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    SubjectRe: [PATCH 0/8] use struct pt_regs based syscall calling for x86-64
    On Thu, Apr 05, 2018 at 05:19:33PM +0200, Ingo Molnar wrote:
    > Ok, this series looks mostly good to me, but AFAICS this breaks the UML build:
    >
    > make[2]: *** No rule to make target 'archheaders'. Stop.
    > arch/um/Makefile:119: recipe for target 'archheaders' failed
    > make[1]: *** [archheaders] Error 2
    > make[1]: *** Waiting for unfinished jobs....

    Ah, that's caused by patch 8/8 which I did and do not like all that much
    anyway: UML re-uses syscall_64.tbl which now has x86-specific entries like
    __sys_x86_pread64, but expects the generic syscall stub sys_pread64
    referenced there. Fixup patch below; could be folded with patch 8/8. Or
    patch 8/8 could simply be dropped from the series altogether...

    Thanks,
    Dominik

    --------------------------------------------------------------------------
    From f5049ea4e1e5e7751e72a22cbc1b3a9389959a04 Mon Sep 17 00:00:00 2001
    From: Dominik Brodowski <linux@dominikbrodowski.net>
    Date: Thu, 5 Apr 2018 22:16:23 +0200
    Subject: [PATCH] syscalls/x86: fix UML syscall table

    To differentiate the different calling regime used on x86, the syscall
    functions received __sys_x86_ as prefix (instead of sys_). This breaks
    the build of UML on 64-bit x86, as it re-uses the same syscall table.

    To fix this, replace the __sys_x86_ prefix with sys_ during the generation
    of <asm/syscalls_64.h>.

    Fixes: syscalls/x86: rename struct pt_regs-based sys_*() to __sys_x86_*()
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: x86@kernel.org
    Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

    diff --git a/arch/x86/entry/syscalls/syscalltbl.sh b/arch/x86/entry/syscalls/syscalltbl.sh
    index d71ef4bd3615..d6376b87ecb2 100644
    --- a/arch/x86/entry/syscalls/syscalltbl.sh
    +++ b/arch/x86/entry/syscalls/syscalltbl.sh
    @@ -20,17 +20,47 @@ syscall_macro() {
    echo "__SYSCALL_${abi}($nr, $real_entry, $qualifier)"
    }

    -emit() {
    +emit64() {
    abi="$1"
    nr="$2"
    entry="$3"
    compat="$4"

    - if [ "$abi" = "64" -a -n "$compat" ]; then
    + if [ "$abi" = "I386" ]; then
    + echo "emit64() called for a 32-bit syscall" >&2
    + exit 1
    + fi
    +
    + if [ -n "$compat" ]; then
    echo "a compat entry for a 64-bit syscall makes no sense" >&2
    exit 1
    fi

    + if [ -n "$entry" ]; then
    + # For CONFIG_UML, we need to strip the __sys_x86 prefix
    + if [ "${entry}" = "${entry#__compat_sys}" ]; then
    + umlentry="sys${entry#__sys_x86}"
    + fi
    +
    + echo "#ifdef CONFIG_X86"
    + syscall_macro "$abi" "$nr" "$entry"
    + echo "#else /* CONFIG_UML */"
    + syscall_macro "$abi" "$nr" "$umlentry"
    + echo "#endif"
    + fi
    +}
    +
    +emit32() {
    + abi="$1"
    + nr="$2"
    + entry="$3"
    + compat="$4"
    +
    + if [ "$abi" = "64" ]; then
    + echo "emit32() called for a 64-bit syscall" >&2
    + exit 1
    + fi
    +
    if [ -z "$compat" ]; then
    if [ -n "$entry" ]; then
    syscall_macro "$abi" "$nr" "$entry"
    @@ -53,14 +83,14 @@ grep '^[0-9]' "$in" | sort -n | (
    # COMMON is the same as 64, except that we don't expect X32
    # programs to use it. Our expectation has nothing to do with
    # any generated code, so treat them the same.
    - emit 64 "$nr" "$entry" "$compat"
    + emit64 64 "$nr" "$entry" "$compat"
    elif [ "$abi" = "X32" ]; then
    # X32 is equivalent to 64 on an X32-compatible kernel.
    echo "#ifdef CONFIG_X86_X32_ABI"
    - emit 64 "$nr" "$entry" "$compat"
    + emit64 64 "$nr" "$entry" "$compat"
    echo "#endif"
    elif [ "$abi" = "I386" ]; then
    - emit "$abi" "$nr" "$entry" "$compat"
    + emit32 "$abi" "$nr" "$entry" "$compat"
    else
    echo "Unknown abi $abi" >&2
    exit 1
    \
     
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      Last update: 2018-04-05 22:33    [W:2.708 / U:0.076 seconds]
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