Le 02/03/2018 à 14:51, Michael Clark a écrit :
> Implementation of linux user emulation for RISC-V.
>
> Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
> Signed-off-by: Sagar Karandikar <sag...@eecs.berkeley.edu>
> Signed-off-by: Michael Clark <m...@sifive.com>
> ---
> linux-user/elfload.c | 22 +++
> linux-user/main.c | 99 +++++++++++++
> linux-user/riscv/syscall_nr.h | 287
> ++++++++++++++++++++++++++++++++++++++
> linux-user/riscv/target_cpu.h | 18 +++
> linux-user/riscv/target_elf.h | 14 ++
> linux-user/riscv/target_signal.h | 23 +++
> linux-user/riscv/target_structs.h | 46 ++++++
> linux-user/riscv/target_syscall.h | 56 ++++++++
> linux-user/riscv/termbits.h | 222 +++++++++++++++++++++++++++++
> linux-user/signal.c | 203 ++++++++++++++++++++++++++-
> linux-user/syscall.c | 2 +
> linux-user/syscall_defs.h | 13 +-
> target/riscv/cpu_user.h | 13 ++
> 13 files changed, 1012 insertions(+), 6 deletions(-)
> create mode 100644 linux-user/riscv/syscall_nr.h
> create mode 100644 linux-user/riscv/target_cpu.h
> create mode 100644 linux-user/riscv/target_elf.h
> create mode 100644 linux-user/riscv/target_signal.h
> create mode 100644 linux-user/riscv/target_structs.h
> create mode 100644 linux-user/riscv/target_syscall.h
> create mode 100644 linux-user/riscv/termbits.h
> create mode 100644 target/riscv/cpu_user.h
>
...
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 9a380b9..4d3f244 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
...
> +static abi_ulong get_sigframe(struct target_sigaction *ka,
> + CPURISCVState *regs, size_t framesize)
> +{
> + abi_ulong sp = regs->gpr[xSP];
> + int onsigstack = on_sig_stack(sp);
> +
> + /* redzone */
> + /* This is the X/Open sanctioned signal stack switching. */
> + if ((ka->sa_flags & TARGET_SA_ONSTACK) != 0 && !onsigstack) {
> + sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
> + }
> +
> + sp -= framesize;
> + sp &= ~3UL; /* align sp on 4-byte boundary */
kernel aligns using 0xf. Why do you use a different alignment?
> +
> + /* If we are on the alternate signal stack and would overflow it, don't.
> + Return an always-bogus address instead so we will die with SIGSEGV. */
> + if (onsigstack && !likely(on_sig_stack(sp))) {
> + return -1L;
> + }
> +
> + return sp;
> +}
Other question why don't you use the same logic as in kernel?
1- check for signal stack overflow
2- check for X/Open sanctioned signal stack switching
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs, size_t framesize)
{
unsigned long sp;
/* Default to using normal stack */
sp = regs->sp;
/*
* If we are on the alternate signal stack and would overflow
it, don't.
* Return an always-bogus address instead so we will die with
SIGSEGV.
*/
if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
return (void __user __force *)(-1UL);
/* This is the X/Open sanctioned signal stack switching. */
sp = sigsp(sp, ksig) - framesize;
/* Align the stack frame. */
sp &= ~0xfUL;
return (void __user *)sp;
}
Thanks,
Laurent
