diff mbox series

[v13,7/8] powerpc/mm: implement set_memory_attr()

Message ID 20210510011828.4006623-8-jniethe5@gmail.com (mailing list archive)
State Superseded
Headers show
Series powerpc: Further Strict RWX support | expand
Related show

Checks

Context Check Description
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/merge (fcc98c6d0289241dded10b74f8198fc4ecb22bd1)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/next (f96271cefe6dfd1cb04195b76f4a33e185cd7f92)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linus/master (6efb943b8616ec53a5e444193dccf1af9ad627b5)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/fixes (791f9e36599d94af5a76d3f74d04e16326761aae)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linux-next (dd860052c99b1e088352bdd4fb7aef46f8d2ef47)
snowpatch_ozlabs/apply_patch fail Failed to apply to any branch

Commit Message

Jordan Niethe May 10, 2021, 1:18 a.m. UTC 
From: Christophe Leroy <christophe.leroy@csgroup.eu>

In addition to the set_memory_xx() functions which allows to change
the memory attributes of not (yet) used memory regions, implement a
set_memory_attr() function to:
- set the final memory protection after init on currently used
kernel regions.
- enable/disable kernel memory regions in the scope of DEBUG_PAGEALLOC.

Unlike the set_memory_xx() which can act in three step as the regions
are unused, this function must modify 'on the fly' as the kernel is
executing from them. At the moment only PPC32 will use it and changing
page attributes on the fly is not an issue.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reported-by: kbuild test robot <lkp@intel.com>
[ruscur: cast "data" to unsigned long instead of int]
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/include/asm/set_memory.h |  2 ++
 arch/powerpc/mm/pageattr.c            | 33 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/set_memory.h b/arch/powerpc/include/asm/set_memory.h
index 64011ea444b4..b040094f7920 100644
--- a/arch/powerpc/include/asm/set_memory.h
+++ b/arch/powerpc/include/asm/set_memory.h
@@ -29,4 +29,6 @@  static inline int set_memory_x(unsigned long addr, int numpages)
 	return change_memory_attr(addr, numpages, SET_MEMORY_X);
 }
 
+int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot);
+
 #endif
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
index acfdde78e0fb..7dee30cd6b48 100644
--- a/arch/powerpc/mm/pageattr.c
+++ b/arch/powerpc/mm/pageattr.c
@@ -98,3 +98,36 @@  int change_memory_attr(unsigned long addr, int numpages, long action)
 	return apply_to_existing_page_range(&init_mm, start, size,
 					    change_page_attr, (void *)action);
 }
+
+/*
+ * Set the attributes of a page:
+ *
+ * This function is used by PPC32 at the end of init to set final kernel memory
+ * protection. It includes changing the maping of the page it is executing from
+ * and data pages it is using.
+ */
+static int set_page_attr(pte_t *ptep, unsigned long addr, void *data)
+{
+	pgprot_t prot = __pgprot((unsigned long)data);
+
+	spin_lock(&init_mm.page_table_lock);
+
+	set_pte_at(&init_mm, addr, ptep, pte_modify(*ptep, prot));
+	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+
+	spin_unlock(&init_mm.page_table_lock);
+
+	return 0;
+}
+
+int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot)
+{
+	unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
+	unsigned long sz = numpages * PAGE_SIZE;
+
+	if (numpages <= 0)
+		return 0;
+
+	return apply_to_existing_page_range(&init_mm, start, sz, set_page_attr,
+					    (void *)pgprot_val(prot));
+}