Commit Graph

70 Commits

Author SHA1 Message Date
Ravi Bangoria 83afab4ce0 powerpc/sstep: Fix kernel crash if VSX is not present
emulate_step() is not checking runtime VSX feature flag before
emulating an instruction. This is causing kernel crash when kernel
is compiled with CONFIG_VSX=y but running on a machine where VSX
is not supported or disabled. Ex, while running emulate_step tests
on P6 machine:

  Oops: Exception in kernel mode, sig: 4 [#1]
  NIP [c000000000095c24] .load_vsrn+0x28/0x54
  LR [c000000000094bdc] .emulate_loadstore+0x167c/0x17b0
  Call Trace:
    0x40fe240c7ae147ae (unreliable)
    .emulate_loadstore+0x167c/0x17b0
    .emulate_step+0x25c/0x5bc
    .test_lxvd2x_stxvd2x+0x64/0x154
    .test_emulate_step+0x38/0x4c
    .do_one_initcall+0x5c/0x2c0
    .kernel_init_freeable+0x314/0x4cc
    .kernel_init+0x24/0x160
    .ret_from_kernel_thread+0x58/0xb4

With fix:
  emulate_step_test: lxvd2x         : FAIL
  emulate_step_test: stxvd2x        : FAIL

Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-06-04 00:39:08 +10:00
Ravi Bangoria e6684d07e4 powerpc/sstep: Introduce GETTYPE macro
Replace 'op->type & INSTR_TYPE_MASK' expression with GETTYPE(op->type)
macro.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-06-03 21:19:40 +10:00
Finn Thain 20acf7fc94 powerpc/lib: Fix "integer constant is too large" build failure
My powerpc-linux-gnu-gcc v4.4.5 compiler can't build a 32-bit kernel
any more:

arch/powerpc/lib/sstep.c: In function 'do_popcnt':
arch/powerpc/lib/sstep.c:1068: error: integer constant is too large for 'long' type
arch/powerpc/lib/sstep.c:1069: error: integer constant is too large for 'long' type
arch/powerpc/lib/sstep.c:1069: error: integer constant is too large for 'long' type
arch/powerpc/lib/sstep.c:1070: error: integer constant is too large for 'long' type
arch/powerpc/lib/sstep.c:1079: error: integer constant is too large for 'long' type
arch/powerpc/lib/sstep.c: In function 'do_prty':
arch/powerpc/lib/sstep.c:1117: error: integer constant is too large for 'long' type

This file gets compiled with -std=gnu89 which means a constant can be
given the type 'long' even if it won't fit. Fix the errors with a 'ULL'
suffix on the relevant constants.

Fixes: 2c979c489f ("powerpc/lib/sstep: Add prty instruction emulation")
Fixes: dcbd19b48d ("powerpc/lib/sstep: Add popcnt instruction emulation")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-05-18 16:04:02 +10:00
Mathieu Malaterre 174b701d3d powerpc/32: Move the inline keyword at the beginning of function declaration
The inline keyword was not at the beginning of the function declaration.
Fix the following warning (treated as error in W=1):

  arch/powerpc/lib/sstep.c:283:1: error: ‘inline’ is not at beginning of declaration
   static int nokprobe_inline copy_mem_in(u8 *dest, unsigned long ea, int nb,
  arch/powerpc/lib/sstep.c:388:1: error: ‘inline’ is not at beginning of declaration
   static int nokprobe_inline copy_mem_out(u8 *dest, unsigned long ea, int nb,

