Commit Graph

73 Commits

Author SHA1 Message Date
Nicholas Piggin aebd1fb45c powerpc: flexible GPR range save/restore macros
Introduce macros that operate on a (start, end) range of GPRs, which
reduces lines of code and need to do mental arithmetic while reading the
code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211022061322.2671178-1-npiggin@gmail.com
2021-11-29 23:15:20 +11:00
Nicholas Piggin 81291383ff powerpc/32e: Ignore ESR in instruction storage interrupt handler
A e5500 machine running a 32-bit kernel sometimes hangs at boot,
seemingly going into an infinite loop of instruction storage interrupts.

The ESR (Exception Syndrome Register) has a value of 0x800000 (store)
when this happens, which is likely set by a previous store. An
instruction TLB miss interrupt would then leave ESR unchanged, and if no
PTE exists it calls directly to the instruction storage interrupt
handler without changing ESR.

access_error() does not cause a segfault due to a store to a read-only
vma because is_exec is true. Most subsequent fault handling does not
check for a write fault on a read-only vma, and might do strange things
like create a writeable PTE or call page_mkwrite on a read only vma or
file. It's not clear what happens here to cause the infinite faulting in
this case, a fault handler failure or low level PTE or TLB handling.

In any case this can be fixed by having the instruction storage
interrupt zero regs->dsisr rather than storing the ESR value to it.

Fixes: a01a3f2ddb ("powerpc: remove arguments from fault handler functions")
Cc: stable@vger.kernel.org # v5.12+
Reported-by: Jacques de Laval <jacques.delaval@protonmail.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Jacques de Laval <jacques.delaval@protonmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211028133043.4159501-1-npiggin@gmail.com
2021-10-29 23:12:37 +11:00
Christophe Leroy b5cfc9cd7b powerpc/32: Fix critical and debug interrupts on BOOKE
32 bits BOOKE have special interrupts for debug and other
critical events.

When handling those interrupts, dedicated registers are saved
in the stack frame in addition to the standard registers, leading
to a shift of the pt_regs struct.

Since commit db297c3b07 ("powerpc/32: Don't save thread.regs on
interrupt entry"), the pt_regs struct is expected to be at the
same place all the time.

Instead of handling a special struct in addition to pt_regs, just
add those special registers to struct pt_regs.

Fixes: db297c3b07 ("powerpc/32: Don't save thread.regs on interrupt entry")
Cc: stable@vger.kernel.org
Reported-by: Radu Rendec <radu.rendec@gmail.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/028d5483b4851b01ea4334d0751e7f260419092b.1625637264.git.christophe.leroy@csgroup.eu
2021-08-07 08:53:59 +10:00
Christophe Leroy a27755d57e powerpc/32: Avoid #ifdef nested with FTR_SECTION on booke syscall entry
On booke, SYSCALL_ENTRY macro nests an FTR_SECTION with a #ifdef
CONFIG_KVM_BOOKE_HV.

Duplicate the single instruction alternative to avoid nesting.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/33db61d5f85146262dbe26648f8f87eca3cae393.1622818435.git.christophe.leroy@csgroup.eu
2021-06-25 00:07:11 +10:00
Christophe Leroy 4bd9e05ac7 powerpc/32: Reduce code duplication of system call entry
booke and non booke do pretty similar things in SYSCALL_ENTRY macro
just before calling jumping to transfer_to_syscall().

Do them in transfer_to_syscall() instead.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/552e27fa09394a6bc70585fcdfa237f99a5d1267.1622818435.git.christophe.leroy@csgroup.eu
2021-06-25 00:07:10 +10:00
Christophe Leroy 275dcf24e2 powerpc/32: Interchange r1 and r11 in SYSCALL_ENTRY on booke
To better match non booke version of SYSCALL_ENTRY macro,
interchange r1 and r11 in the booke version.

While at it, in both versions use r1 instead of r11 to save
_NIP and _CCR.

