mirror of https://gitee.com/openkylin/linux.git
x86/asm/entry/32: Use smaller PUSH instructions instead of MOV, to build 'pt_regs' on stack
This mimics the recent similar 64-bit change. Saves ~110 bytes of code. 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. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-2-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Denys Vlasenko
Ingo Molnar
parent
4416c5a6da
commit
4c9c0e919f
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@ -126,26 +126,27 @@ ENTRY(ia32_sysenter_target)
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movl %ebp, %ebp
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movl %eax, %eax
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/* Construct iret frame (ss,rsp,rflags,cs,rip) */
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pushq_cfi $__USER32_DS
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/*CFI_REL_OFFSET ss,0*/
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pushq_cfi %rbp
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CFI_REL_OFFSET rsp,0
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pushfq_cfi
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/*CFI_REL_OFFSET rflags,0*/
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movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 3*8), %r10d
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movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d
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CFI_REGISTER rip,r10
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pushq_cfi $__USER32_CS
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/*CFI_REL_OFFSET cs,0*/
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/* Store thread_info->sysenter_return in rip stack slot */
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pushq_cfi %r10
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CFI_REL_OFFSET rip,0
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/* Store orig_ax */
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pushq_cfi %rax
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/* Construct the rest of "struct pt_regs" */
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/* Construct struct pt_regs on stack */
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pushq_cfi $__USER32_DS /* pt_regs->ss */
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pushq_cfi %rbp /* pt_regs->sp */
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CFI_REL_OFFSET rsp,0
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pushfq_cfi /* pt_regs->flags */
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pushq_cfi $__USER32_CS /* pt_regs->cs */
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pushq_cfi %r10 /* pt_regs->ip = thread_info->sysenter_return */
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CFI_REL_OFFSET rip,0
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pushq_cfi_reg rax /* pt_regs->orig_ax */
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pushq_cfi_reg rdi /* pt_regs->di */
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pushq_cfi_reg rsi /* pt_regs->si */
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pushq_cfi_reg rdx /* pt_regs->dx */
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pushq_cfi_reg rcx /* pt_regs->cx */
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pushq_cfi_reg rax /* pt_regs->ax */
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cld
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ALLOC_PT_GPREGS_ON_STACK
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SAVE_C_REGS_EXCEPT_R891011
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sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
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CFI_ADJUST_CFA_OFFSET 10*8
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/*
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* no need to do an access_ok check here because rbp has been
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* 32bit zero extended
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@ -334,20 +335,24 @@ ENTRY(ia32_cstar_target)
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/* Zero-extending 32-bit regs, do not remove */
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movl %eax,%eax
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ALLOC_PT_GPREGS_ON_STACK 6*8 /* 6*8: space for orig_ax and iret frame */
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SAVE_C_REGS_EXCEPT_RCX_R891011
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movq %rax,ORIG_RAX(%rsp)
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movq %rcx,RIP(%rsp)
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CFI_REL_OFFSET rip,RIP
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movq %rbp,RCX(%rsp) /* this lies slightly to ptrace */
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/* Construct struct pt_regs on stack */
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pushq_cfi $__USER32_DS /* pt_regs->ss */
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pushq_cfi %r8 /* pt_regs->sp */
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CFI_REL_OFFSET rsp,0
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pushq_cfi %r11 /* pt_regs->flags */
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pushq_cfi $__USER32_CS /* pt_regs->cs */
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pushq_cfi %rcx /* pt_regs->ip */
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CFI_REL_OFFSET rip,0
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pushq_cfi_reg rax /* pt_regs->orig_ax */
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pushq_cfi_reg rdi /* pt_regs->di */
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pushq_cfi_reg rsi /* pt_regs->si */
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pushq_cfi_reg rdx /* pt_regs->dx */
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pushq_cfi_reg rbp /* pt_regs->cx */
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movl %ebp,%ecx
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movq $__USER32_CS,CS(%rsp)
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movq $__USER32_DS,SS(%rsp)
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movq %r11,EFLAGS(%rsp)
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/*CFI_REL_OFFSET rflags,EFLAGS*/
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movq %r8,RSP(%rsp)
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CFI_REL_OFFSET rsp,RSP
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/* iret stack frame is complete now */
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pushq_cfi_reg rax /* pt_regs->ax */
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sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
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CFI_ADJUST_CFA_OFFSET 10*8
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/*
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* no need to do an access_ok check here because r8 has been
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* 32bit zero extended
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@ -478,12 +483,17 @@ ENTRY(ia32_syscall)
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/* Zero-extending 32-bit regs, do not remove */
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movl %eax,%eax
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pushq_cfi %rax /* store orig_ax */
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/* Construct struct pt_regs on stack (iret frame is already on stack) */
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pushq_cfi_reg rax /* pt_regs->orig_ax */
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pushq_cfi_reg rdi /* pt_regs->di */
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pushq_cfi_reg rsi /* pt_regs->si */
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pushq_cfi_reg rdx /* pt_regs->dx */
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pushq_cfi_reg rcx /* pt_regs->cx */
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pushq_cfi_reg rax /* pt_regs->ax */
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cld
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/* note the registers are not zero extended to the sf.
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this could be a problem. */
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ALLOC_PT_GPREGS_ON_STACK
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SAVE_C_REGS_EXCEPT_R891011
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sub $(10*8),%rsp /* pt_regs->r8-11,bp,bx,r12-15 not saved */
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CFI_ADJUST_CFA_OFFSET 10*8
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orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
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testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
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jnz ia32_tracesys
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