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| author |   Max Filippov <jcmvbkbc@gmail.com> | 2015-01-12 09:44:44 +0300 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2019-09-01 13:11:57 -0700 |
| commit | 09f8a6db20e6ed8eab1b2b23d09d2458f6e15062 (patch) | |
| tree | 1c3b6baee5c51968f10d2af9c97e35208542ed53 /arch/xtensa/include/asm/processor.h | |
| parent | xtensa: clean up PS_WOE_BIT usage (diff) | |
| download | linux-dev-09f8a6db20e6ed8eab1b2b23d09d2458f6e15062.tar.xz linux-dev-09f8a6db20e6ed8eab1b2b23d09d2458f6e15062.zip | |
xtensa: add support for call0 ABI in userspace
Provide a Kconfig choice to select whether only the default ABI, only
call0 ABI or both are supported. The default for XEA2 is windowed, but
it may change for XEA3. Call0 only runs userspace with PS.WOE disabled.
Supporting both windowed and call0 ABIs is tricky, as there's no
indication in the ELF binaries which ABI they use. So it is done by
probing: each process is started with PS.WOE disabled, but the handler
of an illegal instruction exception taken with PS.WOE retries faulting
instruction after enabling PS.WOE. It must happen before any signal is
delivered to the process, otherwise it may be delivered incorrectly.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/include/asm/processor.h')
| -rw-r--r-- | arch/xtensa/include/asm/processor.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index 0b4efec9e19e..7495520d7a3e 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -176,14 +176,21 @@ struct thread_struct { /* * Do necessary setup to start up a newly executed thread. - * Note: We set-up ps as if we did a call4 to the new pc. + * Note: When windowed ABI is used for userspace we set-up ps + * as if we did a call4 to the new pc. * set_thread_state in signal.c depends on it. */ +#if IS_ENABLED(CONFIG_USER_ABI_CALL0) +#define USER_PS_VALUE ((USER_RING << PS_RING_SHIFT) | \ + (1 << PS_UM_BIT) | \ + (1 << PS_EXCM_BIT)) +#else #define USER_PS_VALUE (PS_WOE_MASK | \ (1 << PS_CALLINC_SHIFT) | \ (USER_RING << PS_RING_SHIFT) | \ (1 << PS_UM_BIT) | \ (1 << PS_EXCM_BIT)) +#endif /* Clearing a0 terminates the backtrace. */ #define start_thread(regs, new_pc, new_sp) \ |