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Subject[PATCH 2/2] arm64: cleanup {COMPAT_,}SET_PERSONALITY() macro
Date
There is some work that should be done after setting the personality.
Currently it's done in the macro, which is not the best idea.

In this patch new arch_setup_new_exec() routine is introduced, and all
setup code is moved there, as suggested by Catalin:
https://lkml.org/lkml/2017/8/4/494

v2:
- don't move clearing READ_IMPLIES_EXEC flag from SET_PERSONALITY()

Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
CC: Pratyush Anand <panand@redhat.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm64/include/asm/elf.h | 7 +++++--
arch/arm64/include/asm/thread_info.h | 3 +++
arch/arm64/kernel/process.c | 8 ++++++++
3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 517b9ff0456c..9c4434b8a9a8 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -137,9 +137,13 @@ typedef struct user_fpsimd_state elf_fpregset_t;
*/
#define ELF_PLAT_INIT(_r, load_addr) (_r)->regs[0] = 0

+/*
+ * Don't modify this macro unless you add new personality.
+ * All personality-related setup should be done at proper place.
+ * If not sure, consider the arch_setup_new_exec() function.
+ */
#define SET_PERSONALITY(ex) \
({ \
- current->mm->context.flags = 0; \
clear_thread_flag(TIF_32BIT); \
current->personality &= ~READ_IMPLIES_EXEC; \
})
@@ -195,7 +199,6 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
*/
#define COMPAT_SET_PERSONALITY(ex) \
({ \
- current->mm->context.flags = MMCF_AARCH32; \
set_thread_flag(TIF_32BIT); \
})
#define COMPAT_ARCH_DLINFO
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 46c3b93cf865..c823d2f12b4c 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -68,6 +68,9 @@ struct thread_info {
#define thread_saved_fp(tsk) \
((unsigned long)(tsk->thread.cpu_context.fp))

+void arch_setup_new_exec(void);
+#define arch_setup_new_exec arch_setup_new_exec
+
#endif

/*
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 659ae8094ed5..e99012c4803a 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -417,3 +417,11 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
else
return randomize_page(mm->brk, SZ_1G);
}
+
+/*
+ * Called immediately after a successful exec.
+ */
+void arch_setup_new_exec(void)
+{
+ current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0;
+}
--
2.11.0
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