| Message ID | 20190916141544.17540-1-peter.maydell@linaro.org |
|---|---|
| Headers | show |
| Series | target/arm: Implement semihosting v2.0 | expand |
Ping for code review, please? thanks -- PMM On Mon, 16 Sep 2019 at 15:15, Peter Maydell <peter.maydell@linaro.org> wrote: > > This patchset implements support in QEMU for v2.0 of the > Arm semihosting specification: > https://developer.arm.com/docs/100863/latest/preface > > Specifically, v2.0 has: > * a mechanism for detection of optional extra features, > which works by allowing the guest to open a magic file > named ":semihosting-features" and read some feature > flags from it > * two defined extensions: > - STDOUT_STDERR lets the guest separately open stdout and > stderr via the ":tt" magic filename (v1.0 only allowed > access to stdout) > - EXIT_EXTENDED lets A32/T32 guests exit with a specified > exit status (otherwise only available to A64 guests). > This is something that people have been complaining > about for a long time. > > (Technically some of the things we already support, like > having an A64 semihosting interface at all, are also part of > the v2.0 spec.) > > This patchset: > * fixes some bugs relating to errnos in some cases > * makes semihosting hand out its own filedescriptors rather > than just passing out host fd numbers > * abstracts out the fd-related semihosting calls so they > indirect via a function table based on the type of the fd > * adds a new type of fd representing the magic file > ":semihosting-features" which is used for feature-detection > * implements both of the extensions defined by the v2.0 spec > > I've tested this by improving my semihosting test suite: > https://git.linaro.org/people/peter.maydell/semihosting-tests.git/ > (if people have other guest binaries that make much use of > semihosting then testing would certainly be welcome.) > > Changes v1->v2: > * Added a patch which corrects misunderstanding in a FIXME > comment about the when the callback function is called > for arm_gdb_syscall() > * in patch 4, if the SYS_open is going via the gdbstub, we > must do the associate_guestfd() work in the gdbstub callback > function. This is because in softmmu mode the callback will > not be called until after do_arm_semihosting() returns. > (The v1 series effectively broke SYS_open in the gdbstub > + softmmu config) > * Pass CPUARMState* to set_swi_errno(), rather than creating > an odd local-to-this-file typedef of TaskState for the > softmmu compilation > * New patch: avoid ifdeffery in gdb callback fns by > using set_swi_errno() rather than doing it by-hand > * The various 'factor out SYS_foo' patches are basically > unchanged, but all the functions no longer need to take > a TaskState*. This seemed kind of borderline as to whether > to retain Alex's reviewed-by tags, so I dropped them. > * Since we need 'env' for set_swi_errno(), we don't need > to put the variable declaration inside ifdefs any more > in the host_readfn() etc. > > I do plan to have a go at fixing the odd FIXME surrounding > arm_gdb_syscall() which patch 3 clarifies/states in a comment. > But I thought it better to not tangle that up with this > patchset, which is already pretty long. > > thanks > -- PMM > > > Peter Maydell (15): > target/arm/arm-semi: Capture errno in softmmu version of > set_swi_errno() > target/arm/arm-semi: Always set some kind of errno for failed calls > target/arm/arm-semi: Correct comment about gdb syscall races > target/arm/arm-semi: Make semihosting code hand out its own file > descriptors > target/arm/arm-semi: Restrict use of TaskState* > target/arm/arm-semi: Use set_swi_errno() in gdbstub callback functions > target/arm/arm-semi: Factor out implementation of SYS_CLOSE > target/arm/arm-semi: Factor out implementation of SYS_WRITE > target/arm/arm-semi: Factor out implementation of SYS_READ > target/arm/arm-semi: Factor out implementation of SYS_ISTTY > target/arm/arm-semi: Factor out implementation of SYS_SEEK > target/arm/arm-semi: Factor out implementation of SYS_FLEN > target/arm/arm-semi: Implement support for semihosting feature > detection > target/arm/arm-semi: Implement SH_EXT_EXIT_EXTENDED extension > target/arm/arm-semi: Implement SH_EXT_STDOUT_STDERR extension > > target/arm/arm-semi.c | 707 ++++++++++++++++++++++++++++++++++-------- > 1 file changed, 577 insertions(+), 130 deletions(-) > > -- > 2.20.1
