[Buildroot] [PATCH] package/binutils: fix XTENSA_NDIFF handling for PR ld/25861

Romain Naour romain.naour at gmail.com
Thu May 7 21:10:54 UTC 2020


Hi Max,

Le 01/05/2020 à 21:25, Romain Naour a écrit :
> Hi Max,
> 
> Le 30/04/2020 à 07:08, Max Filippov a écrit :
>> Fix for xtensa PR ld/25861 introduced a regression in handling negative
>> symbol differences resulting in linker performing incorrect relaxation
>> or failing to link. Fix XTENSA_NDIFF relocation handling.
>>
>> Backported from:
>> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=d548f47df4d2e3d117d504a4c9977982c78a0556
>>
>> Fixes: f0291ef4aba0 ("package/binutils: fix xtensa PR ld/25861")
>> Signed-off-by: Max Filippov <jcmvbkbc at gmail.com>

It seems elf2flt used by qemu_xtensa_lx60_nommu_defconfig doesn't support
R_XTENSA_PDIFF32:

  elf2flt: 267 bad relocs

https://gitlab.com/kubu93/buildroot/-/jobs/543293510

(Note gcc 9.3.0 is used here in gitlab and reproduced locally with gcc 8.4.0).

Best regards,
Romain


> 
> Tested-by: Romain Naour <romain.naour at gmail.com>
> 
> Best regards,
> Romain
> 
> 
>> ---
>>  ...TENSA_NDIFF-handling-for-PR-ld-25861.patch | 128 ++++++++++++++++++
>>  ...TENSA_NDIFF-handling-for-PR-ld-25861.patch | 128 ++++++++++++++++++
>>  ...TENSA_NDIFF-handling-for-PR-ld-25861.patch | 128 ++++++++++++++++++
>>  3 files changed, 384 insertions(+)
>>  create mode 100644 package/binutils/2.31.1/0020-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>>  create mode 100644 package/binutils/2.32/0009-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>>  create mode 100644 package/binutils/2.33.1/0006-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>>
>> diff --git a/package/binutils/2.31.1/0020-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch b/package/binutils/2.31.1/0020-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>> new file mode 100644
>> index 000000000000..ebb08fd7dffe
>> --- /dev/null
>> +++ b/package/binutils/2.31.1/0020-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>> @@ -0,0 +1,128 @@
>> +From 735321812435ae278d3766a3371f55937dc776d6 Mon Sep 17 00:00:00 2001
>> +From: Max Filippov <jcmvbkbc at gmail.com>
>> +Date: Sat, 25 Apr 2020 00:40:25 -0700
>> +Subject: [PATCH] xtensa: fix XTENSA_NDIFF handling for PR ld/25861
>> +
>> +Fields marked with XTENSA_NDIFF relocations are not negated, they only
>> +have sign bits removed. Don't negate their values when relaxation is
>> +performed. Don't add sign bits when the value is zero. Report overflow
>> +when the result has negative sign but all significant bits are zero.
>> +
>> +2020-04-29  Max Filippov  <jcmvbkbc at gmail.com>
>> +bfd/
>> +	* elf32-xtensa.c (relax_section): Don't negate diff_value for
>> +	XTENSA_NDIFF relocations. Don't add sign bits whe diff_value
>> +	equals 0. Report overflow when the result has negative sign but
>> +	all significant bits are zero.
>> +
>> +Signed-off-by: Max Filippov <jcmvbkbc at gmail.com>
>> +---
>> +Backported from: d548f47df4d2e3d117d504a4c9977982c78a0556
>> +
>> + bfd/elf32-xtensa.c                   | 26 +++++++++++++++-----------
>> + 1 file changed, 15 insertions(+), 11 deletions(-)
>> +
>> +diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
>> +index fded42d52a9a..4327b027911f 100644
>> +--- a/bfd/elf32-xtensa.c
>> ++++ b/bfd/elf32-xtensa.c
>> +@@ -9670,37 +9670,44 @@ relax_section (bfd *abfd, asection *sec, struct bfd_link_info *link_info)
>> + 		  switch (r_type)
>> + 		    {
>> + 		    case R_XTENSA_DIFF8:
>> ++		      diff_mask = 0x7f;
>> + 		      diff_value =
>> + 			bfd_get_signed_8 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF16:
>> ++		      diff_mask = 0x7fff;
>> + 		      diff_value =
>> + 			bfd_get_signed_16 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF32:
>> ++		      diff_mask = 0x7fffffff;
>> + 		      diff_value =
>> + 			bfd_get_signed_32 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF8:
>> + 		    case R_XTENSA_NDIFF8:
>> ++		      diff_mask = 0xff;
>> + 		      diff_value =
>> + 			bfd_get_8 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF16:
