FROMLIST: BACKPORT: [PATCH 2/6] arm64: elf: Set AT_SYSINFO_EHDR in co…

…mpat processes

(cherry pick from url https://patchwork.kernel.org/patch/10060431/)

If the compat vDSO is enabled, we need to set AT_SYSINFO_EHDR in the
auxiliary vector of compat processes to the address of the vDSO code
page, so that the dynamic linker can find it (just like the regular vDSO).

Note that we cast context.vdso to Elf64_Off, instead of elf_addr_t,
because elf_addr_t is Elf32_Off in compat_binfmt_elf.c, and casting
context.vdso to u32 would trigger a pointer narrowing warning.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Bug: 63737556
Bug: 20045882
Orig-Change-Id: I5d0b191d3b2f4c0b2ec31fe9faef0246253635ce
Change-Id: I263cec90507c7193c114237d78a34dc5eef3c3b0
Signed-off-by: khusika <khusikadhamar@gmail.com>

arch/arm64/include/asm/elf.h

@@ -137,11 +137,12 @@ typedef struct user_fpsimd_state elf_fpregset_t;
 
 #define SET_PERSONALITY(ex)		clear_thread_flag(TIF_32BIT);
 
-#define ARCH_DLINFO							\
+#define _SET_AUX_ENT_VDSO						\
 do {									\
 	NEW_AUX_ENT(AT_SYSINFO_EHDR,					\
-		    (elf_addr_t)current->mm->context.vdso);		\
+		    (Elf64_Off)current->mm->context.vdso);		\
 } while (0)
+#define ARCH_DLINFO _SET_AUX_ENT_VDSO
 
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES
 struct linux_binprm;
@@ -187,7 +188,11 @@ do {									\
 	set_thread_flag(TIF_32BIT);					\
 } while (0)
 
+#ifdef CONFIG_VDSO32
+#define COMPAT_ARCH_DLINFO	_SET_AUX_ENT_VDSO
+#else
 #define COMPAT_ARCH_DLINFO
+#endif
 extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
 				      int uses_interp);
 #define compat_arch_setup_additional_pages \