[PATCH 1/3] x86_64: remove KERNEL_STACK_OFFSET from THREAD_INFO macro

From: Alexander van Heukelum
Date: Sat Jan 17 2015 - 20:18:01 EST

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Next in thread: Alexander van Heukelum: "[PATCH 2/3] x86_64: don't use KERNEL_STACK_OFFSET for syscall and sysenter"
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In the macro THREAD_INFO(reg,offset), the offset is relative to
KERNEL_STACK_OFFSET. 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@xxxxxxxxxxx>
---
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

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Next message: Alexander van Heukelum: "[PATCH 0/3] x86_64, entry: some cleanup and simplification..."
Previous message: Rickard Strandqvist: "[PATCH v2] staging: rtl8712: recv_linux: Remove unused function"
In reply to: Alexander van Heukelum: "[PATCH 0/3] x86_64, entry: some cleanup and simplification..."
Next in thread: Alexander van Heukelum: "[PATCH 2/3] x86_64: don't use KERNEL_STACK_OFFSET for syscall and sysenter"
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