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Commit 0a987645 authored by Florian Fainelli's avatar Florian Fainelli Committed by Richard Weinberger
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um: Allow building and running on older hosts 



Commit a78ff111 ("um: add extended processor state save/restore
support") and b6024b21 ("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: a78ff111 ("um: add extended processor state save/restore support")
Fixes: b6024b21 ("um: extend fpstate to _xstate to support YMM registers")
Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent f44f1e7d

arch/x86/um/os-Linux/registers.c

+8 −4
Original line number Diff line number Diff line
@@ -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) {
@@ -34,10 +35,10 @@ 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) {
@@ -56,10 +58,10 @@ 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__

int have_fpx_regs = 1;
@@ -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

arch/x86/um/user-offsets.c

+4 −0
Original line number Diff line number Diff line
@@ -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);