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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-11-03 10:12:13 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-11-03 10:12:13 +0000
commit06e944b8e5fc4bec83f102f98c1ee4f972f5f072 (patch)
treed53b1c3ca270f49f1cae63bbe117cc8587e51510 /arch/arm/mm/init.c
parentf114040e3ea6e07372334ade75d1ee0775c355e1 (diff)
parent80d6b0c2eed2a504f6740cd1f5ea76dc50abfc4d (diff)
downloadblackbird-op-linux-06e944b8e5fc4bec83f102f98c1ee4f972f5f072.tar.gz
blackbird-op-linux-06e944b8e5fc4bec83f102f98c1ee4f972f5f072.zip
Merge tag 'ronx-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into devel-stable
generic fixmaps ARM support for CONFIG_DEBUG_RODATA
Diffstat (limited to 'arch/arm/mm/init.c')
-rw-r--r--arch/arm/mm/init.c149
1 files changed, 147 insertions, 2 deletions
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 92bba32d9230..67b15426b9c6 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -29,6 +29,7 @@
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/setup.h>
+#include <asm/system_info.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>
@@ -570,7 +571,7 @@ void __init mem_init(void)
MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
MLK(ITCM_OFFSET, (unsigned long) itcm_end),
#endif
- MLK(FIXADDR_START, FIXADDR_TOP),
+ MLK(FIXADDR_START, FIXADDR_END),
MLM(VMALLOC_START, VMALLOC_END),
MLM(PAGE_OFFSET, (unsigned long)high_memory),
#ifdef CONFIG_HIGHMEM
@@ -615,7 +616,145 @@ void __init mem_init(void)
}
}
-void free_initmem(void)
+#ifdef CONFIG_ARM_KERNMEM_PERMS
+struct section_perm {
+ unsigned long start;
+ unsigned long end;
+ pmdval_t mask;
+ pmdval_t prot;
+ pmdval_t clear;
+};
+
+static struct section_perm nx_perms[] = {
+ /* Make pages tables, etc before _stext RW (set NX). */
+ {
+ .start = PAGE_OFFSET,
+ .end = (unsigned long)_stext,
+ .mask = ~PMD_SECT_XN,
+ .prot = PMD_SECT_XN,
+ },
+ /* Make init RW (set NX). */
+ {
+ .start = (unsigned long)__init_begin,
+ .end = (unsigned long)_sdata,
+ .mask = ~PMD_SECT_XN,
+ .prot = PMD_SECT_XN,
+ },
+#ifdef CONFIG_DEBUG_RODATA
+ /* Make rodata NX (set RO in ro_perms below). */
+ {
+ .start = (unsigned long)__start_rodata,
+ .end = (unsigned long)__init_begin,
+ .mask = ~PMD_SECT_XN,
+ .prot = PMD_SECT_XN,
+ },
+#endif
+};
+
+#ifdef CONFIG_DEBUG_RODATA
+static struct section_perm ro_perms[] = {
+ /* Make kernel code and rodata RX (set RO). */
+ {
+ .start = (unsigned long)_stext,
+ .end = (unsigned long)__init_begin,
+#ifdef CONFIG_ARM_LPAE
+ .mask = ~PMD_SECT_RDONLY,
+ .prot = PMD_SECT_RDONLY,
+#else
+ .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
+ .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
+ .clear = PMD_SECT_AP_WRITE,
+#endif
+ },
+};
+#endif
+
+/*
+ * Updates section permissions only for the current mm (sections are
+ * copied into each mm). During startup, this is the init_mm. Is only
+ * safe to be called with preemption disabled, as under stop_machine().
+ */
+static inline void section_update(unsigned long addr, pmdval_t mask,
+ pmdval_t prot)
+{
+ struct mm_struct *mm;
+ pmd_t *pmd;
+
+ mm = current->active_mm;
+ pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
+
+#ifdef CONFIG_ARM_LPAE
+ pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
+#else
+ if (addr & SECTION_SIZE)
+ pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
+ else
+ pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
+#endif
+ flush_pmd_entry(pmd);
+ local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
+}
+
+/* Make sure extended page tables are in use. */
+static inline bool arch_has_strict_perms(void)
+{
+ if (cpu_architecture() < CPU_ARCH_ARMv6)
+ return false;
+
+ return !!(get_cr() & CR_XP);
+}
+
+#define set_section_perms(perms, field) { \
+ size_t i; \
+ unsigned long addr; \
+ \
+ if (!arch_has_strict_perms()) \
+ return; \
+ \
+ for (i = 0; i < ARRAY_SIZE(perms); i++) { \
+ if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) || \
+ !IS_ALIGNED(perms[i].end, SECTION_SIZE)) { \
+ pr_err("BUG: section %lx-%lx not aligned to %lx\n", \
+ perms[i].start, perms[i].end, \
+ SECTION_SIZE); \
+ continue; \
+ } \
+ \
+ for (addr = perms[i].start; \
+ addr < perms[i].end; \
+ addr += SECTION_SIZE) \
+ section_update(addr, perms[i].mask, \
+ perms[i].field); \
+ } \
+}
+
+static inline void fix_kernmem_perms(void)
+{
+ set_section_perms(nx_perms, prot);
+}
+
+#ifdef CONFIG_DEBUG_RODATA
+void mark_rodata_ro(void)
+{
+ set_section_perms(ro_perms, prot);
+}
+
+void set_kernel_text_rw(void)
+{
+ set_section_perms(ro_perms, clear);
+}
+
+void set_kernel_text_ro(void)
+{
+ set_section_perms(ro_perms, prot);
+}
+#endif /* CONFIG_DEBUG_RODATA */
+
+#else
+static inline void fix_kernmem_perms(void) { }
+#endif /* CONFIG_ARM_KERNMEM_PERMS */
+
+void free_tcmmem(void)
{
#ifdef CONFIG_HAVE_TCM
extern char __tcm_start, __tcm_end;
@@ -623,6 +762,12 @@ void free_initmem(void)
poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
#endif
+}
+
+void free_initmem(void)
+{
+ fix_kernmem_perms();
+ free_tcmmem();
poison_init_mem(__init_begin, __init_end - __init_begin);
if (!machine_is_integrator() && !machine_is_cintegrator())
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