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110 Commits

Author SHA1 Message Date
Josh Poimboeuf
ec24b927c1 objtool: Get rid of reloc->rel[a] 
Get the relocation entry info from the underlying rsec->data.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 35.12G
- After:  peak heap memory consumption: 29.93G

Link: https://lore.kernel.org/r/2be32323de6d8cc73179ee0ff14b71f4e7cefaa0.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:26 -07:00
Josh Poimboeuf
02b5400106 objtool: Shrink elf hash nodes 
Instead of using hlist for the 'struct elf' hashes, use a custom
single-linked list scheme.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 36.89G
- After:  peak heap memory consumption: 35.12G

Link: https://lore.kernel.org/r/6e8cd305ed22e743c30d6e72cfdc1be20fb94cd4.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:25 -07:00
Josh Poimboeuf
890f10a433 objtool: Shrink reloc->sym_reloc_entry 
Convert it to a singly-linked list.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 38.64G
- After:  peak heap memory consumption: 36.89G

Link: https://lore.kernel.org/r/a51f0a6f9bbf2494d5a3a449807307e78a940988.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:25 -07:00
Josh Poimboeuf
be2f0b1e12 objtool: Get rid of reloc->jump_table_start 
Rework the jump table logic slightly so 'jump_table_start' is no longer
needed.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 40.37G
- After:  peak heap memory consumption: 38.64G

Link: https://lore.kernel.org/r/e1602ed8a6171ada3cfac0bd8449892ec82bd188.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:24 -07:00
Josh Poimboeuf
0696b6e314 objtool: Get rid of reloc->addend 
Get the addend from the embedded GElf_Rel[a] struct.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 42.10G
- After:  peak heap memory consumption: 40.37G

Link: https://lore.kernel.org/r/ad2354f95d9ddd86094e3f7687acfa0750657784.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:23 -07:00
Josh Poimboeuf
fcee899d27 objtool: Get rid of reloc->type 
Get the type from the embedded GElf_Rel[a] struct.

Link: https://lore.kernel.org/r/d1c1f8da31e4f052a2478aea585fcf355cacc53a.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:22 -07:00
Josh Poimboeuf
e4cbb9b81f objtool: Get rid of reloc->offset 
Get the offset from the embedded GElf_Rel[a] struct.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 43.83G
- After:  peak heap memory consumption: 42.10G

Link: https://lore.kernel.org/r/2b9ec01178baa346a99522710bf2e82159412e3a.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:21 -07:00
Josh Poimboeuf
be9a4c1168 objtool: Get rid of reloc->idx 
Use the array offset to calculate the reloc index.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 45.56G
- After:  peak heap memory consumption: 43.83G

Link: https://lore.kernel.org/r/7351d2ebad0519027db14a32f6204af84952574a.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:21 -07:00
Josh Poimboeuf
ebcef730a1 objtool: Get rid of reloc->list 
Now that all relocs are allocated in an array, the linked list is no
longer needed.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 49.02G
- After:  peak heap memory consumption: 45.56G

Link: https://lore.kernel.org/r/71e7a2c017dbc46bb497857ec97d67214f832d10.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:20 -07:00
Josh Poimboeuf
caa4a6b74b objtool: Add for_each_reloc() 
Link: https://lore.kernel.org/r/dbfcb1037d8b958e52d097b67829c4c6811c24bb.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:19 -07:00
Josh Poimboeuf
6342a20efb objtool: Add elf_create_section_pair() 
When creating an annotation section, allocate the reloc section data at
the beginning.  This simplifies the data model a bit and also saves
memory due to the removal of malloc() in elf_rebuild_reloc_section().

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 53.49G
- After:  peak heap memory consumption: 49.02G

Link: https://lore.kernel.org/r/048e908f3ede9b66c15e44672b6dda992b1dae3e.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:17 -07:00
Josh Poimboeuf
ff4082730c objtool: Add mark_sec_changed() 
Ensure elf->changed always gets set when sec->changed gets set.

Link: https://lore.kernel.org/r/9a810a8d2e28af6ba07325362d0eb4703bb09d3a.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:16 -07:00
Josh Poimboeuf
eb0481bbc4 objtool: Fix reloc_hash size 
With CONFIG_DEBUG_INFO, DWARF creates a lot of relocations and
reloc_hash is woefully undersized, which can affect performance
significantly.  Fix that.

Link: https://lore.kernel.org/r/38ef60dc8043270bf3b9dfd139ae2a30ca3f75cc.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:16 -07:00
Josh Poimboeuf
53257a977a objtool: Consolidate rel/rela handling 
The GElf_Rel[a] structs have more similarities than differences.  It's
safe to hard-code the assumptions about their shared fields as they will
never change.  Consolidate their handling where possible, getting rid of
duplicated code.

Also, at least for now we only ever create rela sections, so simplify
the relocation creation code to be rela-only.

Link: https://lore.kernel.org/r/dcabf6df400ca500ea929f1e4284f5e5ec0b27c8.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:15 -07:00
Josh Poimboeuf
a5bd623653 objtool: Improve reloc naming 
- The term "reloc" is overloaded to mean both "an instance of struct
  reloc" and "a reloc section".  Change the latter to "rsec".

- For variable names, use "sec" for regular sections and "rsec" for rela
  sections to prevent them getting mixed up.

