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  • [PATCH v4 19/27] x86: assembly, make some functions local

    From Ard Biesheuvel@21:1/5 to Jiri Slaby on Mon Oct 2 14:50:02 2017
    On 2 October 2017 at 10:12, Jiri Slaby <jslaby@suse.cz> wrote:
    There is a couple of assembly functions, which are invoked only locally
    in the file they are defined. In C, we mark them "static". In assembly, annotate them using SYM_{FUNC,CODE}_START_LOCAL (and switch their
    ENDPROC to SYM_{FUNC,CODE}_END too). Whether FUNC or CODE depends on ENDPROC/END for a particular function (C or non-C).


    I wasn't cc'ed on the cover letter, so I am missing the rationale of
    replacing ENTRY/ENDPROC with other macros.


    Signed-off-by: Jiri Slaby <jslaby@suse.cz>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: x86@kernel.org
    Cc: Matt Fleming <matt@codeblueprint.co.uk>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: linux-efi@vger.kernel.org
    Cc: xen-devel@lists.xenproject.org
    ---
    arch/x86/boot/compressed/efi_thunk_64.S | 8 ++++----
    arch/x86/entry/entry_64.S | 25 +++++++++++++------------
    arch/x86/lib/copy_page_64.S | 4 ++--
    arch/x86/lib/memcpy_64.S | 12 ++++++------
    arch/x86/lib/memset_64.S | 8 ++++----
    arch/x86/platform/efi/efi_thunk_64.S | 12 ++++++------
    arch/x86/xen/xen-pvh.S | 4 ++--
    7 files changed, 37 insertions(+), 36 deletions(-)

    diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S
    index 86528f120962..c072711d8d62 100644
    --- a/arch/x86/boot/compressed/efi_thunk_64.S
    +++ b/arch/x86/boot/compressed/efi_thunk_64.S
    @@ -98,12 +98,12 @@ ENTRY(efi64_thunk)
    ret
    ENDPROC(efi64_thunk)

    -ENTRY(efi_exit32)
    +SYM_FUNC_START_LOCAL(efi_exit32)
    movq func_rt_ptr(%rip), %rax
    push %rax
    mov %rdi, %rax
    ret
    -ENDPROC(efi_exit32)
    +SYM_FUNC_END(efi_exit32)

    .code32
    /*
    @@ -111,7 +111,7 @@ ENDPROC(efi_exit32)
    *
    * The stack should represent the 32-bit calling convention.
    */
    -ENTRY(efi_enter32)
    +SYM_FUNC_START_LOCAL(efi_enter32)
    movl $__KERNEL_DS, %eax
    movl %eax, %ds
    movl %eax, %es
    @@ -171,7 +171,7 @@ ENTRY(efi_enter32)
    btsl $X86_CR0_PG_BIT, %eax
    movl %eax, %cr0
    lret
    -ENDPROC(efi_enter32)
    +SYM_FUNC_END(efi_enter32)

    .data
    .balign 8
    diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
    index 509504db0e2a..ff4964dac2dc 100644
    --- a/arch/x86/entry/entry_64.S
    +++ b/arch/x86/entry/entry_64.S
    @@ -324,7 +324,7 @@ opportunistic_sysret_failed:
    jmp restore_c_regs_and_iret
    END(entry_SYSCALL_64)

    -ENTRY(stub_ptregs_64)
    +SYM_CODE_START_LOCAL(stub_ptregs_64)
    /*
    * Syscalls marked as needing ptregs land here.
    * If we are on the fast path, we need to save the extra regs,
    @@ -349,7 +349,7 @@ ENTRY(stub_ptregs_64)

    1:
    jmp *%rax /* Called from C */ -END(stub_ptregs_64)
    +SYM_CODE_END(stub_ptregs_64)

    .macro ptregs_stub func
    ENTRY(ptregs_\func)
    @@ -976,7 +976,8 @@ idtentry hypervisor_callback xen_do_hypervisor_callback has_error_code=0
    * existing activation in its critical region -- if so, we pop the current
    * activation and restart the handler using the previous one.
    */
    -ENTRY(xen_do_hypervisor_callback) /* do_hypervisor_callback(struct *pt_regs) */
    +/* do_hypervisor_callback(struct *pt_regs) */ +SYM_CODE_START_LOCAL(xen_do_hypervisor_callback)

    /*
    * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
    @@ -994,7 +995,7 @@ ENTRY(xen_do_hypervisor_callback) /* do_hypervisor_callback(struct *pt_regs) */
    call xen_maybe_preempt_hcall
    #endif
    jmp error_exit
    -END(xen_do_hypervisor_callback)
    +SYM_CODE_END(xen_do_hypervisor_callback)

