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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 <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Guo Ren
2019-04-08 11:12:25 +08:00
parent bf24168293
commit f62e31623d
8 changed files with 106 additions and 31 deletions
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6
arch/csky/kernel/entry.S
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@@ -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
@@ -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

5
arch/csky/kernel/setup.c
View File

@@ -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();