From: Fangrui Song <i@maskray.me>
To: Nick Clifton <nickc@redhat.com>
Cc: binutils@sourceware.org
Subject: Re: Commit: readelf: Improve display of RELR relocations
Date: Fri, 12 Apr 2024 15:04:28 -0700 [thread overview]
Message-ID: <DS7PR12MB57659BE02086ACBECDD35B0ACB042@DS7PR12MB5765.namprd12.prod.outlook.com> (raw)
In-Reply-To: <CAN30aBFj+_Yfs8+WrC7aM0ZWQihGoZ8nMk2DHO7Xkxzw6PgqSA@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 3450 bytes --]
On Fri, Apr 12, 2024 at 11:44 AM Fangrui Song <i@maskray.me> wrote:
>
> On Thu, Apr 11, 2024 at 8:56 AM Nick Clifton <nickc@redhat.com> wrote:
> >
> > Hi Guys,
> >
> > Currently readelf's display of RELR relocations is woefully lacking in
> > information. So I am going to apply the attached patch in order to
> > improve this. For example:
> >
> > readelf -r /lib64/libc.so.6
> >
> > Before patch:
> >
> > Relocation section '.relr.dyn' at offset 0x259c0 contains 32 entries:
> > 1067 offsets
> > 00000000001d4ca0
> > 00000000001d4cb0
> > 00000000001d4cb8
> > 00000000001d4cc0
> > 00000000001d4ce0
> > 00000000001d4d00
> > ...
>
> Hi Nick,
>
> Thanks for the improvement!
>
> > After patch:
> >
> > Relocation section '.relr.dyn' at offset 0x259c0 contains 32 entries:
> > Index: Entry: Address relocated Symbolic Address
> > 0000: 00000000001d4ca0 00000000001d4ca0 __FRAME_END__ + 0x1ddc
> > 0001: ffffdff8ee15911d 00000000001d4cb0 __FRAME_END__ + 0x1dec
> > 00000000001d4cb8 __FRAME_END__ + 0x1df4
> > 00000000001d4cc0 __dso_handle
> > 00000000001d4ce0 _nl_C_LC_CTYPE
> > 00000000001d4d00 _nl_C_LC_CTYPE + 0x20
> > ...
> > In particular this new format shows the actual values held in the RELR
> > section - allowing a user to potentially spot problems - as well as
> > providing an address to symbol mapping for ease in understanding what
> > is being relocated.
> >
> > The patch also checks for malformed RELR entries (such as an entry
> > with a value of just 1).
> >
> > The patch includes a new binutils test and updates to linker tests
> > that were checking the RELR relocations.
> >
> > Cheers
> > Nick
> >
>
> I have some minor suggestions.
>
> * Do we need the ":" in "Entry:"? I presume not because the strings
> don't end with ":".
> * "Address relocated" feels verbose. Would a simple "Address" be
> acceptable? That aligns with "Offset" (instead of "Offset relocated")
> for REL/RELA output.
> * Do we need the "Notes" column (new starting address, start of
> bitmap)? The start of a new address/bitmap can be inferred from the
> presence of the "Index" or "Entry" column string. The user needs to
> look at the odd/even bit to figure out whether it is a start address
> or a bitmap, but this information seems straightforward. Omitting the
> column might make parsing slightly easier.
>
>
> Relocation section '.relr.dyn' at offset 0x7ae8 contains 6372 entries:
> Index: Entry: Address relocated Symbolic Address Notes
> 0000: 00000000042c0350 00000000042c0350
> __do_global_dtors_aux_fini_array_entry (new starting address)
> 0001: ffffffffffffffff 00000000042c0358
> __frame_dummy_init_array_entry (start of bitmap) #### (start of
> bitmap) makes it slightly awkward to parse the symbolic address
> 00000000042c0360 __frame_dummy_init_array_entry + 0x8
> 00000000042c0368 __frame_dummy_init_array_entry + 0x10
> 00000000042c0370 __frame_dummy_init_array_entry + 0x18
> 00000000042c0378 __frame_dummy_init_array_entry + 0x20
>
Let's see if some of the ideas in the attached patch are practical :)
[-- Attachment #2: readelf-relr.patch --]
[-- Type: text/x-patch, Size: 10945 bytes --]
From 34a3e029e6f360d3b0fdc6ac6cc2f33ae21c0308 Mon Sep 17 00:00:00 2001
From: Fangrui Song <maskray@gcc.gnu.org>
Date: Fri, 12 Apr 2024 14:29:28 -0700
Subject: [PATCH] readelf: Adjust display of RELR relocations
* Remove the colon for "Entry"
* Unify "Address relocated" (--wide) and "Address" (narrow) to "Address".