All other uses of r11 will go away in next patch, so don't
bother changing them for now.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1684c39724a069b0ce1aa82eaee6ec194e354e4e.1622818435.git.christophe.leroy@csgroup.eu
2021-06-25 00:07:10 +10:00
Christophe Leroy b5efec00b6 powerpc/32s: Move KUEP locking/unlocking in C
This can be done in C, do it.

Unrolling the loop gains approx. 15% performance.

From now on, prepare_transfer_to_handler() is only for
interrupts from kernel.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4eadd873927e9a73c3d1dfe2f9497353465514cf.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:10 +11:00
Christophe Leroy a2b3e09ae4 powerpc/32: Only use prepare_transfer_to_handler function on book3s/32 and e500
Only book3s/32 and e500 have significative work to do in
prepare_transfer_to_handler.

Other 32 bit have nothing to do at all.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b5e29ca0e557c11340415a13fe8b107189d315e1.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:10 +11:00
Christophe Leroy 16db54369d powerpc/32: Save remaining registers in exception prolog
Save non volatile registers, XER, CTR, MSR and NIP in exception prolog.

Also assign proper value to r2 and r3 there.

For now, recalculate thread pointer in prepare_transfer_to_handler.
It will disappear once KUAP is ported to C.

And remove the comment which is now completely wrong.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/56f0cde9dd0362edf2ddba4d887552013eee7329.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:10 +11:00
Christophe Leroy a305597850 powerpc/32: Refactor saving of volatile registers in exception prologs
Exception prologs all do the same at the end:
- Save trapno in stack
- Mark stack with exception marker
- Save r0
- Save r3 to r8

Refactor that into a COMMON_EXCEPTION_PROLOG_END macro.
At the same time use r1 instead of r11.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e1c45d2e895e0693c42d2a6840df1105a148efea.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:10 +11:00
Christophe Leroy acc142b623 powerpc/32: Remove the xfer parameter in EXCEPTION() macro
The xfer parameter is not used anymore, remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/17c7d68bd18f7d2f1ab24a1a20d9ed33bbcda741.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:09 +11:00
Christophe Leroy 4c0104a83f powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE
In order to get more control in exception prolog, dismantle
all non standard exception macros, finishing with EXC_XFER_STD
and EXC_XFER_LITE and EXC_XFER_TEMPLATE.

Also remove transfer_to_handler_full and ret_from_except and
ret_from_except_full as they are not used anymore.

Last parameter of EXCEPTION() is now ignored, will be removed
in a later patch to avoid too much churn.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ca5795d04a220586b7037dbbbe6951dfa9e768eb.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:09 +11:00
Christophe Leroy 8f6ff5bd9b powerpc/32: Only restore non volatile registers when required
Until now, non volatile registers were restored everytime they
were saved, ie using EXC_XFER_STD meant saving and restoring
them while EXC_XFER_LITE meant neither saving not restoring them.

Now that they are always saved, EXC_XFER_STD means to restore
them and EXC_XFER_LITE means to not restore them.

Most of the users of EXC_XFER_STD only need to retrieve the
non volatile registers. For them there is no need to restore
the non volatile registers as they have not been modified.

Only very few exceptions require non volatile registers restore.

Opencode the few places which require saving of non volatile
registers.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d1cb12d8023cc6afc1f07150565571373c04945c.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:09 +11:00
Christophe Leroy bce4c26a4e powerpc/32: Add a prepare_transfer_to_handler macro for exception prologs
In order to increase flexibility, add a macro that will for now
call transfer_to_handler.

As transfer_to_handler doesn't do the actual transfer anymore,
also name it prepare_transfer_to_handler. The following patches
will progressively remove the use of transfer_to_handler label.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7f757c52518ab1d7b27ad5113b10f860e803f467.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:09 +11:00
Christophe Leroy 719e7e212c powerpc/32: Save trap number on stack in exception prolog
Saving the trap number into the stack goes into
the exception prolog, as EXC_XFER_xxx will soon disappear.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2ac7a0c9cde2ec2b23cd79e3a54cfedd816a91ae.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:08 +11:00
Christophe Leroy af6f2ce84b powerpc/32: Call bad_page_fault() from do_page_fault()
Now that non volatile registers are saved at all time, no
need to split bad_page_fault() out of do_page_fault().