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-13 15:50:33 +11:00
Naveen N. Rao 67ac0bfe29 powerpc/kprobes: Blacklist emulate_update_regs() from kprobes
Commit 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't
modify *regs") introduced emulate_update_regs() to perform part of what
emulate_step() was doing earlier. However, this function was not added
to the kprobes blacklist. Add it so as to prevent it from being probed.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-12 23:51:42 +11:00
Michael Ellerman a54c61f46e Merge branch 'fixes' into next
We have some dependencies & conflicts between patches in fixes and
things to go in next, both in the radix TLB flush code and the IMC PMU
driver. So merge fixes into next.
2017-11-10 20:55:03 +11:00
Sandipan Das b0490a04e7 powerpc/lib/sstep: Fix count leading zeros instructions
According to the GCC documentation, the behaviour of __builtin_clz()
and __builtin_clzl() is undefined if the value of the input argument
is zero. Without handling this special case, these builtins have been
used for emulating the following instructions:
  * Count Leading Zeros Word (cntlzw[.])
  * Count Leading Zeros Doubleword (cntlzd[.])

This fixes the emulated behaviour of these instructions by adding an
additional check for this special case.

Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-10 20:16:32 +11:00
Sandipan Das 0a75aff178 powerpc/lib/sstep: Fix fixed-point shift instructions that set CA32
This fixes the emulated behaviour of existing fixed-point shift right
algebraic instructions that are supposed to set both the CA and CA32
bits of XER when running on a system that is compliant with POWER ISA
v3.0 independent of whether the system is executing in 32-bit mode or
64-bit mode. The following instructions are affected:
  * Shift Right Algebraic Word Immediate (srawi[.])
  * Shift Right Algebraic Word (sraw[.])
  * Shift Right Algebraic Doubleword Immediate (sradi[.])
  * Shift Right Algebraic Doubleword (srad[.])

Fixes: 0016a4cf55 ("powerpc: Emulate most Book I instructions in emulate_step()")
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:28:04 +11:00
Sandipan Das dc39c1d68f powerpc/lib/sstep: Fix fixed-point arithmetic instructions that set CA32
There are existing fixed-point arithmetic instructions that always set the
CA bit of XER to reflect the carry out of bit 0 in 64-bit mode and out of
bit 32 in 32-bit mode. In ISA v3.0, these instructions also always set the
CA32 bit of XER to reflect the carry out of bit 32.

This fixes the emulated behaviour of such instructions when running on a
system that is compliant with POWER ISA v3.0. The following instructions
are affected:
  * Add Immediate Carrying (addic)
  * Add Immediate Carrying and Record (addic.)
  * Subtract From Immediate Carrying (subfic)
  * Add Carrying (addc[.])
  * Subtract From Carrying (subfc[.])
  * Add Extended (adde[.])
  * Subtract From Extended (subfe[.])
  * Add to Minus One Extended (addme[.])
  * Subtract From Minus One Extended (subfme[.])
  * Add to Zero Extended (addze[.])
  * Subtract From Zero Extended (subfze[.])

Fixes: 0016a4cf55 ("powerpc: Emulate most Book I instructions in emulate_step()")
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:28:03 +11:00
Sandipan Das 924c8feb04 powerpc/lib/sstep: Add XER bits introduced in POWER ISA v3.0
This adds definitions for the OV32 and CA32 bits of XER that
were introduced in POWER ISA v3.0. There are some existing
instructions that currently set the OV and CA bits based on
certain conditions.

The emulation behaviour of all these instructions needs to
be updated to set these new bits accordingly.

Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04 11:28:03 +11:00
Anton Blanchard 1575fe06f6 powerpc/sstep: mullw should calculate a 64 bit signed result
mullw should do a 32 bit signed multiply and create a 64 bit signed
result. It currently truncates the result to 32 bits.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-20 13:30:09 +10:00
Anton Blanchard 5bcaa4cc41 powerpc/sstep: Fix issues with mcrf
mcrf broke when we changed analyse_instr() to not modify the register
state. The instruction writes to the CR, so we need to store the result
in op->ccval, not op->val.

Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-20 13:30:09 +10:00
Anton Blanchard ad47ff3e33 powerpc/sstep: Fix issues with set_cr0()
set_cr0() broke when we changed analyse_instr() to not modify the
register state. Instead of looking at regs->gpr[x] which has not
been updated yet, we need to look at op->val.

