From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: luto@kernel.org, tglx@linutronix.de
Cc: hpa@zytor.com, bp@alien8.de, rric@kernel.org,
peterz@infradead.org, mingo@redhat.com, x86@kernel.org,
linux-kernel@vger.kernel.org,
Gabriel Krisman Bertazi <krisman@collabora.com>,
kernel@collabora.com
Subject: [PATCH 5/6] x86: elf: Use e_machine to select start_thread for x32
Date: Sat, 12 Sep 2020 03:05:52 -0400 [thread overview]
Message-ID: <20200912070553.330622-6-krisman@collabora.com> (raw)
In-Reply-To: <20200912070553.330622-1-krisman@collabora.com>
Since TIF_X32 is going away, avoid using it to find the ELF type on
compat_start_thread
According to SysV AMD64 ABI Draft, an AMD64 ELF object using ILP32 must
have ELFCLASS32 with (E_MACHINE == EM_X86_64), so use that ELF field to
differentiate a x32 object from a IA32 object when executing
start_thread in compat mode.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
---
arch/x86/include/asm/elf.h | 11 +++++++++--
arch/x86/kernel/process_64.c | 11 +++++++----
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 9220efc65d78..33c1c9be2e07 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -186,8 +186,15 @@ static inline void elf_common_init(struct thread_struct *t,
#define COMPAT_ELF_PLAT_INIT(regs, load_addr) \
elf_common_init(¤t->thread, regs, __USER_DS)
-void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp);
-#define compat_start_thread compat_start_thread
+void compat_start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp);
+void compat_start_thread_x32(struct pt_regs *regs, u32 new_ip, u32 new_sp);
+#define compat_start_thread(regs, new_ip, new_sp) \
+do { \
+ if (elf_ex->e_machine == EM_X86_64) \
+ compat_start_thread_x32(regs, new_ip, new_sp); \
+ else \
+ compat_start_thread_ia32(regs, new_ip, new_sp); \
+} while (0)
void set_personality_ia32(bool);
#define COMPAT_SET_PERSONALITY(ex) \
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9afefe325acb..56e882c339e6 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -511,12 +511,15 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
EXPORT_SYMBOL_GPL(start_thread);
#ifdef CONFIG_COMPAT
-void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp)
+void compat_start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
{
start_thread_common(regs, new_ip, new_sp,
- test_thread_flag(TIF_X32)
- ? __USER_CS : __USER32_CS,
- __USER_DS, __USER_DS);
+ __USER32_CS, __USER_DS, __USER_DS);
+}
+void compat_start_thread_x32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
+{
+ start_thread_common(regs, new_ip, new_sp,
+ __USER_CS, __USER_DS, __USER_DS);
}
#endif
--
2.28.0
next prev parent reply other threads:[~2020-09-12 7:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-12 7:05 [PATCH 0/6] Prepare for removal of TIF_IA32 and TIF_X32 Gabriel Krisman Bertazi
2020-09-12 7:05 ` [PATCH 1/6] x86: events: Avoid TIF_IA32 when checking 64bit mode Gabriel Krisman Bertazi
2020-09-14 10:33 ` peterz
2020-09-12 7:05 ` [PATCH 2/6] x86: Simplify compat syscall userspace allocation Gabriel Krisman Bertazi
2020-09-12 7:08 ` Christoph Hellwig
2020-09-12 7:54 ` Gabriel Krisman Bertazi
2020-09-12 7:05 ` [PATCH 3/6] x86: oprofile: Avoid TIF_IA32 when checking 64bit mode Gabriel Krisman Bertazi
2020-09-12 7:05 ` [PATCH 4/6] x86: elf: Use e_machine to choose DLINFO in compat Gabriel Krisman Bertazi
2020-09-12 7:05 ` Gabriel Krisman Bertazi [this message]
2020-09-12 7:05 ` [PATCH 6/6] x86: elf: Use e_machine to select setup_additional_pages for x32 Gabriel Krisman Bertazi
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