[patch 1/1] uml: fix handling of no fpx_regs [critical, for 2.6.12]

[patch 1/1] uml: fix handling of no fpx_regs [critical, for 2.6.12]

[blaisorblade]

From: Andree Leidenfrost <aleidenf@bigpond.net.au>, Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>

Fix the error path, which is triggered when the processor misses the fpx regs
(i.e. the "fxsr" cpuinfo feature). For instance by VIA C3 Samuel2. Tested and
obvious, please merge ASAP.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---

 linux-2.6.12-paolo/arch/um/os-Linux/sys-i386/registers.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff -puN arch/um/os-Linux/sys-i386/registers.c~uml-fix-no_fpx_regs_handling arch/um/os-Linux/sys-i386/registers.c
--- linux-2.6.12/arch/um/os-Linux/sys-i386/registers.c~uml-fix-no_fpx_regs_handling	2005-04-25 21:03:11.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/os-Linux/sys-i386/registers.c	2005-04-25 21:08:07.000000000 +0200
@@ -105,14 +105,15 @@ void init_registers(int pid)
 		panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
 		      err);
 
+	errno = 0;
 	err = ptrace(PTRACE_GETFPXREGS, pid, 0, exec_fpx_regs);
 	if(!err)
 		return;
+	if(errno != EIO)
+		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
+		      errno);
 
 	have_fpx_regs = 0;
-	if(err != EIO)
-		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
-		      err);
 
 	err = ptrace(PTRACE_GETFPREGS, pid, 0, exec_fp_regs);
 	if(err)
_

Re: [patch 1/1] uml: fix handling of no fpx_regs [critical, for 2.6.12]

[Alexander Nyberg]

mån 2005-04-25 klockan 21:12 +0200 skrev blaisorblade@yahoo.it:
> From: Andree Leidenfrost <aleidenf@bigpond.net.au>, Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
> 
> Fix the error path, which is triggered when the processor misses the fpx regs
> (i.e. the "fxsr" cpuinfo feature). For instance by VIA C3 Samuel2. Tested and
> obvious, please merge ASAP.
> 
> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
> ---
> 
>  linux-2.6.12-paolo/arch/um/os-Linux/sys-i386/registers.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff -puN arch/um/os-Linux/sys-i386/registers.c~uml-fix-no_fpx_regs_handling arch/um/os-Linux/sys-i386/registers.c
> --- linux-2.6.12/arch/um/os-Linux/sys-i386/registers.c~uml-fix-no_fpx_regs_handling	2005-04-25 21:03:11.000000000 +0200
> +++ linux-2.6.12-paolo/arch/um/os-Linux/sys-i386/registers.c	2005-04-25 21:08:07.000000000 +0200
> @@ -105,14 +105,15 @@ void init_registers(int pid)
>  		panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
>  		      err);
>  
> +	errno = 0;
>  	err = ptrace(PTRACE_GETFPXREGS, pid, 0, exec_fpx_regs);
>  	if(!err)
>  		return;
> +	if(errno != EIO)
> +		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
> +		      errno);

Looks like you mean "if (err != EIO)" here


>  	have_fpx_regs = 0;
> -	if(err != EIO)
> -		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
> -		      err);
>  
>  	err = ptrace(PTRACE_GETFPREGS, pid, 0, exec_fp_regs);
>  	if(err)

Re: [patch 1/1] uml: fix handling of no fpx_regs [critical, for 2.6.12]

[Andree Leidenfrost]

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Hi Alexander

On Mon, 2005-04-25 at 21:57 +0200, Alexander Nyberg wrote:
> mån 2005-04-25 klockan 21:12 +0200 skrev blaisorblade@yahoo.it:
> > From: Andree Leidenfrost <aleidenf@bigpond.net.au>, Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
> > 
> > Fix the error path, which is triggered when the processor misses the fpx regs
> > (i.e. the "fxsr" cpuinfo feature). For instance by VIA C3 Samuel2. Tested and
> > obvious, please merge ASAP.
> > 
> > Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
> > ---
> > 
> >  linux-2.6.12-paolo/arch/um/os-Linux/sys-i386/registers.c |    7 ++++---
> >  1 files changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff -puN arch/um/os-Linux/sys-i386/registers.c~uml-fix-no_fpx_regs_handling arch/um/os-Linux/sys-i386/registers.c
> > --- linux-2.6.12/arch/um/os-Linux/sys-i386/registers.c~uml-fix-no_fpx_regs_handling	2005-04-25 21:03:11.000000000 +0200
> > +++ linux-2.6.12-paolo/arch/um/os-Linux/sys-i386/registers.c	2005-04-25 21:08:07.000000000 +0200
> > @@ -105,14 +105,15 @@ void init_registers(int pid)
> >  		panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
> >  		      err);
> >  
> > +	errno = 0;
> >  	err = ptrace(PTRACE_GETFPXREGS, pid, 0, exec_fpx_regs);
> >  	if(!err)
> >  		return;
> > +	if(errno != EIO)
> > +		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
> > +		      errno);
> 
> Looks like you mean "if (err != EIO)" here

No. The patch is correct.

ptrace will always return -1 in case of an error. The actual error code
is in errno, hence this is what needs to be compared to EIO. Please also
see the ptrace manpage.

> >  	have_fpx_regs = 0;
> > -	if(err != EIO)
> > -		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
> > -		      err);
> >  
> >  	err = ptrace(PTRACE_GETFPREGS, pid, 0, exec_fp_regs);
> >  	if(err)

Best regards
Andree
-- 
Andree Leidenfrost
Sydney - Australia


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