- For struct reloc variables, use "reloc" instead of "rel" everywhere
  for consistency.

Link: https://lore.kernel.org/r/8b790e403df46f445c21003e7893b8f53b99a6f3.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:14 -07:00
Josh Poimboeuf
2707579dfa objtool: Remove flags argument from elf_create_section() 
Simplify the elf_create_section() interface a bit by removing the flags
argument.  Most callers don't care about changing the section header
flags.  If needed, they can be modified afterwards, just like any other
section header field.

Link: https://lore.kernel.org/r/515235d9cf62637a14bee37bfa9169ef20065471.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:13 -07:00
Josh Poimboeuf
809373e17b objtool: Tidy elf.h 
Reorganize elf.h a bit:

- Move the prototypes higher up so they can be used by the inline
  functions.

- Move hash-related code to the bottom.

- Remove the unused ELF_HASH_BITS macro.

No functional changes.

Link: https://lore.kernel.org/r/b1490ed85951868219a6ece177a7cd30a6454d66.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:13 -07:00
Josh Poimboeuf
1e4b619185 objtool: Allow stack operations in UNWIND_HINT_UNDEFINED regions 
If the code specified UNWIND_HINT_UNDEFINED, skip the "undefined stack
state" warning due to a stack operation.  Just ignore the stack op and
continue to propagate the undefined state.

Link: https://lore.kernel.org/r/820c5b433f17c84e8761fb7465a8d319d706b1cf.1685981486.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-06-07 10:03:11 -07:00
Josh Poimboeuf
ced23d2e37 objtool: Include backtrace in verbose mode 
Include backtrace in verbose mode.  This makes it easy to gather all the
information needed for diagnosing objtool warnings.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/c255224fabcf7e64bac232fec1c77c9fc2d7d7ab.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-05-16 06:31:52 -07:00
Josh Poimboeuf
ca653464dd objtool: Add verbose option for disassembling affected functions 
When a warning is associated with a function, add an option to
disassemble that function.

This makes it easier for reporters to submit the information needed to
diagnose objtool warnings.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/dd0fe13428ede186f09c74059a8001f4adcea5fc.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-05-16 06:31:51 -07:00
Josh Poimboeuf
5e3992fe72 objtool: Limit unreachable warnings to once per function 
Unreachable instruction warnings are limited to once per object file.
That no longer makes sense for vmlinux validation, which might have
more unreachable instructions lurking in other places.  Change it to
once per function.

Note this affects some other (much rarer) non-fatal warnings as well.
In general I think one-warning-per-function makes sense, as related
warnings can accumulate quickly and we want to eventually get back to
failing the build with -Werror anyway.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/9d38f881bfc34e031c74e4e90064ccb3e49f599a.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-05-16 06:31:51 -07:00
Josh Poimboeuf
9290e772ba objtool: Add symbol iteration helpers 
Add [sec_]for_each_sym() and use them.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/59023e5886ab125aa30702e633be7732b1acaa7e.1681325924.git.jpoimboe@kernel.org
 2023-04-14 16:08:29 +02:00
Josh Poimboeuf
246b2c8548 objtool: Add WARN_INSN() 
It's easier to use and also gives easy access to the instruction's
containing function, which is useful for printing that function's
symbol.  It will also be useful in the future for rate-limiting and
disassembly of warned functions.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/2eaa3155c90fba683d8723599f279c46025b75f3.1681325924.git.jpoimboe@kernel.org
 2023-04-14 16:08:28 +02:00
Josh Poimboeuf
4708ea14be x86,objtool: Separate unret validation from unwind hints 
The ENTRY unwind hint type is serving double duty as both an empty
unwind hint and an unret validation annotation.

Unret validation is unrelated to unwinding. Separate it out into its own
annotation.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/ff7448d492ea21b86d8a90264b105fbd0d751077.1677683419.git.jpoimboe@kernel.org
 2023-03-23 23:18:58 +01:00
Josh Poimboeuf
00c8f01c4e objtool: Fix ORC 'signal' propagation 
There have been some recently reported ORC unwinder warnings like:

  WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
  WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271

And a KASAN warning:

  BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)

It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.

Fixes: ffb1b4a410 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/97eef9db60cd86d376a9a40d49d77bb67a8f6526.1676579666.git.jpoimboe@kernel.org
 2023-02-23 09:21:50 +01:00
Peter Zijlstra
1c34496e58 objtool: Remove instruction::list 
Replace the instruction::list by allocating instructions in arrays of
256 entries and stringing them together by (amortized) find_insn().
This shrinks instruction by 16 bytes and brings it down to 128.

