ia64: Add .opd based function descriptor dereference

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).

Link: http://lkml.kernel.org/r/20171109234830.5067-3-sergey.senozhatsky@gmail.com
To: Fenghua Yu <fenghua.yu@intel.com>
To: Helge Deller <deller@gmx.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Paul Mackerras <paulus@samba.org>
To: Michael Ellerman <mpe@ellerman.id.au>
To: James Bottomley <jejb@parisc-linux.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Tony Luck <tony.luck@intel.com> #ia64
Signed-off-by: Petr Mladek <pmladek@suse.com>

diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index f3481408594e029b5bbac1c1cd117384ae07725c..cea15f2dd38df7556bd054fdf18024ccaac29608 100644 (file)
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h
@@ -27,6 +27,8 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b
 extern char __start_unwind[], __end_unwind[];
 extern char __start_ivt_text[], __end_ivt_text[];
 
+#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
+
 #undef dereference_function_descriptor
 static inline void *dereference_function_descriptor(void *ptr)
 {
@@ -38,6 +40,12 @@ static inline void *dereference_function_descriptor(void *ptr)
        return ptr;
 }
 
+#undef dereference_kernel_function_descriptor
+static inline void *dereference_kernel_function_descriptor(void *ptr)
+{
+       if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
+               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 853b5611a894d5a2770606f983782ea1a9a6dbc5..326448f9df16068392e49af096afd1c8b2713131 100644 (file)
--- a/arch/ia64/kernel/module.c
+++ b/arch/ia64/kernel/module.c
@@ -36,6 +36,7 @@
 
 #include <asm/patch.h>
 #include <asm/unaligned.h>
+#include <asm/sections.h>
 
 #define ARCH_MODULE_DEBUG 0
 
@@ -918,3 +919,14 @@ module_arch_cleanup (struct module *mod)
        if (mod->arch.core_unw_table)
                unw_remove_unwind_table(mod->arch.core_unw_table);
 }
+
+void *dereference_module_function_descriptor(struct module *mod, void *ptr)
+{
+       Elf64_Shdr *opd = mod->arch.opd;
+
+       if (ptr < (void *)opd->sh_addr ||
+                       ptr >= (void *)(opd->sh_addr + opd->sh_size))
+               return ptr;
+
+       return dereference_function_descriptor(ptr);
+}

diff --git a/arch/ia64/kernel/vmlinux.lds.S b/arch/ia64/kernel/vmlinux.lds.S
index 58db59da0bd87042c8d0d457a77268f7b043e40f..31e688981b4b7b4945428e1167b351c4ac578800 100644 (file)
--- a/arch/ia64/kernel/vmlinux.lds.S
+++ b/arch/ia64/kernel/vmlinux.lds.S
@@ -108,7 +108,9 @@ SECTIONS {
        RODATA
 
        .opd : AT(ADDR(.opd) - LOAD_OFFSET) {
+               __start_opd = .;
                *(.opd)
+               __end_opd = .;
        }
 
        /*