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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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: e27f71e5ff3c ("powerpc/lib/sstep: Add isel instruction emulation")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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: 6888199f7fe5 ("[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>
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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: cf87c3f6b647 ("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>
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Along similar lines as commit 9326638cbee2 ("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>
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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>
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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>
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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>
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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>
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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>
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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>
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Commit be96f63375a1 ("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: be96f63375a1 ("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>
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Commit be96f63375a1 ("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>
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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>
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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>
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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>
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This fixes some bugs in emulate_step(). First, the setting of the carry
bit for the arithmetic right-shift instructions was not correct on 64-bit
machines because we were masking with a mask of type int rather than
unsigned long. Secondly, the sld (shift left doubleword) instruction was
using the wrong instruction field for the register containing the shift
count.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Commit cd64d1697cf0 ("powerpc: mtmsrd not defined") added a check for
CONFIG_PPC_CPU were a check for CONFIG_PPC_FPU was clearly intended.
Fixes: cd64d1697cf0 ("powerpc: mtmsrd not defined")
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch addresses unaligned single precision floating point loads
and stores in the single-step code. The old implementation
improperly treated an 8 byte structure as an array of two 4 byte
words, which is a classic little endian bug.
Signed-off-by: Tom Musta <tmusta@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch modifies the unaligned access routines of the sstep.c
module so that it properly reverses the bytes of storage operands
in the little endian kernel kernel. This is implemented by
breaking an unaligned little endian access into a combination of
single byte accesses plus an overal byte reversal operation.
Signed-off-by: Tom Musta <tmusta@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We've been keeping that field in thread_struct for a while, it contains
the "limit" of the current stack pointer and is meant to be used for
detecting stack overflows.
It has a few problems however:
- First, it was never actually *used* on 64-bit. Set and updated but
not actually exploited
- When switching stack to/from irq and softirq stacks, it's update
is racy unless we hard disable interrupts, which is costly. This
is fine on 32-bit as we don't soft-disable there but not on 64-bit.
Thus rather than fixing 2 in order to implement 1 in some hypothetical
future, let's remove the code completely from 64-bit. In order to avoid
a clutter of ifdef's, we remove the updates from C code completely
during interrupt stack switching, and instead maintain it from the
asm helper that is used to do the stack switching in the first place.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The stmw instruction was incorrectly decoded as an update form instruction
and thus the RA register was being clobbered.
Also, the utility routine to write memory to unaligned addresses breaks the
operation into smaller aligned accesses but was incorrectly incrementing
the address by only one; it needs to increment the address by the size of
the smaller aligned chunk.
Signed-off-by: Tom Musta <tmusta@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Check truncate_if_32bit() on final write to nip.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We don't do the real store operation for kprobing 'stwu Rx,(y)R1'
since this may corrupt the exception frame, now we will do this
operation safely in exception return code after migrate current
exception frame below the kprobed function stack.
So we only update gpr[1] here and trigger a thread flag to mask
this.
Note we should make sure if we trigger kernel stack over flow.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (152 commits)
powerpc: Fix hard CPU IDs detection
powerpc/pmac: Update via-pmu to new syscore_ops
powerpc/kvm: Fix the build for 32-bit Book 3S (classic) processors
powerpc/kvm: Fix kvmppc_core_pending_dec
powerpc: Remove last piece of GEMINI
powerpc: Fix for Pegasos keyboard and mouse
powerpc: Make early memory scan more resilient to out of order nodes
powerpc/pseries/iommu: Cleanup ddw naming
powerpc/pseries/iommu: Find windows after kexec during boot
powerpc/pseries/iommu: Remove ddw property when destroying window
powerpc/pseries/iommu: Add additional checks when changing iommu mask
powerpc/pseries/iommu: Use correct return type in dupe_ddw_if_already_created
powerpc: Remove unused/obsolete CONFIG_XICS
misc: Add CARMA DATA-FPGA Programmer support
misc: Add CARMA DATA-FPGA Access Driver
powerpc: Make IRQ_NOREQUEST last to clear, first to set
powerpc: Integrated Flash controller device tree bindings
powerpc/85xx: Create dts of each core in CAMP mode for P1020RDB
powerpc/85xx: Fix PCIe IDSEL for Px020RDB
powerpc/85xx: P2020 DTS: re-organize dts files
...
