* [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
@ 2021-10-20 9:58 Todor Buyukliev
2021-12-10 15:16 ` Todor Buyukliev
2021-12-10 15:29 ` H.J. Lu
0 siblings, 2 replies; 4+ messages in thread
From: Todor Buyukliev @ 2021-10-20 9:58 UTC (permalink / raw)
To: binutils
hi all,
here’s a patch that we need. it’s against 2.34. can it be merged to master?
regards,
todor
[PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
---
gas/ChangeLog | 9 +++++++++
gas/config/tc-i386.c | 15 +++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/gas/ChangeLog b/gas/ChangeLog
index ac92d076ef9..f70c8d45db9 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,12 @@
+2021-05-28 Todor Buyukliev <tbuyukliev@vmware.com>
+
+ * config/t-i386.c (disable_plt32): New declaration.
+ (md_show_usage): Add -mno-plt32.
+ (need_plt32_p): Return false if disable_plt32 is set.
+ (OPTION_MNO_PLT32): New define.
+ (md_longopts): Support mno-plt32 option.
+ (md_parse_option): Likewise.
+
2020-02-10 H.J. Lu <hongjiu.lu@intel.com>
PR gas/25516
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 3f1d4cab7e5..1af97c0d149 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -592,6 +592,9 @@ static int use_big_obj = 0;
#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
/* 1 if generating code for a shared library. */
static int shared = 0;
+
+/* Non-zero to disable PLT32 relocations. */
+static int disable_plt32 = 0;
#endif
/* 1 for intel syntax,
@@ -7991,6 +7994,10 @@ need_plt32_p (symbolS *s)
return FALSE;
#endif
+ /* Don't emit PLT32 relocation if asked to. */
+ if (disable_plt32)
+ return FALSE;
+
/* Since there is no need to prepare for PLT branch on x86-64, we
can generate R_X86_64_PLT32, instead of R_X86_64_PC32, which can
be used as a marker for 32-bit PC-relative branches. */
@@ -12051,6 +12058,7 @@ const char *md_shortopts = "qnO::";
#define OPTION_MALIGN_BRANCH_PREFIX_SIZE (OPTION_MD_BASE + 28)
#define OPTION_MALIGN_BRANCH (OPTION_MD_BASE + 29)
#define OPTION_MBRANCHES_WITH_32B_BOUNDARIES (OPTION_MD_BASE + 30)
+#define OPTION_MNO_PLT32 (OPTION_MD_BASE + 31)
struct option md_longopts[] =
{
@@ -12063,6 +12071,7 @@ struct option md_longopts[] =
{"x32", no_argument, NULL, OPTION_X32},
{"mshared", no_argument, NULL, OPTION_MSHARED},
{"mx86-used-note", required_argument, NULL, OPTION_X86_USED_NOTE},
+ {"mno-plt32", no_argument, NULL, OPTION_MNO_PLT32},
#endif
{"divide", no_argument, NULL, OPTION_DIVIDE},
{"march", required_argument, NULL, OPTION_MARCH},
@@ -12193,6 +12202,10 @@ md_parse_option (int c, const char *arg)
else
as_fatal (_("32bit x86_64 is only supported for ELF"));
break;
+
+ case OPTION_MNO_PLT32:
+ disable_plt32 = 1;
+ break;
#endif
case OPTION_32:
@@ -12791,6 +12804,8 @@ md_show_usage (FILE *stream)
fprintf (stream, _("(default: no)\n"));
fprintf (stream, _("\
generate x86 used ISA and feature properties\n"));
+ fprintf (stream, _("\
+ -mno-plt32 don't generate PLT32 relocations\n"));
#endif
#if defined (TE_PE) || defined (TE_PEP)
fprintf (stream, _("\
--
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
2021-10-20 9:58 [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations Todor Buyukliev
@ 2021-12-10 15:16 ` Todor Buyukliev
2021-12-13 5:17 ` Fangrui Song
2021-12-10 15:29 ` H.J. Lu
1 sibling, 1 reply; 4+ messages in thread
From: Todor Buyukliev @ 2021-12-10 15:16 UTC (permalink / raw)
To: binutils
hi, any interest in this?