This patchset implements support in QEMU for v2.0 of the Arm semihosting specification: https://developer.arm.com/docs/100863/latest/preface Specifically, v2.0 has: * a mechanism for detection of optional extra features, which works by allowing the guest to open a magic file named ":semihosting-features" and read some feature flags from it * two defined extensions: - STDOUT_STDERR lets the guest separately open stdout and stderr via the ":tt" magic filename (v1.0 only allowed access to stdout) - EXIT_EXTENDED lets A32/T32 guests exit with a specified exit status (otherwise only available to A64 guests). This is something that people have been complaining about for a long time. (Technically some of the things we already support, like having an A64 semihosting interface at all, are also part of the v2.0 spec.) This patchset: * fixes some bugs relating to errnos in some cases * makes semihosting hand out its own filedescriptors rather than just passing out host fd numbers * abstracts out the fd-related semihosting calls so they indirect via a function table based on the type of the fd * adds a new type of fd representing the magic file ":semihosting-features" which is used for feature-detection * implements both of the extensions defined by the v2.0 spec I've tested this by improving my semihosting test suite: https://git.linaro.org/people/peter.maydell/semihosting-tests.git/ (if people have other guest binaries that make much use of semihosting then testing would certainly be welcome.) Changes v1->v2: * Added a patch which corrects misunderstanding in a FIXME comment about the when the callback function is called for arm_gdb_syscall() * in patch 4, if the SYS_open is going via the gdbstub, we must do the associate_guestfd() work in the gdbstub callback function. This is because in softmmu mode the callback will not be called until after do_arm_semihosting() returns. (The v1 series effectively broke SYS_open in the gdbstub + softmmu config) * Pass CPUARMState* to set_swi_errno(), rather than creating an odd local-to-this-file typedef of TaskState for the softmmu compilation * New patch: avoid ifdeffery in gdb callback fns by using set_swi_errno() rather than doing it by-hand * The various 'factor out SYS_foo' patches are basically unchanged, but all the functions no longer need to take a TaskState*. This seemed kind of borderline as to whether to retain Alex's reviewed-by tags, so I dropped them. * Since we need 'env' for set_swi_errno(), we don't need to put the variable declaration inside ifdefs any more in the host_readfn() etc. I do plan to have a go at fixing the odd FIXME surrounding arm_gdb_syscall() which patch 3 clarifies/states in a comment. But I thought it better to not tangle that up with this patchset, which is already pretty long. thanks -- PMM Peter Maydell (15): target/arm/arm-semi: Capture errno in softmmu version of set_swi_errno() target/arm/arm-semi: Always set some kind of errno for failed calls target/arm/arm-semi: Correct comment about gdb syscall races target/arm/arm-semi: Make semihosting code hand out its own file descriptors target/arm/arm-semi: Restrict use of TaskState* target/arm/arm-semi: Use set_swi_errno() in gdbstub callback functions target/arm/arm-semi: Factor out implementation of SYS_CLOSE target/arm/arm-semi: Factor out implementation of SYS_WRITE target/arm/arm-semi: Factor out implementation of SYS_READ target/arm/arm-semi: Factor out implementation of SYS_ISTTY target/arm/arm-semi: Factor out implementation of SYS_SEEK target/arm/arm-semi: Factor out implementation of SYS_FLEN target/arm/arm-semi: Implement support for semihosting feature detection target/arm/arm-semi: Implement SH_EXT_EXIT_EXTENDED extension target/arm/arm-semi: Implement SH_EXT_STDOUT_STDERR extension target/arm/arm-semi.c | 707 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 577 insertions(+), 130 deletions(-)