 struct instruction {
-	struct list_head           list;                 /*     0    16 */
-	struct hlist_node          hash;                 /*    16    16 */
-	struct list_head           call_node;            /*    32    16 */
-	struct section *           sec;                  /*    48     8 */
-	long unsigned int          offset;               /*    56     8 */
-	/* --- cacheline 1 boundary (64 bytes) --- */
-	long unsigned int          immediate;            /*    64     8 */
-	unsigned int               len;                  /*    72     4 */
-	u8                         type;                 /*    76     1 */
-
-	/* Bitfield combined with previous fields */
+	struct hlist_node          hash;                 /*     0    16 */
+	struct list_head           call_node;            /*    16    16 */
+	struct section *           sec;                  /*    32     8 */
+	long unsigned int          offset;               /*    40     8 */
+	long unsigned int          immediate;            /*    48     8 */
+	u8                         len;                  /*    56     1 */
+	u8                         prev_len;             /*    57     1 */
+	u8                         type;                 /*    58     1 */
+	s8                         instr;                /*    59     1 */
+	u32                        idx:8;                /*    60: 0  4 */
+	u32                        dead_end:1;           /*    60: 8  4 */
+	u32                        ignore:1;             /*    60: 9  4 */
+	u32                        ignore_alts:1;        /*    60:10  4 */
+	u32                        hint:1;               /*    60:11  4 */
+	u32                        save:1;               /*    60:12  4 */
+	u32                        restore:1;            /*    60:13  4 */
+	u32                        retpoline_safe:1;     /*    60:14  4 */
+	u32                        noendbr:1;            /*    60:15  4 */
+	u32                        entry:1;              /*    60:16  4 */
+	u32                        visited:4;            /*    60:17  4 */
+	u32                        no_reloc:1;           /*    60:21  4 */

-	u16                        dead_end:1;           /*    76: 8  2 */
-	u16                        ignore:1;             /*    76: 9  2 */
-	u16                        ignore_alts:1;        /*    76:10  2 */
-	u16                        hint:1;               /*    76:11  2 */
-	u16                        save:1;               /*    76:12  2 */
-	u16                        restore:1;            /*    76:13  2 */
-	u16                        retpoline_safe:1;     /*    76:14  2 */
-	u16                        noendbr:1;            /*    76:15  2 */
-	u16                        entry:1;              /*    78: 0  2 */
-	u16                        visited:4;            /*    78: 1  2 */
-	u16                        no_reloc:1;           /*    78: 5  2 */
+	/* XXX 10 bits hole, try to pack */

-	/* XXX 2 bits hole, try to pack */
-	/* Bitfield combined with next fields */
-
-	s8                         instr;                /*    79     1 */
-	struct alt_group *         alt_group;            /*    80     8 */
-	struct instruction *       jump_dest;            /*    88     8 */
-	struct instruction *       first_jump_src;       /*    96     8 */
+	/* --- cacheline 1 boundary (64 bytes) --- */
+	struct alt_group *         alt_group;            /*    64     8 */
+	struct instruction *       jump_dest;            /*    72     8 */
+	struct instruction *       first_jump_src;       /*    80     8 */
 	union {
-		struct symbol *    _call_dest;           /*   104     8 */
-		struct reloc *     _jump_table;          /*   104     8 */
-	};                                               /*   104     8 */
-	struct alternative *       alts;                 /*   112     8 */
-	struct symbol *            sym;                  /*   120     8 */
-	/* --- cacheline 2 boundary (128 bytes) --- */
-	struct stack_op *          stack_ops;            /*   128     8 */
-	struct cfi_state *         cfi;                  /*   136     8 */
+		struct symbol *    _call_dest;           /*    88     8 */
+		struct reloc *     _jump_table;          /*    88     8 */
+	};                                               /*    88     8 */
+	struct alternative *       alts;                 /*    96     8 */
+	struct symbol *            sym;                  /*   104     8 */
+	struct stack_op *          stack_ops;            /*   112     8 */
+	struct cfi_state *         cfi;                  /*   120     8 */

-	/* size: 144, cachelines: 3, members: 28 */
-	/* sum members: 142 */
-	/* sum bitfield members: 14 bits, bit holes: 1, sum bit holes: 2 bits */
-	/* last cacheline: 16 bytes */
+	/* size: 128, cachelines: 2, members: 29 */
+	/* sum members: 124 */
+	/* sum bitfield members: 22 bits, bit holes: 1, sum bit holes: 10 bits */
 };

pre:	5:38.18 real,   213.25 user,    124.90 sys,     23449040 mem
post:	5:03.34 real,   210.75 user,    88.80 sys,      20241232 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.851307606@infradead.org
 2023-02-23 09:21:44 +01:00
Peter Zijlstra
c6f5dc28fb objtool: Union instruction::{call_dest,jump_table} 
The instruction call_dest and jump_table members can never be used at
the same time, their usage depends on type.

 struct instruction {
 	struct list_head           list;                 /*     0    16 */
 	struct hlist_node          hash;                 /*    16    16 */
 	struct list_head           call_node;            /*    32    16 */
 	struct section *           sec;                  /*    48     8 */
 	long unsigned int          offset;               /*    56     8 */
 	/* --- cacheline 1 boundary (64 bytes) --- */
 	long unsigned int          immediate;            /*    64     8 */
 	unsigned int               len;                  /*    72     4 */
 	u8                         type;                 /*    76     1 */

 	/* Bitfield combined with previous fields */

 	u16                        dead_end:1;           /*    76: 8  2 */
 	u16                        ignore:1;             /*    76: 9  2 */
 	u16                        ignore_alts:1;        /*    76:10  2 */
 	u16                        hint:1;               /*    76:11  2 */
 	u16                        save:1;               /*    76:12  2 */
 	u16                        restore:1;            /*    76:13  2 */
 	u16                        retpoline_safe:1;     /*    76:14  2 */
 	u16                        noendbr:1;            /*    76:15  2 */
 	u16                        entry:1;              /*    78: 0  2 */
 	u16                        visited:4;            /*    78: 1  2 */
 	u16                        no_reloc:1;           /*    78: 5  2 */

