This mimics the recent similar 64-bit change.
Saves ~110 bytes of code.
Signed-off-by: Denys Vlasenko <[email protected]>
CC: Linus Torvalds <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: "H. Peter Anvin" <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Oleg Nesterov <[email protected]>
CC: Frederic Weisbecker <[email protected]>
CC: Alexei Starovoitov <[email protected]>
CC: Will Drewry <[email protected]>
CC: Kees Cook <[email protected]>
CC: [email protected]
CC: [email protected]
---
Patch was run-tested on 32 and 64 bits, Intel and AMD CPU.
I also looked at the diff of entry_64.o disassembly, to have
a different view of the changes.
arch/x86/ia32/ia32entry.S | 82 ++++++++++++++++++++++++++---------------------
1 file changed, 46 insertions(+), 36 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index dec8c1d..8d01cce 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -126,26 +126,27 @@ ENTRY(ia32_sysenter_target)
movl %ebp, %ebp
movl %eax, %eax
- /* Construct iret frame (ss,rsp,rflags,cs,rip) */
- pushq_cfi $__USER32_DS
- /*CFI_REL_OFFSET ss,0*/
- pushq_cfi %rbp
- CFI_REL_OFFSET rsp,0
- pushfq_cfi
- /*CFI_REL_OFFSET rflags,0*/
- movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 3*8), %r10d
+ movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d
CFI_REGISTER rip,r10
- pushq_cfi $__USER32_CS
- /*CFI_REL_OFFSET cs,0*/
- /* Store thread_info->sysenter_return in rip stack slot */
- pushq_cfi %r10
- CFI_REL_OFFSET rip,0
- /* Store orig_ax */
- pushq_cfi %rax
- /* Construct the rest of "struct pt_regs" */
+
+ /* Construct struct pt_regs on stack */
+ pushq_cfi $__USER32_DS /* pt_regs->ss */
+ pushq_cfi %rbp /* pt_regs->sp */
+ CFI_REL_OFFSET rsp,0
+ pushfq_cfi /* pt_regs->flags */
+ pushq_cfi $__USER32_CS /* pt_regs->cs */
+ pushq_cfi %r10 /* pt_regs->ip = thread_info->sysenter_return */
+ CFI_REL_OFFSET rip,0
+ pushq_cfi_reg rax /* pt_regs->orig_ax */
+ pushq_cfi_reg rdi /* pt_regs->di */
+ pushq_cfi_reg rsi /* pt_regs->si */
+ pushq_cfi_reg rdx /* pt_regs->dx */
+ pushq_cfi_reg rcx /* pt_regs->cx */
+ pushq_cfi_reg rax /* pt_regs->ax */
cld
- ALLOC_PT_GPREGS_ON_STACK
- SAVE_C_REGS_EXCEPT_R891011
+ sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
+ CFI_ADJUST_CFA_OFFSET 10*8
+
/*
* no need to do an access_ok check here because rbp has been
* 32bit zero extended
@@ -334,20 +335,24 @@ ENTRY(ia32_cstar_target)
/* Zero-extending 32-bit regs, do not remove */
movl %eax,%eax
- ALLOC_PT_GPREGS_ON_STACK 6*8 /* 6*8: space for orig_ax and iret frame */
- SAVE_C_REGS_EXCEPT_RCX_R891011
- movq %rax,ORIG_RAX(%rsp)
- movq %rcx,RIP(%rsp)
- CFI_REL_OFFSET rip,RIP
- movq %rbp,RCX(%rsp) /* this lies slightly to ptrace */
+ /* Construct struct pt_regs on stack */
+ pushq_cfi $__USER32_DS /* pt_regs->ss */
+ pushq_cfi %r8 /* pt_regs->sp */
+ CFI_REL_OFFSET rsp,0
+ pushq_cfi %r11 /* pt_regs->flags */
+ pushq_cfi $__USER32_CS /* pt_regs->cs */
+ pushq_cfi %rcx /* pt_regs->ip */
+ CFI_REL_OFFSET rip,0
+ pushq_cfi_reg rax /* pt_regs->orig_ax */
+ pushq_cfi_reg rdi /* pt_regs->di */
+ pushq_cfi_reg rsi /* pt_regs->si */
+ pushq_cfi_reg rdx /* pt_regs->dx */
+ pushq_cfi_reg rbp /* pt_regs->cx */
movl %ebp,%ecx
- movq $__USER32_CS,CS(%rsp)
- movq $__USER32_DS,SS(%rsp)
- movq %r11,EFLAGS(%rsp)
- /*CFI_REL_OFFSET rflags,EFLAGS*/
- movq %r8,RSP(%rsp)
- CFI_REL_OFFSET rsp,RSP
- /* iret stack frame is complete now */
+ pushq_cfi_reg rax /* pt_regs->ax */
+ sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
+ CFI_ADJUST_CFA_OFFSET 10*8
+
/*
* no need to do an access_ok check here because r8 has been
* 32bit zero extended
@@ -478,12 +483,17 @@ ENTRY(ia32_syscall)
/* Zero-extending 32-bit regs, do not remove */
movl %eax,%eax
- pushq_cfi %rax /* store orig_ax */
+ /* Construct struct pt_regs on stack (iret frame is already on stack) */
+ pushq_cfi_reg rax /* pt_regs->orig_ax */
+ pushq_cfi_reg rdi /* pt_regs->di */
+ pushq_cfi_reg rsi /* pt_regs->si */
+ pushq_cfi_reg rdx /* pt_regs->dx */
+ pushq_cfi_reg rcx /* pt_regs->cx */
+ pushq_cfi_reg rax /* pt_regs->ax */
cld
- /* note the registers are not zero extended to the sf.
- this could be a problem. */
- ALLOC_PT_GPREGS_ON_STACK
- SAVE_C_REGS_EXCEPT_R891011
+ sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
+ CFI_ADJUST_CFA_OFFSET 10*8
+
orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp,
SIZEOF_PTREGS)
jnz ia32_tracesys
--
1.8.1.4
--
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