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From: Alexander van Heukelum <heukelum@fastmail.fm>
To: Andy Lutomirski <luto@amacapital.net>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>, Borislav Petkov <bp@suse.de>,
	Rik van Riel <riel@redhat.com>
Subject: [PATCHv2 1/4] x86_64: cleanup THREAD_INFO(reg,offset) macro
Date: Sun, 18 Jan 2015 12:45:17 +0100	[thread overview]
Message-ID: <1421581520-2816-2-git-send-email-heukelum@fastmail.fm> (raw)
In-Reply-To: <1421581520-2816-1-git-send-email-heukelum@fastmail.fm>

The macro THREAD_INFO(reg,offset) is used in assembly to compute the
offset between the user ptregs and the thread_info struct. Change
the macro and all its uses so that offset is given as the current
top of stack in the pt_regs frame. The generated code is identical.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
 arch/x86/ia32/ia32entry.S          | 30 +++++++++++++++---------------
 arch/x86/include/asm/calling.h     |  1 +
 arch/x86/include/asm/thread_info.h |  2 +-
 arch/x86/kernel/entry_64.S         |  4 ++--
 4 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 156ebca..1c74f39 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -135,7 +135,7 @@ ENTRY(ia32_sysenter_target)
 	CFI_REL_OFFSET rsp,0
 	pushfq_cfi
 	/*CFI_REL_OFFSET rflags,0*/
-	movl	TI_sysenter_return+THREAD_INFO(%rsp,3*8-KERNEL_STACK_OFFSET),%r10d
+	movl	TI_sysenter_return+THREAD_INFO(%rsp,EFLAGS),%r10d
 	CFI_REGISTER rip,r10
 	pushq_cfi $__USER32_CS
 	/*CFI_REL_OFFSET cs,0*/
@@ -161,8 +161,8 @@ ENTRY(ia32_sysenter_target)
 	jnz sysenter_fix_flags
 sysenter_flags_fixed:
 
-	orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
-	testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
+	testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	CFI_REMEMBER_STATE
 	jnz  sysenter_tracesys
 	cmpq	$(IA32_NR_syscalls-1),%rax
@@ -174,10 +174,10 @@ sysenter_dispatch:
 	movq	%rax,RAX-ARGOFFSET(%rsp)
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
-	testl	$_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl	$_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jnz	sysexit_audit
 sysexit_from_sys_call:
-	andl    $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	andl    $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
 	/* clear IF, that popfq doesn't enable interrupts early */
 	andl	$~0x200,EFLAGS-ARGOFFSET(%rsp)
 	movl	RIP-ARGOFFSET(%rsp),%edx		/* User %eip */
@@ -216,7 +216,7 @@ sysexit_from_sys_call:
 	.endm
 
 	.macro auditsys_exit exit
-	testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jnz ia32_ret_from_sys_call
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
@@ -231,7 +231,7 @@ sysexit_from_sys_call:
 	movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
-	testl %edi,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl %edi,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jz \exit
 	CLEAR_RREGS -ARGOFFSET
 	jmp int_with_check
@@ -253,7 +253,7 @@ sysenter_fix_flags:
 
 sysenter_tracesys:
 #ifdef CONFIG_AUDITSYSCALL
-	testl	$(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl	$(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jz	sysenter_auditsys
 #endif
 	SAVE_REST
@@ -324,8 +324,8 @@ ENTRY(ia32_cstar_target)
 1:	movl	(%r8),%r9d
 	_ASM_EXTABLE(1b,ia32_badarg)
 	ASM_CLAC
-	orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
-	testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
+	testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	CFI_REMEMBER_STATE
 	jnz   cstar_tracesys
 	cmpq $IA32_NR_syscalls-1,%rax
@@ -337,10 +337,10 @@ cstar_dispatch:
 	movq %rax,RAX-ARGOFFSET(%rsp)
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
-	testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jnz sysretl_audit
 sysretl_from_sys_call:
-	andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
 	RESTORE_ARGS 0,-ARG_SKIP,0,0,0
 	movl RIP-ARGOFFSET(%rsp),%ecx
 	CFI_REGISTER rip,rcx
@@ -368,7 +368,7 @@ sysretl_audit:
 
