[tip: x86/cleanups] elf: Expose ELF header on arch_setup_additional_pages()

[tip-bot2 for Gabriel Krisman Bertazi]

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     9a29a671902c2be05d636045a4dd365219ca716c
Gitweb:        https://git.kernel.org/tip/9a29a671902c2be05d636045a4dd365219ca716c
Author:        Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
AuthorDate:    Sat, 03 Oct 2020 23:25:33 -04:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 26 Oct 2020 13:46:47 +01:00

elf: Expose ELF header on arch_setup_additional_pages()

Like it is done for SET_PERSONALITY with ARM, which requires the ELF
header to select correct personality parameters, x86 requires the
headers when selecting which VDSO to load, instead of relying on the
going-away TIF_IA32/X32 flags.

Add an indirection macro to arch_setup_additional_pages(), that x86 can
reimplement to receive the extra parameter just for ELF files.  This
requires no changes to other architectures, who can continue to use the
original arch_setup_additional_pages for ELF and non-ELF binaries.

Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20201004032536.1229030-8-krisman@xxxxxxxxxxxxx

---
 fs/binfmt_elf.c        |  2 +-
 fs/compat_binfmt_elf.c | 11 ++++++++---
 include/linux/elf.h    |  5 +++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index b23f755..aabc11f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1246,7 +1246,7 @@ out_free_interp:
 	set_binfmt(&elf_format);
 
 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
-	retval = arch_setup_additional_pages(bprm, !!interpreter);
+	retval = ARCH_SETUP_ADDITIONAL_PAGES(bprm, elf_ex, !!interpreter);
 	if (retval < 0)
 		goto out;
 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c
index 12b9913..2c55722 100644
--- a/fs/compat_binfmt_elf.c
+++ b/fs/compat_binfmt_elf.c
@@ -115,11 +115,16 @@
 #define START_THREAD		COMPAT_START_THREAD
 #endif
 
-#ifdef	compat_arch_setup_additional_pages
+#ifdef compat_arch_setup_additional_pages
+#define COMPAT_ARCH_SETUP_ADDITIONAL_PAGES(bprm, ex, interpreter) \
+	compat_arch_setup_additional_pages(bprm, interpreter)
+#endif
+
+#ifdef	COMPAT_ARCH_SETUP_ADDITIONAL_PAGES
 #undef	ARCH_HAS_SETUP_ADDITIONAL_PAGES
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
-#undef	arch_setup_additional_pages
-#define	arch_setup_additional_pages compat_arch_setup_additional_pages
+#undef	ARCH_SETUP_ADDITIONAL_PAGES
+#define	ARCH_SETUP_ADDITIONAL_PAGES COMPAT_ARCH_SETUP_ADDITIONAL_PAGES
 #endif
 
 #ifdef	compat_elf_read_implies_exec
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 6dbcfe7..c9a46c4 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -27,6 +27,11 @@
 	start_thread(regs, elf_entry, start_stack)
 #endif
 
+#if defined(ARCH_HAS_SETUP_ADDITIONAL_PAGES) && !defined(ARCH_SETUP_ADDITIONAL_PAGES)
+#define ARCH_SETUP_ADDITIONAL_PAGES(bprm, ex, interpreter) \
+	arch_setup_additional_pages(bprm, interpreter)
+#endif
+
 #define ELF32_GNU_PROPERTY_ALIGN	4
 #define ELF64_GNU_PROPERTY_ALIGN	8