[PATCH 1/2] x86/unwind/orc: Add 'signal' field to ORC metadata

From: Josh Poimboeuf
Date: Fri Feb 10 2023 - 17:42:20 EST

Next message: Josh Poimboeuf: "[PATCH 0/2] x86/unwind/orc: Fix unwinding from kprobe on PUSH/POP instruction"
Previous message: Linus Walleij: "[GIT PULL] pin control fixes for the v6.2 series"
In reply to: Josh Poimboeuf: "[PATCH 0/2] x86/unwind/orc: Fix unwinding from kprobe on PUSH/POP instruction"
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Add a 'signal' field which allows unwind hints to specify whether the
instruction pointer should be taken literally (like for most interrupts
and exceptions) rather than decremented (like for call stack return
addresses) when used to find the next ORC entry.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/include/asm/orc_types.h | 4 +++-
arch/x86/include/asm/unwind_hints.h | 10 +++++-----
arch/x86/kernel/unwind_orc.c | 5 ++---
include/linux/objtool.h | 11 +++++++----
tools/arch/x86/include/asm/orc_types.h | 4 +++-
tools/include/linux/objtool.h | 11 +++++++----
tools/objtool/orc_dump.c | 4 ++--
7 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index 5a2baf28a1dc..1343a62106de 100644
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -57,12 +57,14 @@ struct orc_entry {
unsigned sp_reg:4;
unsigned bp_reg:4;
unsigned type:2;
+ unsigned signal:1;
unsigned end:1;
#elif defined(__BIG_ENDIAN_BITFIELD)
unsigned bp_reg:4;
unsigned sp_reg:4;
- unsigned unused:5;
+ unsigned unused:4;
unsigned end:1;
+ unsigned signal:1;
unsigned type:2;
#endif
} __packed;
diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
index f66fbe6537dd..e7c71750b309 100644
--- a/arch/x86/include/asm/unwind_hints.h
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -15,7 +15,7 @@
UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1
.endm

-.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
+.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0 signal=1
.if \base == %rsp
.if \indirect
.set sp_reg, ORC_REG_SP_INDIRECT
@@ -45,11 +45,11 @@
.set type, UNWIND_HINT_TYPE_REGS
.endif

- UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type signal=\signal
.endm

-.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
- UNWIND_HINT_REGS base=\base offset=\offset partial=1
+.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 signal=1
+ UNWIND_HINT_REGS base=\base offset=\offset partial=1 signal=\signal
.endm

.macro UNWIND_HINT_FUNC
@@ -67,7 +67,7 @@
#else

#define UNWIND_HINT_FUNC \
- UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0)
+ UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0, 0)

#endif /* __ASSEMBLY__ */

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index cdf6c6060170..37307b40f8da 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -484,6 +484,8 @@ bool unwind_next_frame(struct unwind_state *state)
goto the_end;
}

+ state->signal = orc->signal;
+
/* Find the previous frame's stack: */
switch (orc->sp_reg) {
case ORC_REG_SP:
@@ -563,7 +565,6 @@ bool unwind_next_frame(struct unwind_state *state)
state->sp = sp;
state->regs = NULL;
state->prev_regs = NULL;
- state->signal = false;
break;

case UNWIND_HINT_TYPE_REGS:
@@ -587,7 +588,6 @@ bool unwind_next_frame(struct unwind_state *state)
state->regs = (struct pt_regs *)sp;
state->prev_regs = NULL;
state->full_regs = true;
- state->signal = true;
break;

case UNWIND_HINT_TYPE_REGS_PARTIAL:
@@ -604,7 +604,6 @@ bool unwind_next_frame(struct unwind_state *state)
state->prev_regs = state->regs;
state->regs = (void *)sp - IRET_FRAME_OFFSET;
state->full_regs = false;
- state->signal = true;
break;

default:
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 62c54ffbeeaa..9ac3df3fccf0 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -15,6 +15,7 @@ struct unwind_hint {
s16 sp_offset;
u8 sp_reg;
u8 type;
+ u8 signal;
u8 end;
};
#endif
@@ -49,7 +50,7 @@ struct unwind_hint {