 	/* XXX 2 bits hole, try to pack */
 	/* Bitfield combined with next fields */

 	s8                         instr;                /*    79     1 */
 	struct alt_group *         alt_group;            /*    80     8 */
-	struct symbol *            call_dest;            /*    88     8 */
-	struct instruction *       jump_dest;            /*    96     8 */
-	struct instruction *       first_jump_src;       /*   104     8 */
-	struct reloc *             jump_table;           /*   112     8 */
-	struct alternative *       alts;                 /*   120     8 */
+	struct instruction *       jump_dest;            /*    88     8 */
+	struct instruction *       first_jump_src;       /*    96     8 */
+	union {
+		struct symbol *    _call_dest;           /*   104     8 */
+		struct reloc *     _jump_table;          /*   104     8 */
+	};                                               /*   104     8 */
+	struct alternative *       alts;                 /*   112     8 */
+	struct symbol *            sym;                  /*   120     8 */
 	/* --- cacheline 2 boundary (128 bytes) --- */
-	struct symbol *            sym;                  /*   128     8 */
-	struct stack_op *          stack_ops;            /*   136     8 */
-	struct cfi_state *         cfi;                  /*   144     8 */
+	struct stack_op *          stack_ops;            /*   128     8 */
+	struct cfi_state *         cfi;                  /*   136     8 */

-	/* size: 152, cachelines: 3, members: 29 */
-	/* sum members: 150 */
+	/* size: 144, cachelines: 3, members: 28 */
+	/* sum members: 142 */
 	/* sum bitfield members: 14 bits, bit holes: 1, sum bit holes: 2 bits */
-	/* last cacheline: 24 bytes */
+	/* last cacheline: 16 bytes */
 };

pre:	5:39.35 real,   215.58 user,    123.69 sys,     23448736 mem
post:	5:38.18 real,   213.25 user,    124.90 sys,     23449040 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.640914454@infradead.org
 2023-02-23 09:21:27 +01:00
Peter Zijlstra
0932dbe1f5 objtool: Remove instruction::reloc 
Instead of caching the reloc for each instruction, only keep a
negative cache of not having a reloc (by far the most common case).

 struct instruction {
 	struct list_head           list;                 /*     0    16 */
 	struct hlist_node          hash;                 /*    16    16 */
 	struct list_head           call_node;            /*    32    16 */
 	struct section *           sec;                  /*    48     8 */
 	long unsigned int          offset;               /*    56     8 */
 	/* --- cacheline 1 boundary (64 bytes) --- */
 	long unsigned int          immediate;            /*    64     8 */
 	unsigned int               len;                  /*    72     4 */
 	u8                         type;                 /*    76     1 */

 	/* Bitfield combined with previous fields */

 	u16                        dead_end:1;           /*    76: 8  2 */
 	u16                        ignore:1;             /*    76: 9  2 */
 	u16                        ignore_alts:1;        /*    76:10  2 */
 	u16                        hint:1;               /*    76:11  2 */
 	u16                        save:1;               /*    76:12  2 */
 	u16                        restore:1;            /*    76:13  2 */
 	u16                        retpoline_safe:1;     /*    76:14  2 */
 	u16                        noendbr:1;            /*    76:15  2 */
 	u16                        entry:1;              /*    78: 0  2 */
 	u16                        visited:4;            /*    78: 1  2 */
+	u16                        no_reloc:1;           /*    78: 5  2 */

-	/* XXX 3 bits hole, try to pack */
+	/* XXX 2 bits hole, try to pack */
 	/* Bitfield combined with next fields */

 	s8                         instr;                /*    79     1 */
 	struct alt_group *         alt_group;            /*    80     8 */
 	struct symbol *            call_dest;            /*    88     8 */
 	struct instruction *       jump_dest;            /*    96     8 */
 	struct instruction *       first_jump_src;       /*   104     8 */
 	struct reloc *             jump_table;           /*   112     8 */
-	struct reloc *             reloc;                /*   120     8 */
+	struct alternative *       alts;                 /*   120     8 */
 	/* --- cacheline 2 boundary (128 bytes) --- */
-	struct alternative *       alts;                 /*   128     8 */
-	struct symbol *            sym;                  /*   136     8 */
-	struct stack_op *          stack_ops;            /*   144     8 */
-	struct cfi_state *         cfi;                  /*   152     8 */
+	struct symbol *            sym;                  /*   128     8 */
+	struct stack_op *          stack_ops;            /*   136     8 */
+	struct cfi_state *         cfi;                  /*   144     8 */

-	/* size: 160, cachelines: 3, members: 29 */
-	/* sum members: 158 */
-	/* sum bitfield members: 13 bits, bit holes: 1, sum bit holes: 3 bits */
-	/* last cacheline: 32 bytes */
+	/* size: 152, cachelines: 3, members: 29 */
+	/* sum members: 150 */
+	/* sum bitfield members: 14 bits, bit holes: 1, sum bit holes: 2 bits */
+	/* last cacheline: 24 bytes */
 };

pre:	5:48.89 real,   220.96 user,    127.55 sys,     24834672 mem
post:	5:39.35 real,   215.58 user,    123.69 sys,     23448736 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.572145269@infradead.org
 2023-02-23 09:21:17 +01:00
Peter Zijlstra
8b2de41215 objtool: Shrink instruction::{type,visited} 
Since we don't have that many types in enum insn_type, force it into a
u8 and re-arrange member to get rid of the holes, saves another 8
bytes.

