Thread (38 messages) 38 messages, 5 authors, 2021-10-14

Re: [PATCH v1 05/10] asm-generic: Define 'funct_descr_t' to commonly describe function descriptors

From: Kees Cook <hidden>
Date: 2021-10-13 07:01:53
Also in: linux-mm, linuxppc-dev, lkml

On Mon, Oct 11, 2021 at 05:25:32PM +0200, Christophe Leroy wrote:
We have three architectures using function descriptors, each with its
own name.

Add a common typedef that can be used in generic code.

Also add a stub typedef for architecture without function descriptors,
nit: funct_descr_t reads weird to me. why not func_desc_t ? Either way:

Reviewed-by: Kees Cook <redacted>

quoted hunk ↗ jump to hunk
to avoid a forest of #ifdefs.

Signed-off-by: Christophe Leroy <redacted>
---
 arch/ia64/include/asm/sections.h    | 1 +
 arch/parisc/include/asm/sections.h  | 1 +
 arch/powerpc/include/asm/sections.h | 1 +
 include/asm-generic/sections.h      | 3 +++
 4 files changed, 6 insertions(+)
diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index 80f5868afb06..929b5c535620 100644
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h
@@ -8,6 +8,7 @@
  */
 
 #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
+typedef struct fdesc funct_descr_t;
 
 #include <linux/elf.h>
 #include <linux/uaccess.h>
diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
index 2e781ee19b66..329e80f7af0a 100644
--- a/arch/parisc/include/asm/sections.h
+++ b/arch/parisc/include/asm/sections.h
@@ -4,6 +4,7 @@
 
 #ifdef CONFIG_64BIT
 #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
+typedef Elf64_Fdesc funct_descr_t;
 #endif
 
 /* nothing to see, move along */
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index b7f1ba04e756..d0d5287fa568 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -10,6 +10,7 @@
 
 #ifdef PPC64_ELF_ABI_v1
 #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
+typedef struct ppc64_opd_entry funct_descr_t;
 #endif
 
 #include <asm-generic/sections.h>
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 1db5cfd69817..436412d94054 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -63,6 +63,9 @@ extern __visible const void __nosave_begin, __nosave_end;
 #else
 #define dereference_function_descriptor(p) ((void *)(p))
 #define dereference_kernel_function_descriptor(p) ((void *)(p))
+typedef struct {
+	unsigned long addr;
+} funct_descr_t;
 #endif
 
 /* random extra sections (if any).  Override
-- 
2.31.1
-- 
Kees Cook
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