Fixes: 3cdfcbfd32 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-20 13:30:09 +10:00
Michael Ellerman 3b79b26101 powerpc/sstep: Avoid used uninitialized error
Older compilers think val may be used uninitialized:

  arch/powerpc/lib/sstep.c: In function 'emulate_loadstore':
  arch/powerpc/lib/sstep.c:2758:23: error: 'val' may be used uninitialized in this function

We know better, but initialise val to 0 to avoid breaking the build.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-02 08:04:26 +10:00
Paul Mackerras 45f62159f3 powerpc: Wrap register number correctly for string load/store instructions
Michael Ellerman reported that emulate_loadstore() was trying to
access element 32 of regs->gpr[], which doesn't exist, when
emulating a string store instruction.  This is because the string
load and store instructions (lswi, lswx, stswi and stswx) are
defined to wrap around from register 31 to register 0 if the number
of bytes being loaded or stored is sufficiently large.  This wrapping
was not implemented in the emulation code.  To fix it, we mask the
register number after incrementing it.

Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Fixes: c9f6f4ed95 ("powerpc: Implement emulation of string loads and stores")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:44 +10:00
Paul Mackerras d2b65ac652 powerpc: Emulate load/store floating point as integer word instructions
This adds emulation for the lfiwax, lfiwzx and stfiwx instructions.
This necessitated adding a new flag to indicate whether a floating
point or an integer conversion was needed for LOAD_FP and STORE_FP,
so this moves the size field in op->type up 4 bits.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:44 +10:00
Paul Mackerras a53d5182e2 powerpc: Separate out load/store emulation into its own function
This moves the parts of emulate_step() that deal with emulating
load and store instructions into a new function called
emulate_loadstore().  This is to make it possible to reuse this
code in the alignment handler.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:42:41 +10:00
Paul Mackerras d955189ae4 powerpc: Handle opposite-endian processes in emulation code
This adds code to the load and store emulation code to byte-swap
the data appropriately when the process being emulated is set to
the opposite endianness to that of the kernel.

This also enables the emulation for the multiple-register loads
and stores (lmw, stmw, lswi, stswi, lswx, stswx) to work for
little-endian.  In little-endian mode, the partial word at the
end of a transfer for lsw*/stsw* (when the byte count is not a
multiple of 4) is loaded/stored at the least-significant end of
the register.  Additionally, this fixes a bug in the previous
code in that it could call read_mem/write_mem with a byte count
that was not 1, 2, 4 or 8.

Note that this only works correctly on processors with "true"
little-endian mode, such as IBM POWER processors from POWER6 on, not
the so-called "PowerPC" little-endian mode that uses address swizzling
as implemented on the old 32-bit 603, 604, 740/750, 74xx CPUs.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:55 +10:00
Paul Mackerras b9da9c8a48 powerpc: Set regs->dar if memory access fails in emulate_step()
This adds code to the instruction emulation code to set regs->dar
to the address of any memory access that fails.  This address is
not necessarily the same as the effective address of the instruction,
because if the memory access is unaligned, it might cross a page
boundary and fault on the second page.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:54 +10:00
Paul Mackerras b2543f7b20 powerpc: Emulate the dcbz instruction
This adds code to analyse_instr() and emulate_step() to understand the
dcbz (data cache block zero) instruction.  The emulate_dcbz() function
is made public so it can be used by the alignment handler in future.
(The apparently unnecessary cropping of the address to 32 bits is
there because it will be needed in that situation.)

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:54 +10:00
Paul Mackerras 1f41fb7904 powerpc: Emulate load/store floating double pair instructions
This adds lfdp[x] and stfdp[x] to the set of instructions that
analyse_instr() and emulate_step() understand.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:53 +10:00
Paul Mackerras e61ccc7b0c powerpc: Emulate vector element load/store instructions
This adds code to analyse_instr() and emulate_step() to handle the
vector element loads and stores:

lvebx, lvehx, lvewx, stvebx, stvehx, stvewx.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:53 +10:00
Paul Mackerras c22435a5f3 powerpc: Emulate FP/vector/VSX loads/stores correctly when regs not live
At present, the analyse_instr/emulate_step code checks for the
relevant MSR_FP/VEC/VSX bit being set when a FP/VMX/VSX load
or store is decoded, but doesn't recheck the bit before reading or
writing the relevant FP/VMX/VSX register in emulate_step().