 struct instruction {
 	struct list_head           list;                 /*     0    16 */
 	struct hlist_node          hash;                 /*    16    16 */
 	struct list_head           call_node;            /*    32    16 */
 	struct section *           sec;                  /*    48     8 */
 	long unsigned int          offset;               /*    56     8 */
 	/* --- cacheline 1 boundary (64 bytes) --- */
-	unsigned int               len;                  /*    64     4 */
-	enum insn_type             type;                 /*    68     4 */
-	long unsigned int          immediate;            /*    72     8 */
-	u16                        dead_end:1;           /*    80: 0  2 */
-	u16                        ignore:1;             /*    80: 1  2 */
-	u16                        ignore_alts:1;        /*    80: 2  2 */
-	u16                        hint:1;               /*    80: 3  2 */
-	u16                        save:1;               /*    80: 4  2 */
-	u16                        restore:1;            /*    80: 5  2 */
-	u16                        retpoline_safe:1;     /*    80: 6  2 */
-	u16                        noendbr:1;            /*    80: 7  2 */
-	u16                        entry:1;              /*    80: 8  2 */
+	long unsigned int          immediate;            /*    64     8 */
+	unsigned int               len;                  /*    72     4 */
+	u8                         type;                 /*    76     1 */

-	/* XXX 7 bits hole, try to pack */
+	/* Bitfield combined with previous fields */

-	s8                         instr;                /*    82     1 */
-	u8                         visited;              /*    83     1 */
+	u16                        dead_end:1;           /*    76: 8  2 */
+	u16                        ignore:1;             /*    76: 9  2 */
+	u16                        ignore_alts:1;        /*    76:10  2 */
+	u16                        hint:1;               /*    76:11  2 */
+	u16                        save:1;               /*    76:12  2 */
+	u16                        restore:1;            /*    76:13  2 */
+	u16                        retpoline_safe:1;     /*    76:14  2 */
+	u16                        noendbr:1;            /*    76:15  2 */
+	u16                        entry:1;              /*    78: 0  2 */
+	u16                        visited:4;            /*    78: 1  2 */

-	/* XXX 4 bytes hole, try to pack */
+	/* XXX 3 bits hole, try to pack */
+	/* Bitfield combined with next fields */

-	struct alt_group *         alt_group;            /*    88     8 */
-	struct symbol *            call_dest;            /*    96     8 */
-	struct instruction *       jump_dest;            /*   104     8 */
-	struct instruction *       first_jump_src;       /*   112     8 */
-	struct reloc *             jump_table;           /*   120     8 */
+	s8                         instr;                /*    79     1 */
+	struct alt_group *         alt_group;            /*    80     8 */
+	struct symbol *            call_dest;            /*    88     8 */
+	struct instruction *       jump_dest;            /*    96     8 */
+	struct instruction *       first_jump_src;       /*   104     8 */
+	struct reloc *             jump_table;           /*   112     8 */
+	struct reloc *             reloc;                /*   120     8 */
 	/* --- cacheline 2 boundary (128 bytes) --- */
-	struct reloc *             reloc;                /*   128     8 */
-	struct alternative *       alts;                 /*   136     8 */
-	struct symbol *            sym;                  /*   144     8 */
-	struct stack_op *          stack_ops;            /*   152     8 */
-	struct cfi_state *         cfi;                  /*   160     8 */
+	struct alternative *       alts;                 /*   128     8 */
+	struct symbol *            sym;                  /*   136     8 */
+	struct stack_op *          stack_ops;            /*   144     8 */
+	struct cfi_state *         cfi;                  /*   152     8 */

-	/* size: 168, cachelines: 3, members: 29 */
-	/* sum members: 162, holes: 1, sum holes: 4 */
-	/* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 7 bits */
-	/* last cacheline: 40 bytes */
+	/* size: 160, cachelines: 3, members: 29 */
+	/* sum members: 158 */
+	/* sum bitfield members: 13 bits, bit holes: 1, sum bit holes: 3 bits */
+	/* last cacheline: 32 bytes */
 };

pre:	5:48.86 real,   220.30 user,    128.34 sys,     24834672 mem
post:	5:48.89 real,   220.96 user,    127.55 sys,     24834672 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.501847188@infradead.org
 2023-02-23 09:21:12 +01:00
Peter Zijlstra
d540665461 objtool: Make instruction::alts a single-linked list 
struct instruction {
 	struct list_head           list;                 /*     0    16 */
 	struct hlist_node          hash;                 /*    16    16 */
 	struct list_head           call_node;            /*    32    16 */
 	struct section *           sec;                  /*    48     8 */
 	long unsigned int          offset;               /*    56     8 */
 	/* --- cacheline 1 boundary (64 bytes) --- */
 	unsigned int               len;                  /*    64     4 */
 	enum insn_type             type;                 /*    68     4 */
 	long unsigned int          immediate;            /*    72     8 */
 	u16                        dead_end:1;           /*    80: 0  2 */
 	u16                        ignore:1;             /*    80: 1  2 */
 	u16                        ignore_alts:1;        /*    80: 2  2 */
 	u16                        hint:1;               /*    80: 3  2 */
 	u16                        save:1;               /*    80: 4  2 */
 	u16                        restore:1;            /*    80: 5  2 */
 	u16                        retpoline_safe:1;     /*    80: 6  2 */
 	u16                        noendbr:1;            /*    80: 7  2 */
 	u16                        entry:1;              /*    80: 8  2 */

