Le 05/11/2020 à 22:23, Peter Maydell a écrit :
> The various structs that make up the SPARC target_ucontext had some
> errors:
> * target structures must not include fields which are host pointers,
> which might be the wrong size. These should be abi_ulong instead
> * because we don't have the 'long double' part of the mcfpu_fregs
> union in our version of the target_mc_fpu struct, we need to
> manually force it to be 16-aligned
>
> In particular, the lack of 16-alignment caused sparc64_get_context()
> and sparc64_set_context() to read and write all the registers at the
> wrong offset, which triggered a guest glibc stack check in
> siglongjmp:
> *** longjmp causes uninitialized stack frame ***: terminated
> when trying to run bash.
>
> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
> ---
> linux-user/sparc/signal.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/linux-user/sparc/signal.c b/linux-user/sparc/signal.c
> index d796f50f665..57ea1593bfc 100644
> --- a/linux-user/sparc/signal.c
> +++ b/linux-user/sparc/signal.c
> @@ -349,10 +349,15 @@ typedef abi_ulong target_mc_greg_t;
> typedef target_mc_greg_t target_mc_gregset_t[SPARC_MC_NGREG];
>
> struct target_mc_fq {
> - abi_ulong *mcfq_addr;
> + abi_ulong mcfq_addr;
> uint32_t mcfq_insn;
> };
>
> +/*
> + * Note the manual 16-alignment; the kernel gets this because it
> + * includes a "long double qregs[16]" in the mcpu_fregs union,
> + * which we can't do.
> + */
> struct target_mc_fpu {
> union {
> uint32_t sregs[32];
> @@ -362,11 +367,11 @@ struct target_mc_fpu {
> abi_ulong mcfpu_fsr;
> abi_ulong mcfpu_fprs;
> abi_ulong mcfpu_gsr;
> - struct target_mc_fq *mcfpu_fq;
> + abi_ulong mcfpu_fq;
> unsigned char mcfpu_qcnt;
> unsigned char mcfpu_qentsz;
> unsigned char mcfpu_enab;
> -};
> +} __attribute__((aligned(16)));
> typedef struct target_mc_fpu target_mc_fpu_t;
>
> typedef struct {
> @@ -377,7 +382,7 @@ typedef struct {
> } target_mcontext_t;
>
> struct target_ucontext {
> - struct target_ucontext *tuc_link;
> + abi_ulong tuc_link;
> abi_ulong tuc_flags;
> target_sigset_t tuc_sigmask;
> target_mcontext_t tuc_mcontext;
>
Applied to my linux-user-for-5.2 branch.
Thanks,
Laurent