From: Todor Buyukliev <tbuyukliev@vmware.com>
Date: Wednesday, 20 October 2021, 12:58
To: binutils@sourceware.org <binutils@sourceware.org>
Subject: [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
hi all,
here’s a patch that we need. it’s against 2.34. can it be merged to master?
regards,
todor
[PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
---
gas/ChangeLog | 9 +++++++++
gas/config/tc-i386.c | 15 +++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/gas/ChangeLog b/gas/ChangeLog
index ac92d076ef9..f70c8d45db9 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,12 @@
+2021-05-28 Todor Buyukliev <tbuyukliev@vmware.com>
+
+ * config/t-i386.c (disable_plt32): New declaration.
+ (md_show_usage): Add -mno-plt32.
+ (need_plt32_p): Return false if disable_plt32 is set.
+ (OPTION_MNO_PLT32): New define.
+ (md_longopts): Support mno-plt32 option.
+ (md_parse_option): Likewise.
+
2020-02-10 H.J. Lu <hongjiu.lu@intel.com>
PR gas/25516
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 3f1d4cab7e5..1af97c0d149 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -592,6 +592,9 @@ static int use_big_obj = 0;
#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
/* 1 if generating code for a shared library. */
static int shared = 0;
+
+/* Non-zero to disable PLT32 relocations. */
+static int disable_plt32 = 0;
#endif
/* 1 for intel syntax,
@@ -7991,6 +7994,10 @@ need_plt32_p (symbolS *s)
return FALSE;
#endif
+ /* Don't emit PLT32 relocation if asked to. */
+ if (disable_plt32)
+ return FALSE;
+
/* Since there is no need to prepare for PLT branch on x86-64, we
can generate R_X86_64_PLT32, instead of R_X86_64_PC32, which can
be used as a marker for 32-bit PC-relative branches. */
@@ -12051,6 +12058,7 @@ const char *md_shortopts = "qnO::";
#define OPTION_MALIGN_BRANCH_PREFIX_SIZE (OPTION_MD_BASE + 28)
#define OPTION_MALIGN_BRANCH (OPTION_MD_BASE + 29)
#define OPTION_MBRANCHES_WITH_32B_BOUNDARIES (OPTION_MD_BASE + 30)
+#define OPTION_MNO_PLT32 (OPTION_MD_BASE + 31)
struct option md_longopts[] =
{
@@ -12063,6 +12071,7 @@ struct option md_longopts[] =
{"x32", no_argument, NULL, OPTION_X32},
{"mshared", no_argument, NULL, OPTION_MSHARED},
{"mx86-used-note", required_argument, NULL, OPTION_X86_USED_NOTE},
+ {"mno-plt32", no_argument, NULL, OPTION_MNO_PLT32},
#endif
{"divide", no_argument, NULL, OPTION_DIVIDE},
{"march", required_argument, NULL, OPTION_MARCH},
@@ -12193,6 +12202,10 @@ md_parse_option (int c, const char *arg)
else
as_fatal (_("32bit x86_64 is only supported for ELF"));
break;
+
+ case OPTION_MNO_PLT32:
+ disable_plt32 = 1;
+ break;
#endif
case OPTION_32:
@@ -12791,6 +12804,8 @@ md_show_usage (FILE *stream)
fprintf (stream, _("(default: no)\n"));
fprintf (stream, _("\
generate x86 used ISA and feature properties\n"));
+ fprintf (stream, _("\
+ -mno-plt32 don't generate PLT32 relocations\n"));
#endif
#if defined (TE_PE) || defined (TE_PEP)
fprintf (stream, _("\
--
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
2021-12-10 15:16 ` Todor Buyukliev
@ 2021-12-13 5:17 ` Fangrui Song
0 siblings, 0 replies; 4+ messages in thread
From: Fangrui Song @ 2021-12-13 5:17 UTC (permalink / raw)
To: Todor Buyukliev; +Cc: binutils
On 2021-12-10, Todor Buyukliev via Binutils wrote:
>hi, any interest in this?
This goes in the wrong direction.
Can you elaborate why your projects cannot handle R_X86_64_PLT32?
Using R_X86_64_PC32/R_386_PC32 is actually not good because it carries
strictly less information when the intention is to jump to the target.
See https://maskray.me/blog/2021-01-09-copy-relocations-canonical-plt-entries-and-protected
about canonical PLT entries.
>From: Todor Buyukliev <tbuyukliev@vmware.com>
>Date: Wednesday, 20 October 2021, 12:58
>To: binutils@sourceware.org <binutils@sourceware.org>
>Subject: [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
>hi all,
>
>here’s a patch that we need. it’s against 2.34. can it be merged to master?
