From 1042d21159497fbb206538f94fe5ac417adfee31 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Sat, 30 Aug 2008 11:26:27 +1000 Subject: [PATCH] powerpc: Only make kernel text pages of linear mapping executable Commit 5655634fc3adf2c918b901e24d02611e2a0ce9d5 ("powerpc/mm: Fix attribute confusion with htab_bolt_mapping()") moved the check for whether we should make pages of the linear mapping executable from htab_bolt_mapping into its callers, including htab_initialize. A side-effect of this is that the decision is now made once for each contiguous section in the LMB array rather than for each page individually. This can often mean that the whole of the linear mapping ends up being executable. This reverts to the previous behaviour, where individual pages are checked for being part of the kernel text or not, by moving the check back down into htab_bolt_mapping. Acked-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras --- arch/powerpc/mm/hash_utils_64.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 14be408dfc9bd..8920eea345284 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -191,12 +191,17 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend, unsigned long hash, hpteg; unsigned long vsid = get_kernel_vsid(vaddr, ssize); unsigned long va = hpt_va(vaddr, vsid, ssize); + unsigned long tprot = prot; + + /* Make kernel text executable */ + if (in_kernel_text(vaddr)) + tprot &= ~HPTE_R_N; hash = hpt_hash(va, shift, ssize); hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP); BUG_ON(!ppc_md.hpte_insert); - ret = ppc_md.hpte_insert(hpteg, va, paddr, prot, + ret = ppc_md.hpte_insert(hpteg, va, paddr, tprot, HPTE_V_BOLTED, psize, ssize); if (ret < 0) @@ -584,7 +589,7 @@ void __init htab_initialize(void) { unsigned long table; unsigned long pteg_count; - unsigned long prot, tprot; + unsigned long prot; unsigned long base = 0, size = 0, limit; int i; @@ -660,10 +665,9 @@ void __init htab_initialize(void) for (i=0; i < lmb.memory.cnt; i++) { base = (unsigned long)__va(lmb.memory.region[i].base); size = lmb.memory.region[i].size; - tprot = prot | (in_kernel_text(base) ? _PAGE_EXEC : 0); DBG("creating mapping for region: %lx..%lx (prot: %x)\n", - base, size, tprot); + base, size, prot); #ifdef CONFIG_U3_DART /* Do not map the DART space. Fortunately, it will be aligned @@ -680,21 +684,21 @@ void __init htab_initialize(void) unsigned long dart_table_end = dart_tablebase + 16 * MB; if (base != dart_tablebase) BUG_ON(htab_bolt_mapping(base, dart_tablebase, - __pa(base), tprot, + __pa(base), prot, mmu_linear_psize, mmu_kernel_ssize)); if ((base + size) > dart_table_end) BUG_ON(htab_bolt_mapping(dart_tablebase+16*MB, base + size, __pa(dart_table_end), - tprot, + prot, mmu_linear_psize, mmu_kernel_ssize)); continue; } #endif /* CONFIG_U3_DART */ BUG_ON(htab_bolt_mapping(base, base + size, __pa(base), - tprot, mmu_linear_psize, mmu_kernel_ssize)); + prot, mmu_linear_psize, mmu_kernel_ssize)); } /* -- 2.39.5