From: Richard Henderson Date: Wed, 29 Sep 2021 13:05:36 +0000 (-0400) Subject: linux-user/hppa: Document non-use of setup_sigtramp X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a22fccd8b7de9e21fc31cc048e2bf9c15947f4a4;p=qemu.git linux-user/hppa: Document non-use of setup_sigtramp We cannot use a raw sigtramp page for hppa, but must wait for full vdso support. Reviewed-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson Message-Id: <20210929130553.121567-10-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- diff --git a/linux-user/hppa/target_signal.h b/linux-user/hppa/target_signal.h index 7f525362e9..d558119ee7 100644 --- a/linux-user/hppa/target_signal.h +++ b/linux-user/hppa/target_signal.h @@ -71,4 +71,18 @@ typedef struct target_sigaltstack { /* mask for all SS_xxx flags */ #define TARGET_SS_FLAG_BITS TARGET_SS_AUTODISARM +/* + * We cannot use a bare sigtramp page for hppa-linux. + * + * Unlike other guests where we use the instructions at PC to validate + * an offset from SP, the hppa libgcc signal frame fallback unwinding uses + * the PC address itself to find the frame. This is due to the fact that + * the hppa grows the stack upward, and the frame is of unknown size. + * + * TODO: We should be able to use a VDSO to address this, by providing + * proper unwind info for the sigtramp code, at which point the fallback + * unwinder will not be used. + */ +#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 0 + #endif /* HPPA_TARGET_SIGNAL_H */