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cputlb: Provide cpu_(ld,st}*_mmuidx_ra for user-only

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This finishes the new interface began with the previous patch.
Document the interface and deprecate MMU_MODE<N>_SUFFIX.

Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2019-12-09 21:10:04 -08:00
parent fc4120a378
commit f4e1bae259
2 changed files with 230 additions and 61 deletions
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211
docs/devel/loads-stores.rst
View File

@ -72,31 +72,34 @@ Regexes for git grep
- ``\<ldn_\([hbl]e\)?_p\>``
- ``\<stn_\([hbl]e\)?_p\>``
``cpu_{ld,st}_*``
~~~~~~~~~~~~~~~~~
``cpu_{ld,st}*_mmuidx_ra``
~~~~~~~~~~~~~~~~~~~~~~~~~~
These functions operate on a guest virtual address. Be aware
that these functions may cause a guest CPU exception to be
taken (e.g. for an alignment fault or MMU fault) which will
result in guest CPU state being updated and control longjumping
out of the function call. They should therefore only be used
in code that is implementing emulation of the target CPU.
These functions operate on a guest virtual address plus a context,
known as a "mmu index" or ``mmuidx``, which controls how that virtual
address is translated. The meaning of the indexes are target specific,
but specifying a particular index might be necessary if, for instance,
the helper requires an "always as non-privileged" access rather that
the default access for the current state of the guest CPU.
These functions may throw an exception (longjmp() back out
to the top level TCG loop). This means they must only be used
from helper functions where the translator has saved all
necessary CPU state before generating the helper function call.
It's usually better to use the ``_ra`` variants described below
from helper functions, but these functions are the right choice
for calls made from hooks like the CPU do_interrupt hook or
when you know for certain that the translator had to save all
the CPU state that ``cpu_restore_state()`` would restore anyway.
These functions may cause a guest CPU exception to be taken
(e.g. for an alignment fault or MMU fault) which will result in
guest CPU state being updated and control longjmp'ing out of the
function call. They should therefore only be used in code that is
implementing emulation of the guest CPU.
The ``retaddr`` parameter is used to control unwinding of the
guest CPU state in case of a guest CPU exception. This is passed
to ``cpu_restore_state()``. Therefore the value should either be 0,
to indicate that the guest CPU state is already synchronized, or
the result of ``GETPC()`` from the top level ``HELPER(foo)``
function, which is a return address into the generated code.
Function names follow the pattern:
load: ``cpu_ld{sign}{size}_{mmusuffix}(env, ptr)``
load: ``cpu_ld{sign}{size}_mmuidx_ra(env, ptr, mmuidx, retaddr)``
store: ``cpu_st{size}_{mmusuffix}(env, ptr, val)``
store: ``cpu_st{size}_mmuidx_ra(env, ptr, val, mmuidx, retaddr)``
``sign``
- (empty) : for 32 or 64 bit sizes
@ -109,56 +112,151 @@ store: ``cpu_st{size}_{mmusuffix}(env, ptr, val)``
- ``l`` : 32 bits
- ``q`` : 64 bits
``mmusuffix`` is one of the generic suffixes ``data`` or ``code``, or
(for softmmu configs) a target-specific MMU mode suffix as defined
in the target's ``cpu.h``.
Regexes for git grep:
- ``\<cpu_ld[us]\?[bwlq]_mmuidx_ra\>``
- ``\<cpu_st[bwlq]_mmuidx_ra\>``
Regexes for git grep
- ``\<cpu_ld[us]\?[bwlq]_[a-zA-Z0-9]\+\>``
- ``\<cpu_st[bwlq]_[a-zA-Z0-9]\+\>``
``cpu_{ld,st}*_data_ra``
~~~~~~~~~~~~~~~~~~~~~~~~
``cpu_{ld,st}_*_ra``
~~~~~~~~~~~~~~~~~~~~
These functions work like the ``cpu_{ld,st}_*`` functions except
that they also take a ``retaddr`` argument. This extra argument
allows for correct unwinding of any exception that is taken,
and should generally be the result of GETPC() called directly
from the top level HELPER(foo) function (i.e. the return address
in the generated code).
These functions work like the ``cpu_{ld,st}_mmuidx_ra`` functions
except that the ``mmuidx`` parameter is taken from the current mode
of the guest CPU, as determined by ``cpu_mmu_index(env, false)``.
These are generally the preferred way to do accesses by guest
virtual address from helper functions; see the documentation
of the non-``_ra`` variants for when those would be better.
Calling these functions with a ``retaddr`` argument of 0 is
equivalent to calling the non-``_ra`` version of the function.
virtual address from helper functions, unless the access should
be performed with a context other than the default.