    /*
    * Hypervisor uses this for application faults while it executes.
    @@ -1078,7 +1079,7 @@ idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vec
    * Use slow, but surefire "are we in kernel?" check.
    * Return: ebx=0: need swapgs on exit, ebx=1: otherwise
    */
    -ENTRY(paranoid_entry)
    +SYM_CODE_START_LOCAL(paranoid_entry)
    UNWIND_HINT_FUNC
    cld
    SAVE_C_REGS 8
    @@ -1092,7 +1093,7 @@ ENTRY(paranoid_entry)
    SWAPGS
    xorl %ebx, %ebx
    1: ret
    -END(paranoid_entry)
    +SYM_CODE_END(paranoid_entry)

    /*
    * "Paranoid" exit path from exception stack. This is invoked
    @@ -1106,7 +1107,7 @@ END(paranoid_entry)
    *
    * On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it)
    */
    -ENTRY(paranoid_exit)
    +SYM_CODE_START_LOCAL(paranoid_exit)
    UNWIND_HINT_REGS
    DISABLE_INTERRUPTS(CLBR_ANY)
    TRACE_IRQS_OFF_DEBUG
    @@ -1122,13 +1123,13 @@ paranoid_exit_restore:
    RESTORE_C_REGS
    REMOVE_PT_GPREGS_FROM_STACK 8
    INTERRUPT_RETURN
    -END(paranoid_exit)
    +SYM_CODE_END(paranoid_exit)

    /*
    * Save all registers in pt_regs, and switch gs if needed.
    * Return: EBX=0: came from user mode; EBX=1: otherwise
    */
    -ENTRY(error_entry)
    +SYM_CODE_START_LOCAL(error_entry)
    UNWIND_HINT_FUNC
    cld
    SAVE_C_REGS 8
    @@ -1205,7 +1206,7 @@ ENTRY(error_entry)
    mov %rax, %rsp
    decl %ebx
    jmp .Lerror_entry_from_usermode_after_swapgs
    -END(error_entry)
    +SYM_CODE_END(error_entry)


    /*
    @@ -1213,14 +1214,14 @@ END(error_entry)
    * 1: already in kernel mode, don't need SWAPGS
    * 0: user gsbase is loaded, we need SWAPGS and standard preparation for return to usermode
    */
    -ENTRY(error_exit)
    +SYM_CODE_START_LOCAL(error_exit)
    UNWIND_HINT_REGS
    DISABLE_INTERRUPTS(CLBR_ANY)
    TRACE_IRQS_OFF
    testl %ebx, %ebx
    jnz retint_kernel
    jmp retint_user
    -END(error_exit)
    +SYM_CODE_END(error_exit)

    /* Runs on exception stack */
    /* XXX: broken on Xen PV */
    diff --git a/arch/x86/lib/copy_page_64.S b/arch/x86/lib/copy_page_64.S
    index e8508156c99d..e1ee50bc161a 100644
    --- a/arch/x86/lib/copy_page_64.S
    +++ b/arch/x86/lib/copy_page_64.S
    @@ -20,7 +20,7 @@ ENTRY(copy_page)
    ENDPROC(copy_page)
    EXPORT_SYMBOL(copy_page)

    -ENTRY(copy_page_regs)
    +SYM_FUNC_START_LOCAL(copy_page_regs)
    subq $2*8, %rsp
    movq %rbx, (%rsp)
    movq %r12, 1*8(%rsp)
    @@ -85,4 +85,4 @@ ENTRY(copy_page_regs)
    movq 1*8(%rsp), %r12
    addq $2*8, %rsp
    ret
    -ENDPROC(copy_page_regs)
    +SYM_FUNC_END(copy_page_regs)
    diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
    index 4911b1c61aa8..728703c47d58 100644
    --- a/arch/x86/lib/memcpy_64.S
    +++ b/arch/x86/lib/memcpy_64.S
    @@ -27,7 +27,7 @@
    * rax original destination
    */
    SYM_FUNC_START_ALIAS(__memcpy)
    -ENTRY(memcpy)
    +SYM_FUNC_START_LOCAL(memcpy)
    ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
    "jmp memcpy_erms", X86_FEATURE_ERMS