* Remove the "Notes" column. The information can be inferred from entry%2.
---
binutils/readelf.c | 20 +++-----------------
ld/testsuite/ld-elf/dt-relr-2b.d | 4 ++--
ld/testsuite/ld-elf/dt-relr-2c.d | 4 ++--
ld/testsuite/ld-elf/dt-relr-2d.d | 4 ++--
ld/testsuite/ld-elf/dt-relr-2e.d | 4 ++--
ld/testsuite/ld-elf/dt-relr-2i.d | 4 ++--
ld/testsuite/ld-i386/dt-relr-1a.d | 4 ++--
ld/testsuite/ld-i386/dt-relr-1b.d | 4 ++--
ld/testsuite/ld-powerpc/abs-pie-relr.r | 4 ++--
ld/testsuite/ld-powerpc/abs-shared-relr.r | 4 ++--
ld/testsuite/ld-x86-64/dt-relr-1a-x32.d | 4 ++--
ld/testsuite/ld-x86-64/dt-relr-1a.d | 4 ++--
ld/testsuite/ld-x86-64/dt-relr-1b-x32.d | 4 ++--
ld/testsuite/ld-x86-64/dt-relr-1b.d | 4 ++--
14 files changed, 29 insertions(+), 43 deletions(-)
diff --git a/binutils/readelf.c b/binutils/readelf.c
index fcf95ee3047..e0cf718aa28 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -1665,20 +1665,10 @@ dump_relr_relocations (Filedata * filedata,
be used later on for some other purpose. */
qsort (symtab, nsyms, sizeof (Elf_Internal_Sym), symcmp);
- if (do_wide)
- {
- if (relr_entsize == 4)
- printf (_("Index: Entry: Address Symbolic Address Notes\n"));
- else
- printf (_("Index: Entry: Address relocated Symbolic Address Notes\n"));
- }
+ if (relr_entsize == 4)
+ printf (_ ("Index: Entry Address Symbolic Address\n"));
else
- {
- if (relr_entsize == 4)
- printf (_("Index: Entry: Address Symbolic Address\n"));
- else
- printf (_("Index: Entry: Address relocated Symbolic Address\n"));
- }
+ printf (_ ("Index: Entry Address Symbolic Address\n"));
for (i = 0; i < nentries; i++)
{
@@ -1698,8 +1688,6 @@ dump_relr_relocations (Filedata * filedata,
{
where = entry;
print_relr_addr_and_sym (symtab, nsyms, strtab, strtablen, where);
- if (do_wide)
- printf (_(" (new starting address)"));
printf ("\n");
where += relr_entsize;
}
@@ -1722,8 +1710,6 @@ dump_relr_relocations (Filedata * filedata,
if (first)
{
print_relr_addr_and_sym (symtab, nsyms, strtab, strtablen, addr);
- if (do_wide)
- printf (_(" (start of bitmap)"));
first = false;
}
else
diff --git a/ld/testsuite/ld-elf/dt-relr-2b.d b/ld/testsuite/ld-elf/dt-relr-2b.d
index 48a3eb7f15c..f9c688087f9 100644
--- a/ld/testsuite/ld-elf/dt-relr-2b.d
+++ b/ld/testsuite/ld-elf/dt-relr-2b.d
@@ -14,8 +14,8 @@ Relocation section '\.rel(a|)\.dyn' at offset 0x[0-9a-f]+ contains 1 entry:
#...
Relocation section '\.relr\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +data \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+ \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +data
+0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
#pass
diff --git a/ld/testsuite/ld-elf/dt-relr-2c.d b/ld/testsuite/ld-elf/dt-relr-2c.d
index 7f6383b0184..d9e3698a8f0 100644
--- a/ld/testsuite/ld-elf/dt-relr-2c.d
+++ b/ld/testsuite/ld-elf/dt-relr-2c.d
@@ -14,7 +14,7 @@ Relocation section '\.rel(a|)\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
#...
