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Subject[PATCHv3 5/7] parisc64: Add .opd based function descriptor dereference
Date
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].

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Tested-by: Helge Deller <deller@gmx.de> # parisc64
Tested-by: Santosh Sivaraj <santosh@fossix.org> # powerpc64
Acked-by: Michael Ellerman <mpe@ellerman.id.au> # powerpc64
Tested-by: Tony Luck <tony.luck@intel.com> # ia64
---
arch/parisc/boot/compressed/vmlinux.lds.S | 2 ++
arch/parisc/include/asm/sections.h | 2 ++
arch/parisc/kernel/module.c | 17 +++++++++++++++++
arch/parisc/kernel/process.c | 9 +++++++++
arch/parisc/kernel/vmlinux.lds.S | 2 ++
5 files changed, 32 insertions(+)

diff --git a/arch/parisc/boot/compressed/vmlinux.lds.S b/arch/parisc/boot/compressed/vmlinux.lds.S
index a4ce3314e78e..4ebd4e65524c 100644
--- 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 59fbe0067112..845ddc9a3421 100644
--- a/arch/parisc/include/asm/sections.h
+++ b/arch/parisc/include/asm/sections.h
@@ -7,6 +7,8 @@
#ifdef CONFIG_64BIT
#undef dereference_function_descriptor
unsigned long dereference_function_descriptor(unsigned long);
+#undef dereference_kernel_function_descriptor
+unsigned long dereference_kernel_function_descriptor(unsigned long);
#endif

#endif
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index f1a76935a314..28f89b3dcc11 100644
--- 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 +955,19 @@ void module_arch_cleanup(struct module *mod)
{
deregister_unwind_table(mod);
}
+
+#ifdef CONFIG_64BIT
+unsigned long dereference_module_function_descriptor(struct module *mod,
+ unsigned long addr)
+{
+ 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 (addr < start_opd || addr >= end_opd)
+ return addr;
+
+ return dereference_function_descriptor(addr);
+}
+#endif
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index d350aa913acc..423bbfe90e2b 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -276,6 +276,15 @@ unsigned long dereference_function_descriptor(unsigned long ptr)
ptr = (unsigned long)p;
return ptr;
}
+
+unsigned long dereference_kernel_function_descriptor(unsigned long addr)
+{
+ if (addr < (unsigned long)__start_opd ||
+ addr >= (unsigned long)__end_opd)
+ return addr;
+
+ return dereference_function_descriptor(addr);
+}
#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 ffe2cbf52d1a..ab030895dd1e 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -99,7 +99,9 @@ SECTIONS
. = ALIGN(16);
/* Linkage tables */
.opd : {
+ __start_opd = .;
*(.opd)
+ __end_opd = .;
} PROVIDE (__gp = .);
.plt : {
*(.plt)
--
2.14.2
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