Remove handle_page_fault() and use do_page_fault() directly.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cfb95be8863204cc2bf45a22ea44dd1d0dc16b7f.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:08 +11:00
Christophe Leroy e72915560b powerpc/32: Set regs parameter in r3 in transfer_to_handler
All exception handlers take regs as first parameter.

Instead of setting r3 just before each call to a handler, set
it in transfer_to_handler.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f994a379bb895a2cbd518cb82460ad3f3d3ccdf5.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:08 +11:00
Christophe Leroy e9f99704aa powerpc/32: Always save non volatile registers on exception entry
In preparation of handling exception entry and exit in C,
in order to simplify the handling, always save non volatile registers
when entering an exception.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3ce8ced87a4f1467fa36fcc50763d53b45e466c1.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:07 +11:00
Christophe Leroy 0f2793e33d powerpc/32: Perform normal function call in exception entry
Now that the MMU is re-enabled before calling the transfer function,
we don't need anymore that hack with the address of the handler and
the return function sitting just after the 'bl' to the transfer
fonction, that function is retrieving via a read relative to 'lr'.

Do a regular call to the transfer function, then to the handler,
then branch to the return function.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/73c00f3361ca280ef8fd7814c291bd1f5b6e2081.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:07 +11:00
Christophe Leroy 32d2ca0e96 powerpc/32: Refactor booke critical registers saving
Refactor booke critical registers saving into a few macros
and move it into the exception prolog directly.

Keep the dedicated transfert_to_handler entry point for the
moment allthough they are empty. They will be removed in a
later patch to reduce churn.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/269171496f1f5f22afa621695bded22976c9d48d.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:07 +11:00
Christophe Leroy 9b6150fb89 powerpc/32: Enable instruction translation at the same time as data translation
On 40x and 8xx, kernel text is pinned.
On book3s/32, kernel text is mapped by BATs.

Enable instruction translation at the same time as data translation, it
makes things simpler.

In syscall handler, MSR_RI can also be set at the same time because
srr0/srr1 are already saved and r1 is set properly.

On booke, translation is always on, so at the end all PPC32
have translation on early. Just update msr.

Also update comment in power_save_ppc32_restore().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5269c7e5f5d2117358af3a89744d75a116be27b0.1615552867.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:05 +11:00
Christophe Leroy 5747230645 powerpc/32: Remove ksp_limit
ksp_limit is there to help detect stack overflows.
That is specific to ppc32 as it was removed from ppc64 in
commit cbc9565ee8 ("powerpc: Remove ksp_limit on ppc64").

There are other means for detecting stack overflows.

As ppc64 has proven to not need it, ppc32 should be able to do
without it too.

Lets remove it and simplify exception handling.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d789c3385b22e07bedc997613c0d26074cb513e7.1615552866.git.christophe.leroy@csgroup.eu
2021-03-29 13:22:05 +11:00
Christophe Leroy d524dda719 powerpc/32: Handle bookE debugging in C in syscall entry/exit
The handling of SPRN_DBCR0 and other registers can easily
be done in C instead of ASM.

For that, create booke_load_dbcr0() and booke_restore_dbcr0().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1a7515f9258b27a9177de88491a8bb79b255ceb7.1612898425.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:12 +11:00
Christophe Leroy eb595eca74 powerpc/32: Remove the counter in global_dbcr0
global_dbcr0 has two parts, 4 bytes to save/restore the
value of SPRN_DBCR0, and 4 bytes that are incremented/decremented
everytime something is saving/loading the above value.

This counter is only incremented/decremented, its value is never
used and never read.