Relocation section '\.relr\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#pass
diff --git a/ld/testsuite/ld-elf/dt-relr-2d.d b/ld/testsuite/ld-elf/dt-relr-2d.d
index f1184fefeb2..69863bddec4 100644
--- a/ld/testsuite/ld-elf/dt-relr-2d.d
+++ b/ld/testsuite/ld-elf/dt-relr-2d.d
@@ -14,8 +14,8 @@ Relocation section '\.rel(a|)\.dyn' at offset 0x[0-9a-f]+ contains 1 entry:
#...
Relocation section '\.relr\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +data \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+ \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +data
+0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
#pass
diff --git a/ld/testsuite/ld-elf/dt-relr-2e.d b/ld/testsuite/ld-elf/dt-relr-2e.d
index eddb5e3d14e..e047c0d6529 100644
--- a/ld/testsuite/ld-elf/dt-relr-2e.d
+++ b/ld/testsuite/ld-elf/dt-relr-2e.d
@@ -14,8 +14,8 @@ Relocation section '\.rel(a|)\.data' at offset 0x[0-9a-f]+ contains 1 entry:
#...
Relocation section '\.relr\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +data \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+ \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +data
+0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
#pass
diff --git a/ld/testsuite/ld-elf/dt-relr-2i.d b/ld/testsuite/ld-elf/dt-relr-2i.d
index 55e8c256b92..a328ccb92e5 100644
--- a/ld/testsuite/ld-elf/dt-relr-2i.d
+++ b/ld/testsuite/ld-elf/dt-relr-2i.d
@@ -14,8 +14,8 @@ Relocation section '\.rel(a|)\.dyn' at offset 0x[0-9a-f]+ contains 1 entry:
#...
Relocation section '\.relr\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +data \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+ \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +data
+0001: +[0-9a-f]+ [0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
+[0-9a-f]+ +data \+ 0x[0-9a-f]+
#pass
diff --git a/ld/testsuite/ld-i386/dt-relr-1a.d b/ld/testsuite/ld-i386/dt-relr-1a.d
index 3944911e4f7..89cc636f4bc 100644
--- a/ld/testsuite/ld-i386/dt-relr-1a.d
+++ b/ld/testsuite/ld-i386/dt-relr-1a.d
@@ -15,8 +15,8 @@ Relocation section '\.rel\.plt' at offset 0x[0-9a-f]+ contains 1 entry:
Relocation section '.relr.dyn' at offset 0x[a-f0-9]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#...
Symbol table '.symtab' contains [0-9]+ entries:
diff --git a/ld/testsuite/ld-i386/dt-relr-1b.d b/ld/testsuite/ld-i386/dt-relr-1b.d
index 947d8354b23..6e7f3ca0a25 100644
--- a/ld/testsuite/ld-i386/dt-relr-1b.d
+++ b/ld/testsuite/ld-i386/dt-relr-1b.d
@@ -18,8 +18,8 @@ Relocation section '\.rel\.plt' at offset 0x[0-9a-f]+ contains 1 entry:
Relocation section '.relr.dyn' at offset 0x[a-f0-9]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#...
Symbol table '.symtab' contains [0-9]+ entries:
diff --git a/ld/testsuite/ld-powerpc/abs-pie-relr.r b/ld/testsuite/ld-powerpc/abs-pie-relr.r
index 049cd7aa983..e84b0af115b 100644
--- a/ld/testsuite/ld-powerpc/abs-pie-relr.r
+++ b/ld/testsuite/ld-powerpc/abs-pie-relr.r
@@ -4,5 +4,5 @@
#readelf: -rW
Relocation section '\.relr\.dyn' at offset .* contains 1 entry:
-Index: Entry: +Address relocated Symbolic Address +Notes
-0000: +[0-9a-f]+ [0-9a-f]+ +x \(new starting address\)
+Index: Entry Address Symbolic Address
+0000: +[0-9a-f]+ [0-9a-f]+ +x
diff --git a/ld/testsuite/ld-powerpc/abs-shared-relr.r b/ld/testsuite/ld-powerpc/abs-shared-relr.r
index 3ce70f740e2..ce1a7eee339 100644
--- a/ld/testsuite/ld-powerpc/abs-shared-relr.r
+++ b/ld/testsuite/ld-powerpc/abs-shared-relr.r
@@ -13,6 +13,6 @@ Relocation section '\.rela\.dyn' at offset .* contains 6 entries:
0+10450 0+400000026 R_PPC64_ADDR64 123456789abcdef0 c \+ 0
Relocation section '\.relr\.dyn' at offset .* contains 1 entry:
-Index: Entry: +Address relocated Symbolic Address +Notes
-0000: +[0-9a-f]+ [0-9a-f]+ +x \(new starting address\)
+Index: Entry Address Symbolic Address
+0000: +[0-9a-f]+ [0-9a-f]+ +x
diff --git a/ld/testsuite/ld-x86-64/dt-relr-1a-x32.d b/ld/testsuite/ld-x86-64/dt-relr-1a-x32.d
index 78ffda9ce15..863e97a7980 100644
--- a/ld/testsuite/ld-x86-64/dt-relr-1a-x32.d
+++ b/ld/testsuite/ld-x86-64/dt-relr-1a-x32.d
@@ -15,8 +15,8 @@ Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry:
Relocation section '.relr.dyn' at offset 0x[a-f0-9]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#...
