this pointer
will not be impacted by the move of THREAD_INFO.

Also make it available on 64-bit, as we'll need it there when we
activate THREAD_INFO_IN_TASK.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Make available on 64-bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

[text copied from commit 9bbd4c56


("arm64: prep stack walkers for THREAD_INFO_IN_TASK")]

When CONFIG_THREAD_INFO_IN_TASK is selected, task stacks may be freed
before a task is destroyed. To account for this, the stacks are
refcounted, and when manipulating the stack of another task, it is
necessary to get/put the stack to ensure it isn't freed and/or re-used
while we do so.

This patch reworks the powerpc stack walking code to account for this.
When CONFIG_THREAD_INFO_IN_TASK is not selected these perform no
refcounting, and this should only be a structural change that does not
affect behaviour.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move try_get_task_stack() below tsk == NULL check in show_stack()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When moving to CONFIG_THREAD_INFO_IN_TASK, the thread_info 'cpu' field
gets moved into task_struct and only defined when CONFIG_SMP is set.

This patch ensures that TI_CPU is only used when CONFIG_SMP is set and
that task_struct 'cpu' field is not used directly out of SMP code.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When activating CONFIG_THREAD_INFO_IN_TASK, linux/sched.h includes
asm/current.h. This generates a circular dependency. To avoid that,
asm/processor.h shall not be included in mmu-hash.h.

In order to do that, this patch moves into a new header called
asm/task_size_64/32.h all the TASK_SIZE related constants, which can
then be included in mmu-hash.h directly.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out all the TASK_SIZE constants not just 64-bit ones]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Since only the virtual address of allocated blocks is used,
lets use functions returning directly virtual address.

Those functions have the advantage of also zeroing the block.

Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

In __secondary_start() we load the thread_info of the idle task of the
secondary CPU from current_set[cpu], and then convert it into a stack
pointer before storing that back to paca->kstack.

As pointed out in commit f761622e ("powerpc: Initialise
paca->kstack before early_setup_secondary") it's important that we
initialise paca->kstack before calling the MMU setup code, in
particular slb_initialize(), because it will bolt the SLB entry for
the kstack into the SLB.

However we have already setup paca->kstack in cpu_idle_thread_init(),
since commit 3b575064

 ("[POWERPC] Bolt in SLB entry for kernel
stack on secondary cpus") (May 2008).

It's also in cpu_idle_thread_init() that we initialise current_set[cpu]
with the thread_info pointer, so there is no issue of the timing being
different between the two.

Therefore the initialisation of paca->kstack in __setup_secondary() is
completely redundant, so remove it.

This has the added benefit of removing code that runs in real mode,
and is therefore restricted by the RMO, and so opens the way for us to
enable THREAD_INFO_IN_TASK.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently in system_call_exit() we have an optimisation where we
disable MSR_RI (recoverable interrupt) and MSR_EE (external interrupt
enable) in a single mtmsrd instruction.

Unfortunately this will no longer work with THREAD_INFO_IN_TASK,
because then the load of TI_FLAGS might fault and faulting with MSR_RI
clear is treated as an unrecoverable exception which leads to a
panic().

So change the code to only clear MSR_EE prior to loading TI_FLAGS,
leaving the clear of MSR_RI until later. We have some latitude in
where do the clear of MSR_RI. A bit of experimentation has shown that
this location gives the least slow down.

This still causes a noticeable slow down in our null_syscall
performance. On a Power9 DD2.2:

  Before        After         Delta     Delta %
  955 cycles    999 cycles    -44	-4.6%

On the plus side this does simplify the code somewhat, because we
don't have to reenable MSR_RI on the restore_math() or
syscall_exit_work() paths which was necessitated previously by the
optimisation.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

kcov provides kernel coverage data that's useful for fuzzing tools like
syzkaller.

Wire up kcov support on powerpc. Disable kcov instrumentation on the same
files where we currently disable gcov and UBSan instrumentation, plus some
additional exclusions which appear necessary to boot on book3e machines.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Daniel Axtens <dja@axtens.net> # e6500
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

On 8xx, large pages (512kb or 8M) are used to map kernel linear
memory. Aligning to 8M reduces TLB misses as only 8M pages are used
in that case. We make 8M the default for data.

This patchs allows the user to do it via Kconfig.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch implements handling of STRICT_KERNEL_RWX with
large TLBs directly in the TLB miss handlers.

To do so, etext and sinittext are aligned on 512kB boundaries
and the miss handlers use 512kB pages instead of 8Mb pages for
addresses close to the boundaries.

It sets RO PP flags for addresses under sinittext.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Depending on the number of available BATs for mapping the different
kernel areas, it might be needed to increase the alignment of _etext
and/or of data areas.

This patchs allows the user to do it via Kconfig.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Today, STRICT_KERNEL_RWX is based on the use of regular pages
to map kernel pages.

