ARM: mm: Recreate kernel mappings in early_paging_init()
This patch adds a step in the init sequence, in order to recreate
the kernel code/data page table mappings prior to full paging
initialization. This is necessary on LPAE systems that run out of
a physical address space outside the 4G limit. On these systems,
this implementation provides a machine descriptor hook that allows
the PHYS_OFFSET to be overridden in a machine specific fashion.
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: R Sricharan <r.sricharan@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index b1d17ee..78eeeca 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -28,6 +28,8 @@
#include <asm/highmem.h>
#include <asm/system_info.h>
#include <asm/traps.h>
+#include <asm/procinfo.h>
+#include <asm/memory.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
@@ -1315,6 +1317,86 @@
}
}
+#ifdef CONFIG_ARM_LPAE
+/*
+ * early_paging_init() recreates boot time page table setup, allowing machines
+ * to switch over to a high (>4G) address space on LPAE systems
+ */
+void __init early_paging_init(const struct machine_desc *mdesc,
+ struct proc_info_list *procinfo)
+{
+ pmdval_t pmdprot = procinfo->__cpu_mm_mmu_flags;
+ unsigned long map_start, map_end;
+ pgd_t *pgd0, *pgdk;
+ pud_t *pud0, *pudk, *pud_start;
+ pmd_t *pmd0, *pmdk;
+ phys_addr_t phys;
+ int i;
+
+ if (!(mdesc->init_meminfo))
+ return;
+
+ /* remap kernel code and data */
+ map_start = init_mm.start_code;
+ map_end = init_mm.brk;
+
+ /* get a handle on things... */
+ pgd0 = pgd_offset_k(0);
+ pud_start = pud0 = pud_offset(pgd0, 0);
+ pmd0 = pmd_offset(pud0, 0);
+
+ pgdk = pgd_offset_k(map_start);
+ pudk = pud_offset(pgdk, map_start);
+ pmdk = pmd_offset(pudk, map_start);
+
+ mdesc->init_meminfo();
+
+ /* Run the patch stub to update the constants */
+ fixup_pv_table(&__pv_table_begin,
+ (&__pv_table_end - &__pv_table_begin) << 2);
+
+ /*
+ * Cache cleaning operations for self-modifying code
+ * We should clean the entries by MVA but running a
+ * for loop over every pv_table entry pointer would
+ * just complicate the code.
+ */
+ flush_cache_louis();
+ dsb();
+ isb();
+
+ /* remap level 1 table */
+ for (i = 0; i < PTRS_PER_PGD; pud0++, i++) {
+ set_pud(pud0,
+ __pud(__pa(pmd0) | PMD_TYPE_TABLE | L_PGD_SWAPPER));
+ pmd0 += PTRS_PER_PMD;
+ }
+
+ /* remap pmds for kernel mapping */
+ phys = __pa(map_start) & PMD_MASK;
+ do {
+ *pmdk++ = __pmd(phys | pmdprot);
+ phys += PMD_SIZE;
+ } while (phys < map_end);
+
+ flush_cache_all();
+ cpu_switch_mm(pgd0, &init_mm);
+ cpu_set_ttbr(1, __pa(pgd0) + TTBR1_OFFSET);
+ local_flush_bp_all();
+ local_flush_tlb_all();
+}
+
+#else
+
+void __init early_paging_init(const struct machine_desc *mdesc,
+ struct proc_info_list *procinfo)
+{
+ if (mdesc->init_meminfo)
+ mdesc->init_meminfo();
+}
+
+#endif
+
/*
* paging_init() sets up the page tables, initialises the zone memory
* maps, and sets up the zero page, bad page and bad page tables.