On 08/03/2022, 14:50:42, Nicholas Piggin wrote: > PAPR specifies that RTAS may be called with MSR[RI] enabled if the > calling context is recoverable, and RTAS will manage RI as necessary. > Call the rtas entry point with RI enabled, and add a check to ensure > the caller has RI enabled. > > Signed-off-by: Nicholas Piggin <npig...@gmail.com> > --- > arch/powerpc/kernel/rtas.c | 1 + > arch/powerpc/kernel/rtas_entry.S | 13 +++---------- > 2 files changed, 4 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c > index 87ede1877816..fece066115f0 100644 > --- a/arch/powerpc/kernel/rtas.c > +++ b/arch/powerpc/kernel/rtas.c > @@ -57,6 +57,7 @@ static noinline void do_enter_rtas(unsigned long args) > hard_irq_disable(); > > msr = mfmsr(); > + BUG_ON(!(msr & MSR_RI)); > mtmsr(msr & ~(MSR_IR|MSR_DR)); > enter_rtas(args); > mtmsr(msr); > diff --git a/arch/powerpc/kernel/rtas_entry.S > b/arch/powerpc/kernel/rtas_entry.S > index 292551684bbd..72b27b14ccc9 100644 > --- a/arch/powerpc/kernel/rtas_entry.S > +++ b/arch/powerpc/kernel/rtas_entry.S > @@ -95,7 +95,7 @@ _GLOBAL(enter_rtas) > clrldi r4,r4,2 /* convert to realmode address */ > mtlr r4 > > - LOAD_REG_IMMEDIATE(r6, MSR_ME) > + LOAD_REG_IMMEDIATE(r6, MSR_ME|MSR_RI) > > LOAD_REG_ADDR(r4, rtas) > ld r5,RTASENTRY(r4) /* get the rtas->entry value */ > @@ -113,15 +113,8 @@ _ASM_NOKPROBE_SYMBOL(enter_rtas) > rtas_return_loc: > FIXUP_ENDIAN > > - /* > - * Clear RI and set SF before anything. > - */ > - mfmsr r6 > - li r0,MSR_RI > - andc r6,r6,r0 > - sldi r0,r0,(MSR_SF_LG - MSR_RI_LG) > - or r6,r6,r0 > - sync > + /* Set SF before anything. */ > + LOAD_REG_IMMEDIATE(r6, MSR_KERNEL & ~(MSR_IR|MSR_DR))
I guess we cannot directly load a MSR value stored in the PACA at that time, isn't it? > mtmsrd r6 > > GET_PACA(r13)