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Commit e66eed651fd1 ("list: remove prefetching from regular list
iterators") removed the include of prefetch.h from list.h, which
uncovered several cases that had apparently relied on that rather
obscure header file dependency.
So this fixes things up a bit, using
grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')
to guide us in finding files that either need <linux/prefetch.h>
inclusion, or have it despite not needing it.
There are more of them around (mostly network drivers), but this gets
many core ones.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We check MSR_SF a lot in sstep.c, to decide if we need to emulate the
truncation of values when running in 32-bit mode. Factor out that code
into a helper, and convert it and the other uses to use MSR_64BIT.
This fixes a bug on BOOK3E where kprobes would end up returning to a
32-bit address, because regs->nip was truncated, because (msr & MSR_SF)
was false.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Replace the BOOK3S_64 specific mtmsrd with the generic MTMSRD macro.
Only enable ldstfp when CONFIG_PPC_FPU is set.
Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This extends the emulate_step() function to handle a large proportion
of the Book I instructions implemented on current 64-bit server
processors. The aim is to handle all the load and store instructions
used in the kernel, plus all of the instructions that appear between
l[wd]arx and st[wd]cx., so this handles the Altivec/VMX lvx and stvx
and the VSX lxv2dx and stxv2dx instructions (implemented in POWER7).
The new code can emulate user mode instructions, and checks the
effective address for a load or store if the saved state is for
user mode. It doesn't handle little-endian mode at present.
For floating-point, Altivec/VMX and VSX instructions, it checks
that the saved MSR has the enable bit for the relevant facility
set, and if so, assumes that the FP/VMX/VSX registers contain
valid state, and does loads or stores directly to/from the
FP/VMX/VSX registers, using assembly helpers in ldstfp.S.
Instructions supported now include:
* Loads and stores, including some but not all VMX and VSX instructions,
and lmw/stmw
* Atomic loads and stores (l[dw]arx, st[dw]cx.)
* Arithmetic instructions (add, subtract, multiply, divide, etc.)
* Compare instructions
* Rotate and mask instructions
* Shift instructions
* Logical instructions (and, or, xor, etc.)
* Condition register logical instructions
* mtcrf, cntlz[wd], exts[bhw]
* isync, sync, lwsync, ptesync, eieio
* Cache operations (dcbf, dcbst, dcbt, dcbtst)
The overflow-checking arithmetic instructions are not included, but
they appear not to be ever used in C code.
This uses decimal values for the minor opcodes in the switch statements
because that is what appears in the Power ISA specification, thus it is
easier to check that they are correct if they are in decimal.
If this is used to single-step an instruction where a data breakpoint
interrupt occurred, then there is the possibility that the instruction
is a lwarx or ldarx. In that case we have to be careful not to lose the
reservation until we get to the matching st[wd]cx., or we'll never make
forward progress. One alternative is to try to arrange that we can
return from interrupts and handle data breakpoint interrupts without
losing the reservation, which means not using any spinlocks, mutexes,
or atomic ops (including bitops). That seems rather fragile. The
other alternative is to emulate the larx/stcx and all the instructions
in between. This is why this commit adds support for a wide range
of integer instructions.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Currently emulate_step() emulates mr. instructions without updating cr0
and this can be disastrous. Don't emulate mr.
This bug has been around for a while, but I am not sure if its a worthy
-stable candidate. I'll leave it to Ben do decide.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Emulate a few more instructions in software - especially useful during
singlestepping (xmon/kprobes).
Instructions emulated with this patch are mfcr/mtcr rX, mfxer/mtxer rX,
mflr/mtlr rX, mfctr/mtctr rX and mr rA,rB.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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On powerpc, probing on emulate_step function will crash 2.6.18.1 when
it is triggered.
When kprobe is triggered, emulate_step() is on its kernel path and
will cause recursive kprobe fault. And branch_taken() is called
in emulate_step(). This disallows kprobes on both of them.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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