RE: [PATCH] Correct printk %pF to work on all architectures

James Bottomley
2008-09-09T14:12:45Z

OK, so could we get this in to -rc5 please? It's a bug fix for parisc
since we're currently printing rubbish.

James

---
From: James Bottomley <James.Bottomley@HansenPartnership.com>
Date: Wed, 3 Sep 2008 20:43:36 -0500
Subject: lib: Correct printk %pF to work on all architectures

It was introduced by

commit 0fe1ef24f7bd0020f29ffe287dfdb9ead33ca0b2
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sun Jul 6 16:43:12 2008 -0700

vsprintf: add support for '%pS' and '%pF' pointer formats

However, the current way its coded doesn't work on parisc64. For two
reasons: 1) parisc isn't in the #ifdef and 2) parisc has a different
format for function descriptors

Make dereference_function_descriptor() more accommodating by allowing
architecture overrides. I put the three overrides (for parisc64, ppc64
and ia64) in arch/kernel/module.c because that's where the kernel
internal linker which knows how to deal with function descriptors sits.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Tony Luck <tony.luck@intel.com>
---
arch/ia64/include/asm/sections.h | 3 +++
arch/ia64/kernel/module.c | 12 ++++++++++++
arch/parisc/kernel/module.c | 14 ++++++++++++++
arch/powerpc/include/asm/sections.h | 3 +++
arch/powerpc/kernel/module_64.c | 13 ++++++++++++-
include/asm-generic/sections.h | 6 ++++++
include/asm-parisc/sections.h | 5 +++++
lib/vsprintf.c | 11 +----------
8 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index 7286e4a..a7acad2 100644
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h
@@ -21,5 +21,8 @@ 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[];

+#undef dereference_function_descriptor
+void *dereference_function_descriptor(void *);
+
#endif /* _ASM_IA64_SECTIONS_H */

diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c
index 29aad34..545626f 100644
--- a/arch/ia64/kernel/module.c
+++ b/arch/ia64/kernel/module.c
@@ -31,9 +31,11 @@
#include <linux/elf.h>
#include <linux/moduleloader.h>
#include <linux/string.h>
+#include <linux/uaccess.h>
#include <linux/vmalloc.h>

#include <asm/patch.h>
+#include <asm/sections.h>
#include <asm/unaligned.h>

#define ARCH_MODULE_DEBUG 0
@@ -941,3 +943,13 @@ module_arch_cleanup (struct module *mod)
if (mod->arch.core_unw_table)
unw_remove_unwind_table(mod->arch.core_unw_table);
}
+
+void *dereference_function_descriptor(void *ptr)
+{
+ struct fdesc *desc = ptr;
+ void *p;
+
+ if (!probe_kernel_address(&desc->ip, p))
+ ptr = p;
+ return ptr;
+}
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index fdacdd4..44138c3 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -47,7 +47,9 @@
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/bug.h>
+#include <linux/uaccess.h>

+#include <asm/sections.h>
#include <asm/unwind.h>

#if 0
@@ -860,3 +862,15 @@ void module_arch_cleanup(struct module *mod)
deregister_unwind_table(mod);
module_bug_cleanup(mod);
}
+
+#ifdef CONFIG_64BIT
+void *dereference_function_descriptor(void *ptr)
+{
+ Elf64_Fdesc *desc = ptr;
+ void *p;
+
+ if (!probe_kernel_address(&desc->addr, p))
+ ptr = p;
+ return ptr;
+}
+#endif
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index 916018e..7710e9e 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -16,6 +16,9 @@ static inline int in_kernel_text(unsigned long addr)
return 0;
}

+#undef dereference_function_descriptor
+void *dereference_function_descriptor(void *);
+
#endif

#endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index ee6a298..ad79de2 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -21,8 +21,9 @@
#include <linux/err.h>
#include <linux/vmalloc.h>
#include <linux/bug.h>
+#include <linux/uaccess.h>
#include <asm/module.h>
-#include <asm/uaccess.h>
+#include <asm/sections.h>
#include <asm/firmware.h>
#include <asm/code-patching.h>
#include <linux/sort.h>
@@ -451,3 +452,13 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,

return 0;
}
+
+void *dereference_function_descriptor(void *ptr)
+{
+ struct ppc64_opd_entry *desc = ptr;
+ void *p;
+
+ if (!probe_kernel_address(&desc->funcaddr, p))
+ ptr = p;
+ return ptr;
+}
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 8feeae1..79a7ff9 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -14,4 +14,10 @@ extern char __kprobes_text_start[], __kprobes_text_end[];
extern char __initdata_begin[], __initdata_end[];
extern char __start_rodata[], __end_rodata[];

+/* function descriptor handling (if any). Override
+ * in asm/sections.h */
+#ifndef dereference_function_descriptor
+#define dereference_function_descriptor(p) (p)
+#endif
+
#endif /* _ASM_GENERIC_SECTIONS_H_ */
diff --git a/include/asm-parisc/sections.h b/include/asm-parisc/sections.h
index fdd43ec..9d13c35 100644
--- a/include/asm-parisc/sections.h
+++ b/include/asm-parisc/sections.h
@@ -4,4 +4,9 @@
/* nothing to see, move along */
#include <asm-generic/sections.h>

+#ifdef CONFIG_64BIT
+#undef dereference_function_descriptor
+void *dereference_function_descriptor(void *);
+#endif
+
#endif
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index d8d1d11..c399bc1 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -27,6 +27,7 @@

#include <asm/page.h> /* for PAGE_SIZE */
#include <asm/div64.h>
+#include <asm/sections.h> /* for dereference_function_descriptor() */

/* Works only for digits and letters, but small and fast */
#define TOLOWER(x) ((x) | 0x20)
@@ -513,16 +514,6 @@ static char *string(char *buf, char *end, char *s, int field_width, int precisio
return buf;
}

-static inline void *dereference_function_descriptor(void *ptr)
-{
-#if defined(CONFIG_IA64) || defined(CONFIG_PPC64)
- void *p;
- if (!probe_kernel_address(ptr, p))
- ptr = p;
-#endif
- return ptr;
-}
-
static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int precision, int flags)
{
unsigned long value = (unsigned long) ptr;
--
1.5.5.1