>> + 		    case R_XTENSA_NDIFF16:
>> ++		      diff_mask = 0xffff;
>> + 		      diff_value =
>> + 			bfd_get_16 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF32:
>> + 		    case R_XTENSA_NDIFF32:
>> ++		      diff_mask = 0xffffffff;
>> + 		      diff_value =
>> + 			bfd_get_32 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    }
>> + 
>> + 		  if (r_type >= R_XTENSA_NDIFF8
>> +-		      && r_type <= R_XTENSA_NDIFF32)
>> +-		    diff_value = -diff_value;
>> ++		      && r_type <= R_XTENSA_NDIFF32
>> ++		      && diff_value)
>> ++		    diff_value |= ~diff_mask;
>> + 
>> + 		  new_end_offset = offset_with_removed_text_map
>> + 		    (&target_relax_info->action_list,
>> +@@ -9710,43 +9717,40 @@ relax_section (bfd *abfd, asection *sec, struct bfd_link_info *link_info)
>> + 		  switch (r_type)
>> + 		    {
>> + 		    case R_XTENSA_DIFF8:
>> +-		      diff_mask = 0x7f;
>> + 		      bfd_put_signed_8 (abfd, diff_value,
>> + 				 &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF16:
>> +-		      diff_mask = 0x7fff;
>> + 		      bfd_put_signed_16 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF32:
>> +-		      diff_mask = 0x7fffffff;
>> + 		      bfd_put_signed_32 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF8:
>> + 		    case R_XTENSA_NDIFF8:
>> +-		      diff_mask = 0xff;
>> + 		      bfd_put_8 (abfd, diff_value,
>> + 				 &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF16:
>> + 		    case R_XTENSA_NDIFF16:
>> +-		      diff_mask = 0xffff;
>> + 		      bfd_put_16 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF32:
>> + 		    case R_XTENSA_NDIFF32:
>> +-		      diff_mask = 0xffffffff;
>> + 		      bfd_put_32 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    }
>> + 
>> +-		  /* Check for overflow. Sign bits must be all zeroes or all ones */
>> +-		  if ((diff_value & ~diff_mask) != 0 &&
>> +-		      (diff_value & ~diff_mask) != (-1 & ~diff_mask))
>> ++		  /* Check for overflow. Sign bits must be all zeroes or
>> ++		     all ones.  When sign bits are all ones diff_value
>> ++		     may not be zero.  */
>> ++		  if (((diff_value & ~diff_mask) != 0
>> ++		       && (diff_value & ~diff_mask) != ~diff_mask)
>> ++		      || (diff_value && (bfd_vma) diff_value == ~diff_mask))
>> + 		    {
>> + 		      (*link_info->callbacks->reloc_dangerous)
>> + 			(link_info, _("overflow after relaxation"),
>> +-- 
>> +2.20.1
>> +
>> diff --git a/package/binutils/2.32/0009-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch b/package/binutils/2.32/0009-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>> new file mode 100644
>> index 000000000000..ebb08fd7dffe
>> --- /dev/null
>> +++ b/package/binutils/2.32/0009-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>> @@ -0,0 +1,128 @@
>> +From 735321812435ae278d3766a3371f55937dc776d6 Mon Sep 17 00:00:00 2001
>> +From: Max Filippov <jcmvbkbc at gmail.com>
>> +Date: Sat, 25 Apr 2020 00:40:25 -0700
>> +Subject: [PATCH] xtensa: fix XTENSA_NDIFF handling for PR ld/25861
>> +
>> +Fields marked with XTENSA_NDIFF relocations are not negated, they only
>> +have sign bits removed. Don't negate their values when relaxation is
>> +performed. Don't add sign bits when the value is zero. Report overflow
>> +when the result has negative sign but all significant bits are zero.
>> +
>> +2020-04-29  Max Filippov  <jcmvbkbc at gmail.com>
>> +bfd/
>> +	* elf32-xtensa.c (relax_section): Don't negate diff_value for
>> +	XTENSA_NDIFF relocations. Don't add sign bits whe diff_value
>> +	equals 0. Report overflow when the result has negative sign but
>> +	all significant bits are zero.
>> +
>> +Signed-off-by: Max Filippov <jcmvbkbc at gmail.com>
>> +---
>> +Backported from: d548f47df4d2e3d117d504a4c9977982c78a0556
>> +
>> + bfd/elf32-xtensa.c                   | 26 +++++++++++++++-----------
>> + 1 file changed, 15 insertions(+), 11 deletions(-)
>> +
>> +diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
>> +index fded42d52a9a..4327b027911f 100644
>> +--- a/bfd/elf32-xtensa.c
>> ++++ b/bfd/elf32-xtensa.c