Since we don't have preemption disabled, it is possible that we get
preempted between checking the MSR bit and doing the register access.
If that happened, then the registers would have been saved to the
thread_struct for the current process.  Accesses to the CPU registers
would then potentially read stale values, or write values that would
never be seen by the user process.

Another way that the registers can become non-live is if a page
fault occurs when accessing user memory, and the page fault code
calls a copy routine that wants to use the VMX or VSX registers.

To fix this, the code for all the FP/VMX/VSX loads gets restructured
so that it forms an image in a local variable of the desired register
contents, then disables preemption, checks the MSR bit and either
sets the CPU register or writes the value to the thread struct.
Similarly, the code for stores checks the MSR bit, copies either the
CPU register or the thread struct to a local variable, then reenables
preemption and then copies the register image to memory.

If the instruction being emulated is in the kernel, then we must not
use the register values in the thread_struct.  In this case, if the
relevant MSR enable bit is not set, then emulate_step refuses to
emulate the instruction.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:52 +10:00
Paul Mackerras e0a0986b44 powerpc: Make load/store emulation use larger memory accesses
At the moment, emulation of loads and stores of up to 8 bytes to
unaligned addresses on a little-endian system uses a sequence of
single-byte loads or stores to memory.  This is rather inefficient,
and the code is hard to follow because it has many ifdefs.
In addition, the Power ISA has requirements on how unaligned accesses
are performed, which are not met by doing all accesses as
sequences of single-byte accesses.

Emulation of VSX loads and stores uses __copy_{to,from}_user,
which means the emulation code has no control on the size of
accesses.

To simplify this, we add new copy_mem_in() and copy_mem_out()
functions for accessing memory.  These use a sequence of the largest
possible aligned accesses, up to 8 bytes (or 4 on 32-bit systems),
to copy memory between a local buffer and user memory.  We then
rewrite {read,write}_mem_unaligned and the VSX load/store
emulation using these new functions.

These new functions also simplify the code in do_fp_load() and
do_fp_store() for the unaligned cases.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:51 +10:00
Paul Mackerras 958465ee54 powerpc: Add emulation for the addpcis instruction
The addpcis instruction puts the sum of the next instruction address
plus a constant into a register.  Since the result depends on the
address of the instruction, it will give an incorrect result if it
is single-stepped out of line, which is what the *probes subsystem
will currently do if a probe is placed on an addpcis instruction.
This fixes the problem by adding emulation of it to analyse_instr().

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:51 +10:00
Paul Mackerras 5762e08344 powerpc: Don't update CR0 in emulation of popcnt, prty, bpermd instructions
The architecture shows the least-significant bit of the instruction
word as reserved for the popcnt[bwd], prty[wd] and bpermd
instructions, that is, these instructions never update CR0.
Therefore this changes the emulation of these instructions to
skip the CR0 update.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:50 +10:00
Paul Mackerras f1bbb99f41 powerpc: Fix emulation of the isel instruction
The case added for the isel instruction was added inside a switch
statement which uses the 10-bit minor opcode field in the 0x7fe
bits of the instruction word.  However, for the isel instruction,
the minor opcode field is only the 0x3e bits, and the 0x7c0 bits
are used for the "BC" field, which indicates which CR bit to use
to select the result.

Therefore, for the isel emulation to work correctly when BC != 0,
we need to match on ((instr >> 1) & 0x1f) == 15).  To do this, we
pull the isel case out of the switch statement and put it in an
if statement of its own.

