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-rw-r--r--debian/patches/bugfix/x86/retbleed/0040-objtool-Re-add-UNWIND_HINT_-SAVE_RESTORE.patch209
1 files changed, 209 insertions, 0 deletions
diff --git a/debian/patches/bugfix/x86/retbleed/0040-objtool-Re-add-UNWIND_HINT_-SAVE_RESTORE.patch b/debian/patches/bugfix/x86/retbleed/0040-objtool-Re-add-UNWIND_HINT_-SAVE_RESTORE.patch
new file mode 100644
index 000000000..b24134fe5
--- /dev/null
+++ b/debian/patches/bugfix/x86/retbleed/0040-objtool-Re-add-UNWIND_HINT_-SAVE_RESTORE.patch
@@ -0,0 +1,209 @@
+From: Josh Poimboeuf <jpoimboe@kernel.org>
+Date: Fri, 24 Jun 2022 12:52:40 +0200
+Subject: objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}
+Origin: https://git.kernel.org/linus/8faea26e611189e933ea2281975ff4dc7c1106b6
+
+Commit
+
+ c536ed2fffd5 ("objtool: Remove SAVE/RESTORE hints")
+
+removed the save/restore unwind hints because they were no longer
+needed. Now they're going to be needed again so re-add them.
+
+Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+---
+ arch/x86/include/asm/unwind_hints.h | 12 ++++++--
+ include/linux/objtool.h | 6 ++--
+ tools/include/linux/objtool.h | 6 ++--
+ tools/objtool/check.c | 40 +++++++++++++++++++++++++++
+ tools/objtool/include/objtool/check.h | 19 +++++++------
+ 5 files changed, 68 insertions(+), 15 deletions(-)
+
+diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
+index 6f70fe4c93f2..f66fbe6537dd 100644
+--- a/arch/x86/include/asm/unwind_hints.h
++++ b/arch/x86/include/asm/unwind_hints.h
+@@ -8,11 +8,11 @@
+ #ifdef __ASSEMBLY__
+
+ .macro UNWIND_HINT_EMPTY
+- UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1
++ UNWIND_HINT type=UNWIND_HINT_TYPE_CALL end=1
+ .endm
+
+ .macro UNWIND_HINT_ENTRY
+- UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_ENTRY end=1
++ UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1
+ .endm
+
+ .macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
+@@ -56,6 +56,14 @@
+ UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC
+ .endm
+
++.macro UNWIND_HINT_SAVE
++ UNWIND_HINT type=UNWIND_HINT_TYPE_SAVE
++.endm
++
++.macro UNWIND_HINT_RESTORE
++ UNWIND_HINT type=UNWIND_HINT_TYPE_RESTORE
++.endm
++
+ #else
+
+ #define UNWIND_HINT_FUNC \
+diff --git a/include/linux/objtool.h b/include/linux/objtool.h
+index b026f1ae39c6..10bc88cc3bf6 100644
+--- a/include/linux/objtool.h
++++ b/include/linux/objtool.h
+@@ -40,6 +40,8 @@ struct unwind_hint {
+ #define UNWIND_HINT_TYPE_REGS_PARTIAL 2
+ #define UNWIND_HINT_TYPE_FUNC 3
+ #define UNWIND_HINT_TYPE_ENTRY 4
++#define UNWIND_HINT_TYPE_SAVE 5
++#define UNWIND_HINT_TYPE_RESTORE 6
+
+ #ifdef CONFIG_OBJTOOL
+
+@@ -127,7 +129,7 @@ struct unwind_hint {
+ * the debuginfo as necessary. It will also warn if it sees any
+ * inconsistencies.