    @@ -39,7 +39,7 @@ ENTRY(memcpy)
    movl %edx, %ecx
    rep movsb
    ret
    -ENDPROC(memcpy)
    +SYM_FUNC_END(memcpy)
    SYM_FUNC_END_ALIAS(__memcpy)
    EXPORT_SYMBOL(memcpy)
    EXPORT_SYMBOL(__memcpy)
    @@ -48,14 +48,14 @@ EXPORT_SYMBOL(__memcpy)
    * memcpy_erms() - enhanced fast string memcpy. This is faster and
    * simpler than memcpy. Use memcpy_erms when possible.
    */
    -ENTRY(memcpy_erms)
    +SYM_FUNC_START_LOCAL(memcpy_erms)
    movq %rdi, %rax
    movq %rdx, %rcx
    rep movsb
    ret
    -ENDPROC(memcpy_erms)
    +SYM_FUNC_END(memcpy_erms)

    -ENTRY(memcpy_orig)
    +SYM_FUNC_START_LOCAL(memcpy_orig)
    movq %rdi, %rax

    cmpq $0x20, %rdx
    @@ -180,7 +180,7 @@ ENTRY(memcpy_orig)

    .Lend:
    retq
    -ENDPROC(memcpy_orig)
    +SYM_FUNC_END(memcpy_orig)

    #ifndef CONFIG_UML
    /*
    diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S
    index 0d3a1d341e60..c63ae9987612 100644
    --- a/arch/x86/lib/memset_64.S
    +++ b/arch/x86/lib/memset_64.S
    @@ -58,16 +58,16 @@ EXPORT_SYMBOL(__memset)
    *
    * rax original destination
    */
    -ENTRY(memset_erms)
    +SYM_FUNC_START_LOCAL(memset_erms)
    movq %rdi,%r9
    movb %sil,%al
    movq %rdx,%rcx
    rep stosb
    movq %r9,%rax
    ret
    -ENDPROC(memset_erms)
    +SYM_FUNC_END(memset_erms)

    -ENTRY(memset_orig)
    +SYM_FUNC_START_LOCAL(memset_orig)
    movq %rdi,%r10

    /* expand byte value */
    @@ -138,4 +138,4 @@ ENTRY(memset_orig)
    subq %r8,%rdx
    jmp .Lafter_bad_alignment
    .Lfinal:
    -ENDPROC(memset_orig)
    +SYM_FUNC_END(memset_orig)
    diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S
    index ff85d28c50f2..d18697df1fe9 100644
    --- a/arch/x86/platform/efi/efi_thunk_64.S
    +++ b/arch/x86/platform/efi/efi_thunk_64.S
    @@ -66,7 +66,7 @@ ENDPROC(efi64_thunk)
    *
    * This function must be invoked with a 1:1 mapped stack.
    */
    -ENTRY(__efi64_thunk)
    +SYM_FUNC_START_LOCAL(__efi64_thunk)
    movl %ds, %eax
    push %rax
    movl %es, %eax
    @@ -113,14 +113,14 @@ ENTRY(__efi64_thunk)
    or %rcx, %rax
    1:
    ret
    -ENDPROC(__efi64_thunk)
    +SYM_FUNC_END(__efi64_thunk)

    -ENTRY(efi_exit32)
    +SYM_FUNC_START_LOCAL(efi_exit32)
    movq func_rt_ptr(%rip), %rax
    push %rax
    mov %rdi, %rax
    ret
    -ENDPROC(efi_exit32)
    +SYM_FUNC_END(efi_exit32)

    .code32
    /*
    @@ -128,7 +128,7 @@ ENDPROC(efi_exit32)
    *
    * The stack should represent the 32-bit calling convention.
    */
    -ENTRY(efi_enter32)
    +SYM_FUNC_START_LOCAL(efi_enter32)
    movl $__KERNEL_DS, %eax
    movl %eax, %ds
    movl %eax, %es
    @@ -144,7 +144,7 @@ ENTRY(efi_enter32)
    pushl %eax

    lret
    -ENDPROC(efi_enter32)
    +SYM_FUNC_END(efi_enter32)

    .data
    .balign 8
    diff --git a/arch/x86/xen/xen-pvh.S b/arch/x86/xen/xen-pvh.S
    index 1b78837bad06..ba5aad3b3d6a 100644
    --- a/arch/x86/xen/xen-pvh.S
    +++ b/arch/x86/xen/xen-pvh.S
    @@ -54,7 +54,7 @@
    * charge of setting up it's own stack, GDT and IDT.
    */

    -ENTRY(pvh_start_xen)
    +SYM_CODE_START_LOCAL(pvh_start_xen)
    cld

    lgdt (_pa(gdt))
    @@ -133,7 +133,7 @@ ENTRY(pvh_start_xen)

    ljmp $__BOOT_CS, $_pa(startup_32)
    #endif
    -END(pvh_start_xen)
    +SYM_CODE_END(pvh_start_xen)

    .section ".init.data","aw"
    .balign 8
    --
    2.14.2


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