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-rw-r--r--arch/powerpc/mm/hash_utils_64.c83
1 files changed, 69 insertions, 14 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 9326a69..7b4cacb 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -637,7 +637,7 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
* For now this makes the whole process use 4k pages.
*/
#ifdef CONFIG_PPC_64K_PAGES
-static void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
+void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
{
if (mm->context.user_psize == MMU_PAGE_4K)
return;
@@ -645,13 +645,62 @@ static void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
#ifdef CONFIG_SPU_BASE
spu_flush_all_slbs(mm);
#endif
+ if (get_paca()->context.user_psize != MMU_PAGE_4K) {
+ get_paca()->context = mm->context;
+ slb_flush_and_rebolt();
+ }
}
#endif /* CONFIG_PPC_64K_PAGES */
+#ifdef CONFIG_PPC_SUBPAGE_PROT
+/*
+ * This looks up a 2-bit protection code for a 4k subpage of a 64k page.
+ * Userspace sets the subpage permissions using the subpage_prot system call.
+ *
+ * Result is 0: full permissions, _PAGE_RW: read-only,
+ * _PAGE_USER or _PAGE_USER|_PAGE_RW: no access.
+ */
+static int subpage_protection(pgd_t *pgdir, unsigned long ea)
+{
+ struct subpage_prot_table *spt = pgd_subpage_prot(pgdir);
+ u32 spp = 0;
+ u32 **sbpm, *sbpp;
+
+ if (ea >= spt->maxaddr)
+ return 0;
+ if (ea < 0x100000000) {
+ /* addresses below 4GB use spt->low_prot */
+ sbpm = spt->low_prot;
+ } else {
+ sbpm = spt->protptrs[ea >> SBP_L3_SHIFT];
+ if (!sbpm)
+ return 0;
+ }
+ sbpp = sbpm[(ea >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)];
+ if (!sbpp)
+ return 0;
+ spp = sbpp[(ea >> PAGE_SHIFT) & (SBP_L1_COUNT - 1)];
+
+ /* extract 2-bit bitfield for this 4k subpage */
+ spp >>= 30 - 2 * ((ea >> 12) & 0xf);
+
+ /* turn 0,1,2,3 into combination of _PAGE_USER and _PAGE_RW */
+ spp = ((spp & 2) ? _PAGE_USER : 0) | ((spp & 1) ? _PAGE_RW : 0);
+ return spp;
+}
+
+#else /* CONFIG_PPC_SUBPAGE_PROT */
+static inline int subpage_protection(pgd_t *pgdir, unsigned long ea)
+{
+ return 0;
+}
+#endif
+
/* Result code is:
* 0 - handled
* 1 - normal page fault
* -1 - critical hash insertion error
+ * -2 - access not permitted by subpage protection mechanism
*/
int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
{
@@ -802,7 +851,14 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
rc = __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize);
else
#endif /* CONFIG_PPC_HAS_HASH_64K */
- rc = __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize);
+ {
+ int spp = subpage_protection(pgdir, ea);
+ if (access & spp)
+ rc = -2;
+ else
+ rc = __hash_page_4K(ea, access, vsid, ptep, trap,
+ local, ssize, spp);
+ }
#ifndef CONFIG_PPC_64K_PAGES
DBG_LOW(" o-pte: %016lx\n", pte_val(*ptep));
@@ -874,7 +930,8 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
__hash_page_64K(ea, access, vsid, ptep, trap, local, ssize);
else
#endif /* CONFIG_PPC_HAS_HASH_64K */
- __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize);
+ __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize,
+ subpage_protection(pgdir, ea));
local_irq_restore(flags);
}
@@ -919,19 +976,17 @@ void flush_hash_range(unsigned long number, int local)
* low_hash_fault is called when we the low level hash code failed
* to instert a PTE due to an hypervisor error
*/
-void low_hash_fault(struct pt_regs *regs, unsigned long address)
+void low_hash_fault(struct pt_regs *regs, unsigned long address, int rc)
{
if (user_mode(regs)) {
- siginfo_t info;
-
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRERR;
- info.si_addr = (void __user *)address;
- force_sig_info(SIGBUS, &info, current);
- return;
- }
- bad_page_fault(regs, address, SIGBUS);
+#ifdef CONFIG_PPC_SUBPAGE_PROT
+ if (rc == -2)
+ _exception(SIGSEGV, regs, SEGV_ACCERR, address);
+ else
+#endif
+ _exception(SIGBUS, regs, BUS_ADRERR, address);
+ } else
+ bad_page_fault(regs, address, SIGBUS);
}
#ifdef CONFIG_DEBUG_PAGEALLOC