Le 07/07/2017 à 04:20, Richard Henderson a écrit :
> We translate gUSA regions atomically in a parallel context.
> But in a serial context a gUSA region may be interrupted.
> In that case, restart the region as the kernel would.
>
> Signed-off-by: Richard Henderson <[email protected]>
> ---
> linux-user/signal.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 3d18d1b..a537778 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -3471,6 +3471,25 @@ static abi_ulong get_sigframe(struct target_sigaction
> *ka,
> return (sp - frame_size) & -8ul;
> }
>
> +/* Notice when we're in the middle of a gUSA region and reset.
> + Note that this will only occur for !parallel_cpus, as we will
> + translate such sequences differently in a parallel context. */
> +static void unwind_gusa(CPUSH4State *regs)
> +{
> + /* If the stack pointer is sufficiently negative ... */
> + if ((regs->gregs[15] & 0xc0000000u) == 0xc0000000u
> + /* ... and we haven't completed the sequence ... */
> + && regs->pc < regs->gregs[0]) {
> + /* Reset the PC to before the gUSA region, as computed from
> + R0 = region end, SP = -(region size), plus one more insn
> + that actually sets SP to the region size. */
> + regs->pc = regs->gregs[0] + regs->gregs[15] - 2;
> +
> + /* Reset the SP to the saved version in R1. */
> + regs->gregs[15] = regs->gregs[1];
> + }
> +}
> +
> static void setup_sigcontext(struct target_sigcontext *sc,
> CPUSH4State *regs, unsigned long mask)
> {
> @@ -3534,6 +3553,8 @@ static void setup_frame(int sig, struct
> target_sigaction *ka,
> abi_ulong frame_addr;
> int i;
>
> + unwind_gusa(regs);
> +
> frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
I think unwind_gusa() should be moved after the get_sigfram() (in both
cases), because r15 can be updated and the sigframe base lost.
@@ -3551,9 +3552,8 @@ static void setup_frame(int sig, struct
target_sigaction *
ka,
abi_ulong frame_addr;
int i;
- unwind_gusa(regs);
-
frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
+ unwind_gusa(regs);
trace_user_setup_frame(regs, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
@@ -3602,9 +3602,8 @@ static void setup_rt_frame(int sig, struct
target_sigaction *ka,
abi_ulong frame_addr;
int i;
- unwind_gusa(regs);
-
frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
+ unwind_gusa(regs);
trace_user_setup_rt_frame(regs, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
Laurent
