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um: Allow building and running on older hosts

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Commit a78ff11122 ("um: add extended processor state save/restore
support") and b6024b21fe ("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: a78ff11122 ("um: add extended processor state save/restore support")
Fixes: b6024b21fe ("um: extend fpstate to _xstate to support YMM registers")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Florian Fainelli 2017-05-25 11:36:26 -07:00 committed by Richard Weinberger
parent f44f1e7da7
commit 0a98764567
2 changed files with 12 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

12
arch/x86/um/os-Linux/registers.c
View file

@ -26,6 +26,7 @@ int save_i387_registers(int pid, unsigned long *fp_regs)
int save_fp_registers(int pid, unsigned long *fp_regs)
{
#ifdef PTRACE_GETREGSET
struct iovec iov;
if (have_xstate_support) {
@ -34,9 +35,9 @@ int save_fp_registers(int pid, unsigned long *fp_regs)
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
return 0;
} else {
} else
#endif
return save_i387_registers(pid, fp_regs);
}
}
int restore_i387_registers(int pid, unsigned long *fp_regs)
@ -48,6 +49,7 @@ int restore_i387_registers(int pid, unsigned long *fp_regs)
int restore_fp_registers(int pid, unsigned long *fp_regs)
{
#ifdef PTRACE_SETREGSET
struct iovec iov;
if (have_xstate_support) {
@ -56,9 +58,9 @@ int restore_fp_registers(int pid, unsigned long *fp_regs)
if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
return -errno;
return 0;
} else {
} else
#endif
return restore_i387_registers(pid, fp_regs);
}
}
#ifdef __i386__
@ -122,6 +124,7 @@ int put_fp_registers(int pid, unsigned long *regs)
void arch_init_registers(int pid)
{
#ifdef PTRACE_GETREGSET
struct _xstate fp_regs;
struct iovec iov;
@ -129,6 +132,7 @@ void arch_init_registers(int pid)
iov.iov_len = sizeof(struct _xstate);
if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
have_xstate_support = 1;
#endif
}
#endif

4
arch/x86/um/user-offsets.c
View file

@ -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);