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Commit a5f6096c authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: floating point signal delivery fixes 



Handle floating point state in across signals correctly.  UML/i386 needs to
know whether the host does PTRACE_[GS]ETFPXREGS, so an arch_init_registers
hook is added, which on x86_64 does nothing.

UML doesn't save and restore floating point registers on kernel entry and
exit, so they need to be copied between the host process and the sigcontext.
save_fpx_registers and restore_fpx_registers are added for this purpose.
save_fp_registers and restore_fp_registers already exist.

There was a bunch of floating point state conversion code in
arch/um/sys-i386/ptrace.c which isn't needed there, but is needed in signal.c,
so it is moved over.

The i386 code now distinguishes between fp and fpx state and handles them
correctly.  The x86_64 code just needs to copy state as-is between the host
process and the stack.  There are also some fixes there to pass the correct
address of the floating point state around.

Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 189872f9

arch/um/include/registers.h

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
extern void init_thread_registers(struct uml_pt_regs *to);

extern int save_fp_registers(int pid, unsigned long *fp_regs);

extern int restore_fp_registers(int pid, unsigned long *fp_regs);

extern int save_fpx_registers(int pid, unsigned long *fp_regs);

extern int restore_fpx_registers(int pid, unsigned long *fp_regs);

extern void save_registers(int pid, struct uml_pt_regs *regs);

extern void restore_registers(int pid, struct uml_pt_regs *regs);

extern void init_registers(int pid);

arch/um/include/sysdep-i386/ptrace.h

+2 −0
Original line number Diff line number Diff line
@@ -168,4 +168,6 @@ struct syscall_args { 


#define UPT_FAULTINFO(r) (&(r)->faultinfo)



extern void arch_init_registers(int pid);



#endif

arch/um/include/sysdep-x86_64/ptrace.h

+4 −0
Original line number Diff line number Diff line
@@ -234,4 +234,8 @@ struct syscall_args { 


#define UPT_FAULTINFO(r) (&(r)->faultinfo)



static inline void arch_init_registers(int pid)

{

}



#endif

arch/um/os-Linux/registers.c

+2 −0
Original line number Diff line number Diff line
@@ -47,6 +47,8 @@ void init_registers(int pid) 
	if (err)

		panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",

		      errno);



	arch_init_registers(pid);

}



void get_safe_registers(unsigned long *regs)

arch/um/os-Linux/sys-i386/registers.c

+32 −3
Original line number Diff line number Diff line
@@ -8,9 +8,6 @@ 
#include "longjmp.h"

#include "user.h"



/* XXX These need to use [GS]ETFPXREGS and copy_sc_{to,from}_user_skas needs

 * to pass in a sufficiently large buffer

 */

int save_fp_registers(int pid, unsigned long *fp_regs)

{

	if(ptrace(PTRACE_GETFPREGS, pid, 0, fp_regs) < 0)
@@ -25,6 +22,20 @@ int restore_fp_registers(int pid, unsigned long *fp_regs) 
	return 0;

}



int save_fpx_registers(int pid, unsigned long *fp_regs)

{

	if(ptrace(PTRACE_GETFPXREGS, pid, 0, fp_regs) < 0)

		return -errno;

	return 0;

}



int restore_fpx_registers(int pid, unsigned long *fp_regs)

{

	if(ptrace(PTRACE_SETFPXREGS, pid, 0, fp_regs) < 0)

		return -errno;

	return 0;

}



unsigned long get_thread_reg(int reg, jmp_buf *buf)

{

	switch(reg){
@@ -36,3 +47,21 @@ unsigned long get_thread_reg(int reg, jmp_buf *buf) 
		return 0;

	}

}



int have_fpx_regs = 1;



void arch_init_registers(int pid)

{

	unsigned long fpx_regs[HOST_XFP_SIZE];

	int err;



	err = ptrace(PTRACE_GETFPXREGS, pid, 0, fpx_regs);

	if(!err)

		return;



	if(errno != EIO)

		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",

		      errno);



	have_fpx_regs = 0;

}