 	/* XXX 7 bits hole, try to pack */

 	s8                         instr;                /*    82     1 */
 	u8                         visited;              /*    83     1 */

 	/* XXX 4 bytes hole, try to pack */

 	struct alt_group *         alt_group;            /*    88     8 */
 	struct symbol *            call_dest;            /*    96     8 */
 	struct instruction *       jump_dest;            /*   104     8 */
 	struct instruction *       first_jump_src;       /*   112     8 */
 	struct reloc *             jump_table;           /*   120     8 */
 	/* --- cacheline 2 boundary (128 bytes) --- */
 	struct reloc *             reloc;                /*   128     8 */
-	struct list_head           alts;                 /*   136    16 */
-	struct symbol *            sym;                  /*   152     8 */
-	struct stack_op *          stack_ops;            /*   160     8 */
-	struct cfi_state *         cfi;                  /*   168     8 */
+	struct alternative *       alts;                 /*   136     8 */
+	struct symbol *            sym;                  /*   144     8 */
+	struct stack_op *          stack_ops;            /*   152     8 */
+	struct cfi_state *         cfi;                  /*   160     8 */

-	/* size: 176, cachelines: 3, members: 29 */
-	/* sum members: 170, holes: 1, sum holes: 4 */
+	/* size: 168, cachelines: 3, members: 29 */
+	/* sum members: 162, holes: 1, sum holes: 4 */
 	/* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 7 bits */
-	/* last cacheline: 48 bytes */
+	/* last cacheline: 40 bytes */
 };

pre:	5:58.50 real,   229.64 user,    128.65 sys,     26221520 mem
post:	5:48.86 real,   220.30 user,    128.34 sys,     24834672 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.430556498@infradead.org
 2023-02-23 09:21:06 +01:00
Peter Zijlstra
3ee88df1b0 objtool: Make instruction::stack_ops a single-linked list 
struct instruction {
 	struct list_head           list;                 /*     0    16 */
 	struct hlist_node          hash;                 /*    16    16 */
 	struct list_head           call_node;            /*    32    16 */
 	struct section *           sec;                  /*    48     8 */
 	long unsigned int          offset;               /*    56     8 */
 	/* --- cacheline 1 boundary (64 bytes) --- */
 	unsigned int               len;                  /*    64     4 */
 	enum insn_type             type;                 /*    68     4 */
 	long unsigned int          immediate;            /*    72     8 */
 	u16                        dead_end:1;           /*    80: 0  2 */
 	u16                        ignore:1;             /*    80: 1  2 */
 	u16                        ignore_alts:1;        /*    80: 2  2 */
 	u16                        hint:1;               /*    80: 3  2 */
 	u16                        save:1;               /*    80: 4  2 */
 	u16                        restore:1;            /*    80: 5  2 */
 	u16                        retpoline_safe:1;     /*    80: 6  2 */
 	u16                        noendbr:1;            /*    80: 7  2 */
 	u16                        entry:1;              /*    80: 8  2 */

 	/* XXX 7 bits hole, try to pack */

 	s8                         instr;                /*    82     1 */
 	u8                         visited;              /*    83     1 */

 	/* XXX 4 bytes hole, try to pack */

 	struct alt_group *         alt_group;            /*    88     8 */
 	struct symbol *            call_dest;            /*    96     8 */
 	struct instruction *       jump_dest;            /*   104     8 */
 	struct instruction *       first_jump_src;       /*   112     8 */
 	struct reloc *             jump_table;           /*   120     8 */
 	/* --- cacheline 2 boundary (128 bytes) --- */
 	struct reloc *             reloc;                /*   128     8 */
 	struct list_head           alts;                 /*   136    16 */
 	struct symbol *            sym;                  /*   152     8 */
-	struct list_head           stack_ops;            /*   160    16 */
-	struct cfi_state *         cfi;                  /*   176     8 */
+	struct stack_op *          stack_ops;            /*   160     8 */
+	struct cfi_state *         cfi;                  /*   168     8 */

-	/* size: 184, cachelines: 3, members: 29 */
-	/* sum members: 178, holes: 1, sum holes: 4 */
+	/* size: 176, cachelines: 3, members: 29 */
+	/* sum members: 170, holes: 1, sum holes: 4 */
 	/* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 7 bits */
-	/* last cacheline: 56 bytes */
+	/* last cacheline: 48 bytes */
 };

pre:	5:58.22 real,   226.69 user,    131.22 sys,     26221520 mem
post:	5:58.50 real,   229.64 user,    128.65 sys,     26221520 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.362196959@infradead.org
 2023-02-23 09:20:59 +01:00
Peter Zijlstra
20a554638d objtool: Change arch_decode_instruction() signature 
In preparation to changing struct instruction around a bit, avoid
passing it's members by pointer and instead pass the whole thing.

