parisc64: Add .opd based function descriptor dereference

We are moving towards separate kernel and module function descriptor
dereference callbacks. This patch enables it for parisc64.

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/20171109234830.5067-5-sergey.senozhatsky@gmail.com
To: Tony Luck <tony.luck@intel.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: Helge Deller <deller@gmx.de> #parisc64
Signed-off-by: Petr Mladek <pmladek@suse.com>

diff --git a/arch/parisc/boot/compressed/vmlinux.lds.S b/arch/parisc/boot/compressed/vmlinux.lds.S
index a4ce3314e78e04a1e47ac977234eee5f731248f2..4ebd4e65524cd3cf6347a2948dede9163a4807b9 100644 (file)
--- a/arch/parisc/boot/compressed/vmlinux.lds.S
+++ b/arch/parisc/boot/compressed/vmlinux.lds.S
@@ -29,7 +29,9 @@ SECTIONS
        . = ALIGN(16);
        /* Linkage tables */
        .opd : {
+               __start_opd = .;
                *(.opd)
+               __end_opd = .;
        } PROVIDE (__gp = .);
        .plt : {
                *(.plt)

diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
index accdf40aa5b7402396a40be069d6c84e04981a69..5a40b51df80ce1f6f5cb331975ca273575db622e 100644 (file)
--- a/arch/parisc/include/asm/sections.h
+++ b/arch/parisc/include/asm/sections.h
@@ -6,8 +6,14 @@
 #include <asm-generic/sections.h>
 
 #ifdef CONFIG_64BIT
+
+#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
+
 #undef dereference_function_descriptor
 void *dereference_function_descriptor(void *);
+
+#undef dereference_kernel_function_descriptor
+void *dereference_kernel_function_descriptor(void *);
 #endif
 
 #endif

diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index f1a76935a3149495c8a65faeee8028295c24e559..b5b3cb00f1fb0f4cb2368812c461a9821350c48f 100644 (file)
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -66,6 +66,7 @@
 
 #include <asm/pgtable.h>
 #include <asm/unwind.h>
+#include <asm/sections.h>
 
 #if 0
 #define DEBUGP printk
@@ -954,3 +955,18 @@ void module_arch_cleanup(struct module *mod)
 {
        deregister_unwind_table(mod);
 }
+
+#ifdef CONFIG_64BIT
+void *dereference_module_function_descriptor(struct module *mod, void *ptr)
+{
+       unsigned long start_opd = (Elf64_Addr)mod->core_layout.base +
+                                  mod->arch.fdesc_offset;
+       unsigned long end_opd = start_opd +
+                               mod->arch.fdesc_count * sizeof(Elf64_Fdesc);
+
+       if (ptr < (void *)start_opd || ptr >= (void *)end_opd)
+               return ptr;
+
+       return dereference_function_descriptor(ptr);
+}
+#endif

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 30f92391a93ef6d5a90970b81921a2133d5e2eb0..6c4585103a912e52babe30258f52d2a56223f7b9 100644 (file)
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -276,6 +276,15 @@ void *dereference_function_descriptor(void *ptr)
                ptr = p;
        return ptr;
 }
+
+void *dereference_kernel_function_descriptor(void *ptr)
+{
+       if (ptr < (void *)__start_opd ||
+                       ptr >= (void *)__end_opd)
+               return ptr;
+
+       return dereference_function_descriptor(ptr);
+}
 #endif
 
 static inline unsigned long brk_rnd(void)

diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index 159a2ec0b4e01f148c1ed6e4c5539abb504ac1b6..da2e31190efa1b98f4975c0be5e4c633e4bc6e87 100644 (file)
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -100,7 +100,9 @@ SECTIONS
        . = ALIGN(16);
        /* Linkage tables */
        .opd : {
+               __start_opd = .;
                *(.opd)
+               __end_opd = .;
        } PROVIDE (__gp = .);
        .plt : {
                *(.plt)