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csky: Support dynamic start physical address
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Before this patch csky-linux need CONFIG_RAM_BASE to determine start
physical address. Now we use phys_offset variable to replace the macro
of PHYS_OFFSET and we setup phys_offset with real physical address which
is determined during startup in head.S.

With this patch we needn't re-compile kernel for different start
physical address. ie: 0x0 / 0xc0000000 start physical address could use
the same vmlinux, be care different start address must be 512MB aligned.

Signed-off-by: Guo Ren <[email protected]>
Cc: Arnd Bergmann <[email protected]>
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@guoren83
guoren83 committed Apr 22, 2019
1 parent bf24168 commit f62e316
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Showing 8 changed files with 106 additions and 31 deletions.
20 changes: 20 additions & 0 deletions arch/csky/abiv1/inc/abi/ckmmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,26 @@ static inline void write_mmu_entryhi(int value)
cpwcr("cpcr4", value);
}

static inline unsigned long read_mmu_msa0(void)
{
return cprcr("cpcr30");
}

static inline void write_mmu_msa0(unsigned long value)
{
cpwcr("cpcr30", value);
}

static inline unsigned long read_mmu_msa1(void)
{
return cprcr("cpcr31");
}

static inline void write_mmu_msa1(unsigned long value)
{
cpwcr("cpcr31", value);
}

/*
* TLB operations.
*/
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19 changes: 17 additions & 2 deletions arch/csky/abiv1/inc/abi/entry.h
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Original file line number Diff line number Diff line change
Expand Up @@ -144,9 +144,24 @@
.endm

.macro SETUP_MMU rx
lrw \rx, PHYS_OFFSET | 0xe
/* Select MMU as co-processor */
cpseti cp15

/*
* cpcr30 format:
* 31 - 29 | 28 - 4 | 3 | 2 | 1 | 0
* BA Reserved C D V
*/
cprcr \rx, cpcr30
lsri \rx, 28
lsli \rx, 28
addi \rx, 0xe
cpwcr \rx, cpcr30
lrw \rx, (PHYS_OFFSET + 0x20000000) | 0xe

lsri \rx, 28
addi \rx, 2
lsli \rx, 28
addi \rx, 0xe
cpwcr \rx, cpcr31
.endm

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20 changes: 20 additions & 0 deletions arch/csky/abiv2/inc/abi/ckmmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,26 @@ static inline void write_mmu_entryhi(int value)
mtcr("cr<4, 15>", value);
}

static inline unsigned long read_mmu_msa0(void)
{
return mfcr("cr<30, 15>");
}

static inline void write_mmu_msa0(unsigned long value)
{
mtcr("cr<30, 15>", value);
}

static inline unsigned long read_mmu_msa1(void)
{
return mfcr("cr<31, 15>");
}

static inline void write_mmu_msa1(unsigned long value)
{
mtcr("cr<31, 15>", value);
}

/*
* TLB operations.
*/
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24 changes: 22 additions & 2 deletions arch/csky/abiv2/inc/abi/entry.h
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Original file line number Diff line number Diff line change
Expand Up @@ -163,9 +163,29 @@
.endm

.macro SETUP_MMU rx
lrw \rx, PHYS_OFFSET | 0xe
/* Check MMU on | off */
mfcr \rx, cr18
btsti \rx, 0
bt 1f
grs \rx, 1f
br 2f
1:
/*
* cr<30, 15> format:
* 31 - 29 | 28 - 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
* BA Reserved SH WA B SO SEC C D V
*/
mfcr \rx, cr<30, 15>
2:
lsri \rx, 28
lsli \rx, 28
addi \rx, 0x1ce
mtcr \rx, cr<30, 15>
lrw \rx, (PHYS_OFFSET + 0x20000000) | 0xe

lsri \rx, 28
addi \rx, 2
lsli \rx, 28
addi \rx, 0x1ce
mtcr \rx, cr<31, 15>
.endm

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4 changes: 2 additions & 2 deletions arch/csky/include/asm/mmu_context.h
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
static inline void tlbmiss_handler_setup_pgd(unsigned long pgd, bool kernel)
{
pgd -= PAGE_OFFSET;
pgd += PHYS_OFFSET;
pgd += phys_offset;
pgd |= 1;
setup_pgd(pgd, kernel);
}
Expand All @@ -29,7 +29,7 @@ static inline void tlbmiss_handler_setup_pgd(unsigned long pgd, bool kernel)

static inline unsigned long tlb_get_pgd(void)
{
return ((get_pgd() - PHYS_OFFSET) & ~1) + PAGE_OFFSET;
return ((get_pgd() - phys_offset) & ~1) + PAGE_OFFSET;
}