>> +@@ -9670,37 +9670,44 @@ relax_section (bfd *abfd, asection *sec, struct bfd_link_info *link_info)
>> + 		  switch (r_type)
>> + 		    {
>> + 		    case R_XTENSA_DIFF8:
>> ++		      diff_mask = 0x7f;
>> + 		      diff_value =
>> + 			bfd_get_signed_8 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF16:
>> ++		      diff_mask = 0x7fff;
>> + 		      diff_value =
>> + 			bfd_get_signed_16 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF32:
>> ++		      diff_mask = 0x7fffffff;
>> + 		      diff_value =
>> + 			bfd_get_signed_32 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF8:
>> + 		    case R_XTENSA_NDIFF8:
>> ++		      diff_mask = 0xff;
>> + 		      diff_value =
>> + 			bfd_get_8 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF16:
>> + 		    case R_XTENSA_NDIFF16:
>> ++		      diff_mask = 0xffff;
>> + 		      diff_value =
>> + 			bfd_get_16 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF32:
>> + 		    case R_XTENSA_NDIFF32:
>> ++		      diff_mask = 0xffffffff;
>> + 		      diff_value =
>> + 			bfd_get_32 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    }
>> + 
>> + 		  if (r_type >= R_XTENSA_NDIFF8
>> +-		      && r_type <= R_XTENSA_NDIFF32)
>> +-		    diff_value = -diff_value;
>> ++		      && r_type <= R_XTENSA_NDIFF32
>> ++		      && diff_value)
>> ++		    diff_value |= ~diff_mask;
>> + 
>> + 		  new_end_offset = offset_with_removed_text_map
>> + 		    (&target_relax_info->action_list,
>> +@@ -9710,43 +9717,40 @@ relax_section (bfd *abfd, asection *sec, struct bfd_link_info *link_info)
>> + 		  switch (r_type)
>> + 		    {
>> + 		    case R_XTENSA_DIFF8:
>> +-		      diff_mask = 0x7f;
>> + 		      bfd_put_signed_8 (abfd, diff_value,
>> + 				 &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF16:
>> +-		      diff_mask = 0x7fff;
>> + 		      bfd_put_signed_16 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF32:
>> +-		      diff_mask = 0x7fffffff;
>> + 		      bfd_put_signed_32 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF8:
>> + 		    case R_XTENSA_NDIFF8:
>> +-		      diff_mask = 0xff;
>> + 		      bfd_put_8 (abfd, diff_value,
>> + 				 &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF16:
>> + 		    case R_XTENSA_NDIFF16:
>> +-		      diff_mask = 0xffff;
>> + 		      bfd_put_16 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF32:
>> + 		    case R_XTENSA_NDIFF32:
>> +-		      diff_mask = 0xffffffff;
>> + 		      bfd_put_32 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    }
>> + 
>> +-		  /* Check for overflow. Sign bits must be all zeroes or all ones */
>> +-		  if ((diff_value & ~diff_mask) != 0 &&
>> +-		      (diff_value & ~diff_mask) != (-1 & ~diff_mask))
>> ++		  /* Check for overflow. Sign bits must be all zeroes or
>> ++		     all ones.  When sign bits are all ones diff_value
>> ++		     may not be zero.  */
>> ++		  if (((diff_value & ~diff_mask) != 0
>> ++		       && (diff_value & ~diff_mask) != ~diff_mask)
>> ++		      || (diff_value && (bfd_vma) diff_value == ~diff_mask))
>> + 		    {
>> + 		      (*link_info->callbacks->reloc_dangerous)
>> + 			(link_info, _("overflow after relaxation"),
>> +-- 
>> +2.20.1
>> +
>> diff --git a/package/binutils/2.33.1/0006-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch b/package/binutils/2.33.1/0006-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>> new file mode 100644
>> index 000000000000..ebb08fd7dffe
>> --- /dev/null
>> +++ b/package/binutils/2.33.1/0006-xtensa-fix-XTENSA_NDIFF-handling-for-PR-ld-25861.patch
>> @@ -0,0 +1,128 @@
>> +From 735321812435ae278d3766a3371f55937dc776d6 Mon Sep 17 00:00:00 2001
>> +From: Max Filippov <jcmvbkbc at gmail.com>
>> +Date: Sat, 25 Apr 2020 00:40:25 -0700
>> +Subject: [PATCH] xtensa: fix XTENSA_NDIFF handling for PR ld/25861
>> +
>> +Fields marked with XTENSA_NDIFF relocations are not negated, they only
>> +have sign bits removed. Don't negate their values when relaxation is
>> +performed. Don't add sign bits when the value is zero. Report overflow
>> +when the result has negative sign but all significant bits are zero.