On Book3s 32, it has three consequences:
- Using pages instead of BAT for mapping kernel linear memory severely
impacts performance.
- Exec protection is not effective because no-execute cannot be set at
page level (except on 603 which doesn't have hash tables)
- Write protection is not effective because PP bits do not provide RO
mode for kernel-only pages (except on 603 which handles it in software
via PAGE_DIRTY)

On the 603+, we have:
- Independent IBAT and DBAT allowing limitation of exec parts.
- NX bit can be set in segment registers to forbit execution on memory
mapped by pages.
- RO mode on DBATs even for kernel-only blocks.

On the 601, there is nothing much we can do other than warn the user
about it, because:
- BATs are common to instructions and data.
- BAT do not provide RO mode for kernel-only blocks.
- segment registers don't have the NX bit.

In order to use IBAT for exec protection, this patch:
- Aligns _etext to BAT block sizes (128kb)
- Set NX bit in kernel segment register (Except on vmalloc area when
CONFIG_MODULES is selected)
- Maps kernel text with IBATs.

In order to use DBAT for exec protection, this patch:
- Aligns RW DATA to BAT block sizes (4M)
- Maps kernel RO area with write prohibited DBATs
- Maps remaining memory with remaining DBATs

Here is what we get with this patch on a 832x when activating
STRICT_KERNEL_RWX:

Symbols:
c0000000 T _stext
c0680000 R __start_rodata
c0680000 R _etext
c0800000 T __init_begin
c0800000 T _sinittext

~# cat /sys/kernel/debug/block_address_translation
---[ Instruction Block Address Translation ]---
0: 0xc0000000-0xc03fffff 0x00000000 Kernel EXEC coherent
1: 0xc0400000-0xc05fffff 0x00400000 Kernel EXEC coherent
2: 0xc0600000-0xc067ffff 0x00600000 Kernel EXEC coherent
3:         -
4:         -
5:         -
6:         -
7:         -

---[ Data Block Address Translation ]---
0: 0xc0000000-0xc07fffff 0x00000000 Kernel RO coherent
1: 0xc0800000-0xc0ffffff 0x00800000 Kernel RW coherent
2: 0xc1000000-0xc1ffffff 0x01000000 Kernel RW coherent
3: 0xc2000000-0xc3ffffff 0x02000000 Kernel RW coherent
4: 0xc4000000-0xc7ffffff 0x04000000 Kernel RW coherent
5: 0xc8000000-0xcfffffff 0x08000000 Kernel RW coherent
6: 0xd0000000-0xdfffffff 0x10000000 Kernel RW coherent
7:         -

~# cat /sys/kernel/debug/segment_registers
---[ User Segments ]---
0x00000000-0x0fffffff Kern key 1 User key 1 VSID 0xa085d0
0x10000000-0x1fffffff Kern key 1 User key 1 VSID 0xa086e1
0x20000000-0x2fffffff Kern key 1 User key 1 VSID 0xa087f2
0x30000000-0x3fffffff Kern key 1 User key 1 VSID 0xa08903
0x40000000-0x4fffffff Kern key 1 User key 1 VSID 0xa08a14
0x50000000-0x5fffffff Kern key 1 User key 1 VSID 0xa08b25
0x60000000-0x6fffffff Kern key 1 User key 1 VSID 0xa08c36
0x70000000-0x7fffffff Kern key 1 User key 1 VSID 0xa08d47
0x80000000-0x8fffffff Kern key 1 User key 1 VSID 0xa08e58
0x90000000-0x9fffffff Kern key 1 User key 1 VSID 0xa08f69
0xa0000000-0xafffffff Kern key 1 User key 1 VSID 0xa0907a
0xb0000000-0xbfffffff Kern key 1 User key 1 VSID 0xa0918b

---[ Kernel Segments ]---
0xc0000000-0xcfffffff Kern key 0 User key 1 No Exec VSID 0x000ccc
0xd0000000-0xdfffffff Kern key 0 User key 1 No Exec VSID 0x000ddd
0xe0000000-0xefffffff Kern key 0 User key 1 No Exec VSID 0x000eee
0xf0000000-0xffffffff Kern key 0 User key 1 No Exec VSID 0x000fff

Aligning _etext to 128kb allows to map up to 32Mb text with 8 IBATs:
16Mb + 8Mb + 4Mb + 2Mb + 1Mb + 512kb + 256kb + 128kb (+ 128kb) = 32Mb
(A 9th IBAT is unneeded as 32Mb would need only a single 32Mb block)

Aligning data to 4M allows to map up to 512Mb data with 8 DBATs:
16Mb + 8Mb + 4Mb + 4Mb + 32Mb + 64Mb + 128Mb + 256Mb = 512Mb

Because some processors only have 4 BATs and because some targets need
DBATs for mapping other areas, the following patch will allow to
modify _etext and data alignment.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

setibat() and clearibat() allows to manipulate IBATs independently
of DBATs.

update_bats() allows to update bats after init. This is done
with MMU off.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

CONFIG_STRICT_KERNEL_RWX requires a special alignment
for DATA for some subarches. Today it is just defined
as an #ifdef in vmlinux.lds.S

In order to get more flexibility, this patch moves the
definition of this alignment in Kconfig

On some subarches, CONFIG_STRICT_KERNEL_RWX will
require a special alignment of _etext.

