On Thu, 2018-10-04 at 01:27 +0200, Eugene Syromiatnikov wrote:

On Fri, Sep 21, 2018 at 08:03:45AM -0700, Yu-cheng Yu wrote:

[...]

quoted

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 0d157d2a1e2a..5b5f169c5c07 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h

@@ -382,4 +382,9 @@ struct va_alignment {
 
 extern struct va_alignment va_align;
 extern unsigned long align_vdso_addr(unsigned long);
+
+#ifdef CONFIG_ARCH_HAS_PROGRAM_PROPERTIES
+extern int arch_setup_features(void *ehdr, void *phdr, struct file *file,
+			       bool interp);
+#endif
 #endif /* _ASM_X86_ELF_H */

diff --git a/arch/x86/include/uapi/asm/elf_property.h

b/arch/x86/include/uapi/asm/elf_property.h
new file mode 100644
index 000000000000..af361207718c

--- /dev/null
+++ b/arch/x86/include/uapi/asm/elf_property.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _UAPI_ASM_X86_ELF_PROPERTY_H
+#define _UAPI_ASM_X86_ELF_PROPERTY_H
+
+/*
+ * pr_type
+ */
+#define GNU_PROPERTY_X86_FEATURE_1_AND (0xc0000002)
+
+/*
+ * Bits for GNU_PROPERTY_X86_FEATURE_1_AND
+ */
+#define GNU_PROPERTY_X86_FEATURE_1_SHSTK	(0x00000002)

Hm, these defeinitions aren't much different comparing to NT_*
definitions in include/uapi/linux/elf.h, is it expected that those
properties have to be parsed individually for each architecture?

Yes, we have NT_GNU_PROPERTY_TYPE_0 defined in include/uapi/linux/elf.h.
GNU_PROPERTY_X86_FEATURE_1_xxxx is for X86 only.

[...]

There's a lot of similar code with bpf stackmap .build-id code (commit
v4.17-rc1~148^2~156^2~3^2~1), it might be worthy generalising some ELF
traversal routines, since there's general need of parsing ELF property
segments.

Only a small similarity exists.  The routine find_note_type_0() does a lot more
validation.  It appears stack_map_get_build_id() does not need that.

Yu-cheng