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Subject[PATCHv4 4/6] 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>
---
arch/parisc/boot/compressed/vmlinux.lds.S | 2 ++
arch/parisc/include/asm/sections.h | 6 ++++++
arch/parisc/kernel/module.c | 16 ++++++++++++++++
arch/parisc/kernel/process.c | 9 +++++++++
arch/parisc/kernel/vmlinux.lds.S | 2 ++
5 files changed, 35 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 accdf40aa5b7..5a40b51df80c 100644
--- 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 f1a76935a314..b5b3cb00f1fb 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 +955,18 @@ 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 30f92391a93e..6c4585103a91 100644
--- 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 159a2ec0b4e0..da2e31190efa 100644
--- 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)
--
2.15.0
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