Function names follow the pattern:
load: ``cpu_ld{sign}{size}_{mmusuffix}_ra(env, ptr, retaddr)``
load: ``cpu_ld{sign}{size}_data_ra(env, ptr, ra)``
store: ``cpu_st{sign}{size}_{mmusuffix}_ra(env, ptr, val, retaddr)``
store: ``cpu_st{size}_data_ra(env, ptr, val, ra)``
``sign``
- (empty) : for 32 or 64 bit sizes
- ``u`` : unsigned
- ``s`` : signed
``size``
- ``b`` : 8 bits
- ``w`` : 16 bits
- ``l`` : 32 bits
- ``q`` : 64 bits
Regexes for git grep:
- ``\<cpu_ld[us]\?[bwlq]_data_ra\>``
- ``\<cpu_st[bwlq]_data_ra\>``
``cpu_{ld,st}*_data``
~~~~~~~~~~~~~~~~~~~~~
These functions work like the ``cpu_{ld,st}_data_ra`` functions
except that the ``retaddr`` parameter is 0, and thus does not
unwind guest CPU state.
This means they must only be used from helper functions where the
translator has saved all necessary CPU state. These functions are
the right choice for calls made from hooks like the CPU ``do_interrupt``
hook or when you know for certain that the translator had to save all
the CPU state anyway.
Function names follow the pattern:
load: ``cpu_ld{sign}{size}_data(env, ptr)``
store: ``cpu_st{size}_data(env, ptr, val)``
``sign``
- (empty) : for 32 or 64 bit sizes
- ``u`` : unsigned
- ``s`` : signed
``size``
- ``b`` : 8 bits
- ``w`` : 16 bits
- ``l`` : 32 bits
- ``q`` : 64 bits
Regexes for git grep
- ``\<cpu_ld[us]\?[bwlq]_[a-zA-Z0-9]\+_ra\>``
- ``\<cpu_st[bwlq]_[a-zA-Z0-9]\+_ra\>``
- ``\<cpu_ld[us]\?[bwlq]_data\>``
- ``\<cpu_st[bwlq]_data\+\>``
``helper_*_{ld,st}*mmu``
~~~~~~~~~~~~~~~~~~~~~~~~
``cpu_ld*_code``
~~~~~~~~~~~~~~~~
These functions perform a read for instruction execution. The ``mmuidx``
parameter is taken from the current mode of the guest CPU, as determined
by ``cpu_mmu_index(env, true)``. The ``retaddr`` parameter is 0, and
thus does not unwind guest CPU state, because CPU state is always
synchronized while translating instructions. Any guest CPU exception
that is raised will indicate an instruction execution fault rather than
a data read fault.
In general these functions should not be used directly during translation.
There are wrapper functions that are to be used which also take care of
plugins for tracing.
Function names follow the pattern:
load: ``cpu_ld{sign}{size}_code(env, ptr)``
``sign``
- (empty) : for 32 or 64 bit sizes
- ``u`` : unsigned
- ``s`` : signed
``size``
- ``b`` : 8 bits
- ``w`` : 16 bits
- ``l`` : 32 bits
- ``q`` : 64 bits
Regexes for git grep:
- ``\<cpu_ld[us]\?[bwlq]_code\>``
``translator_ld*``
~~~~~~~~~~~~~~~~~~
These functions are a wrapper for ``cpu_ld*_code`` which also perform
any actions required by any tracing plugins. They are only to be
called during the translator callback ``translate_insn``.
There is a set of functions ending in ``_swap`` which, if the parameter
is true, returns the value in the endianness that is the reverse of
the guest native endianness, as determined by ``TARGET_WORDS_BIGENDIAN``.
Function names follow the pattern:
load: ``translator_ld{sign}{size}(env, ptr)``
swap: ``translator_ld{sign}{size}_swap(env, ptr, swap)``
``sign``
- (empty) : for 32 or 64 bit sizes
- ``u`` : unsigned
- ``s`` : signed
``size``
- ``b`` : 8 bits
- ``w`` : 16 bits
- ``l`` : 32 bits
- ``q`` : 64 bits
Regexes for git grep
- ``\<translator_ld[us]\?[bwlq]\(_swap\)\?\>``
``helper_*_{ld,st}*_mmu``
~~~~~~~~~~~~~~~~~~~~~~~~~
These functions are intended primarily to be called by the code
generated by the TCG backend. They may also be called by target
CPU helper function code. Like the ``cpu_{ld,st}_*_ra`` functions
they perform accesses by guest virtual address; the difference is
that these functions allow you to specify an ``opindex`` parameter
which encodes (among other things) the mmu index to use for the
access. This is necessary if your helper needs to make an access
via a specific mmu index (for instance, an "always as non-privileged"
access) rather than using the default mmu index for the current state
of the guest CPU.
CPU helper function code. Like the ``cpu_{ld,st}_mmuidx_ra`` functions
they perform accesses by guest virtual address, with a given ``mmuidx``.
The ``opindex`` parameter should be created by calling ``make_memop_idx()``.
