Re: [PATCH 07/10] tcg: implement bulletproof JIT

[Philippe Mathieu-Daudé]

Hi Joelle,

On 10/13/20 1:29 AM, Joelle van Dyne wrote:
> From: osy <osy86@users.noreply.github.com>
>
> On iOS, we cannot allocate RWX pages without special entitlements. As a
> workaround, we can a RX region and then mirror map it to a separate RX
> region. Then we can write to one region and execute from the other one.
>
> To better keep track of pointers to RW/RX memory, we mark any tcg_insn_unit
> pointers as `const` if they will never be written to. We also define a new
> macro `TCG_CODE_PTR_RW` that returns a pointer to RW memory. Only the
> difference between the two regions is stored in the TCG context.

^ one change,

v another change. Consider splitting in 2 patches to ease review.

> To ensure cache coherency, we flush the data cache in the RW mapping and
> then invalidate the instruction cache in the RX mapping (where applicable).
> Because data cache flush is OS defined on some architectures, we do not
> provide implementations for non iOS platforms (ARM/x86).
>
> Signed-off-by: Joelle van Dyne <j@getutm.app>
> ---
>   accel/tcg/cpu-exec.c         |  7 +++-
>   accel/tcg/translate-all.c    | 78 ++++++++++++++++++++++++++++++++++--
>   configure                    |  1 +
>   docs/devel/ios.rst           | 40 ++++++++++++++++++
>   include/exec/exec-all.h      |  8 ++++
>   include/tcg/tcg.h            | 18 +++++++--
>   tcg/aarch64/tcg-target.c.inc | 48 +++++++++++++---------
>   tcg/aarch64/tcg-target.h     | 13 +++++-
>   tcg/arm/tcg-target.c.inc     | 33 ++++++++-------
>   tcg/arm/tcg-target.h         |  9 ++++-
>   tcg/i386/tcg-target.c.inc    | 28 ++++++-------
>   tcg/i386/tcg-target.h        | 24 ++++++++++-
>   tcg/mips/tcg-target.c.inc    | 64 +++++++++++++++++------------
>   tcg/mips/tcg-target.h        |  8 +++-
>   tcg/ppc/tcg-target.c.inc     | 55 ++++++++++++++++---------
>   tcg/ppc/tcg-target.h         |  8 +++-
>   tcg/riscv/tcg-target.c.inc   | 51 +++++++++++++----------
>   tcg/riscv/tcg-target.h       |  9 ++++-
>   tcg/s390/tcg-target.c.inc    | 25 ++++++------
>   tcg/s390/tcg-target.h        | 13 +++++-
>   tcg/sparc/tcg-target.c.inc   | 33 +++++++++------
>   tcg/sparc/tcg-target.h       |  8 +++-
>   tcg/tcg-ldst.c.inc           |  2 +-
>   tcg/tcg-pool.c.inc           |  9 +++--
>   tcg/tcg.c                    | 60 +++++++++++++++++----------
>   tcg/tci/tcg-target.c.inc     |  8 ++--
>   tcg/tci/tcg-target.h         |  9 ++++-
>   27 files changed, 481 insertions(+), 188 deletions(-)
>   create mode 100644 docs/devel/ios.rst

When posting big series, consider using scripts/git.orderfile.

Regards,

Phil.