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ARCv3: Allow for flexible link base #117

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ARCv3: Allow for flexible link base #117

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8 changes: 5 additions & 3 deletions arch/arc/include/asm/page.h
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Original file line number Diff line number Diff line change
Expand Up @@ -31,12 +31,14 @@
/*
* TODO: Only one kernel-user split for each MMU currently supported.
*/
#define PAGE_OFFSET_SHIFT (CONFIG_LINUX_LINK_BASE - CONFIG_LINUX_RAM_BASE)

#if defined(CONFIG_ARC_MMU_V6_48)
#define PAGE_OFFSET _AC(0xffff000000000000, UL)
#define PAGE_OFFSET (_AC(0xffff000000000000, UL) + PAGE_OFFSET_SHIFT)
#elif defined(CONFIG_ARC_MMU_V6_52)
#define PAGE_OFFSET _AC(0xfff0000000000000, UL)
#define PAGE_OFFSET (_AC(0xfff0000000000000, UL) + PAGE_OFFSET_SHIFT)
#else
#define PAGE_OFFSET _AC(0x80000000, UL) /* Kernel starts at 2G onwrds */
#define PAGE_OFFSET (_AC(0x80000000, UL) + PAGE_OFFSET_SHIFT) /* Kernel starts at 2G onwrds */
#endif

#define PAGE_MASK (~(PAGE_SIZE-1))
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16 changes: 11 additions & 5 deletions arch/arc/mm/tlb-arcv3.c
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Original file line number Diff line number Diff line change
Expand Up @@ -338,10 +338,11 @@ int __init arc_map_memory_in_mm(struct mm_struct *mm)

/*
* Kernel (__pa(PAGE_OFFSET) to __pa(_end) is already mapped by
* arc_map_kernel_in_mm(), so map only >= __pa(_end).
* arc_map_kernel_in_mm(), let's maping also for 'addr < __pa(PAGE_OFFSET)'
* and 'addr >= __pa(_end)'.
*
* We expect that kernel is mapped to the start of physical memory,
* so start >= __pa(PAGE_OFFSET).
* Since we don't expect that kernel is always mapped to the start of physical
* memory, then we also need to map a hole between start and CONFIG_LINUX_LINK_BASE.
*/
for_each_mem_range(i, &start, &end) {
if (start >= end)
Expand All @@ -350,6 +351,13 @@ int __init arc_map_memory_in_mm(struct mm_struct *mm)
if (end <= __pa(_end))
continue;

if (start < CONFIG_LINUX_LINK_BASE) {
arc_map_segment_in_mm(mm,
(unsigned long)__va(start),
PAGE_OFFSET,
PAGE_KERNEL_RW);
}

if (start < __pa(_end))
start = __pa(_end);

Expand Down Expand Up @@ -380,8 +388,6 @@ void __init arc_mmu_init(void)
* Make sure that early mapping does not need more then one struct
* per level (pgd/pud/pmd).
*/
/* It is always true when PAGE_OFFSET is aligned to pmd. */
BUILD_BUG_ON(pmd_index(PAGE_OFFSET) != 0);

if (mmuinfo.pg_sz_k != TO_KB(PAGE_SIZE))
panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
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