 cstar_tracesys:
 #ifdef CONFIG_AUDITSYSCALL
-	testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jz cstar_auditsys
 #endif
 	xchgl %r9d,%ebp
@@ -434,8 +434,8 @@ ENTRY(ia32_syscall)
 	/* note the registers are not zero extended to the sf.
 	   this could be a problem. */
 	SAVE_ARGS 0,1,0
-	orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
-	testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
+	testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jnz ia32_tracesys
 	cmpq $(IA32_NR_syscalls-1),%rax
 	ja ia32_badsys
diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h
index 1f1297b..16ab13d 100644
--- a/arch/x86/include/asm/calling.h
+++ b/arch/x86/include/asm/calling.h
@@ -81,6 +81,7 @@ For 32-bit we have the following conventions - kernel is built with
 #define EFLAGS		144
 #define RSP		152
 #define SS		160
+#define PTREGS_SIZE	168
 
 #define ARGOFFSET	R11
 
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index e82e95a..471037d 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -190,7 +190,7 @@ static inline unsigned long current_stack_pointer(void)
  * Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
  * a certain register (to be used in assembler memory operands).
  */
-#define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg)
+#define THREAD_INFO(reg, off) PTREGS_SIZE-(off)-THREAD_SIZE(reg)
 
 #endif
 
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index db13655..9f9ca20 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -343,7 +343,7 @@ GLOBAL(system_call_after_swapgs)
 	movq_cfi rax,(ORIG_RAX-ARGOFFSET)
 	movq  %rcx,RIP-ARGOFFSET(%rsp)
 	CFI_REL_OFFSET rip,RIP-ARGOFFSET
-	testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jnz tracesys
 system_call_fastpath:
 #if __SYSCALL_MASK == ~0
@@ -361,7 +361,7 @@ system_call_fastpath:
  * Has incomplete stack frame and undefined top of stack.
  */
 ret_from_sys_call:
-	testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+	testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
 	jnz int_ret_from_sys_call_fixup	/* Go the the slow path */
 
 	LOCKDEP_SYS_EXIT
-- 
2.1.0


  reply	other threads:[~2015-01-18 11:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-18 11:45 [PATCHv2 0/4] x86, entry: some cleanup and simplification Alexander van Heukelum
2015-01-18 11:45 ` Alexander van Heukelum [this message]
2015-01-21 13:40   ` [PATCHv2 1/4] x86_64: cleanup THREAD_INFO(reg,offset) macro Denys Vlasenko
2015-01-21 16:20     ` Alexander van Heukelum
2015-01-21 18:04       ` Borislav Petkov
2015-01-21 18:48         ` Alexander van Heukelum
2015-01-18 11:45 ` [PATCHv2 2/4] x86_64: embrace KERNEL_STACK_OFFSET Alexander van Heukelum
2015-01-21 13:44   ` Denys Vlasenko
2015-01-21 16:29     ` Alexander van Heukelum
2015-01-23  0:53       ` Denys Vlasenko
2015-01-18 11:45 ` [PATCHv2 3/4] i386: clean up KERNEL_STACK_OFFSET Alexander van Heukelum
2015-01-18 11:45 ` [PATCHv2 4/4] x86_64, entry: Create IRET-compatible stack frame at syscall entry Alexander van Heukelum
2015-01-18 16:38   ` Andy Lutomirski
2015-01-18 17:22     ` Alexander van Heukelum
2015-01-18 12:05 ` [PATCHv2 0/4] x86, entry: some cleanup and simplification Borislav Petkov
2015-01-18 15:47   ` Alexander van Heukelum
2015-01-21 13:26     ` Denys Vlasenko
2015-01-21 15:51       ` Alexander van Heukelum

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