Fixes: e27f71e5ff ("powerpc/lib/sstep: Add isel instruction emulation")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:49 +10:00
Paul Mackerras d120cdbce6 powerpc/64: Fix update forms of loads and stores to write 64-bit EA
When a 64-bit processor is executing in 32-bit mode, the update forms
of load and store instructions are required by the architecture to
write the full 64-bit effective address into the RA register, though
only the bottom 32 bits are used to address memory.  Currently,
the instruction emulation code writes the truncated address to the
RA register.  This fixes it by keeping the full 64-bit EA in the
instruction_op structure, truncating the address in emulate_step()
where it is used to address memory, rather than in the address
computations in analyse_instr().

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:49 +10:00
Paul Mackerras 350779a29f powerpc: Handle most loads and stores in instruction emulation code
This extends the instruction emulation infrastructure in sstep.c to
handle all the load and store instructions defined in the Power ISA
v3.0, except for the atomic memory operations, ldmx (which was never
implemented), lfdp/stfdp, and the vector element load/stores.

The instructions added are:

Integer loads and stores: lbarx, lharx, lqarx, stbcx., sthcx., stqcx.,
lq, stq.

VSX loads and stores: lxsiwzx, lxsiwax, stxsiwx, lxvx, lxvl, lxvll,
lxvdsx, lxvwsx, stxvx, stxvl, stxvll, lxsspx, lxsdx, stxsspx, stxsdx,
lxvw4x, lxsibzx, lxvh8x, lxsihzx, lxvb16x, stxvw4x, stxsibx, stxvh8x,
stxsihx, stxvb16x, lxsd, lxssp, lxv, stxsd, stxssp, stxv.

These instructions are handled both in the analyse_instr phase and in
the emulate_step phase.

The code for lxvd2ux and stxvd2ux has been taken out, as those
instructions were never implemented in any processor and have been
taken out of the architecture, and their opcodes have been reused for
other instructions in POWER9 (lxvb16x and stxvb16x).

The emulation for the VSX loads and stores uses helper functions
which don't access registers or memory directly, which can hopefully
be reused by KVM later.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:48 +10:00
Paul Mackerras ee0a54d797 powerpc: Don't check MSR FP/VMX/VSX enable bits in analyse_instr()
This removes the checks for the FP/VMX/VSX enable bits in the MSR
from analyse_instr() and adds them to emulate_step() instead.

The reason for this is that we may want to use analyse_instr() in
a situation where the FP/VMX/VSX register values are stored in the
current thread_struct and the FP/VMX/VSX enable bits in the MSR
image in the pt_regs are zero.  Since analyse_instr() doesn't make
any changes to register state, it is reasonable for it to indicate
what the effect of an instruction would be even though the relevant
enable bit is off.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:48 +10:00
Paul Mackerras 3cdfcbfd32 powerpc: Change analyse_instr so it doesn't modify *regs
The analyse_instr function currently doesn't just work out what an
instruction does, it also executes those instructions whose effect
is only to update CPU registers that are stored in struct pt_regs.
This is undesirable because optprobes uses analyse_instr to work out
if an instruction could be successfully emulated in future.

This changes analyse_instr so it doesn't modify *regs; instead it
stores information in the instruction_op structure to indicate what
registers (GPRs, CR, XER, LR) would be set and what value they would
be set to.  A companion function called emulate_update_regs() can
then use that information to update a pt_regs struct appropriately.

As a minor cleanup, this replaces inline asm using the cntlzw and
cntlzd instructions with calls to __builtin_clz() and __builtin_clzl().

