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From:   Brian Gerst <brgerst@gmail.com>
To:     linux-kernel@vger.kernel.org, x86@kernel.org
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Brian Gerst <brgerst@gmail.com>
Subject: [PATCH 4/8] x86: Remove __USER32_DS
Date:   Mon,  6 Jun 2022 16:37:58 -0400
Message-Id: <20220606203802.158958-5-brgerst@gmail.com>
In-Reply-To: <20220606203802.158958-1-brgerst@gmail.com>
References: <20220606203802.158958-1-brgerst@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Replace all users with the equivalent __USER_DS, which will make merging
native and compat code simpler.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
 arch/x86/entry/entry_64_compat.S |  4 ++--
 arch/x86/ia32/ia32_signal.c      | 14 +++++++-------
 arch/x86/include/asm/elf.h       |  4 ----
 arch/x86/include/asm/segment.h   |  1 -
 arch/x86/xen/xen-asm.S           |  8 ++++----
 5 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index d1052742ad0c..cd51d1f70382 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -59,7 +59,7 @@ SYM_CODE_START(entry_SYSENTER_compat)
 	movq	PER_CPU_VAR(cpu_current_top_of_stack), %rsp
 
 	/* Construct struct pt_regs on stack */
-	pushq	$__USER32_DS		/* pt_regs->ss */
+	pushq	$__USER_DS		/* pt_regs->ss */
 	pushq	$0			/* pt_regs->sp = 0 (placeholder) */
 
 	/*
@@ -192,7 +192,7 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL)
 	ANNOTATE_NOENDBR
 
 	/* Construct struct pt_regs on stack */
-	pushq	$__USER32_DS		/* pt_regs->ss */
+	pushq	$__USER_DS		/* pt_regs->ss */
 	pushq	%r8			/* pt_regs->sp */
 	pushq	%r11			/* pt_regs->flags */
 	pushq	$__USER32_CS		/* pt_regs->cs */
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index b67e27685d46..a78885e3e85d 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -212,7 +212,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
 	if (ksig->ka.sa.sa_flags & SA_ONSTACK)
 		sp = sigsp(sp, ksig);
 	/* This is the legacy signal stack switching. */
-	else if (regs->ss != __USER32_DS &&
+	else if (regs->ss != __USER_DS &&
 		!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
 		 ksig->ka.sa.sa_restorer)
 		sp = (unsigned long) ksig->ka.sa.sa_restorer;
@@ -284,11 +284,11 @@ int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs)
 	regs->dx = 0;
 	regs->cx = 0;
 
-	loadsegment(ds, __USER32_DS);
-	loadsegment(es, __USER32_DS);
+	loadsegment(ds, __USER_DS);
+	loadsegment(es, __USER_DS);
 
 	regs->cs = __USER32_CS;
-	regs->ss = __USER32_DS;
+	regs->ss = __USER_DS;
 
 	return 0;
 Efault:
@@ -361,11 +361,11 @@ int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 	regs->dx = (unsigned long) &frame->info;
 	regs->cx = (unsigned long) &frame->uc;
 
-	loadsegment(ds, __USER32_DS);
-	loadsegment(es, __USER32_DS);
+	loadsegment(ds, __USER_DS);
+	loadsegment(es, __USER_DS);
 
 	regs->cs = __USER32_CS;
-	regs->ss = __USER32_DS;
+	regs->ss = __USER_DS;
 
 	return 0;
 Efault:
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index cb0ff1055ab1..be8b58da63b9 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -152,10 +152,6 @@ do {						\
 	(elf_check_arch_ia32(x) ||					\
 	 (IS_ENABLED(CONFIG_X86_X32_ABI) && (x)->e_machine == EM_X86_64))
 
-#if __USER32_DS != __USER_DS
-# error "The following code assumes __USER32_DS == __USER_DS"
-#endif
-
 static inline void elf_common_init(struct thread_struct *t,
 				   struct pt_regs *regs, const u16 ds)
 {
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 2e7890dd58a4..e056c29dfcda 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -210,7 +210,6 @@
 #define __KERNEL_DS			(GDT_ENTRY_KERNEL_DS*8)
 #define __USER32_CS			(GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
 #define __USER_DS			(GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
-#define __USER32_DS			__USER_DS
 #define __USER_CS			(GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
 #define __CPUNODE_SEG			(GDT_ENTRY_CPUNODE*8 + 3)
 
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index caa9bc2fa100..350174cf9d71 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -262,10 +262,10 @@ SYM_CODE_START(xen_syscall32_target)
 
 	/*
 	 * Neither Xen nor the kernel really knows what the old SS and
-	 * CS were.  The kernel expects __USER32_DS and __USER32_CS, so
+	 * CS were.  The kernel expects __USER_DS and __USER32_CS, so
 	 * report those values even though Xen will guess its own values.
 	 */
-	movq $__USER32_DS, 4*8(%rsp)
+	movq $__USER_DS, 4*8(%rsp)
 	movq $__USER32_CS, 1*8(%rsp)
 
 	jmp entry_SYSCALL_compat_after_hwframe
@@ -284,10 +284,10 @@ SYM_CODE_START(xen_sysenter_target)
 
 	/*
 	 * Neither Xen nor the kernel really knows what the old SS and
-	 * CS were.  The kernel expects __USER32_DS and __USER32_CS, so
+	 * CS were.  The kernel expects __USER_DS and __USER32_CS, so
 	 * report those values even though Xen will guess its own values.
 	 */
-	movq $__USER32_DS, 4*8(%rsp)
+	movq $__USER_DS, 4*8(%rsp)
 	movq $__USER32_CS, 1*8(%rsp)
 
 	jmp entry_SYSENTER_compat_after_hwframe
-- 
2.35.3