From: Pratyush Anand <panand@redhat.com>
Date: Wed, 2 Nov 2016 09:10:45 +0000 (+0530)
Subject: arm64: introduce mm context flag to keep 32 bit task information
X-Git-Tag: v4.10-rc1~135^2~39
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=06beb72fbe23e348cc423dd9310c6fc02cd7c7da;p=linux.git

arm64: introduce mm context flag to keep 32 bit task information

We need to decide in some cases like uprobe instruction analysis that
whether the current mm context belongs to a 32 bit task or 64 bit.

This patch has introduced an unsigned flag variable in mm_context_t.
Currently, we set and clear TIF_32BIT depending on the condition that
whether an elf binary load sets personality for 32 bit or 64 bit
respectively.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index a55384f4a5d7..5d1700425efe 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -138,7 +138,11 @@ typedef struct user_fpsimd_state elf_fpregset_t;
  */
 #define ELF_PLAT_INIT(_r, load_addr)	(_r)->regs[0] = 0
 
-#define SET_PERSONALITY(ex)		clear_thread_flag(TIF_32BIT);
+#define SET_PERSONALITY(ex)						\
+({									\
+	clear_bit(TIF_32BIT, &current->mm->context.flags);		\
+	clear_thread_flag(TIF_32BIT);					\
+})
 
 /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
 #define ARCH_DLINFO							\
@@ -183,7 +187,11 @@ typedef compat_elf_greg_t		compat_elf_gregset_t[COMPAT_ELF_NGREG];
 					 ((x)->e_flags & EF_ARM_EABI_MASK))
 
 #define compat_start_thread		compat_start_thread
-#define COMPAT_SET_PERSONALITY(ex)	set_thread_flag(TIF_32BIT);
+#define COMPAT_SET_PERSONALITY(ex)					\
+({									\
+	set_bit(TIF_32BIT, &current->mm->context.flags);		\
+	set_thread_flag(TIF_32BIT);					\
+ })
 #define COMPAT_ARCH_DLINFO
 extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
 				      int uses_interp);
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index a81454ad5455..47619411f0ff 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -19,6 +19,7 @@
 typedef struct {
 	atomic64_t	id;
 	void		*vdso;
+	unsigned long	flags;
 } mm_context_t;
 
 /*