Remove the counter and devide the size of global_dbcr0 by 2.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7e381dc58b3f583556cfab37ba5d813bfd5cce1e.1612796617.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:12 +11:00
Christophe Leroy 4d67facbcb powerpc/32: Remove verification of MSR_PR on syscall in the ASM entry
system_call_exception() checks MSR_PR and BUGs if a syscall
is issued from kernel mode.

No need to handle it anymore from the ASM entry code.

null_syscall reduction 2 cycles (348 => 346 cycles)

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1eddb42cb12092b1e3d72608d182c365db3da41d.1612796617.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:11 +11:00
Christophe Leroy 6f76a01173 powerpc/syscall: implement system call entry/exit logic in C for PPC32
That's port of PPC64 syscall entry/exit logic in C to PPC32.

Performancewise on 8xx:
Before : 304 cycles on null_syscall
After  : 348 cycles on null_syscall

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a93b08e1275e9d1f0b1c39043d1b827586b2b401.1612796617.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:11 +11:00
Christophe Leroy fbcee2ebe8 powerpc/32: Always save non volatile GPRs at syscall entry
In preparation for porting syscall entry/exit to C, inconditionally
save non volatile general purpose registers.

Commit 965dd3ad30 ("powerpc/64/syscall: Remove non-volatile GPR save
optimisation") provides detailed explanation.

This increases the number of cycles by 24 cycles on 8xx with
null_syscall benchmark (280 => 304 cycles)

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/21c08162b83655195fe9ead78ff2cfd28508d023.1612796617.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:11 +11:00
Christophe Leroy 76249ddc27 powerpc/32: On syscall entry, enable instruction translation at the same time as data
On 40x and 8xx, kernel text is pinned.
On book3s/32, kernel text is mapped by BATs.

Enable instruction translation at the same time as data translation, it
makes things simpler.

MSR_RI can also be set at the same time because srr0/srr1 are already
saved and r1 is set properly.

On booke, translation is always on, so at the end all PPC32
have translation on early.

This reduces null_syscall benchmark by 13 cycles on 8xx
(296 ==> 283 cycles).

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3fe8891c814103a3549efc1d4e7ffc828bba5993.1612796617.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:08 +11:00
Christophe Leroy eca2411040 powerpc/32: Always enable data translation on syscall entry
If the code can use a stack in vm area, it can also use a
stack in linear space.

Simplify code by removing old non VMAP stack code on PPC32 in syscall.

That means the data translation is now re-enabled early in
syscall entry in all cases, not only when using VMAP stacks.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/412c6c1786922d991bbb89c2ad2e82cffe8ab112.1612796617.git.christophe.leroy@csgroup.eu
2021-02-11 23:35:08 +11:00
Nicholas Piggin 755d664174 powerpc: DebugException remove args
Like other interrupt handler conversions, switch to getting registers
from the pt_regs argument.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-10-npiggin@gmail.com
2021-02-09 00:02:09 +11:00
Nicholas Piggin a01a3f2ddb powerpc: remove arguments from fault handler functions
Make mm fault handlers all just take the pt_regs * argument and load
DAR/DSISR from that. Make those that return a value return long.

This is done to make the function signatures match other handlers, which
will help with a future patch to add wrappers. Explicit arguments could
be added for performance but that would require more wrapper macro
variants.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-7-npiggin@gmail.com
2021-02-09 00:02:08 +11:00
Christophe Leroy 39c8bf2b3c powerpc: Retire e200 core (mpc555x processor)
There is no defconfig selecting CONFIG_E200, and no platform.

e200 is an earlier version of booke, a predecessor of e500,
with some particularities like an unified cache instead of both an
instruction cache and a data cache.

Remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Scott Wood <oss@buserror.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/34ebc3ba2c768d97f363bd5f2deea2356e9ae127.1605589460.git.christophe.leroy@csgroup.eu
2020-12-05 21:49:18 +11:00
Christophe Leroy 120c0518ec powerpc: Replace RFI by rfi on book3s/32 and booke
For book3s/32 and for booke, RFI is just an rfi.
Only 40x has a non trivial RFI.
CONFIG_PPC_RTAS is never selected by 40x platforms.

Make it more explicit by replacing RFI by rfi wherever possible.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b901ddfdeb8a0a3b7cb59999599cdfde1bbfe834.1604854583.git.christophe.leroy@csgroup.eu
2020-11-19 16:56:54 +11:00
Christophe Leroy ca1d3443b4 powerpc: Remove SYNC on non 6xx
SYNC is usefull for Powerpc 601 only. On everything else,
SYNC is empty.

Remove it from code that is not made to run on 6xx.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/27951fa6c9a8f80724d1bc81a6117ac32343a55d.1601362098.git.christophe.leroy@csgroup.eu
2020-10-08 21:17:12 +11:00
Christophe Leroy b711531641 powerpc: Replace _ALIGN_UP() by ALIGN()
_ALIGN_UP() is specific to powerpc
ALIGN() is generic and does the same

Replace _ALIGN_UP() by ALIGN()

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/8a6d7e45f7904c73a0af539642d3962e2a3c7268.1587407777.git.christophe.leroy@c-s.fr
2020-05-11 23:15:15 +10:00
Christophe Leroy 9e27086292 powerpc/32: Warn and return ENOSYS on syscalls from kernel
Since commit b86fb88855 ("powerpc/32: implement fast entry for
syscalls on non BOOKE") and commit 1a4b739bbb ("powerpc/32:
implement fast entry for syscalls on BOOKE"), syscalls from
kernel are unexpected and can have catastrophic consequences
as it will destroy the kernel stack.

Test MSR_PR on syscall entry. In case syscall is from kernel,
emit a warning and return ENOSYS error.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8ee3bdbbdfdfc64ca7001e90c43b2aee6f333578.1580470482.git.christophe.leroy@c-s.fr
2020-02-19 22:46:08 +11:00
Christophe Leroy 1ca9db5b65 powerpc/32: save DEAR/DAR before calling handle_page_fault
handle_page_fault() is the only function that save DAR/DEAR itself.

Save DAR/DEAR before calling handle_page_fault() to prepare for
VMAP stack which will require to save even before.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3a4d58d378091086f00fde42b59610c80289e120.1576916812.git.christophe.leroy@c-s.fr
2020-01-26 22:15:09 +11:00
Christophe Leroy 82f6e266f8 powerpc/32: fix build failure on book3e with KVM
Build failure was introduced by the commit identified below,
due to missed macro expension leading to wrong called function's name.

arch/powerpc/kernel/head_fsl_booke.o: In function `SystemCall':
arch/powerpc/kernel/head_fsl_booke.S:416: undefined reference to `kvmppc_handler_BOOKE_INTERRUPT_SYSCALL_SPRN_SRR1'
Makefile:1052: recipe for target 'vmlinux' failed

The called function should be kvmppc_handler_8_0x01B(). This patch fixes it.

Reported-by: Paul Mackerras <paulus@ozlabs.org>
Fixes: 1a4b739bbb ("powerpc/32: implement fast entry for syscalls on BOOKE")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-06-16 00:03:38 +10:00
Christophe Leroy e8732ffa2e powerpc/booke: fix fast syscall entry on SMP
Use r10 instead of r9 to calculate CPU offset as r9 contains
the value from SRR1 which is used later.

Fixes: 1a4b739bbb ("powerpc/32: implement fast entry for syscalls on BOOKE")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-06-15 23:44:41 +10:00
Christophe Leroy 1a4b739bbb powerpc/32: implement fast entry for syscalls on BOOKE
This patch implements a fast entry for syscalls.

Syscalls don't have to preserve non volatile registers except LR.

This patch then implement a fast entry for syscalls, where
volatile registers get clobbered.

