[PATCH 2/5] ia64: Add .opd based function descriptor dereference
From: Sergey Senozhatsky <hidden>
Date: 2017-09-16 03:58:57
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
We are moving towards separate kernel and module function descriptor dereference callbacks. This patch enables it for IA64. For pointers that belong to the kernel - Added __start_opd and __end_opd pointers, to track the kernel .opd section address range; - Added dereference_kernel_function_descriptor(). Now we will dereference only function pointers that are within [__start_opd, __end_opd]; For pointers that belong to a module - Added dereference_module_function_descriptor() to handle module function descriptor dereference. Now we will dereference only pointers that are within [module->opd.start, module->opd.end]. Signed-off-by: Sergey Senozhatsky <redacted> --- arch/ia64/include/asm/sections.h | 14 +++++++++++++- arch/ia64/kernel/module.c | 13 +++++++++++++ arch/ia64/kernel/vmlinux.lds.S | 2 ++ 3 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index 2ab2003698ef..bff3f3535609 100644
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h@@ -25,8 +25,11 @@ extern char __start_gate_fsyscall_patchlist[], __end_gate_fsyscall_patchlist[]; extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_bubble_down_patchlist[]; extern char __start_unwind[], __end_unwind[]; extern char __start_ivt_text[], __end_ivt_text[]; +extern char __start_opd[], __end_opd[]; #undef dereference_function_descriptor +#undef dereference_kernel_function_descriptor + static inline void *dereference_function_descriptor(void *ptr) { struct fdesc *desc = ptr;
@@ -37,6 +40,15 @@ static inline void *dereference_function_descriptor(void *ptr) return ptr; } +static inline void *dereference_kernel_function_descriptor(void *ptr) +{ + /* + * Check if the ptr is a function descriptor and thus needs to + * be dereferenced. + */ + if (ptr < (void *)__start_opd || (void *)__end_opd < ptr) + return ptr; + return dereference_function_descriptor(ptr); +} #endif /* _ASM_IA64_SECTIONS_H */ -
diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c
index d1d945c6bd05..d42f1e19d75d 100644
--- a/arch/ia64/kernel/module.c
+++ b/arch/ia64/kernel/module.c@@ -35,6 +35,7 @@ #include <asm/patch.h> #include <asm/unaligned.h> +#include <asm/sections.h> #define ARCH_MODULE_DEBUG 0
@@ -917,3 +918,15 @@ module_arch_cleanup (struct module *mod) if (mod->arch.core_unw_table) unw_remove_unwind_table(mod->arch.core_unw_table); } + +unsigned long dereference_module_function_descriptor(struct module *mod, + unsigned long addr) +{ + Elf64_Shdr *opd = mod->arch.opd; + + if (addr < opd->sh_addr || + (opd->sh_addr + opd->sh_size) < addr) + return addr; + + return dereference_function_descriptor(addr); +}
diff --git a/arch/ia64/kernel/vmlinux.lds.S b/arch/ia64/kernel/vmlinux.lds.S
index 798026dde52e..f872ba5ff82a 100644
--- a/arch/ia64/kernel/vmlinux.lds.S
+++ b/arch/ia64/kernel/vmlinux.lds.S@@ -107,7 +107,9 @@ SECTIONS { RODATA .opd : AT(ADDR(.opd) - LOAD_OFFSET) { + __start_opd = .; *(.opd) + __end_opd = .; } /*
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2.14.1