#ifndef __ASSEMBLY__

-#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
"987: \n\t" \
".pushsection .discard.unwind_hints\n\t" \
/* struct unwind_hint */ \
@@ -57,6 +58,7 @@ struct unwind_hint {
".short " __stringify(sp_offset) "\n\t" \
".byte " __stringify(sp_reg) "\n\t" \
".byte " __stringify(type) "\n\t" \
+ ".byte " __stringify(signal) "\n\t" \
".byte " __stringify(end) "\n\t" \
".balign 4 \n\t" \
".popsection\n\t"
@@ -129,7 +131,7 @@ struct unwind_hint {
* the debuginfo as necessary. It will also warn if it sees any
* inconsistencies.
*/
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
.Lunwind_hint_ip_\@:
.pushsection .discard.unwind_hints
/* struct unwind_hint */
@@ -137,6 +139,7 @@ struct unwind_hint {
.short \sp_offset
.byte \sp_reg
.byte \type
+ .byte \signal
.byte \end
.balign 4
.popsection
@@ -174,7 +177,7 @@ struct unwind_hint {

#ifndef __ASSEMBLY__

-#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
"\n\t"
#define STACK_FRAME_NON_STANDARD(func)
#define STACK_FRAME_NON_STANDARD_FP(func)
@@ -182,7 +185,7 @@ struct unwind_hint {
#define ASM_REACHABLE
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h
index 5a2baf28a1dc..1343a62106de 100644
--- a/tools/arch/x86/include/asm/orc_types.h
+++ b/tools/arch/x86/include/asm/orc_types.h
@@ -57,12 +57,14 @@ struct orc_entry {
unsigned sp_reg:4;
unsigned bp_reg:4;
unsigned type:2;
+ unsigned signal:1;
unsigned end:1;
#elif defined(__BIG_ENDIAN_BITFIELD)
unsigned bp_reg:4;
unsigned sp_reg:4;
- unsigned unused:5;
+ unsigned unused:4;
unsigned end:1;
+ unsigned signal:1;
unsigned type:2;
#endif
} __packed;
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
index 62c54ffbeeaa..9ac3df3fccf0 100644
--- a/tools/include/linux/objtool.h
+++ b/tools/include/linux/objtool.h
@@ -15,6 +15,7 @@ struct unwind_hint {
s16 sp_offset;
u8 sp_reg;
u8 type;
+ u8 signal;
u8 end;
};
#endif
@@ -49,7 +50,7 @@ struct unwind_hint {

#ifndef __ASSEMBLY__

-#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
"987: \n\t" \
".pushsection .discard.unwind_hints\n\t" \
/* struct unwind_hint */ \
@@ -57,6 +58,7 @@ struct unwind_hint {
".short " __stringify(sp_offset) "\n\t" \
".byte " __stringify(sp_reg) "\n\t" \
".byte " __stringify(type) "\n\t" \
+ ".byte " __stringify(signal) "\n\t" \
".byte " __stringify(end) "\n\t" \
".balign 4 \n\t" \
".popsection\n\t"
@@ -129,7 +131,7 @@ struct unwind_hint {
* the debuginfo as necessary. It will also warn if it sees any
* inconsistencies.
*/
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
.Lunwind_hint_ip_\@:
.pushsection .discard.unwind_hints
/* struct unwind_hint */
@@ -137,6 +139,7 @@ struct unwind_hint {
.short \sp_offset
.byte \sp_reg
.byte \type
+ .byte \signal
.byte \end
.balign 4
.popsection
@@ -174,7 +177,7 @@ struct unwind_hint {

#ifndef __ASSEMBLY__

-#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+#define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
"\n\t"
#define STACK_FRAME_NON_STANDARD(func)
#define STACK_FRAME_NON_STANDARD_FP(func)
@@ -182,7 +185,7 @@ struct unwind_hint {
#define ASM_REACHABLE
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
-.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 4f1211fec82c..2d8ebdcd1db3 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -211,8 +211,8 @@ int orc_dump(const char *_objname)

print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));

- printf(" type:%s end:%d\n",
- orc_type_name(orc[i].type), orc[i].end);
+ printf(" type:%s signal:%d end:%d\n",
+ orc_type_name(orc[i].type), orc[i].signal, orc[i].end);
}

elf_end(elf);
--
2.39.1

Next message: Josh Poimboeuf: "[PATCH 0/2] x86/unwind/orc: Fix unwinding from kprobe on PUSH/POP instruction"
Previous message: Linus Walleij: "[GIT PULL] pin control fixes for the v6.2 series"
In reply to: Josh Poimboeuf: "[PATCH 0/2] x86/unwind/orc: Fix unwinding from kprobe on PUSH/POP instruction"
Next in thread: tip-bot2 for Josh Poimboeuf: "[tip: objtool/core] x86/unwind/orc: Add 'signal' field to ORC metadata"
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