[PATCH v2] arm64: SSBS/DIT: print SSBS and DIT bit when printing PSTATE

[Will Deacon]

On Wed, Jul 21, 2021 at 09:31:18AM +0100, Vladimir Murzin wrote:
> On 7/21/21 3:43 AM, Shaokun Zhang wrote:
> > From: Lingyan Huang <huanglingyan2 at huawei.com>
> > 
> > The current code to print PSTATE when generating backtraces does not
> > include SSBS bit and DIT bit, so add this information.
> > 
> > Cc: Vladimir Murzin <vladimir.murzin at arm.com>
> > Cc: Catalin Marinas <catalin.marinas at arm.com>
> > Cc: Will Deacon <will at kernel.org>
> > Signed-off-by: Lingyan Huang <huanglingyan2 at huawei.com>
> > Signed-off-by: Shaokun Zhang <zhangshaokun at hisilicon.com>
> > ---
> > ChangeLog:
> > v1-->v2:
> >     1. Address Vladimir's comment on update compat_user_mode
> > 
> >  arch/arm64/kernel/process.c | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> > index c8989b999250..3da2ad00fa0c 100644
> > --- a/arch/arm64/kernel/process.c
> > +++ b/arch/arm64/kernel/process.c
> > @@ -163,7 +163,7 @@ static void print_pstate(struct pt_regs *regs)
> >  	u64 pstate = regs->pstate;
> >  
> >  	if (compat_user_mode(regs)) {
> > -		printk("pstate: %08llx (%c%c%c%c %c %s %s %c%c%c)\n",
> > +		printk("pstate: %08llx (%c%c%c%c %c %s %s %c%c%c %cPAN %cDIT %cSSBS)\n",
> >  			pstate,
> >  			pstate & PSR_AA32_N_BIT ? 'N' : 'n',
> >  			pstate & PSR_AA32_Z_BIT ? 'Z' : 'z',
> > @@ -174,12 +174,15 @@ static void print_pstate(struct pt_regs *regs)
> >  			pstate & PSR_AA32_E_BIT ? "BE" : "LE",
> >  			pstate & PSR_AA32_A_BIT ? 'A' : 'a',
> >  			pstate & PSR_AA32_I_BIT ? 'I' : 'i',
> > -			pstate & PSR_AA32_F_BIT ? 'F' : 'f');
> > +			pstate & PSR_AA32_F_BIT ? 'F' : 'f',
> > +			pstate & PSR_AA32_PAN_BIT ? '+' : '-',
> 
> Hmm, commit message doesn't mention PAN bit... but I leave it to maintainers.

Agreed, I don't see the rationale for exposing PAN for 32-bit userspace
tasks. Please drop this part for v3.

Will