These functions specify an ``opindex`` parameter which encodes
(among other things) the mmu index to use for the access. This parameter
should be created by calling ``make_memop_idx()``.
The ``retaddr`` parameter should be the result of GETPC() called directly
from the top level HELPER(foo) function (or 0 if no guest CPU state
@ -166,8 +264,9 @@ unwinding is required).
**TODO** The names of these functions are a bit odd for historical
reasons because they were originally expected to be called only from
within generated code. We should rename them to bring them
more in line with the other memory access functions.
within generated code. We should rename them to bring them more in
line with the other memory access functions. The explicit endianness
is the only feature they have beyond ``*_mmuidx_ra``.
load: ``helper_{endian}_ld{sign}{size}_mmu(env, addr, opindex, retaddr)``

80
include/exec/cpu_ldst.h
View File

@ -25,9 +25,13 @@
*
* The syntax for the accessors is:
*
* load: cpu_ld{sign}{size}_{mmusuffix}(env, ptr)
* load: cpu_ld{sign}{size}_{mmusuffix}(env, ptr)
* cpu_ld{sign}{size}_{mmusuffix}_ra(env, ptr, retaddr)
* cpu_ld{sign}{size}_mmuidx_ra(env, ptr, mmu_idx, retaddr)
*
* store: cpu_st{sign}{size}_{mmusuffix}(env, ptr, val)
* store: cpu_st{size}_{mmusuffix}(env, ptr, val)
* cpu_st{size}_{mmusuffix}_ra(env, ptr, val, retaddr)
* cpu_st{size}_mmuidx_ra(env, ptr, val, mmu_idx, retaddr)
*
* sign is:
* (empty): for 32 and 64 bit sizes
@ -40,9 +44,10 @@
* l: 32 bits
* q: 64 bits
*
* mmusuffix is one of the generic suffixes "data" or "code", or
* (for softmmu configs) a target-specific MMU mode suffix as defined
* in target cpu.h.
* mmusuffix is one of the generic suffixes "data" or "code", or "mmuidx".
* The "mmuidx" suffix carries an extra mmu_idx argument that specifies
* the index to use; the "data" and "code" suffixes take the index from
* cpu_mmu_index().
*/
#ifndef CPU_LDST_H
#define CPU_LDST_H
@ -145,6 +150,71 @@ static inline void clear_helper_retaddr(void)
#undef MEMSUFFIX
#undef CODE_ACCESS
/*
* Provide the same *_mmuidx_ra interface as for softmmu.
* The mmu_idx argument is ignored.
*/
static inline uint32_t cpu_ldub_mmuidx_ra(CPUArchState *env, abi_ptr addr,
int mmu_idx, uintptr_t ra)
{
return cpu_ldub_data_ra(env, addr, ra);
}
static inline uint32_t cpu_lduw_mmuidx_ra(CPUArchState *env, abi_ptr addr,
int mmu_idx, uintptr_t ra)
{
return cpu_lduw_data_ra(env, addr, ra);
}
static inline uint32_t cpu_ldl_mmuidx_ra(CPUArchState *env, abi_ptr addr,
int mmu_idx, uintptr_t ra)
{
return cpu_ldl_data_ra(env, addr, ra);
}
static inline uint64_t cpu_ldq_mmuidx_ra(CPUArchState *env, abi_ptr addr,
int mmu_idx, uintptr_t ra)
{
return cpu_ldq_data_ra(env, addr, ra);
}
static inline int cpu_ldsb_mmuidx_ra(CPUArchState *env, abi_ptr addr,
int mmu_idx, uintptr_t ra)
{
return cpu_ldsb_data_ra(env, addr, ra);
}
static inline int cpu_ldsw_mmuidx_ra(CPUArchState *env, abi_ptr addr,
int mmu_idx, uintptr_t ra)
{
return cpu_ldsw_data_ra(env, addr, ra);
}
static inline void cpu_stb_mmuidx_ra(CPUArchState *env, abi_ptr addr,
uint32_t val, int mmu_idx, uintptr_t ra)
{
cpu_stb_data_ra(env, addr, val, ra);
}
static inline void cpu_stw_mmuidx_ra(CPUArchState *env, abi_ptr addr,
uint32_t val, int mmu_idx, uintptr_t ra)
{
cpu_stw_data_ra(env, addr, val, ra);
}
static inline void cpu_stl_mmuidx_ra(CPUArchState *env, abi_ptr addr,
uint32_t val, int mmu_idx, uintptr_t ra)
{
cpu_stl_data_ra(env, addr, val, ra);
}
static inline void cpu_stq_mmuidx_ra(CPUArchState *env, abi_ptr addr,
uint64_t val, int mmu_idx, uintptr_t ra)
{
cpu_stq_data_ra(env, addr, val, ra);
}
#else
/* Needed for TCG_OVERSIZED_GUEST */