CC'ing Thomas. We is also facing issues with these commits.
Am 24.05.2017 um 03:08 schrieb Florian Fainelli:
> Commit a78ff1112263 ("um: add extended processor state save/restore
> support") and b6024b21fec8 ("um: extend fpstate to _xstate to support
> YMM registers") forced the use of the x86 FP _xstate and
> PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to
> build UML nor run it anymore with these two commits applied because we
> don't have definitions for struct _xstate nor these two ptrace requests.
>
> We can determine at build time which fp context structure to check
> against, just like we can keep using the old i387 fp save/restore if
> PTRACE_GETRESET/SETREGSET are not defined.
>
> Fixes: a78ff1112263 ("um: add extended processor state save/restore support")
> Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers")
> Signed-off-by: Florian Fainelli <[email protected]>
> ---
> arch/x86/um/os-Linux/registers.c | 13 +++++++++----
> arch/x86/um/user-offsets.c | 4 ++++
> 2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/um/os-Linux/registers.c
> b/arch/x86/um/os-Linux/registers.c
> index 00f54a91bb4b..502bd642e5c2 100644
> --- a/arch/x86/um/os-Linux/registers.c
> +++ b/arch/x86/um/os-Linux/registers.c
> @@ -26,13 +26,14 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
>
> int save_fp_registers(int pid, unsigned long *fp_regs)
> {
> - struct iovec iov;
> -
> if (have_xstate_support) {
> +#ifdef PTRACE_GETREGSET
> + struct iovec iov;
> iov.iov_base = fp_regs;
> iov.iov_len = sizeof(struct _xstate);
> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
> return -errno;
> +#endif
> return 0;
> } else {
> return save_i387_registers(pid, fp_regs);
> @@ -48,13 +49,15 @@ int restore_i387_registers(int pid, unsigned long
> *fp_regs)
>
> int restore_fp_registers(int pid, unsigned long *fp_regs)
> {
> - struct iovec iov;
> -
> if (have_xstate_support) {
> +#ifdef PTRACE_SETREGSET
> + struct iovec iov;
> +
> iov.iov_base = fp_regs;
> iov.iov_len = sizeof(struct _xstate);
> if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
> return -errno;
> +#endif
> return 0;
> } else {
> return restore_i387_registers(pid, fp_regs);
> @@ -127,8 +130,10 @@ void arch_init_registers(int pid)
>
> iov.iov_base = &fp_regs;
> iov.iov_len = sizeof(struct _xstate);
> +#ifdef PTRACE_GETREGSET
> if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
> have_xstate_support = 1;
> +#endif
> }
> #endif
>
> diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
> index cb3c22370cf5..8af0fb5d2780 100644
> --- a/arch/x86/um/user-offsets.c
> +++ b/arch/x86/um/user-offsets.c
> @@ -50,7 +50,11 @@ void foo(void)
> DEFINE(HOST_GS, GS);
> DEFINE(HOST_ORIG_AX, ORIG_EAX);
> #else
> +#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
> DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
> +#else
> + DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
> +#endif
> DEFINE_LONGS(HOST_BX, RBX);
> DEFINE_LONGS(HOST_CX, RCX);
> DEFINE_LONGS(HOST_DI, RDI);
>
