From: Michael Ellerman <mpe@ellerman.id.au>
To: linuxppc-dev@ozlabs.org
Subject: [PATCH 2/3] powerpc/mm/hash: Refactor hash__mark_rodata_ro()
Date: Fri, 14 Jul 2017 16:51:22 +1000 [thread overview]
Message-ID: <1500015083-23511-2-git-send-email-mpe@ellerman.id.au> (raw)
In-Reply-To: <1500015083-23511-1-git-send-email-mpe@ellerman.id.au>
Move the core logic into a helper, so we can use it for changing other
permissions.
We also change the logic to align start down, and end up. This means
calling the function with a range will expand that range to be at
least 1 mmu_linear_psize page in size. We need that so we can use it
on __init_begin ... __init_end which is not a full page in size.
This should always work for _stext/__init_begin, because we align
__init_begin to _stext + 16M in the linker script.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/mm/pgtable-hash64.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index 188b4107584d..73019c52141f 100644
--- a/arch/powerpc/mm/pgtable-hash64.c
+++ b/arch/powerpc/mm/pgtable-hash64.c
@@ -425,33 +425,39 @@ int hash__has_transparent_hugepage(void)
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#ifdef CONFIG_STRICT_KERNEL_RWX
-void hash__mark_rodata_ro(void)
+static bool hash__change_memory_range(unsigned long start, unsigned long end,
+ unsigned long newpp)
{
- unsigned long start = (unsigned long)_stext;
- unsigned long end = (unsigned long)__init_begin;
unsigned long idx;
unsigned int step, shift;
- unsigned long newpp = PP_RXXX;
shift = mmu_psize_defs[mmu_linear_psize].shift;
step = 1 << shift;
- start = ((start + step - 1) >> shift) << shift;
- end = (end >> shift) << shift;
+ start = ALIGN_DOWN(start, step);
+ end = ALIGN(end, step); // aligns up
- pr_devel("marking ro start %lx, end %lx, step %x\n",
- start, end, step);
+ if (start >= end)
+ return false;
- if (start == end) {
- pr_warn("could not set rodata ro, relocate the start"
- " of the kernel to a 0x%x boundary\n", step);
- return;
- }
+ pr_debug("Changing page protection on range 0x%lx-0x%lx, to 0x%lx, step 0x%x\n",
+ start, end, newpp, step);
for (idx = start; idx < end; idx += step)
/* Not sure if we can do much with the return value */
mmu_hash_ops.hpte_updateboltedpp(newpp, idx, mmu_linear_psize,
mmu_kernel_ssize);
+ return true;
+}
+
+void hash__mark_rodata_ro(void)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)_stext;
+ end = (unsigned long)__init_begin;
+
+ WARN_ON(!hash__change_memory_range(start, end, PP_RXXX));
}
#endif
--
2.7.4
next prev parent reply other threads:[~2017-07-14 6:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-14 6:51 [PATCH 1/3] powerpc/mm/radix: Refactor radix__mark_rodata_ro() Michael Ellerman
2017-07-14 6:51 ` Michael Ellerman [this message]
2017-07-18 1:05 ` [PATCH 2/3] powerpc/mm/hash: Refactor hash__mark_rodata_ro() Balbir Singh
2017-07-14 6:51 ` [PATCH 3/3] powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y Michael Ellerman
2017-07-14 23:01 ` kbuild test robot
2017-07-18 9:54 ` Michael Ellerman
2017-08-02 11:01 ` Christophe LEROY
2017-08-09 2:29 ` Michael Ellerman
2017-08-09 6:27 ` Christophe LEROY
2017-08-09 13:13 ` Michael Ellerman
2017-07-18 1:04 ` [PATCH 1/3] powerpc/mm/radix: Refactor radix__mark_rodata_ro() Balbir Singh
2017-07-21 11:13 ` [1/3] " Michael Ellerman
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