+ */
+-.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
++.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+ .Lunwind_hint_ip_\@:
+ .pushsection .discard.unwind_hints
+ /* struct unwind_hint */
+@@ -180,7 +182,7 @@ struct unwind_hint {
+ #define ASM_REACHABLE
+ #else
+ #define ANNOTATE_INTRA_FUNCTION_CALL
+-.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
++.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+ .endm
+ .macro STACK_FRAME_NON_STANDARD func:req
+ .endm
+diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
+index b026f1ae39c6..10bc88cc3bf6 100644
+--- a/tools/include/linux/objtool.h
++++ b/tools/include/linux/objtool.h
+@@ -40,6 +40,8 @@ struct unwind_hint {
+ #define UNWIND_HINT_TYPE_REGS_PARTIAL 2
+ #define UNWIND_HINT_TYPE_FUNC 3
+ #define UNWIND_HINT_TYPE_ENTRY 4
++#define UNWIND_HINT_TYPE_SAVE 5
++#define UNWIND_HINT_TYPE_RESTORE 6
+
+ #ifdef CONFIG_OBJTOOL
+
+@@ -127,7 +129,7 @@ struct unwind_hint {
+ * the debuginfo as necessary. It will also warn if it sees any
+ * inconsistencies.
+ */
+-.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
++.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+ .Lunwind_hint_ip_\@:
+ .pushsection .discard.unwind_hints
+ /* struct unwind_hint */
+@@ -180,7 +182,7 @@ struct unwind_hint {
+ #define ASM_REACHABLE
+ #else
+ #define ANNOTATE_INTRA_FUNCTION_CALL
+-.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
++.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+ .endm
+ .macro STACK_FRAME_NON_STANDARD func:req
+ .endm
+diff --git a/tools/objtool/check.c b/tools/objtool/check.c
+index 822a490e6d87..ddfdd138cc2a 100644
+--- a/tools/objtool/check.c
++++ b/tools/objtool/check.c
+@@ -2032,6 +2032,17 @@ static int read_unwind_hints(struct objtool_file *file)
+
+ insn->hint = true;
+
++ if (hint->type == UNWIND_HINT_TYPE_SAVE) {
++ insn->hint = false;
++ insn->save = true;
++ continue;
++ }
++
++ if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
++ insn->restore = true;
++ continue;
++ }
++
+ if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
+ struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
+
+@@ -3329,6 +3340,35 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
+ state.instr += insn->instr;
+
+ if (insn->hint) {
++ if (insn->restore) {
++ struct instruction *save_insn, *i;
++
++ i = insn;
++ save_insn = NULL;
++
++ sym_for_each_insn_continue_reverse(file, func, i) {
++ if (i->save) {
++ save_insn = i;
++ break;
++ }
++ }
++
++ if (!save_insn) {
++ WARN_FUNC("no corresponding CFI save for CFI restore",
++ sec, insn->offset);
++ return 1;
++ }
++
++ if (!save_insn->visited) {
++ WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
++ sec, insn->offset);
++ return 1;
++ }
++
++ insn->cfi = save_insn->cfi;
++ nr_cfi_reused++;
++ }
++
+ state.cfi = *insn->cfi;
+ } else {
+ /* XXX track if we actually changed state.cfi */
+diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
+index 0eeedeacbefb..036129cebeee 100644
+--- a/tools/objtool/include/objtool/check.h
++++ b/tools/objtool/include/objtool/check.h
+@@ -46,18 +46,19 @@ struct instruction {
+ enum insn_type type;
+ unsigned long immediate;
+
+- u8 dead_end : 1,
+- ignore : 1,
+- ignore_alts : 1,
+- hint : 1,
+- retpoline_safe : 1,
+- noendbr : 1,
+- entry : 1;
+- /* 1 bit hole */
++ u16 dead_end : 1,
++ ignore : 1,
++ ignore_alts : 1,
++ hint : 1,
++ save : 1,
++ restore : 1,
++ retpoline_safe : 1,
++ noendbr : 1,
++ entry : 1;
++ /* 7 bit hole */
+
+ s8 instr;
+ u8 visited;
+- /* u8 hole */
+
+ struct alt_group *alt_group;
+ struct symbol *call_dest;
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-09 02:18:44 +0000