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a257cacc38
Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of 'dereference_function_descriptor' macro to know whether an arch has function descriptors. To limit churn in one of the following patches, use an #ifdef/#else construct with empty first part instead of an #ifndef in asm-generic/sections.h On powerpc, make sure the config option matches the ABI used by the compiler with a BUILD_BUG_ON() and add missing _CALL_ELF=2 when calling 'sparse' so that sparse sees the same piece of code as GCC. And include a helper to check whether an arch has function descriptors or not : have_function_descriptors() Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/4a0f11fb0ea74a3197bc44dd7ba25e53a24fd03d.1644928018.git.christophe.leroy@csgroup.eu
83 lines
1.8 KiB
C
83 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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 <linux/elf.h>
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#include <linux/uaccess.h>
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#include <asm-generic/sections.h>
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extern char __head_end[];
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#ifdef __powerpc64__
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extern char __start_interrupts[];
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extern char __end_interrupts[];
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extern char __prom_init_toc_start[];
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extern char __prom_init_toc_end[];
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#ifdef CONFIG_PPC_POWERNV
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extern char start_real_trampolines[];
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extern char end_real_trampolines[];
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extern char start_virt_trampolines[];
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extern char end_virt_trampolines[];
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#endif
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/*
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* This assumes the kernel is never compiled -mcmodel=small or
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* the total .toc is always less than 64k.
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*/
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static inline unsigned long kernel_toc_addr(void)
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{
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unsigned long toc_ptr;
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asm volatile("mr %0, 2" : "=r" (toc_ptr));
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return toc_ptr;
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}
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static inline int overlaps_interrupt_vector_text(unsigned long start,
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unsigned long end)
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{
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unsigned long real_start, real_end;
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real_start = __start_interrupts - _stext;
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real_end = __end_interrupts - _stext;
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return start < (unsigned long)__va(real_end) &&
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(unsigned long)__va(real_start) < end;
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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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#ifdef PPC64_ELF_ABI_v1
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#undef dereference_function_descriptor
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static inline void *dereference_function_descriptor(void *ptr)
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{
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struct func_desc *desc = ptr;
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void *p;
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if (!get_kernel_nofault(p, (void *)&desc->addr))
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ptr = p;
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return ptr;
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}
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#undef dereference_kernel_function_descriptor
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static inline void *dereference_kernel_function_descriptor(void *ptr)
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{
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if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
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return ptr;
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return dereference_function_descriptor(ptr);
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}
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#endif /* PPC64_ELF_ABI_v1 */
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_SECTIONS_H */
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