As this entry is dedicated to syscall it always sets MSR_EE
and warns in case MSR_EE was previously off

It also assumes that the call is always from user, system calls are
unexpected from kernel.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03 01:20:27 +10:00
Christophe Leroy 1ae99b4b92 powerpc/32: get rid of COPY_EE in exception entry
EXC_XFER_TEMPLATE() is not called with COPY_EE anymore so
we can get rid of copyee parameters and related COPY_EE and NOCOPY
macros.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[splited out from benh RFC patch]

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03 01:20:27 +10:00
Christophe Leroy 642770dd96 powerpc/32: Enter exceptions with MSR_EE unset
All exceptions handlers know when to reenable interrupts, so
it is safer to enter all of them with MSR_EE unset, except
for syscalls.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[splited out from benh RFC patch]

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03 01:20:27 +10:00
Christophe Leroy f97dec21a3 powerpc/32: enter syscall with MSR_EE inconditionaly set
syscalls are expected to be entered with MSR_EE set. Lets
make it inconditional by forcing MSR_EE on syscalls.

This patch adds EXC_XFER_SYS for that.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[splited out from benh RFC patch]

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03 01:20:27 +10:00
Christophe Leroy ed1cd6deb0 powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
This patch activates CONFIG_THREAD_INFO_IN_TASK which
moves the thread_info into task_struct.

Moving thread_info into task_struct has the following advantages:
  - It protects thread_info from corruption in the case of stack
    overflows.
  - Its address is harder to determine if stack addresses are leaked,
    making a number of attacks more difficult.

This has the following consequences:
  - thread_info is now located at the beginning of task_struct.
  - The 'cpu' field is now in task_struct, and only exists when
    CONFIG_SMP is active.
  - thread_info doesn't have anymore the 'task' field.

This patch:
  - Removes all recopy of thread_info struct when the stack changes.
  - Changes the CURRENT_THREAD_INFO() macro to point to current.
  - Selects CONFIG_THREAD_INFO_IN_TASK.
  - Modifies raw_smp_processor_id() to get ->cpu from current without
    including linux/sched.h to avoid circular inclusion and without
    including asm/asm-offsets.h to avoid symbol names duplication
    between ASM constants and C constants.
  - Modifies klp_init_thread_info() to take a task_struct pointer
    argument.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add task_stack.h to livepatch.h to fix build fails]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-02-23 22:31:40 +11:00
Christophe Leroy 8c1fc5abdc powerpc: Rename THREAD_INFO to TASK_STACK
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>
2019-02-23 22:31:40 +11:00
Diana Craciun 039daac552 powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'
Fixed the following build warning:
powerpc-linux-gnu-ld: warning: orphan section `__btb_flush_fixup' from
`arch/powerpc/kernel/head_44x.o' being placed in section
`__btb_flush_fixup'.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-12-30 14:00:47 +11:00
Diana Craciun 7fef436295 powerpc/fsl: Flush the branch predictor at each kernel entry (32 bit)
In order to protect against speculation attacks on
indirect branches, the branch predictor is flushed at
kernel entry to protect for the following situations:
- userspace process attacking another userspace process
- userspace process attacking the kernel
Basically when the privillege level change (i.e.the kernel
is entered), the branch predictor state is flushed.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-12-20 22:59:03 +11:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Bharat Bhushan fc2a6cfe05 powerpc: Fix interrupt range check on debug exception
We do not want to take single step and branch-taken debug exception
in kernel exception code. But the address range check was not covering
all kernel exception handlers address range.

With this patch we defined the interrupt_end label which defines the
end on kernel exception code. So now we check interrupt_base to
interrupt_end range for not handling debug exception in kernel
exception entry.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-05-02 10:31:01 +10:00
Kevin Hao 177c19237b powerpc/booke: Remove obsolete macro FINISH_EXCEPTION
This is stale and not used by anyone now.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-30 15:59:32 +10:00