#define cpu_context(cpu, mm) ((mm)->context.asid[cpu])
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39 changes: 16 additions & 23 deletions arch/csky/include/asm/page.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@
#include <linux/const.h>

/*
* PAGE_SHIFT determines the page size
* PAGE_SHIFT determines the page size: 4KB
*/
#define PAGE_SHIFT 12
#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
Expand All @@ -17,12 +17,18 @@
#define THREAD_MASK (~(THREAD_SIZE - 1))
#define THREAD_SHIFT (PAGE_SHIFT + 1)


/*
* NOTE: virtual isn't really correct, actually it should be the offset into the
* memory node, but we have no highmem, so that works for now.
* TODO: implement (fast) pfn<->pgdat_idx conversion functions, this makes lots
* of the shifts unnecessary.
* For C-SKY "User-space:Kernel-space" is "2GB:2GB" fixed by hardware and there
* are two segment registers (MSA0 + MSA1) to mapping 512MB + 512MB physical
* address region. We use them mapping kernel 1GB direct-map address area and
* for more than 1GB of memory we use highmem.
*/
#define PAGE_OFFSET 0x80000000
#define SSEG_SIZE 0x20000000
#define LOWMEM_LIMIT (SSEG_SIZE * 2)

#define PHYS_OFFSET_OFFSET (CONFIG_RAM_BASE & (SSEG_SIZE - 1))

#ifndef __ASSEMBLY__

Expand Down Expand Up @@ -50,9 +56,6 @@ struct page;

struct vm_area_struct;

/*
* These are used to make use of C type-checking..
*/
typedef struct { unsigned long pte_low; } pte_t;
#define pte_val(x) ((x).pte_low)

Expand All @@ -69,18 +72,13 @@ typedef struct page *pgtable_t;
#define __pgd(x) ((pgd_t) { (x) })
#define __pgprot(x) ((pgprot_t) { (x) })

#endif /* !__ASSEMBLY__ */

#define PHYS_OFFSET (CONFIG_RAM_BASE & ~(LOWMEM_LIMIT - 1))
#define PHYS_OFFSET_OFFSET (CONFIG_RAM_BASE & (LOWMEM_LIMIT - 1))
#define ARCH_PFN_OFFSET PFN_DOWN(CONFIG_RAM_BASE)
extern unsigned long phys_offset;

#define PAGE_OFFSET 0x80000000
#define LOWMEM_LIMIT 0x40000000
#define ARCH_PFN_OFFSET PFN_DOWN(phys_offset + PHYS_OFFSET_OFFSET)

#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + PHYS_OFFSET)
#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + phys_offset)
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - \
PHYS_OFFSET))
phys_offset))
#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0))

#define MAP_NR(x) PFN_DOWN((unsigned long)(x) - PAGE_OFFSET - \
Expand All @@ -90,15 +88,10 @@ typedef struct page *pgtable_t;
#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)

/*
* main RAM and kernel working space are coincident at 0x80000000, but to make
* life more interesting, there's also an uncached virtual shadow at 0xb0000000
* - these mappings are fixed in the MMU
*/

#define pfn_to_kaddr(x) __va(PFN_PHYS(x))

#include <asm-generic/memory_model.h>
#include <asm-generic/getorder.h>

#endif /* !__ASSEMBLY__ */
#endif /* __ASM_CSKY_PAGE_H */
6 changes: 4 additions & 2 deletions arch/csky/kernel/entry.S
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,8 @@ ENTRY(csky_\name)
WR_MCIR a2
#endif
bclri r6, 0
lrw a2, PHYS_OFFSET
lrw a2, phys_offset
ld.w a2, (a2, 0)
subu r6, a2
bseti r6, 31

Expand All @@ -50,7 +51,8 @@ ENTRY(csky_\name)
addu r6, a2
ldw r6, (r6)

lrw a2, PHYS_OFFSET
lrw a2, phys_offset
ld.w a2, (a2, 0)
subu r6, a2
bseti r6, 31

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5 changes: 5 additions & 0 deletions arch/csky/kernel/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -142,11 +142,16 @@ void __init setup_arch(char **cmdline_p)
#endif
}

unsigned long phys_offset;
EXPORT_SYMBOL(phys_offset);

asmlinkage __visible void __init csky_start(unsigned int unused, void *param)
{
/* Clean up bss section */
memset(__bss_start, 0, __bss_stop - __bss_start);

phys_offset = read_mmu_msa0() & ~(SSEG_SIZE - 1);

pre_trap_init();
pre_mmu_init();

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