549e8152de
This implements CONFIG_RELOCATABLE for 64-bit by making the kernel as a position-independent executable (PIE) when it is set. This involves processing the dynamic relocations in the image in the early stages of booting, even if the kernel is being run at the address it is linked at, since the linker does not necessarily fill in words in the image for which there are dynamic relocations. (In fact the linker does fill in such words for 64-bit executables, though not for 32-bit executables, so in principle we could avoid calling relocate() entirely when we're running a 64-bit kernel at the linked address.) The dynamic relocations are processed by a new function relocate(addr), where the addr parameter is the virtual address where the image will be run. In fact we call it twice; once before calling prom_init, and again when starting the main kernel. This means that reloc_offset() returns 0 in prom_init (since it has been relocated to the address it is running at), which necessitated a few adjustments. This also changes __va and __pa to use an equivalent definition that is simpler. With the relocatable kernel, PAGE_OFFSET and MEMORY_START are constants (for 64-bit) whereas PHYSICAL_START is a variable (and KERNELBASE ideally should be too, but isn't yet). With this, relocatable kernels still copy themselves down to physical address 0 and run there. Signed-off-by: Paul Mackerras <paulus@samba.org>
32 lines
631 B
C
32 lines
631 B
C
#ifndef _ASM_POWERPC_SECTIONS_H
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#define _ASM_POWERPC_SECTIONS_H
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#ifdef __KERNEL__
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#include <asm-generic/sections.h>
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#ifdef __powerpc64__
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extern char _end[];
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static inline int in_kernel_text(unsigned long addr)
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{
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if (addr >= (unsigned long)_stext && addr < (unsigned long)__init_end)
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return 1;
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return 0;
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}
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static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
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{
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return start < (unsigned long)__init_end &&
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(unsigned long)_stext < end;
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}
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#undef dereference_function_descriptor
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void *dereference_function_descriptor(void *);
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_SECTIONS_H */
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