>
>regards,
>todor
>
>
>[PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
>
>---
>gas/ChangeLog | 9 +++++++++
>gas/config/tc-i386.c | 15 +++++++++++++++
>2 files changed, 24 insertions(+)
>
>diff --git a/gas/ChangeLog b/gas/ChangeLog
>index ac92d076ef9..f70c8d45db9 100644
>--- a/gas/ChangeLog
>+++ b/gas/ChangeLog
>@@ -1,3 +1,12 @@
>+2021-05-28 Todor Buyukliev <tbuyukliev@vmware.com>
>+
>+ * config/t-i386.c (disable_plt32): New declaration.
>+ (md_show_usage): Add -mno-plt32.
>+ (need_plt32_p): Return false if disable_plt32 is set.
>+ (OPTION_MNO_PLT32): New define.
>+ (md_longopts): Support mno-plt32 option.
>+ (md_parse_option): Likewise.
>+
>2020-02-10 H.J. Lu <hongjiu.lu@intel.com>
> PR gas/25516
>diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
>index 3f1d4cab7e5..1af97c0d149 100644
>--- a/gas/config/tc-i386.c
>+++ b/gas/config/tc-i386.c
>@@ -592,6 +592,9 @@ static int use_big_obj = 0;
>#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
>/* 1 if generating code for a shared library. */
>static int shared = 0;
>+
>+/* Non-zero to disable PLT32 relocations. */
>+static int disable_plt32 = 0;
>#endif
> /* 1 for intel syntax,
>@@ -7991,6 +7994,10 @@ need_plt32_p (symbolS *s)
> return FALSE;
>#endif
>+ /* Don't emit PLT32 relocation if asked to. */
>+ if (disable_plt32)
>+ return FALSE;
>+
> /* Since there is no need to prepare for PLT branch on x86-64, we
> can generate R_X86_64_PLT32, instead of R_X86_64_PC32, which can
> be used as a marker for 32-bit PC-relative branches. */
>@@ -12051,6 +12058,7 @@ const char *md_shortopts = "qnO::";
>#define OPTION_MALIGN_BRANCH_PREFIX_SIZE (OPTION_MD_BASE + 28)
>#define OPTION_MALIGN_BRANCH (OPTION_MD_BASE + 29)
>#define OPTION_MBRANCHES_WITH_32B_BOUNDARIES (OPTION_MD_BASE + 30)
>+#define OPTION_MNO_PLT32 (OPTION_MD_BASE + 31)
> struct option md_longopts[] =
>{
>@@ -12063,6 +12071,7 @@ struct option md_longopts[] =
> {"x32", no_argument, NULL, OPTION_X32},
> {"mshared", no_argument, NULL, OPTION_MSHARED},
> {"mx86-used-note", required_argument, NULL, OPTION_X86_USED_NOTE},
>+ {"mno-plt32", no_argument, NULL, OPTION_MNO_PLT32},
>#endif
> {"divide", no_argument, NULL, OPTION_DIVIDE},
> {"march", required_argument, NULL, OPTION_MARCH},
>@@ -12193,6 +12202,10 @@ md_parse_option (int c, const char *arg)
> else
> as_fatal (_("32bit x86_64 is only supported for ELF"));
> break;
>+
>+ case OPTION_MNO_PLT32:
>+ disable_plt32 = 1;
>+ break;
>#endif
> case OPTION_32:
>@@ -12791,6 +12804,8 @@ md_show_usage (FILE *stream)
> fprintf (stream, _("(default: no)\n"));
> fprintf (stream, _("\
> generate x86 used ISA and feature properties\n"));
>+ fprintf (stream, _("\
>+ -mno-plt32 don't generate PLT32 relocations\n"));
>#endif
>#if defined (TE_PE) || defined (TE_PEP)
> fprintf (stream, _("\
>--
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
2021-10-20 9:58 [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations Todor Buyukliev
2021-12-10 15:16 ` Todor Buyukliev
@ 2021-12-10 15:29 ` H.J. Lu
1 sibling, 0 replies; 4+ messages in thread
From: H.J. Lu @ 2021-12-10 15:29 UTC (permalink / raw)
To: Todor Buyukliev; +Cc: binutils
On Wed, Oct 20, 2021 at 2:59 AM Todor Buyukliev via Binutils
<binutils@sourceware.org> wrote:
>
> hi all,
>
> here’s a patch that we need. it’s against 2.34. can it be merged to master?
