Re: [PATCH v1 03/19] x86/insn: Add an insn_decode() API

From: Masami Hiramatsu
Date: Tue Jan 12 2021 - 06:36:19 EST

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On Fri, 8 Jan 2021 19:59:50 +0100
Borislav Petkov <bp@xxxxxxxxx> wrote:

> On Wed, Jan 06, 2021 at 02:21:14PM +0900, Masami Hiramatsu wrote:
> > So I think it is possible to introduce a keyword in a comment
> > for ignoring sync check something like below. This will allow us
> > a generic pattern matching.
> >
> > The keyword is just an example, "no-sync-check" etc. is OK.
> >
> > What would you think about it?
>
> Yeah, I'd prefer a single keyword which to slap everywhere, see below.
> The patch is only for demonstration, though, it is not complete.

Yes, that looks good to me too.

>
> And while playing with that after having commented out INSN_MODE_KERN in
> the tools/ version, I realized that the build would always fail because
> insn.c references it:
>
> In file included from arch/x86/decode.c:12:
> arch/x86/../../../arch/x86/lib/insn.c: In function ‘insn_decode’:
> arch/x86/../../../arch/x86/lib/insn.c:751:11: error: ‘INSN_MODE_KERN’ undeclared (first use in this function); did you mean ‘INSN_MODE_64’?
> 751 | if (m == INSN_MODE_KERN)
> | ^~~~~~~~~~~~~~
> | INSN_MODE_64
>
> and making that work would turn pretty ugly because I wanna avoid
> slapping that __ignore_sync_check__ or whatever on more than one line.
>
> So I need to think about a better solution here...

Hmm, instead of removing INSN_MODE_KERN, if you just return an error,
it will change one line.

if (m == INSN_MODE_KERN)
return -EINVAL; /* __ignore_sync_check__ */
else
insn_init(insn, kaddr, buf_len, m == INSN_MODE_64);

Or, add one definition before that line.