This patch also adds a configuration item for it in Kconfig

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch defined CONFIG_PPC_PAGE_SHIFT in order
to be able to use PAGE_SHIFT value inside Kconfig.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add a helper to know whether STRICT_KERNEL_RWX is enabled.

This is based on rodata_enabled flag which is defined only
when CONFIG_STRICT_KERNEL_RWX is selected.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch add an helper which wraps 'mtsrin' instruction
to write into segment registers.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Do not set IBAT when setbat() is called without _PAGE_EXEC

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

wii_mmu_mapin_mem2() is not used anymore, remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When CONFIG_BDI_SWITCH is set, the page tables have to be populated
allthough large TLBs are used, because the BDI switch knows nothing
about those large TLBs which are handled directly in TLB miss logic.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Now that mmu_mapin_ram() is able to handle other blocks
than the one starting at 0, the WII can use it for all
its blocks.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch reworks mmu_mapin_ram() to be more generic and map as much
blocks as possible. It now supports blocks not starting at address 0.

It scans DBATs array to find free ones instead of forcing the use of
BAT2 and BAT3.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

At the time being, mmu_mapin_ram() always maps RAM from the beginning.
But some platforms like the WII have to map a second block of RAM.

This patch adds to mmu_mapin_ram() the base address of the block.
At the moment, only base address 0 is supported.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

'nobats' kernel parameter or some options like CONFIG_DEBUG_PAGEALLOC
deny the use of BATS for mapping memory.

This patch makes sure that the specific wii RAM mapping function
takes it into account as well.

Fixes: de32400d

 ("wii: use both mem1 and mem2 as ram")
Cc: stable@vger.kernel.org
Reviewed-by: Jonathan Neuschafer <j.neuschaefer@gmx.net>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

At the time being, initial MMU setup allows 24 Mbytes
of DATA and 8 Mbytes of code.

Some debug setup like CONFIG_KASAN generate huge
kernels with text size over the 8M limit and data over the
24 Mbytes limit.

Here is an 8xx kernel compiled with CONFIG_KASAN_INLINE for
one of my boards:

[root@po16846vm linux-powerpc]# size -x vmlinux
   text	   data	    bss	    dec	    hex	filename
0x111019c	0x41b0d4	0x490de0	26984528	19bc050	vmlinux

This patch maps up to 32 Mbytes code based on _einittext symbol
and allows 32 Mbytes of memory instead of 24.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch replaces most #ifdef mess by IS_ENABLED() in 8xx_mmu.c
This has the advantage of allowing syntax verification at compile
time regardless of selected options.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This adds test cases for the addc[.] instruction.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This adds test cases for the add[.] instruction.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This enhances the current selftest framework for validating
the in-kernel instruction emulation infrastructure by adding
support for compute type instructions i.e. integer ALU-based
instructions. Originally, this framework was limited to only
testing load and store instructions.

While most of the GPRs can be validated, support for SPRs is
limited to LR, CR and XER for now.

When writing the test cases, one must ensure that the Stack
Pointer (GPR1) or the Thread Pointer (GPR13) are not touched
by any means as these are vital non-volatile registers.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
[mpe: Use patch_site for the code patching]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This reverts commit 78ca1108.

It is causing boot failures with qemu mac99 in at least some
configurations.

This patch moves the files related to page table dump in a
dedicated subdirectory.

The purpose is to clean a bit arch/powerpc/mm by regrouping
multiple files handling a dedicated function.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Shorten the file names while we're at it]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When using KASAN, there are parts of the shadow area where all
pages are mapped to the kasan_early_shadow_page. It is pointless
to dump one line for each of those pages (in the example below there
are 7168 entries pointing to the same physical page).

~# cat /sys/kernel/debug/kernel_page_tables
 ...
---[ kasan shadow mem start ]---
0xf7c00000-0xf8bfffff 0x06fac000       16M        rw       present           dirty  accessed
0xf8c00000-0xf8c03fff 0x00cd0000       16K        r        present           dirty  accessed
0xf8c04000-0xf8c07fff 0x00cd0000       16K        r        present           dirty  accessed
0xf8c08000-0xf8c0bfff 0x00cd0000       16K        r        present           dirty  accessed
0xf8c0c000-0xf8c0ffff 0x00cd0000       16K        r        present           dirty  accessed
0xf8c10000-0xf8c13fff 0x00cd0000       16K        r        present           dirty  accessed
 ... 7168 identical lines
0xffbfc000-0xffbfffff 0x00cd0000       16K        r        present           dirty  accessed
---[ kasan shadow mem end ]---
 ...

This patch modifies linux table dump to dump as a single line areas
where all addresses points to the same physical page. That physical
address is put inside [] to show that all virt pages points to the
same phys page.

~# cat /sys/kernel/debug/kernel_page_tables
 ...
---[ kasan shadow mem start ]---
0xf7c00000-0xf8bfffff  0x06fac000        16M        rw       present           dirty  accessed
0xf8c00000-0xffbfffff [0x00cd0000]       16K        r        present           dirty  accessed
---[ kasan shadow mem end ]---
 ...

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

map_hugetlb maps 256Mbytes of memory with default hugepage size.

This patch allows the user to pass the size and page shift as an
argument in order to use different size and page size.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>