>
> regards,
> todor
1. Need an entry in NEWS.
2. Need document change.
3. -mno-plt32 option name is misleading. It doesn't disable PLT32 for
call foo@PLT
It just avoids PLT32 for
call foo
>
> [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations
>
> ---
> gas/ChangeLog | 9 +++++++++
> gas/config/tc-i386.c | 15 +++++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/gas/ChangeLog b/gas/ChangeLog
> index ac92d076ef9..f70c8d45db9 100644
> --- a/gas/ChangeLog
> +++ b/gas/ChangeLog
> @@ -1,3 +1,12 @@
> +2021-05-28 Todor Buyukliev <tbuyukliev@vmware.com>
> +
> + * config/t-i386.c (disable_plt32): New declaration.
> + (md_show_usage): Add -mno-plt32.
> + (need_plt32_p): Return false if disable_plt32 is set.
> + (OPTION_MNO_PLT32): New define.
> + (md_longopts): Support mno-plt32 option.
> + (md_parse_option): Likewise.
> +
> 2020-02-10 H.J. Lu <hongjiu.lu@intel.com>
> PR gas/25516
> diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
> index 3f1d4cab7e5..1af97c0d149 100644
> --- a/gas/config/tc-i386.c
> +++ b/gas/config/tc-i386.c
> @@ -592,6 +592,9 @@ static int use_big_obj = 0;
> #if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
> /* 1 if generating code for a shared library. */
> static int shared = 0;
> +
> +/* Non-zero to disable PLT32 relocations. */
> +static int disable_plt32 = 0;
> #endif
> /* 1 for intel syntax,
> @@ -7991,6 +7994,10 @@ need_plt32_p (symbolS *s)
> return FALSE;
> #endif
> + /* Don't emit PLT32 relocation if asked to. */
> + if (disable_plt32)
> + return FALSE;
> +
> /* Since there is no need to prepare for PLT branch on x86-64, we
> can generate R_X86_64_PLT32, instead of R_X86_64_PC32, which can
> be used as a marker for 32-bit PC-relative branches. */
> @@ -12051,6 +12058,7 @@ const char *md_shortopts = "qnO::";
> #define OPTION_MALIGN_BRANCH_PREFIX_SIZE (OPTION_MD_BASE + 28)
> #define OPTION_MALIGN_BRANCH (OPTION_MD_BASE + 29)
> #define OPTION_MBRANCHES_WITH_32B_BOUNDARIES (OPTION_MD_BASE + 30)
> +#define OPTION_MNO_PLT32 (OPTION_MD_BASE + 31)
> struct option md_longopts[] =
> {
> @@ -12063,6 +12071,7 @@ struct option md_longopts[] =
> {"x32", no_argument, NULL, OPTION_X32},
> {"mshared", no_argument, NULL, OPTION_MSHARED},
> {"mx86-used-note", required_argument, NULL, OPTION_X86_USED_NOTE},
> + {"mno-plt32", no_argument, NULL, OPTION_MNO_PLT32},
> #endif
> {"divide", no_argument, NULL, OPTION_DIVIDE},
> {"march", required_argument, NULL, OPTION_MARCH},
> @@ -12193,6 +12202,10 @@ md_parse_option (int c, const char *arg)
> else
> as_fatal (_("32bit x86_64 is only supported for ELF"));
> break;
> +
> + case OPTION_MNO_PLT32:
> + disable_plt32 = 1;
> + break;
> #endif
> case OPTION_32:
> @@ -12791,6 +12804,8 @@ md_show_usage (FILE *stream)
> fprintf (stream, _("(default: no)\n"));
> fprintf (stream, _("\
> generate x86 used ISA and feature properties\n"));
> + fprintf (stream, _("\
> + -mno-plt32 don't generate PLT32 relocations\n"));
> #endif
> #if defined (TE_PE) || defined (TE_PEP)
> fprintf (stream, _("\
> --
>
--
H.J.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-10-20 9:58 [PATCH] gas, x86: add -mno-plt32 option to disable PLT32 relocations Todor Buyukliev
2021-12-10 15:16 ` Todor Buyukliev
2021-12-13 5:17 ` Fangrui Song
2021-12-10 15:29 ` H.J. Lu
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