#define INSN_MODE_KERN -1 /* __ignore_sync_check__ */

Thank you,

>
> ---
> diff --git a/arch/x86/include/asm/inat.h b/arch/x86/include/asm/inat.h
> index 4cf2ad521f65..b56c5741581a 100644
> --- a/arch/x86/include/asm/inat.h
> +++ b/arch/x86/include/asm/inat.h
> @@ -6,7 +6,7 @@
> *
> * Written by Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> */
> -#include <asm/inat_types.h>
> +#include <asm/inat_types.h> /* __ignore_sync_check__ */
>
> /*
> * Internal bits. Don't use bitmasks directly, because these bits are
> diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h
> index 9f1910284861..601eac7a4973 100644
> --- a/arch/x86/include/asm/insn.h
> +++ b/arch/x86/include/asm/insn.h
> @@ -8,7 +8,7 @@
> */
>
> /* insn_attr_t is defined in inat.h */
> -#include <asm/inat.h>
> +#include <asm/inat.h> /* __ignore_sync_check__ */
>
> struct insn_field {
> union {
> @@ -99,7 +99,7 @@ enum insn_mode {
> INSN_MODE_32,
> INSN_MODE_64,
> /* Mode is determined by the current kernel build. */
> - INSN_MODE_KERN,
> + INSN_MODE_KERN, /* __ignore_sync_check__ */
> INSN_NUM_MODES,
> };
>
> diff --git a/arch/x86/lib/inat.c b/arch/x86/lib/inat.c
> index 12539fca75c4..b0f3b2a62ae2 100644
> --- a/arch/x86/lib/inat.c
> +++ b/arch/x86/lib/inat.c
> @@ -4,7 +4,7 @@
> *
> * Written by Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> */
> -#include <asm/insn.h>
> +#include <asm/insn.h> /* __ignore_sync_check__ */
>
> /* Attribute tables are generated from opcode map */
> #include "inat-tables.c"
> diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
> index 2ab1d0256313..1295003fb4f7 100644
> --- a/arch/x86/lib/insn.c
> +++ b/arch/x86/lib/insn.c
> @@ -10,13 +10,13 @@
> #else
> #include <string.h>
> #endif
> -#include <asm/inat.h>
> -#include <asm/insn.h>
> +#include <asm/inat.h> /*__ignore_sync_check__ */
> +#include <asm/insn.h> /* __ignore_sync_check__ */
>
> #include <linux/errno.h>
> #include <linux/kconfig.h>
>
> -#include <asm/emulate_prefix.h>
> +#include <asm/emulate_prefix.h> /* __ignore_sync_check__ */
>
> /* Verify next sizeof(t) bytes can be on the same instruction */
> #define validate_next(t, insn, n) \
> diff --git a/tools/arch/x86/include/asm/inat.h b/tools/arch/x86/include/asm/inat.h
> index 877827b7c2c3..a61051400311 100644
> --- a/tools/arch/x86/include/asm/inat.h
> +++ b/tools/arch/x86/include/asm/inat.h
> @@ -6,7 +6,7 @@
> *
> * Written by Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> */
> -#include "inat_types.h"
> +#include "inat_types.h" /* __ignore_sync_check__ */
>
> /*
> * Internal bits. Don't use bitmasks directly, because these bits are
> diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h
> index f8772b371452..b12329de4e6e 100644
> --- a/tools/arch/x86/include/asm/insn.h
> +++ b/tools/arch/x86/include/asm/insn.h
> @@ -8,7 +8,7 @@
> */
>
> /* insn_attr_t is defined in inat.h */
> -#include "inat.h"
> +#include "inat.h" /* __ignore_sync_check__ */
>
> struct insn_field {
> union {
> @@ -99,7 +99,7 @@ enum insn_mode {
> INSN_MODE_32,
> INSN_MODE_64,
> /* Mode is determined by the current kernel build. */
> - INSN_MODE_KERN,
> + /* INSN_MODE_KERN, __ignore_sync_check__ */
> INSN_NUM_MODES,
> };
>
> diff --git a/tools/arch/x86/lib/inat.c b/tools/arch/x86/lib/inat.c
> index 4f5ed49e1b4e..dfbcc6405941 100644
> --- a/tools/arch/x86/lib/inat.c
> +++ b/tools/arch/x86/lib/inat.c
> @@ -4,7 +4,7 @@
> *
> * Written by Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> */
> -#include "../include/asm/insn.h"
> +#include "../include/asm/insn.h" /* __ignore_sync_check__ */
>
> /* Attribute tables are generated from opcode map */
> #include "inat-tables.c"
> diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c
> index c224e1569034..0824ae531019 100644
> --- a/tools/arch/x86/lib/insn.c
> +++ b/tools/arch/x86/lib/insn.c
> @@ -10,13 +10,13 @@
> #else
> #include <string.h>
> #endif
> -#include "../include/asm/inat.h"
> -#include "../include/asm/insn.h"
> +#include "../include/asm/inat.h" /* __ignore_sync_check__ */
> +#include "../include/asm/insn.h" /* __ignore_sync_check__ */
>
> #include <linux/errno.h>
> #include <linux/kconfig.h>
>
> -#include "../include/asm/emulate_prefix.h"
> +#include "../include/asm/emulate_prefix.h" /* __ignore_sync_check__ */
>
> /* Verify next sizeof(t) bytes can be on the same instruction */
> #define validate_next(t, insn, n) \
> diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh
> index dded93a2bc89..46ee37c87a80 100755
> --- a/tools/perf/check-headers.sh
> +++ b/tools/perf/check-headers.sh
> @@ -75,6 +75,13 @@ include/uapi/asm-generic/mman-common.h
> include/uapi/asm-generic/unistd.h
> '
>
> +SYNC_CHECK_FILES='
> +arch/x86/include/asm/inat.h
> +arch/x86/include/asm/insn.h
> +arch/x86/lib/inat.c
> +arch/x86/lib/insn.c
> +'
> +
> # These copies are under tools/perf/trace/beauty/ as they are not used to in
> # building object files only by scripts in tools/perf/trace/beauty/ to generate
> # tables that then gets included in .c files for things like id->string syscall
> @@ -129,6 +136,10 @@ for i in $FILES; do
> check $i -B
> done
>
> +for i in $SYNC_CHECK_FILES; do
> + check $i '-I "^.*\/*.*__ignore_sync_check__ \*/.*$"'
> +done
> +
> # diff with extra ignore lines
> check arch/x86/lib/memcpy_64.S '-I "^EXPORT_SYMBOL" -I "^#include <asm/export.h>" -I"^SYM_FUNC_START$_LOCAL$*(memcpy_$erms\|orig$)"'
> check arch/x86/lib/memset_64.S '-I "^EXPORT_SYMBOL" -I "^#include <asm/export.h>" -I"^SYM_FUNC_START$_LOCAL$*(memset_$erms\|orig$)"'
> @@ -137,10 +148,6 @@ check include/uapi/linux/mman.h '-I "^#include <$uapi/$*asm/mman.h>"'
> check include/linux/build_bug.h '-I "^#$ifndef\|endif$$ \/\/$* static_assert$"'
> check include/linux/ctype.h '-I "isdigit("'
> check lib/ctype.c '-I "^EXPORT_SYMBOL" -I "^#include <linux/export.h>" -B'
> -check arch/x86/include/asm/inat.h '-I "^#include [\"<]$asm/$*inat_types.h[\">]"'
> -check arch/x86/include/asm/insn.h '-I "^#include [\"<]$asm/$*inat.h[\">]"'
> -check arch/x86/lib/inat.c '-I "^#include [\"<]$../include/$*asm/insn.h[\">]"'
> -check arch/x86/lib/insn.c '-I "^#include [\"<]$../include/$*asm/in$at\|sn$.h[\">]" -I "^#include [\"<]$../include/$*asm/emulate_prefix.h[\">]"'
>
> # diff non-symmetric files
> check_2 tools/perf/arch/x86/entry/syscalls/syscall_64.tbl arch/x86/entry/syscalls/syscall_64.tbl
>
> --
> Regards/Gruss,
> Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette

--
Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Next message: Muchun Song: "Re: [External] Re: [PATCH v3 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page"
Previous message: Łukasz Majczak: "Re: [PATCH v2] ASoC: Intel: Skylake: Check the kcontrol against NULL"
In reply to: Borislav Petkov: "Re: [PATCH v1 03/19] x86/insn: Add an insn_decode() API"
Next in thread: Borislav Petkov: "Re: [PATCH v1 03/19] x86/insn: Add an insn_decode() API"
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