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-01 16:39:27 +10:00
Matt Brown e27f71e5ff powerpc/lib/sstep: Add isel instruction emulation
This adds emulation for the isel instruction.
Tested for correctness against the isel instruction and its extended
mnemonics (lt, gt, eq) on ppc64le.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 22:30:29 +10:00
Matt Brown 2c979c489f powerpc/lib/sstep: Add prty instruction emulation
This adds emulation for the prtyw and prtyd instructions.
Tested for logical correctness against the prtyw and prtyd instructions
on ppc64le.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 22:30:28 +10:00
Matt Brown f312793dda powerpc/lib/sstep: Add bpermd instruction emulation
This adds emulation for the bpermd instruction.
Tested for correctness against the bpermd instruction on ppc64le.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 22:30:27 +10:00
Matt Brown dcbd19b48d powerpc/lib/sstep: Add popcnt instruction emulation
This adds emulations for the popcntb, popcntw, and popcntd instructions.
Tested for correctness against the popcnt{b,w,d} instructions on ppc64le.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 22:30:27 +10:00
Matt Brown 02c0f62a60 powerpc/lib/sstep: Add cmpb instruction emulation
This patch adds emulation of the cmpb instruction, enabling xmon to
emulate this instruction.
Tested for correctness against the cmpb asm instruction on ppc64le.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 22:30:26 +10:00
Anton Blanchard 64e756c55a powerpc: Fix emulation of mfocrf in emulate_step()
From POWER4 onwards, mfocrf() only places the specified CR field into
the destination GPR, and the rest of it is set to 0. The PowerPC AS
from version 3.0 now requires this behaviour.

The emulation code currently puts the entire CR into the destination GPR.
Fix it.

Fixes: 6888199f7f ("[POWERPC] Emulate more instructions in software")
Cc: stable@vger.kernel.org # v2.6.22+
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-12 16:43:48 +10:00
Anton Blanchard 87c4b83e0f powerpc: Fix emulation of mcrf in emulate_step()
The mcrf emulation code was using the CR field number directly as the shift
value, without taking into account that CR fields are numbered from 0-7 starting
at the high bits. That meant it was looking at the CR fields in the reverse
order.

Fixes: cf87c3f6b6 ("powerpc: Emulate icbi, mcrf and conditional-trap instructions")
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-12 16:43:32 +10:00
Naveen N. Rao 71f6e58e5e powerpc/kprobes: Convert __kprobes to NOKPROBE_SYMBOL()
Along similar lines as commit 9326638cbe ("kprobes, x86: Use NOKPROBE_SYMBOL()
instead of __kprobes annotation"), convert __kprobes annotation to either
NOKPROBE_SYMBOL() or nokprobe_inline. The latter forces inlining, in which case
the caller needs to be added to NOKPROBE_SYMBOL().

Also:
 - blacklist arch_deref_entry_point(), and
 - convert a few regular inlines to nokprobe_inline in lib/sstep.c

A key benefit is the ability to detect such symbols as being
blacklisted. Before this patch:

  $ cat /sys/kernel/debug/kprobes/blacklist | grep read_mem
  $ perf probe read_mem
  Failed to write event: Invalid argument
    Error: Failed to add events.
  $ dmesg | tail -1
  [ 3736.112815] Could not insert probe at _text+10014968: -22

After patch:
  $ cat /sys/kernel/debug/kprobes/blacklist | grep read_mem
  0xc000000000072b50-0xc000000000072d20	read_mem
  $ perf probe read_mem
  read_mem is blacklisted function, skip it.
  Added new events:
    (null):(null)        (on read_mem)
    probe:read_mem       (on read_mem)

  You can now use it in all perf tools, such as:

	  perf record -e probe:read_mem -aR sleep 1

  $ grep " read_mem" /proc/kallsyms
  c000000000072b50 t read_mem
  c0000000005f3b40 t read_mem
  $ cat /sys/kernel/debug/kprobes/list
  c0000000005f3b48  k  read_mem+0x8    [DISABLED]

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Minor change log formatting, fix up some conflicts]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-23 20:32:25 +10:00
Ravi Bangoria e148bd17f4 powerpc: Emulation support for load/store instructions on LE
emulate_step() uses a number of underlying kernel functions that were
initially not enabled for LE. This has been rectified since. So, fix
emulate_step() for LE for the corresponding instructions.