Symbol table '.symtab' contains [0-9]+ entries:
diff --git a/ld/testsuite/ld-x86-64/dt-relr-1a.d b/ld/testsuite/ld-x86-64/dt-relr-1a.d
index 8e099257037..30af87535c9 100644
--- a/ld/testsuite/ld-x86-64/dt-relr-1a.d
+++ b/ld/testsuite/ld-x86-64/dt-relr-1a.d
@@ -15,8 +15,8 @@ Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry:
Relocation section '.relr.dyn' at offset 0x[a-f0-9]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#...
Symbol table '.symtab' contains [0-9]+ entries:
diff --git a/ld/testsuite/ld-x86-64/dt-relr-1b-x32.d b/ld/testsuite/ld-x86-64/dt-relr-1b-x32.d
index c2e3a3a931f..3c37bcd5358 100644
--- a/ld/testsuite/ld-x86-64/dt-relr-1b-x32.d
+++ b/ld/testsuite/ld-x86-64/dt-relr-1b-x32.d
@@ -18,8 +18,8 @@ Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry:
Relocation section '.relr.dyn' at offset 0x[a-f0-9]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#...
Symbol table '.symtab' contains [0-9]+ entries:
diff --git a/ld/testsuite/ld-x86-64/dt-relr-1b.d b/ld/testsuite/ld-x86-64/dt-relr-1b.d
index 03e0202fe81..bc07cf89b26 100644
--- a/ld/testsuite/ld-x86-64/dt-relr-1b.d
+++ b/ld/testsuite/ld-x86-64/dt-relr-1b.d
@@ -18,8 +18,8 @@ Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entry:
Relocation section '.relr.dyn' at offset 0x[a-f0-9]+ contains 2 entries:
#...
-0000: +[0-9a-f]+ [0-9a-f]+ +.* \(new starting address\)
-0001: +[0-9a-f]+ [0-9a-f]+ +.* \(start of bitmap\)
+0000: +[0-9a-f]+ [0-9a-f]+ +.*
+0001: +[0-9a-f]+ [0-9a-f]+ +.*
+[0-9a-f]+ +.*
#...
Symbol table '.symtab' contains [0-9]+ entries:
--
2.44
next prev parent reply other threads:[~2024-04-12 22:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-11 15:56 Nick Clifton
2024-04-12 18:44 ` Fangrui Song
[not found] ` <CAN30aBFj+_Yfs8+WrC7aM0ZWQihGoZ8nMk2DHO7Xkxzw6PgqSA@mail.gmail.com>
2024-04-12 22:04 ` Fangrui Song [this message]
[not found] ` <DS7PR12MB576532E4BB26A2211E7A75AACB042@DS7PR12MB5765.namprd12.prod.outlook.com>
2024-04-16 12:22 ` Nick Clifton
2024-04-18 2:28 ` Fangrui Song
[not found] ` <DS7PR12MB57659F007C5FA3B3CE38A2ECCB0E2@DS7PR12MB5765.namprd12.prod.outlook.com>
2024-04-19 10:55 ` Nick Clifton
2024-04-23 19:37 ` Fangrui Song
[not found] ` <MN0PR12MB5761E8D41391C97D0666D300CB112@MN0PR12MB5761.namprd12.prod.outlook.com>
2024-04-24 11:25 ` Nick Clifton
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