On Sat, 2020-02-15 at 11:17 +0100, Christophe Leroy wrote: > > Le 15/02/2020 à 07:28, Leonardo Bras a écrit : > > On Sun, 2020-02-09 at 18:14 +0000, Christophe Leroy wrote: > > > In ITLB miss handled the line supposed to clear bits 20-23 on the > > > L2 ITLB entry is buggy and does indeed nothing, leading to undefined > > > value which could allow execution when it shouldn't. > > > > > > Properly do the clearing with the relevant instruction. > > > > > > Fixes: 74fabcadfd43 ("powerpc/8xx: don't use r12/SPRN_SPRG_SCRATCH2 in > > > TLB Miss handlers") > > > Cc: sta...@vger.kernel.org > > > Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr> > > > --- > > > arch/powerpc/kernel/head_8xx.S | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/arch/powerpc/kernel/head_8xx.S > > > b/arch/powerpc/kernel/head_8xx.S > > > index 9922306ae512..073a651787df 100644 > > > --- a/arch/powerpc/kernel/head_8xx.S > > > +++ b/arch/powerpc/kernel/head_8xx.S > > > @@ -256,7 +256,7 @@ InstructionTLBMiss: > > > * set. All other Linux PTE bits control the behavior > > > * of the MMU. > > > */ > > > - rlwimi r10, r10, 0, 0x0f00 /* Clear bits 20-23 */ > > > + rlwinm r10, r10, 0, ~0x0f00 /* Clear bits 20-23 */ > > > rlwimi r10, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 > > > */ > > > ori r10, r10, RPN_PATTERN | 0x200 /* Set 22 and 24-27 */ > > > mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ > > > > Looks a valid change. > > rlwimi r10, r10, 0, 0x0f00 means: > > r10 = ((r10 << 0) & 0x0f00) | (r10 & ~0x0f00) which ends up being > > r10 = r10 > > > > On ISA, rlwinm is recommended for clearing high order bits. > > rlwinm r10, r10, 0, ~0x0f00 means: > > r10 = (r10 << 0) & ~0x0f00 > > > > Which does exactly what the comments suggests. > > > > FWIW: > > Reviwed-by: Leonardo Bras <leona...@linux.ibm.com> > > > > I guess you mean > > Reviewed-by: Leonardo Bras <leona...@linux.ibm.com>
Yes, sorry for the typo.
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