A cleanup in it's own right too.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build only
Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run
Link: https://lore.kernel.org/r/20230208172245.291087549@infradead.org
 2023-02-23 09:20:50 +01:00
Thomas Weißschuh
a20717aca3 objtool: Optimize layout of struct special_alt 
Reduce the size of struct special_alt from 72 to 64 bytes.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20221216-objtool-memory-v2-7-17968f85a464@weissschuh.net
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-02-01 09:15:24 -08:00
Thomas Weißschuh
21a899f9fc objtool: Optimize layout of struct symbol 
Reduce the size of struct symbol on x86_64 from 208 to 200 bytes.
This structure is allocated a lot and never freed.

This reduces maximum memory usage while processing vmlinux.o from
2919716 KB to 2917988 KB (-0.5%) on my notebooks "localmodconfig".

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20221216-objtool-memory-v2-6-17968f85a464@weissschuh.net
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-02-01 09:15:24 -08:00
Thomas Weißschuh
8045b8f0b1 objtool: Allocate multiple structures with calloc() 
By using calloc() instead of malloc() in a loop, libc does not have to
keep around bookkeeping information for each single structure.

This reduces maximum memory usage while processing vmlinux.o from
3153325 KB to 3035668 KB (-3.7%) on my notebooks "localmodconfig".

Note this introduces memory leaks, because some additional structs get
added to the lists later after reading the symbols and sections from the
original object.  Luckily we don't really care about memory leaks in
objtool.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20221216-objtool-memory-v2-3-17968f85a464@weissschuh.net
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-02-01 09:15:23 -08:00
Thomas Weißschuh
cfd66e8179 objtool: Make struct check_options static 
It is not used outside of builtin-check.c.

Also remove the unused declaration from builtin.h .

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20221216-objtool-memory-v2-2-17968f85a464@weissschuh.net
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
 2023-02-01 09:15:23 -08:00
Linus Torvalds
5f6e430f93 Merge tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 
Pull powerpc updates from Michael Ellerman:

 - Add powerpc qspinlock implementation optimised for large system
   scalability and paravirt. See the merge message for more details

 - Enable objtool to be built on powerpc to generate mcount locations

 - Use a temporary mm for code patching with the Radix MMU, so the
   writable mapping is restricted to the patching CPU

 - Add an option to build the 64-bit big-endian kernel with the ELFv2
   ABI

 - Sanitise user registers on interrupt entry on 64-bit Book3S

 - Many other small features and fixes

Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn
Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET,
Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang,
Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A.
R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol
Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin,
Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika
Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas
Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng,
XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu,
and Wolfram Sang.

* tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits)
  powerpc/code-patching: Fix oops with DEBUG_VM enabled
  powerpc/qspinlock: Fix 32-bit build
  powerpc/prom: Fix 32-bit build
  powerpc/rtas: mandate RTAS syscall filtering
  powerpc/rtas: define pr_fmt and convert printk call sites
  powerpc/rtas: clean up includes
  powerpc/rtas: clean up rtas_error_log_max initialization
  powerpc/pseries/eeh: use correct API for error log size
  powerpc/rtas: avoid scheduling in rtas_os_term()
  powerpc/rtas: avoid device tree lookups in rtas_os_term()
  powerpc/rtasd: use correct OF API for event scan rate
  powerpc/rtas: document rtas_call()
  powerpc/pseries: unregister VPA when hot unplugging a CPU
  powerpc/pseries: reset the RCU watchdogs after a LPM
  powerpc: Take in account addition CPU node when building kexec FDT
  powerpc: export the CPU node count
  powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state
  powerpc/dts/fsl: Fix pca954x i2c-mux node names
  cxl: Remove unnecessary cxl_pci_window_alignment()
  selftests/powerpc: Fix resource leaks
  ...
 2022-12-19 07:13:33 -06:00
Michael Ellerman
a39818a3fb objtool/powerpc: Implement arch_pc_relative_reloc() 
Provide an implementation for arch_pc_relative_reloc(). It is needed to
pass the build once 61c6065ef7 ("objtool: Allow !PC relative
relocations") is merged.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
 2022-11-23 21:26:10 +11:00
Sathvika Vasireddy
4ca993d498 objtool: Add arch specific function arch_ftrace_match() 
Add architecture specific function to look for relocation records
pointing to architecture specific symbols.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-15-sv@linux.ibm.com
 2022-11-18 19:00:16 +11:00
Sathvika Vasireddy
280981d699 objtool: Add --mnop as an option to --mcount 
Some architectures (powerpc) may not support ftrace locations being nop'ed
out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as
a means for architectures to enable nop'ing of ftrace locations. Add --mnop
as an option to objtool --mcount, to indicate support for the same.

Also, make sure that --mnop can be passed as an option to objtool only when
--mcount is passed.

Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-12-sv@linux.ibm.com
 2022-11-18 19:00:16 +11:00
Christophe Leroy
86ea7f3615 objtool: Use target file class size instead of a compiled constant 
In order to allow using objtool on cross-built kernels,
determine size of long from elf data instead of using
sizeof(long) at build time.

For the time being this covers only mcount.

[Sathvika Vasireddy: Rename variable "size" to "addrsize" and function
"elf_class_size()" to "elf_class_addrsize()", and modify
create_mcount_loc_sections() function to follow reverse christmas tree
format to order local variable declarations.]

Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-11-sv@linux.ibm.com
 2022-11-18 19:00:16 +11:00
Christophe Leroy
0646c28b41 objtool: Use target file endianness instead of a compiled constant 
Some architectures like powerpc support both endianness, it's
therefore not possible to fix the endianness via arch/endianness.h
because there is no easy way to get the target endianness at
build time.

Use the endianness recorded in the file objtool is working on.

Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-10-sv@linux.ibm.com
 2022-11-18 19:00:15 +11:00
Peter Zijlstra
19526717f7 objtool: Optimize elf_dirty_reloc_sym() 
When moving a symbol in the symtab its index changes and any reloc
referring that symtol-table-index will need to be rewritten too.

In order to facilitate this, objtool simply marks the whole reloc
section 'changed' which will cause the whole section to be
re-generated.

However, finding the relocs that use any given symbol is implemented
rather crudely -- a fully iteration of all sections and their relocs.
Given that some builds have over 20k sections (kallsyms etc..)
iterating all that for *each* symbol moved takes a bit of time.

Instead have each symbol keep a list of relocs that reference it.

This *vastly* improves build times for certain configs.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/Y2LlRA7x+8UsE1xf@hirez.programming.kicks-ass.net
 2022-11-05 11:28:02 +01:00
Peter Zijlstra
9a479f766b objtool: Add --cfi to generate the .cfi_sites section 
Add the location of all __cfi_##name symbols (as generated by kCFI) to
a section such that we might re-write things at kernel boot.

Notably; boot time re-hashing and FineIBT are the intended use of
this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221027092842.568039454@infradead.org
 2022-11-01 13:44:10 +01:00
Peter Zijlstra
9f2899fe36 objtool: Add option to generate prefix symbols 
When code is compiled with:

  -fpatchable-function-entry=${PADDING_BYTES},${PADDING_BYTES}

functions will have PADDING_BYTES of NOP in front of them. Unwinders
and other things that symbolize code locations will typically
attribute these bytes to the preceding function.

Given that these bytes nominally belong to the following symbol this
mis-attribution is confusing.

Inspired by the fact that CFI_CLANG emits __cfi_##name symbols to
claim these bytes, allow objtool to emit __pfx_##name symbols to do
the same.

Therefore add the objtool --prefix=N argument, to conditionally place
a __pfx_##name symbol at N bytes ahead of symbol 'name' when: all
these preceding bytes are NOP and name-N is an instruction boundary.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Link: https://lkml.kernel.org/r/20221028194453.526899822@infradead.org
 2022-11-01 13:44:09 +01:00
Peter Zijlstra
13f60e80e1 objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf 
Due to how gelf_update_sym*() requires an Elf_Data pointer, and how
libelf keeps Elf_Data in a linked list per section,
elf_update_symbol() ends up having to iterate this list on each
update to find the correct Elf_Data for the index'ed symbol.

By allocating one Elf_Data per new symbol, the list grows per new
symbol, giving an effective O(n^2) insertion time. This is obviously
bloody terrible.

Therefore over-allocate the Elf_Data when an extention is needed.
Except it turns out libelf disregards Elf_Scn::sh_size in favour of
the sum of Elf_Data::d_size. IOW it will happily write out all the
unused space and fill it with:

  0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND

entries (aka zeros). Which obviously violates the STB_LOCAL placement
rule, and is a general pain in the backside for not being the desired
behaviour.

Manually fix-up the Elf_Data size to avoid this problem before calling
elf_update().

This significantly improves performance when adding a significant
number of symbols.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Link: https://lkml.kernel.org/r/20221028194453.461658986@infradead.org
 2022-11-01 13:44:08 +01:00
Peter Zijlstra
dbcdbdfdf1 objtool: Rework instruction -> symbol mapping 
Currently insn->func contains a instruction -> symbol link for
STT_FUNC symbols. A NULL value is assumed to mean STT_NOTYPE.
However, there are also instructions not covered by any symbol at all.
This can happen due to __weak symbols for example.

Since the current scheme cannot differentiate between no symbol and
STT_NOTYPE symbol, change things around. Make insn->sym point to any
symbol type such that !insn->sym means no symbol and add a helper
insn_func() that check the sym->type to retain the old functionality.

This then prepares the way to add code that depends on the distinction
between STT_NOTYPE and no symbol at all.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
 2022-10-17 16:41:08 +02:00
Peter Zijlstra
5da6aea375 objtool: Fix find_{symbol,func}_containing() 
The current find_{symbol,func}_containing() functions are broken in
the face of overlapping symbols, exactly the case that is needed for a
new ibt/endbr supression.

Import interval_tree_generic.h into the tools tree and convert the
symbol tree to an interval tree to support proper range stabs.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.330203761@infradead.org
 2022-10-17 16:41:08 +02:00
Peter Zijlstra
0c0a6d8934 objtool: Add --hacks=skylake 
Make the call/func sections selectable via the --hacks option.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.120821440@infradead.org
 2022-10-17 16:41:07 +02:00
Peter Zijlstra
00abd38408 objtool: Add .call_sites section 
In preparation for call depth tracking provide a section which collects all
direct calls.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.016511961@infradead.org
 2022-10-17 16:41:07 +02:00