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authorBalbir Singh2017-06-29 03:04:07 +1000
committerMichael Ellerman2017-07-03 23:12:19 +1000
commite71ff982ae4c17d176e9f0132157d54973788377 (patch)
tree9f1875c04c76de6eac686d2724f6c3e4a746776c /arch/powerpc/platforms
parent90653a84052cfbbc1f46427f851dad14083e36df (diff)
powerpc/pseries: Fix passing of pp0 in updatepp() and updateboltedpp()
Once upon a time there were only two PP (page protection) bits. In ISA 2.03 an additional PP bit was added, but because of the layout of the HPTE it could not be made contiguous with the existing PP bits. The result is that we now have three PP bits, named pp0, pp1, pp2, where pp0 occupies bit 63 of dword 1 of the HPTE and pp1 and pp2 occupy bits 1 and 0 respectively. Until recently Linux hasn't used pp0, however with the addition of _PAGE_KERNEL_RO we started using it. The problem arises in the LPAR code, where we need to translate the PP bits into the argument for the H_PROTECT hypercall. Currently the code only passes bits 0-2 of newpp, which covers pp1, pp2 and N (no execute), meaning pp0 is not passed to the hypervisor at all. We can't simply pass it through in bit 63, as that would collide with a different field in the flags argument, as defined in PAPR. Instead we have to shift it down to bit 8 (IBM bit 55). Fixes: e58e87adc8bf ("powerpc/mm: Update _PAGE_KERNEL_RO") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Balbir Singh <bsingharora@gmail.com> [mpe: Simplify the test, rework change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/platforms')
-rw-r--r--arch/powerpc/platforms/pseries/lpar.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 6541d0b03e4c..495ba4e7336d 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -301,7 +301,7 @@ static long pSeries_lpar_hpte_updatepp(unsigned long slot,
int ssize, unsigned long inv_flags)
{
unsigned long lpar_rc;
- unsigned long flags = (newpp & 7) | H_AVPN;
+ unsigned long flags;
unsigned long want_v;
want_v = hpte_encode_avpn(vpn, psize, ssize);
@@ -309,6 +309,11 @@ static long pSeries_lpar_hpte_updatepp(unsigned long slot,
pr_devel(" update: avpnv=%016lx, hash=%016lx, f=%lx, psize: %d ...",
want_v, slot, flags, psize);
+ flags = (newpp & 7) | H_AVPN;
+ if (mmu_has_feature(MMU_FTR_KERNEL_RO))
+ /* Move pp0 into bit 8 (IBM 55) */
+ flags |= (newpp & HPTE_R_PP0) >> 55;
+
lpar_rc = plpar_pte_protect(flags, slot, want_v);
if (lpar_rc == H_NOT_FOUND) {
@@ -380,6 +385,10 @@ static void pSeries_lpar_hpte_updateboltedpp(unsigned long newpp,
BUG_ON(slot == -1);
flags = newpp & 7;
+ if (mmu_has_feature(MMU_FTR_KERNEL_RO))
+ /* Move pp0 into bit 8 (IBM 55) */
+ flags |= (newpp & HPTE_R_PP0) >> 55;
+
lpar_rc = plpar_pte_protect(flags, slot, 0);
BUG_ON(lpar_rc != H_SUCCESS);