x86: introduce save_rest and restructure the PTREGSCALL macro in entry_64.S
Impact: cleanup The save_rest function completes a partial stack frame for use by the PTREGSCALL macro. This also avoids the indirect call in PTREGSCALLs. This adds the macro movq_cfi_restore to hide the CFI_RESTORE annotation when restoring a register from the stack frame. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Alexander van Heukelum
Ingo Molnar
parent
14ae22ba2b
commit
c002a1e6b6
1 changed files with 53 additions and 38 deletions
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@ -78,6 +78,11 @@
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CFI_REL_OFFSET \reg, \offset
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.endm
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.macro movq_cfi_restore offset reg
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movq \offset(%rsp), %\reg
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CFI_RESTORE \reg
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.endm
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#ifdef CONFIG_FUNCTION_TRACER
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#ifdef CONFIG_DYNAMIC_FTRACE
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ENTRY(mcount)
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@ -186,21 +191,21 @@ ENTRY(native_usergs_sysret64)
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*/
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/* %rsp:at FRAMEEND */
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.macro FIXUP_TOP_OF_STACK tmp
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movq %gs:pda_oldrsp,\tmp
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movq \tmp,RSP(%rsp)
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movq $__USER_DS,SS(%rsp)
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movq $__USER_CS,CS(%rsp)
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movq $-1,RCX(%rsp)
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movq R11(%rsp),\tmp /* get eflags */
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movq \tmp,EFLAGS(%rsp)
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.macro FIXUP_TOP_OF_STACK tmp offset=0
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movq %gs:pda_oldrsp,\tmp
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movq \tmp,RSP+\offset(%rsp)
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movq $__USER_DS,SS+\offset(%rsp)
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movq $__USER_CS,CS+\offset(%rsp)
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movq $-1,RCX+\offset(%rsp)
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movq R11+\offset(%rsp),\tmp /* get eflags */
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movq \tmp,EFLAGS+\offset(%rsp)
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.endm
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.macro RESTORE_TOP_OF_STACK tmp,offset=0
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movq RSP-\offset(%rsp),\tmp
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movq \tmp,%gs:pda_oldrsp
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movq EFLAGS-\offset(%rsp),\tmp
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movq \tmp,R11-\offset(%rsp)
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.macro RESTORE_TOP_OF_STACK tmp offset=0
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movq RSP+\offset(%rsp),\tmp
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movq \tmp,%gs:pda_oldrsp
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movq EFLAGS+\offset(%rsp),\tmp
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movq \tmp,R11+\offset(%rsp)
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.endm
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.macro FAKE_STACK_FRAME child_rip
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@ -333,6 +338,21 @@ ENTRY(save_args)
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CFI_ENDPROC
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END(save_args)
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ENTRY(save_rest)
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PARTIAL_FRAME 1 REST_SKIP+8
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movq 5*8+16(%rsp), %r11 /* save return address */
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movq_cfi rbx, RBX+16
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movq_cfi rbp, RBP+16
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movq_cfi r12, R12+16
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movq_cfi r13, R13+16
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movq_cfi r14, R14+16
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movq_cfi r15, R15+16
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movq %r11, 8(%rsp) /* return address */
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FIXUP_TOP_OF_STACK %r11, 16
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ret
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CFI_ENDPROC
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END(save_rest)
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/*
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* A newly forked process directly context switches into this.
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*/
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@ -353,7 +373,7 @@ rff_action:
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je int_ret_from_sys_call
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testl $_TIF_IA32,TI_flags(%rcx)
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jnz int_ret_from_sys_call
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RESTORE_TOP_OF_STACK %rdi,ARGOFFSET
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RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
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jmp ret_from_sys_call
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rff_trace:
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movq %rsp,%rdi
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@ -626,18 +646,20 @@ END(system_call)
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/*
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* Certain special system calls that need to save a complete full stack frame.
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*/
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.macro PTREGSCALL label,func,arg
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.globl \label
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\label:
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leaq \func(%rip),%rax
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leaq -ARGOFFSET+8(%rsp),\arg /* 8 for return address */
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jmp ptregscall_common
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ENTRY(\label)
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PARTIAL_FRAME 1 8 /* offset 8: return address */
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subq $REST_SKIP, %rsp
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CFI_ADJUST_CFA_OFFSET REST_SKIP
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call save_rest
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DEFAULT_FRAME 0 8 /* offset 8: return address */
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leaq 8(%rsp), \arg /* pt_regs pointer */
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call \func
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jmp ptregscall_common
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CFI_ENDPROC
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END(\label)
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.endm
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CFI_STARTPROC
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PTREGSCALL stub_clone, sys_clone, %r8
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PTREGSCALL stub_fork, sys_fork, %rdi
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PTREGSCALL stub_vfork, sys_vfork, %rdi
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@ -645,22 +667,15 @@ END(\label)
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PTREGSCALL stub_iopl, sys_iopl, %rsi
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ENTRY(ptregscall_common)
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popq %r11
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CFI_ADJUST_CFA_OFFSET -8
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CFI_REGISTER rip, r11
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SAVE_REST
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movq %r11, %r15
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CFI_REGISTER rip, r15
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FIXUP_TOP_OF_STACK %r11
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call *%rax
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RESTORE_TOP_OF_STACK %r11
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movq %r15, %r11
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CFI_REGISTER rip, r11
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RESTORE_REST
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pushq %r11
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CFI_ADJUST_CFA_OFFSET 8
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CFI_REL_OFFSET rip, 0
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ret
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DEFAULT_FRAME 1 8 /* offset 8: return address */
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RESTORE_TOP_OF_STACK %r11, 8
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movq_cfi_restore R15+8, r15
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movq_cfi_restore R14+8, r14
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movq_cfi_restore R13+8, r13
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movq_cfi_restore R12+8, r12
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movq_cfi_restore RBP+8, rbp
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movq_cfi_restore RBX+8, rbx
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ret $REST_SKIP /* pop extended registers */
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CFI_ENDPROC
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END(ptregscall_common)
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