>> +
>> +2020-04-29  Max Filippov  <jcmvbkbc at gmail.com>
>> +bfd/
>> +	* elf32-xtensa.c (relax_section): Don't negate diff_value for
>> +	XTENSA_NDIFF relocations. Don't add sign bits whe diff_value
>> +	equals 0. Report overflow when the result has negative sign but
>> +	all significant bits are zero.
>> +
>> +Signed-off-by: Max Filippov <jcmvbkbc at gmail.com>
>> +---
>> +Backported from: d548f47df4d2e3d117d504a4c9977982c78a0556
>> +
>> + bfd/elf32-xtensa.c                   | 26 +++++++++++++++-----------
>> + 1 file changed, 15 insertions(+), 11 deletions(-)
>> +
>> +diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
>> +index fded42d52a9a..4327b027911f 100644
>> +--- a/bfd/elf32-xtensa.c
>> ++++ b/bfd/elf32-xtensa.c
>> +@@ -9670,37 +9670,44 @@ relax_section (bfd *abfd, asection *sec, struct bfd_link_info *link_info)
>> + 		  switch (r_type)
>> + 		    {
>> + 		    case R_XTENSA_DIFF8:
>> ++		      diff_mask = 0x7f;
>> + 		      diff_value =
>> + 			bfd_get_signed_8 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF16:
>> ++		      diff_mask = 0x7fff;
>> + 		      diff_value =
>> + 			bfd_get_signed_16 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF32:
>> ++		      diff_mask = 0x7fffffff;
>> + 		      diff_value =
>> + 			bfd_get_signed_32 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF8:
>> + 		    case R_XTENSA_NDIFF8:
>> ++		      diff_mask = 0xff;
>> + 		      diff_value =
>> + 			bfd_get_8 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF16:
>> + 		    case R_XTENSA_NDIFF16:
>> ++		      diff_mask = 0xffff;
>> + 		      diff_value =
>> + 			bfd_get_16 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF32:
>> + 		    case R_XTENSA_NDIFF32:
>> ++		      diff_mask = 0xffffffff;
>> + 		      diff_value =
>> + 			bfd_get_32 (abfd, &contents[old_source_offset]);
>> + 		      break;
>> + 		    }
>> + 
>> + 		  if (r_type >= R_XTENSA_NDIFF8
>> +-		      && r_type <= R_XTENSA_NDIFF32)
>> +-		    diff_value = -diff_value;
>> ++		      && r_type <= R_XTENSA_NDIFF32
>> ++		      && diff_value)
>> ++		    diff_value |= ~diff_mask;
>> + 
>> + 		  new_end_offset = offset_with_removed_text_map
>> + 		    (&target_relax_info->action_list,
>> +@@ -9710,43 +9717,40 @@ relax_section (bfd *abfd, asection *sec, struct bfd_link_info *link_info)
>> + 		  switch (r_type)
>> + 		    {
>> + 		    case R_XTENSA_DIFF8:
>> +-		      diff_mask = 0x7f;
>> + 		      bfd_put_signed_8 (abfd, diff_value,
>> + 				 &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF16:
>> +-		      diff_mask = 0x7fff;
>> + 		      bfd_put_signed_16 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_DIFF32:
>> +-		      diff_mask = 0x7fffffff;
>> + 		      bfd_put_signed_32 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF8:
>> + 		    case R_XTENSA_NDIFF8:
>> +-		      diff_mask = 0xff;
>> + 		      bfd_put_8 (abfd, diff_value,
>> + 				 &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF16:
>> + 		    case R_XTENSA_NDIFF16:
>> +-		      diff_mask = 0xffff;
>> + 		      bfd_put_16 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    case R_XTENSA_PDIFF32:
>> + 		    case R_XTENSA_NDIFF32:
>> +-		      diff_mask = 0xffffffff;
>> + 		      bfd_put_32 (abfd, diff_value,
>> + 				  &contents[old_source_offset]);
>> + 		      break;
>> + 		    }
>> + 
>> +-		  /* Check for overflow. Sign bits must be all zeroes or all ones */
>> +-		  if ((diff_value & ~diff_mask) != 0 &&
>> +-		      (diff_value & ~diff_mask) != (-1 & ~diff_mask))
>> ++		  /* Check for overflow. Sign bits must be all zeroes or
>> ++		     all ones.  When sign bits are all ones diff_value
>> ++		     may not be zero.  */
>> ++		  if (((diff_value & ~diff_mask) != 0
>> ++		       && (diff_value & ~diff_mask) != ~diff_mask)
>> ++		      || (diff_value && (bfd_vma) diff_value == ~diff_mask))
>> + 		    {
>> + 		      (*link_info->callbacks->reloc_dangerous)
>> + 			(link_info, _("overflow after relaxation"),
>> +-- 
>> +2.20.1
>> +
>>
> 



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