Cc: stable@vger.kernel.org # v3.18+
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-03 11:24:50 +11:00
Markus Elfring 3c4b66a6d0 powerpc/sstep: Return directly after a failed address_ok() in emulate_step()
Setting err and going to ldst_done just returns 0, without using err, so
just return 0 directly. We already do that for other call sites in this
function.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[mpe: Rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-01-25 13:34:21 +11:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Michael Ellerman 5e9d0e3d9e powerpc/lib: Fix randconfig build failure in sstep.c
Under some configs we need to explicitly include cpu_has_feature.h,
otherwise we fail with:

  arch/powerpc/lib/sstep.c:1992:7: error: implicit declaration of function 'cpu_has_feature'

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-11-18 22:40:42 +11:00
Nicholas Piggin 24bfa6a9e0 powerpc: EX_TABLE macro for exception tables
This macro is taken from s390, and allows more flexibility in
changing exception table format.

mpe: Put it in ppc_asm.h and only define one version using
stringinfy_in_c(). Add some empty definitions and headers to keep the
selftests happy.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-11-14 11:11:51 +11:00
Oliver O'Halloran 6670783606 powerpc/sstep: Fix emulation fall-through
There is a switch fallthough in instr_analyze() which can cause an
invalid instruction to be emulated as a different, valid, instruction.
The rld* (opcode 30) case extracts a sub-opcode from bits 3:1 of the
instruction word. However, the only valid values of this field are 001
and 000. These cases are correctly handled, but the others are not which
causes execution to fall through into case 31.

Breaking out of the switch causes the instruction to be marked as
unknown and allows the caller to deal with the invalid instruction in a
manner consistent with other invalid instructions.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:54:08 +10:00
Lennart Sorensen dd21731022 powerpc/sstep: Fix sstep.c compile on powerpcspe
Commit be96f63375 ("powerpc: Split out instruction analysis part of
emulate_step()") introduced ldarx and stdcx into the instructions in
sstep.c, which are not accepted by the assembler on powerpcspe, but does
seem to be accepted by the normal powerpc assembler even in 32 bit mode.

Wrap these two instructions in a __powerpc64__ check like it is
everywhere else in the file.

Fixes: be96f63375 ("powerpc: Split out instruction analysis part of emulate_step()")
Signed-off-by: Len Sorensen <lsorense@csclub.uwaterloo.ca>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:54:07 +10:00
Paul Mackerras 7048c84694 powerpc: Fix compilation of emulate_step()
Commit be96f63375 ("powerpc: Split out instruction analysis
part of emulate_step()") added some calls to do_fp_load()
and do_fp_store(), which fail to compile on configs with
CONFIG_PPC_FPU=n and CONFIG_PPC_EMULATE_SSTEP=y.  This fixes
the compile by adding #ifdef CONFIG_PPC_FPU around the code
that calls these functions.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-11-12 15:54:29 +11:00
Paul Mackerras c9f6f4ed95 powerpc: Implement emulation of string loads and stores
The size field of the op.type word is now the total number of bytes
to be loaded or stored.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25 23:14:52 +10:00
Paul Mackerras cf87c3f6b6 powerpc: Emulate icbi, mcrf and conditional-trap instructions
This extends the instruction emulation done by analyse_instr() and
emulate_step() to handle a few more instructions that are found in
the kernel.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25 23:14:51 +10:00
Paul Mackerras be96f63375 powerpc: Split out instruction analysis part of emulate_step()
This splits out the instruction analysis part of emulate_step() into
a separate analyse_instr() function, which decodes the instruction,
but doesn't execute any load or store instructions.  It does execute
integer instructions and branches which can be executed purely by
updating register values in the pt_regs struct.  For other instructions,
it returns the instruction type and other details in a new
instruction_op struct.  emulate_step() then uses that information
to execute loads, stores, cache operations, mfmsr, mtmsr[d], and
(on 64-bit) sc instructions.

The reason for doing this is so that the KVM code can use it instead
of having its own separate instruction emulation code.  Possibly the
alignment interrupt handler could also use this.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-25 23:14:51 +10:00